Message ID | 20230413160607.4128315-1-sean.anderson@seco.com |
---|---|
Headers | show |
Series | phy: Add support for Lynx 10G SerDes | expand |
Hello, On Thu, 13 Apr 2023 12:05:52 -0400, Sean Anderson wrote: > This series is ready for review by the phy maintainers. I have addressed > all known feedback and there are no outstanding issues. > > Major reconfiguration of baud rate (e.g. 1G->10G) does not work. > > There are several stand-alone commits in this series. Please feel free > to pick them as appropriate. In particular, commits 1, 3, 4, 12, 13, and > 14 are all good candidates for picking. > > - Although this is untested, it should support 2.5G SGMII as well as > 1000BASE-KX. The latter needs MAC and PCS support, but the former > should work out of the box. > - It allows for clock configurations not supported by the RCW. This is > very useful if you want to use e.g. SRDS_PRTCL_S1=0x3333 and =0x1133 > on the same board. This is because the former setting will use PLL1 > as the 1G reference, but the latter will use PLL1 as the 10G > reference. Because we can reconfigure the PLLs, it is possible to > always use PLL1 as the 1G reference. I am an engineer working for NXP and I have access to the majority of hardware that includes the Lynx 10G SERDES, as well as to block guides that are not visible to customers, and to people from the hardware design and validation teams. I have an interest in adding a driver for this SERDES to support dynamic Ethernet protocol reconfiguration, and perhaps the internal PHY for copper backplane modes (1000Base-KX, 10GBase-KR) and its link training procedure - although the latter will need more work. I would like to thank you for starting the effort, but please, stop submitting code for modes that are untested, and do not submit features that do not work. If you do not have the time to fix up the loose ends for this patch submission now, you won't have the time to debug regressions on boards you might not even have access to, which worked fine previously due to the static RCW/PBL configuration. I have downloaded your patches, and although I have objections to some of them already, I will be in the process of evaluating, testing, changing them, for the coming weeks, perhaps even more. Please consider this a NACK for the current patch set due to the SERDES related material, although the unrelated patches (like "dt-bindings: Convert gpio-mmio to yaml") can and should have been submitted separately, so they can be analyzed by their respective maintainers based on their own merit and not as part of an overall problematic set.
On 4/25/23 15:50, Vladimir Oltean wrote: > Hello, > > On Thu, 13 Apr 2023 12:05:52 -0400, Sean Anderson wrote: >> This series is ready for review by the phy maintainers. I have addressed >> all known feedback and there are no outstanding issues. >> >> Major reconfiguration of baud rate (e.g. 1G->10G) does not work. >> >> There are several stand-alone commits in this series. Please feel free >> to pick them as appropriate. In particular, commits 1, 3, 4, 12, 13, and >> 14 are all good candidates for picking. >> >> - Although this is untested, it should support 2.5G SGMII as well as >> 1000BASE-KX. The latter needs MAC and PCS support, but the former >> should work out of the box. >> - It allows for clock configurations not supported by the RCW. This is >> very useful if you want to use e.g. SRDS_PRTCL_S1=0x3333 and =0x1133 >> on the same board. This is because the former setting will use PLL1 >> as the 1G reference, but the latter will use PLL1 as the 10G >> reference. Because we can reconfigure the PLLs, it is possible to >> always use PLL1 as the 1G reference. > > I am an engineer working for NXP and I have access to the majority of > hardware that includes the Lynx 10G SERDES, as well as to block guides > that are not visible to customers, and to people from the hardware > design and validation teams. > > I have an interest in adding a driver for this SERDES to support dynamic > Ethernet protocol reconfiguration, and perhaps the internal PHY for > copper backplane modes (1000Base-KX, 10GBase-KR) and its link training > procedure - although the latter will need more work. > > I would like to thank you for starting the effort, but please, stop > submitting code for modes that are untested, and do not submit features > that do not work. The features which do not work (major protocol changes) are disabled :) If it would cause this series to be immediately merged, I would remove KX/KR and 2.5G which are the only untested link modes. That said, PCS support is necessary for these modes, so it is not even possible to select them. > If you do not have the time to fix up the loose ends > for this patch submission now I have time to fix up any loose ends preventing this series from being applied. However, I am not very sympathetic to larger requests, since there has been extensive time to supply feedback already. > , you won't have the time to debug > regressions on boards you might not even have access to, which worked > fine previously due to the static RCW/PBL configuration. I have gotten no substantive feedback on this driver. I have been working on this series since June last year, and no one has commented on the core algotithms thus far. My capacity for making large changes has decreased because the project funding the development has ended. I appreciate that you are taking interest now, but frankly I think it is rather past time... > I have downloaded your patches, and although I have objections to some > of them already, I will be in the process of evaluating, testing, > changing them, for the coming weeks, perhaps even more. Please consider > this a NACK for the current patch set due to the SERDES related material, > although the unrelated patches (like "dt-bindings: Convert gpio-mmio to > yaml") can and should have been submitted separately, so they can be > analyzed by their respective maintainers based on their own merit and > not as part of an overall problematic set. This patchset has been ready to merge for several revisions now. I do not consider it problematic. However, I do consider the (nonexistant) review process for this subsystem extremely problematic. --Sean
On Tue, Apr 25, 2023 at 04:22:32PM -0400, Sean Anderson wrote: > The features which do not work (major protocol changes) are disabled :) > > If it would cause this series to be immediately merged, I would remove > KX/KR and 2.5G which are the only untested link modes. > > That said, PCS support is necessary for these modes, so it is not even > possible to select them. > > > If you do not have the time to fix up the loose ends > > for this patch submission now > > I have time to fix up any loose ends preventing this series from being > applied. However, I am not very sympathetic to larger requests, since > there has been extensive time to supply feedback already. > > > , you won't have the time to debug > > regressions on boards you might not even have access to, which worked > > fine previously due to the static RCW/PBL configuration. > > I have gotten no substantive feedback on this driver. I have been > working on this series since June last year, and no one has commented on > the core algotithms thus far. My capacity for making large changes has > decreased because the project funding the development has ended. I > appreciate that you are taking interest now, but frankly I think it is > rather past time... > > > I have downloaded your patches, and although I have objections to some > > of them already, I will be in the process of evaluating, testing, > > changing them, for the coming weeks, perhaps even more. Please consider > > this a NACK for the current patch set due to the SERDES related material, > > although the unrelated patches (like "dt-bindings: Convert gpio-mmio to > > yaml") can and should have been submitted separately, so they can be > > analyzed by their respective maintainers based on their own merit and > > not as part of an overall problematic set. > > This patchset has been ready to merge for several revisions now. I do > not consider it problematic. However, I do consider the (nonexistant) > review process for this subsystem extremely problematic. To be very clear, the "larger request" which you are unsympathetic to is to wait. I didn't ask you to change anything. I need to catch up with 14 rounds of patches from you and with the discussions that took place on each version, and understand how you responded to feedback like "don't remove PHY interrupts without finding out why they don't work" and "doesn't changing PLL frequencies on the fly affect other lanes that use those PLLs, like PCIe?". The cognitive dissonance between this and you saying that the review process for this subsystem is absent is mind boggling. You are sufficiently averse to feedback that's not the feedback you want to hear, that it's hard to find a common ground. It's naive to expect that the silicon vendor will respond positively to a change of such magnitude as this one, which was written using the "works for me" work ethics, but which the silicon vendor will have to work with, afterwards. The only reason I sent my previous email was to announce you in advance that I have managed to carve out a sufficient amount of time to explore the topic in detail, and to stop you from pushing this forward in this state. I thought you would understand the concept of engineers being unable to easily reserve large chunks of time for a given project, after all, you brought this argument with your own company... Even if the SERDES and PLL drivers "work for you" in the current form, I doubt the usefulness of a PLL driver if you have to disconnect the SoC's reset request signal on the board to not be stuck in a reboot loop. https://lore.kernel.org/linux-arm-kernel/d3163201-2012-6cf9-c798-916bab9c7f72@seco.com/ Even so, I have not said anything definitive, I have just requested time to take your proposal at face value, and understand whether there is any other alternative. I would advise you to consider whether your follow-up emails on this topic encourage a collaborative atmosphere. I will come back when I have tested the driver in a reasonable amount of setups.
On 4/26/23 06:51, Vladimir Oltean wrote: > On Tue, Apr 25, 2023 at 04:22:32PM -0400, Sean Anderson wrote: >> The features which do not work (major protocol changes) are disabled :) >> >> If it would cause this series to be immediately merged, I would remove >> KX/KR and 2.5G which are the only untested link modes. >> >> That said, PCS support is necessary for these modes, so it is not even >> possible to select them. >> >>> If you do not have the time to fix up the loose ends >>> for this patch submission now >> >> I have time to fix up any loose ends preventing this series from being >> applied. However, I am not very sympathetic to larger requests, since >> there has been extensive time to supply feedback already. >> >>> , you won't have the time to debug >>> regressions on boards you might not even have access to, which worked >>> fine previously due to the static RCW/PBL configuration. >> >> I have gotten no substantive feedback on this driver. I have been >> working on this series since June last year, and no one has commented on >> the core algotithms thus far. My capacity for making large changes has >> decreased because the project funding the development has ended. I >> appreciate that you are taking interest now, but frankly I think it is >> rather past time... >> >>> I have downloaded your patches, and although I have objections to some >>> of them already, I will be in the process of evaluating, testing, >>> changing them, for the coming weeks, perhaps even more. Please consider >>> this a NACK for the current patch set due to the SERDES related material, >>> although the unrelated patches (like "dt-bindings: Convert gpio-mmio to >>> yaml") can and should have been submitted separately, so they can be >>> analyzed by their respective maintainers based on their own merit and >>> not as part of an overall problematic set. >> >> This patchset has been ready to merge for several revisions now. I do >> not consider it problematic. However, I do consider the (nonexistant) >> review process for this subsystem extremely problematic. > > To be very clear, the "larger request" which you are unsympathetic to is > to wait. I didn't ask you to change anything. The maintainers in this subsystem refuse to review any patches which have any kind of feedback. I have been trying to get them to look at this series for literal months. So saying things like "I don't like this series, have a NACK" seriously delays the process of getting feedback... > I need to catch up with 14 rounds of patches from you and with the > discussions that took place on each version, and understand how you > responded to feedback like "don't remove PHY interrupts without finding > out why they don't work" All I can say is that - It doesn't work on my board - The traces are on the bottom of the PCB - The signal goes through an FPGA which (unlike the LS1046ARDB) is closed-source - The alternative is polling once a second (not terribly intensive) I think it's very reasonable to make this change. Anyway, it's in a separate patch so that it can be applied independently. and "doesn't changing PLL frequencies on the > fly affect other lanes that use those PLLs, like PCIe?". This driver is not enable on any boards with PCIe on the same serdes. Therefore, this is irrelevant for the initial submission. > The cognitive > dissonance between this and you saying that the review process for this > subsystem is absent is mind boggling. You are sufficiently averse to > feedback that's not the feedback you want to hear, that it's hard to > find a common ground. I'm opposed to nebulous 11th hour objections. > It's naive to expect that the silicon vendor will respond positively to > a change of such magnitude as this one, which was written using the > "works for me" work ethics, but which the silicon vendor will have to > work with, afterwards. The only reason I sent my previous email was to > announce you in advance that I have managed to carve out a sufficient > amount of time to explore the topic in detail, and to stop you from > pushing this forward in this state. I thought you would understand the > concept of engineers being unable to easily reserve large chunks of time > for a given project, after all, you brought this argument with your own > company... > > Even if the SERDES and PLL drivers "work for you" in the current form, > I doubt the usefulness of a PLL driver if you have to disconnect the > SoC's reset request signal on the board to not be stuck in a reboot loop. I would like to emphasize that this has *nothing to do with this driver*. This behavior is part of the boot ROM (or something like it) and occurs before any user code has ever executed. The problem of course is that certain RCWs expect the reference clocks to be in certain (incompatible) configurations, and will fail the boot without a lock. I think this is rather silly (since you only need PLL lock when you actually want to use the serdes), but that's how it is. And of course, this is only necessary because I was unable to get major reconfiguration to work. In an ideal world, you could always boot with the same RCW (with PLL config matching the board) and choose the major protocol at runtime. > https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2flore.kernel.org%2flinux%2darm%2dkernel%2fd3163201%2d2012%2d6cf9%2dc798%2d916bab9c7f72%40seco.com%2f&umid=b7a538d4-355b-4a0a-bac8-26f0fa0a74c0&auth=d807158c60b7d2502abde8a2fc01f40662980862-e02727a0e4438c72b5e854cb20b9de5379470fd9 > Even so, I have not said anything definitive, I have just requested time > to take your proposal at face value, and understand whether there is any > other alternative. > > I would advise you to consider whether your follow-up emails on this > topic encourage a collaborative atmosphere. Sorry, I was a bit standoffish, but frankly I don't think leading off with "NACK, no feedback for you today" is particularly collaborative either. --Sean
On Wed, Apr 26, 2023 at 10:50:17AM -0400, Sean Anderson wrote: > > I need to catch up with 14 rounds of patches from you and with the > > discussions that took place on each version, and understand how you > > responded to feedback like "don't remove PHY interrupts without finding > > out why they don't work" > > All I can say is that > > - It doesn't work on my board > - The traces are on the bottom of the PCB > - The signal goes through an FPGA which (unlike the LS1046ARDB) is closed-source I don't understand the distinction you are making here. Are the sources for QIXIS bit streams public for any Layerscape board? > - The alternative is polling once a second (not terribly intensive) It makes a difference to performance (forwarded packets per second), believe it or not. > > I think it's very reasonable to make this change. Anyway, it's in a separate > patch so that it can be applied independently. Perhaps better phrased: "discussed separately"... > > Even if the SERDES and PLL drivers "work for you" in the current form, > > I doubt the usefulness of a PLL driver if you have to disconnect the > > SoC's reset request signal on the board to not be stuck in a reboot loop. > > I would like to emphasize that this has *nothing to do with this driver*. > This behavior is part of the boot ROM (or something like it) and occurs before > any user code has ever executed. The problem of course is that certain RCWs > expect the reference clocks to be in certain (incompatible) configurations, > and will fail the boot without a lock. I think this is rather silly (since > you only need PLL lock when you actually want to use the serdes), but that's > how it is. And of course, this is only necessary because I was unable to get > major reconfiguration to work. In an ideal world, you could always boot with > the same RCW (with PLL config matching the board) and choose the major protocol > at runtime. Could you please tell me what are the reference clock frequencies that your board provides at boot time to the 2 PLLs, and which SERDES protocol out of those 2 (1133 and 3333) boots correctly (no RESET_REQ hacks necessary) with those refclks? I will try to get a LS1046A-QDS where I boot from the same refclk + SERDES protocol configuration as you, and use PBI commands in the RCW to reconfigure the lanes (PLL selection and protocol registers) for the other mode, while keeping the FRATE_SEL of the PLLs unmodified.
On 4/29/23 13:24, Vladimir Oltean wrote: > On Wed, Apr 26, 2023 at 10:50:17AM -0400, Sean Anderson wrote: >> > I need to catch up with 14 rounds of patches from you and with the >> > discussions that took place on each version, and understand how you >> > responded to feedback like "don't remove PHY interrupts without finding >> > out why they don't work" >> >> All I can say is that >> >> - It doesn't work on my board >> - The traces are on the bottom of the PCB >> - The signal goes through an FPGA which (unlike the LS1046ARDB) is closed-source > > I don't understand the distinction you are making here. Are the sources > for QIXIS bit streams public for any Layerscape board? Correct. The sources for the LS1046ARDB QIXIS are available for download. >> - The alternative is polling once a second (not terribly intensive) > > It makes a difference to performance (forwarded packets per second), believe it or not. I don't. Please elaborate how link status latency from the phy affects performance. >> >> I think it's very reasonable to make this change. Anyway, it's in a separate >> patch so that it can be applied independently. > > Perhaps better phrased: "discussed separately"... > >> > Even if the SERDES and PLL drivers "work for you" in the current form, >> > I doubt the usefulness of a PLL driver if you have to disconnect the >> > SoC's reset request signal on the board to not be stuck in a reboot loop. >> >> I would like to emphasize that this has *nothing to do with this driver*. >> This behavior is part of the boot ROM (or something like it) and occurs before >> any user code has ever executed. The problem of course is that certain RCWs >> expect the reference clocks to be in certain (incompatible) configurations, >> and will fail the boot without a lock. I think this is rather silly (since >> you only need PLL lock when you actually want to use the serdes), but that's >> how it is. And of course, this is only necessary because I was unable to get >> major reconfiguration to work. In an ideal world, you could always boot with >> the same RCW (with PLL config matching the board) and choose the major protocol >> at runtime. > > Could you please tell me what are the reference clock frequencies that > your board provides at boot time to the 2 PLLs, and which SERDES > protocol out of those 2 (1133 and 3333) boots correctly (no RESET_REQ > hacks necessary) with those refclks? I will try to get a LS1046A-QDS > where I boot from the same refclk + SERDES protocol configuration as > you, and use PBI commands in the RCW to reconfigure the lanes (PLL > selection and protocol registers) for the other mode, while keeping the > FRATE_SEL of the PLLs unmodified. From table 31-1 in the RM, the PLL mapping for 1133 is 2211, and the PLL mapping for 3333 is 2222. As a consequence, for 1133, PLL 2 must be 156.25 MHz and PLL 1 must be either 100 or 125 MHz. And for 3333, PLL 2 must be either 100 or 125 MHz, and PLL 1 should be shut down (as it is unused). This conflict for PLL 2 means that the same reference clock configuration cannot work for both 1133 and 3333. In one of the configurations, SRDS_RST_RR will be set in RSTRQSR1. On our board, reference clock 1 is 156.25 MHz, and reference clock 2 is 125 MHz. Therefore, 3333 will fail to boot. Unfortunately, this reset request occurs before any user-configurable code has run (except the RCW), so it is not possible to fix this issue with e.g. PBI. --Sean not
Hi Vladmir, On 5/1/23 11:03, Sean Anderson wrote: > On 4/29/23 13:24, Vladimir Oltean wrote: >> On Wed, Apr 26, 2023 at 10:50:17AM -0400, Sean Anderson wrote: >>> > I need to catch up with 14 rounds of patches from you and with the >>> > discussions that took place on each version, and understand how you >>> > responded to feedback like "don't remove PHY interrupts without finding >>> > out why they don't work" >>> >>> All I can say is that >>> >>> - It doesn't work on my board >>> - The traces are on the bottom of the PCB >>> - The signal goes through an FPGA which (unlike the LS1046ARDB) is closed-source >> >> I don't understand the distinction you are making here. Are the sources >> for QIXIS bit streams public for any Layerscape board? > > Correct. The sources for the LS1046ARDB QIXIS are available for download. > >>> - The alternative is polling once a second (not terribly intensive) >> >> It makes a difference to performance (forwarded packets per second), believe it or not. > > I don't. Please elaborate how link status latency from the phy affects performance. > >>> >>> I think it's very reasonable to make this change. Anyway, it's in a separate >>> patch so that it can be applied independently. >> >> Perhaps better phrased: "discussed separately"... >> >>> > Even if the SERDES and PLL drivers "work for you" in the current form, >>> > I doubt the usefulness of a PLL driver if you have to disconnect the >>> > SoC's reset request signal on the board to not be stuck in a reboot loop. >>> >>> I would like to emphasize that this has *nothing to do with this driver*. >>> This behavior is part of the boot ROM (or something like it) and occurs before >>> any user code has ever executed. The problem of course is that certain RCWs >>> expect the reference clocks to be in certain (incompatible) configurations, >>> and will fail the boot without a lock. I think this is rather silly (since >>> you only need PLL lock when you actually want to use the serdes), but that's >>> how it is. And of course, this is only necessary because I was unable to get >>> major reconfiguration to work. In an ideal world, you could always boot with >>> the same RCW (with PLL config matching the board) and choose the major protocol >>> at runtime. >> >> Could you please tell me what are the reference clock frequencies that >> your board provides at boot time to the 2 PLLs, and which SERDES >> protocol out of those 2 (1133 and 3333) boots correctly (no RESET_REQ >> hacks necessary) with those refclks? I will try to get a LS1046A-QDS >> where I boot from the same refclk + SERDES protocol configuration as >> you, and use PBI commands in the RCW to reconfigure the lanes (PLL >> selection and protocol registers) for the other mode, while keeping the >> FRATE_SEL of the PLLs unmodified. > > From table 31-1 in the RM, the PLL mapping for 1133 is 2211, and the > PLL mapping for 3333 is 2222. As a consequence, for 1133, PLL 2 must be > 156.25 MHz and PLL 1 must be either 100 or 125 MHz. And for 3333, PLL 2 > must be either 100 or 125 MHz, and PLL 1 should be shut down (as it is > unused). This conflict for PLL 2 means that the same reference clock > configuration cannot work for both 1133 and 3333. In one of the > configurations, SRDS_RST_RR will be set in RSTRQSR1. On our board, > reference clock 1 is 156.25 MHz, and reference clock 2 is 125 MHz. > Therefore, 3333 will fail to boot. Unfortunately, this reset request > occurs before any user-configurable code has run (except the RCW), so > it is not possible to fix this issue with e.g. PBI. Have you had a chance to review this driver? --Sean
On Mon, May 22, 2023 at 10:42:04AM -0400, Sean Anderson wrote:
> Have you had a chance to review this driver?
Partially / too little (and no, I don't have an answer yet). I am
debugging a SERDES protocol change procedure from XFI to SGMII.
On 5/22/23 11:00, Vladimir Oltean wrote: > On Mon, May 22, 2023 at 10:42:04AM -0400, Sean Anderson wrote: >> Have you had a chance to review this driver? > > Partially / too little (and no, I don't have an answer yet). I am > debugging a SERDES protocol change procedure from XFI to SGMII. I'd just like to reiterate that, like I said in the cover letter, I believe this driver still has value even if it cannot yet perform protocol switching. Please send me your feedback, and I will try and incorporate it into the next revision. Previously, you said you had major objections to the contents of this series, but you still have not listed them. --Sean
Hello Sean, On Fri, Jun 09, 2023 at 03:19:22PM -0400, Sean Anderson wrote: > On 5/22/23 11:00, Vladimir Oltean wrote: > > On Mon, May 22, 2023 at 10:42:04AM -0400, Sean Anderson wrote: > >> Have you had a chance to review this driver? > > > > Partially / too little (and no, I don't have an answer yet). I am > > debugging a SERDES protocol change procedure from XFI to SGMII. > > I'd just like to reiterate that, like I said in the cover letter, I > believe this driver still has value even if it cannot yet perform > protocol switching. > > Please send me your feedback, and I will try and incorporate it into the > next revision. Previously, you said you had major objections to the > contents of this series, but you still have not listed them. And if SERDES protocol switching was not physically possible, would this patch set still have value?
On Mon, Jun 12, 2023 at 10:35:21AM -0400, Sean Anderson wrote: > > And if SERDES protocol switching was not physically possible, would this > > patch set still have value? > > Yes. To e.g. set up SGMII25 or to fix the clocking situation. Let me analyze the reasons one by one. The clocking situation only exists due to a hope that protocol changing would be possible. If you were sure it wasn't possible, your board would have had refclks set up for protocol 3333 via the supported PLL mapping 2222. In essence, I consider this almost a non-argument, as it fixes a self-inflicted problem. Have you actually tested changing individual lanes from SGMII to SGMII 2.5? I know it works on LS1028A, but I don't know if that's also true on LS1046A. Your comments do say "LYNX_PROTO_SGMII25, /* Not tested */". Assuming a start from SERDES protocol 3333 with PLL mapping 2222, this protocol change implies powering on PLL 1 (reset state machine wants it to be disabled) and moving those lanes from PLL 2 to PLL 1. At first sight you might appear to have a point related to the fact that PLL register writes are necessary, and thus this whole shebang is necessary. But this can all be done using PBI commands, with the added benefit that U-Boot can also use those SERDES networking ports, and not just Linux. You can use the RCW+PBL specific to your board to inform the SoC that your platform's refclk 1 is 156 MHz (something which the reset state machine seems unable to learn, with protocol 0x3333). You don't have to put that in the device tree. You don't have to push code to any open source project to expose your platform specific details. Then, just like in the case of the Lynx 28G driver on LX2160, the SERDES driver could just treat the PLL configuration as read-only, which would greatly simplify things and eliminate the need for a clk driver. Here is an illustrative example (sorry, I don't have a board with the right refclk on that PLL, to verify all the way): Add this to ./serdes_10g.rcw in the root of the qoriq-rcw repository: /* * Registers for the Lynx 10G SERDES block. * * Must be included by an SoC-specific header that defines the * SRDS_BASE value. */ #define PLLnRSTCTL(n) (SRDS_BASE + (0x20 * (n))) #define PLLnCR0(n) (SRDS_BASE + (0x20 * (n)) + 0x0004) #define POFF(x) (((x) << 31) & 0x80000000) #define REFCLK_SEL(x) (((x) << 28) & 0x70000000) #define REFCLK_EN(x) (((x) << 27) & 0x08000000) #define FRATE_SEL(x) (((x) << 16) & 0x000f0000) #define DLYDIV_SEL(x) ((x) & 0x00000003) #define PCCR8 (SRDS_BASE + 0x0220) #define SGMIIA_KX(x) (((x) << 31) & 0x80000000) #define SGMIIA_CFG(x) (((x) << 28) & 0x70000000) #define SGMIIB_KX(x) (((x) << 27) & 0x08000000) #define SGMIIB_CFG(x) (((x) << 24) & 0x07000000) #define SGMIIC_KX(x) (((x) << 23) & 0x00800000) #define SGMIIC_CFG(x) (((x) << 20) & 0x00700000) #define SGMIID_KX(x) (((x) << 19) & 0x00080000) #define SGMIID_CFG(x) (((x) << 16) & 0x00070000) #define SGMIIE_KX(x) (((x) << 15) & 0x00008000) #define SGMIIE_CFG(x) (((x) << 12) & 0x00007000) #define SGMIIF_KX(x) (((x) << 11) & 0x00000800) #define SGMIIF_CFG(x) (((x) << 8) & 0x00000700) #define SGMIIG_KX(x) (((x) << 7) & 0x00000080) #define SGMIIG_CFG(x) (((x) << 4) & 0x00000070) #define SGMIIH_KX(x) (((x) << 3) & 0x00000008) #define SGMIIH_CFG(x) ((x) & 0x00000007) #define PCCRB (SRDS_BASE + 0x022c) #define XFIA_CFG(x) (((x) << 28) & 0x70000000) #define XFIB_CFG(x) (((x) << 24) & 0x07000000) #define XFIC_CFG(x) (((x) << 20) & 0x00700000) #define XFID_CFG(x) (((x) << 16) & 0x00070000) #define XFIE_CFG(x) (((x) << 12) & 0x00007000) #define XFIF_CFG(x) (((x) << 8) & 0x00000700) #define XFIG_CFG(x) (((x) << 4) & 0x00000070) #define XFIH_CFG(x) ((x) & 0x00000007) #define LNmGCR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0800) #define RPLL_LES(x) (((x) << 31) & 0x80000000) #define RRAT_SEL(x) (((x) << 28) & 0x30000000) #define TPLL_LES(x) (((x) << 27) & 0x08000000) #define TRAT_SEL(x) (((x) << 24) & 0x03000000) #define RRST_B(x) (((x) << 22) & 0x00400000) #define TRST_B(x) (((x) << 21) & 0x00200000) #define RX_PD(x) (((x) << 20) & 0x00100000) #define TX_PD(x) (((x) << 19) & 0x00080000) #define IF20BIT_EN(x) (((x) << 18) & 0x00040000) #define FIRST_LANE(x) (((x) << 16) & 0x00010000) #define GCR0_RSV 0x1000 #define PROTS(x) (((x) << 7) & 0x00000f80) #define LNmGCR1(m) (SRDS_BASE + (0x40 * (m)) + 0x0804) #define RDAT_INV(x) (((x) << 31) & 0x80000000) #define TDAT_INV(x) (((x) << 30) & 0x40000000) #define OPAD_CTL(x) (((x) << 26) & 0x04000000) #define REIDL_TH(x) (((x) << 20) & 0x00700000) #define REIDL_EX_SEL(x) (((x) << 18) & 0x000C0000) #define REIDL_ET_SEL(x) (((x) << 16) & 0x00030000) #define REIDL_EX_MSB(x) (((x) << 15) & 0x00008000) #define REIDL_ET_MSB(x) (((x) << 14) & 0x00004000) #define REQ_CTL_SNP(x) (((x) << 13) & 0x00002000) #define REQ_CDR_SNP(x) (((x) << 12) & 0x00001000) #define TRSTDIR(x) (((x) << 7) & 0x00000080) #define REQ_BIN_SNP(x) (((x) << 6) & 0x00000040) #define ISLEW_RCTL(x) (((x) << 4) & 0x00000030) #define GCR1_RSV 0x8 #define OSLEW_RCTL(x) ((x) & 0x3) #define LNmRECR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0810) #define RXEQ_BST(x) (((x) << 28) & 0x10000000) #define GK2OVD(x) (((x) << 24) & 0x0f000000) #define GK3OVD(x) (((x) << 16) & 0x000f0000) #define GK2OVD_EN(x) (((x) << 15) & 0x00008000) #define GK3OVD_EN(x) (((x) << 14) & 0x00004000) #define OSETOVD_EN(x) (((x) << 13) & 0x00002000) #define BASE_WAND(x) (((x) << 10) & 0x00000c00) #define OSETOVD(x) ((x) & 0x0000007F) #define LNmTECR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0818) #define TEQ_TYPE(x) (((x) << 28) & 0x30000000) #define SGN_PREQ(x) (((x) << 26) & 0x04000000) #define RATIO_PREQ(x) (((x) << 22) & 0x03C00000) #define SGN_POST1Q(x) (((x) << 21) & 0x00200000) #define RATIO_PST1Q(x) (((x) << 16) & 0x001F0000) #define ADPT_EQ(x) (((x) << 8) & 0x00003F00) #define AMP_RED(x) ((x) & 0x0000003f) #define LNmTTLCR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0820) #define LNmTCSR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0830) #define LNmTCSR1(m) (SRDS_BASE + (0x40 * (m)) + 0x0834) #define LNmTCSR2(m) (SRDS_BASE + (0x40 * (m)) + 0x0838) #define LNmTCSR3(m) (SRDS_BASE + (0x40 * (m)) + 0x083c) #define SGMIIaCR1(a) (SRDS_BASE + (0x10 * (a)) + 0x1804) #define SGMII_MDEV_PORT(x) (((x) << 27) & 0xf8000000) #define SGPCS_EN(x) (((x) << 11) & 0x00000800) #define XFIaCR1(a) (SRDS_BASE + (0x10 * (a)) + 0x1984) #define XFI_MDEV_PORT(x) (((x) << 27) & 0xf8000000) Add this to ./ls1046ardb/serdes_pll1_power_on.rcw in the same repo (and finish the writes): /* * Assuming that the SoC starts from SERDES1 protocol 0x3333, power on PLL 1, * which is required by the reset state machine to be disabled. */ #define SRDS_BASE 0xea0000 /* SERDES 1 */ #include <../serdes_10g.rcw> .pbi write PLLnCR0(0), POFF(0) | REFCLK_SEL(2) | REFCLK_EN(0) wait 2500 write PLLnRSTCTL(0), ... .end Add this at the end of your board RCW: #include <../ls1046ardb/serdes_pll1_power_on.rcw> In short, I believe the reasons you have cited do not justify the complexity of the solution that you propose.
On 6/12/23 12:33, Vladimir Oltean wrote: > On Mon, Jun 12, 2023 at 10:35:21AM -0400, Sean Anderson wrote: >> > And if SERDES protocol switching was not physically possible, would this >> > patch set still have value? More to the point, did you make any progress in this area? >> Yes. To e.g. set up SGMII25 or to fix the clocking situation. > > Let me analyze the reasons one by one. > > The clocking situation only exists due to a hope that protocol changing > would be possible. If you were sure it wasn't possible, your board would > have had refclks set up for protocol 3333 via the supported PLL mapping 2222. > In essence, I consider this almost a non-argument, as it fixes a > self-inflicted problem. 2222 also does not work, as outlined above. The clocking is incompatible, and must be fixed by software. The only thing self-inflicted is NXP's conflicting design. > Have you actually tested changing individual lanes from SGMII to SGMII 2.5? > I know it works on LS1028A, but I don't know if that's also true on LS1046A. > Your comments do say "LYNX_PROTO_SGMII25, /* Not tested */". Not yet. This driver would also be a good place to add the KR link training with NXP tried to upstream a few years ago. > Assuming a start from SERDES protocol 3333 with PLL mapping 2222, > this protocol change implies powering on PLL 1 (reset state machine > wants it to be disabled) and moving those lanes from PLL 2 to PLL 1. > > At first sight you might appear to have a point related to the fact that > PLL register writes are necessary, and thus this whole shebang is necessary. > But this can all be done using PBI commands, with the added benefit that > U-Boot can also use those SERDES networking ports, and not just Linux. > You can use the RCW+PBL specific to your board to inform the SoC that > your platform's refclk 1 is 156 MHz (something which the reset state > machine seems unable to learn, with protocol 0x3333). You don't have to > put that in the device tree. You don't have to push code to any open > source project to expose your platform specific details. Then, just like > in the case of the Lynx 28G driver on LX2160, the SERDES driver could > just treat the PLL configuration as read-only, which would greatly > simplify things and eliminate the need for a clk driver. > > Here is an illustrative example (sorry, I don't have a board with the > right refclk on that PLL, to verify all the way): > > ... snip ... (which of course complicates the process of building the PBIs...) > In short, I believe the reasons you have cited do not justify the > complexity of the solution that you propose. The work is done, and it is certainly more flexible than what you propose. E.g. imagine a clock which needs to be configured before it has the correct frequency. Such a thing is difficult to do in a PBI solution, but is trivial in Linux. --Sean
On Mon, Jun 12, 2023 at 04:46:16PM -0400, Sean Anderson wrote: > On 6/12/23 12:33, Vladimir Oltean wrote: > > On Mon, Jun 12, 2023 at 10:35:21AM -0400, Sean Anderson wrote: > >> > And if SERDES protocol switching was not physically possible, would this > >> > patch set still have value? > > More to the point, did you make any progress in this area? Aha. It is two email exchanges later that you've thought of asking that. No, I haven't made progress. Though I managed to get some extra pointers and things to try out, and at this stage I am the limiting factor. I will let you know once the investigation has reached a conclusion. So many things depend on whether major SERDES protocol reconfiguration is possible, that if I were you, my question would be just that, instead of the equivalent of "Vladimir, when can my driver be merged ???". I understand how incredibly frustrating it is that the responses are coming in so slowly, and this is the reason why I am responding at all to your pings even if I have essentially nothing new to say. And it's not that you don't care whether protocol reconfiguration is possible or not - you do, but at the same time you're overcome with this strong attachment to your solution just because it is yours, that I don't know how to deal with. > 2222 also does not work, as outlined above. > > The clocking is incompatible, and must be fixed by software. > > The only thing self-inflicted is NXP's conflicting design. The way things are supposed to work (*if* this works at all) is that the reset state machine starts with a supported PLL / refclk configuration that permits a certain subset of protocols, and the SERDES protocols can be changed from the reset state, as desired, for the individual lanes. What is self-inflicted is that the refclks on your board design are not supportable by any reset state machine configuration, and wiring them that way was a conscious decision. Did your company's board designers receive the recommendation to disconnect RESET_REQ from NXP, and has NXP said that the end result will be something that continues to be supportable? I've searched the customer support database and the answer seems to be no. In any case, if you have to disconnect RESET_REQ from the SoC to make the driver in this form useful, then... yeah, no. You're obviously free to do whatever you want with your products, but that's not how mainline Linux works, it needs to be useful beyond you. If protocol switching works, I will maintain that your board should have wired the refclks to PLLs the other way around (which is supported by the RCW), and then proceed to do protocol switching to reach the desired configuration. So you can see that many things change based on whether protocol reconfig is possible or not. The patch set presented here looks exactly like the product of someone infatuated with form over substance, and who misses the overall picture. My belief is that if you shift your attitude from "is the work done?" to "is the work generally useful?", the interactions will improve by a lot. > > Have you actually tested changing individual lanes from SGMII to SGMII 2.5? > > I know it works on LS1028A, but I don't know if that's also true on LS1046A. > > Your comments do say "LYNX_PROTO_SGMII25, /* Not tested */". > > Not yet. Aha. So concretely, what makes you so confident with moving this forward? You like the code to just be there, no? It helps your board, I understand. But not everything has to stay in mainline if it's not useful for others, and I've proposed an alternative solution which I'm not sure how seriously you took. > This driver would also be a good place to add the KR link training with > NXP tried to upstream a few years ago. Well, speaking as someone who is now also tasked with the copper backplane support, believe me that I know that, and this is why I'm so desperate with the logic you're trying to push forward. It's clear that we should try to collaborate rather than try to push individualistic non-tested non-solutions. > > Assuming a start from SERDES protocol 3333 with PLL mapping 2222, > > this protocol change implies powering on PLL 1 (reset state machine > > wants it to be disabled) and moving those lanes from PLL 2 to PLL 1. > > > > At first sight you might appear to have a point related to the fact that > > PLL register writes are necessary, and thus this whole shebang is necessary. > > But this can all be done using PBI commands, with the added benefit that > > U-Boot can also use those SERDES networking ports, and not just Linux. > > You can use the RCW+PBL specific to your board to inform the SoC that > > your platform's refclk 1 is 156 MHz (something which the reset state > > machine seems unable to learn, with protocol 0x3333). You don't have to > > put that in the device tree. You don't have to push code to any open > > source project to expose your platform specific details. Then, just like > > in the case of the Lynx 28G driver on LX2160, the SERDES driver could > > just treat the PLL configuration as read-only, which would greatly > > simplify things and eliminate the need for a clk driver. > > > > Here is an illustrative example (sorry, I don't have a board with the > > right refclk on that PLL, to verify all the way): > > > > ... snip ... > > (which of course complicates the process of building the PBIs...) Maybe this is the language barrier, but what are you trying to say here? > > In short, I believe the reasons you have cited do not justify the > > complexity of the solution that you propose. > > The work is done, :) > and it is certainly more flexible than what you propose. E.g. imagine > a clock which needs to be configured before it has the correct > frequency. Such a thing is difficult to do in a PBI solution, but is > trivial in Linux. So "a clock which needs to be configured" means a programmable clock generator that provides the refclk to the PLL, correct? With QorIQ/Layerscape SoCs, I imagine that case would typically be done by a board CPLD during the boot sequence, because if the PLL refclks don't have the right frequency, the main SoC doesn't start. You've hacked the RESET_REQ signal so you don't have that problem. But surprise - others haven't - so it's not exactly a relevant argument in favor. It's clear that the hardware has limitations that have impact upon the way in which both boards and software is designed. Because you don't know whether protocol reconfig is possible, you don't know *if* it is possible, *under what circumstances* it will be possible. What if XFI only works with 156 MHz provided to PLL 2, and not to PLL 1? You're trying to push a non-final solution as a final solution. The programmable refclk generator that is reconfigured at runtime is another can of worms, which I'm not sure can be feasibly implemented on this hardware given the fact that multiple lanes share one PLL, and there are many more lanes (4 or 8) than PLLs (2). Again, I need to see some practical functionality that this patch set provides. Do you _actually_ have a programmable clock generator that the CPLD can't program, or is this a "what if" situation? More to the point of the "flexibility" that you claim. You haven't addressed my point of networking over the SERDES ports in U-Boot. You don't need that - I'm clear with that, otherwise we'd be having this conversation on the U-Boot mailing lists - but what if others, wanting to follow your solution, would? Would you see that as an opportunity to write even more code?
Hi Sean, On Tue, Jun 13, 2023 at 05:27:54PM +0300, Vladimir Oltean wrote: > The way things are supposed to work (*if* this works at all) is that the > reset state machine starts with a supported PLL / refclk configuration > that permits a certain subset of protocols, and the SERDES protocols can > be changed from the reset state, as desired, for the individual lanes. > > What is self-inflicted is that the refclks on your board design are not > supportable by any reset state machine configuration, and wiring them > that way was a conscious decision. Did your company's board designers > receive the recommendation to disconnect RESET_REQ from NXP, and has NXP > said that the end result will be something that continues to be supportable? > I've searched the customer support database and the answer seems to be no. > In any case, if you have to disconnect RESET_REQ from the SoC to make > the driver in this form useful, then... yeah, no. You're obviously free > to do whatever you want with your products, but that's not how mainline > Linux works, it needs to be useful beyond you. > > If protocol switching works, I will maintain that your board should have > wired the refclks to PLLs the other way around (which is supported by > the RCW), and then proceed to do protocol switching to reach the desired > configuration. It was quite a journey to piece everything together. There is one thing to be mentioned right from the start, and that is that on some SoCs (including the LS1043A and LS1046A), the SerDes data path is partially controlled by the RCW, and thus, dynamically performing a major SerDes protocol reconfiguration requires a RCW override procedure (undocumented in the SerDes reconfiguration steps, but all the info you need is summarized below). The DCFG block has a set of RCWSR0 - RCWSR15 read-only status registers relative to DCFG_CCSR. What we don't document in the SoC RM, but I got permission to say here, is that the DCFG block exposes a second set of Expert Mode registers in the DCSR address space (base address 2000_0000h). The DCFG_DCSR register region spans from offset 2_0000h to 2_05AC into the DCSR base address. At the exact same offsets into DCFG_DCSR as RCWSR0 - RCWSR15 are into DCFG_CCSR (aka 100h-13ch), one can find the shadow RCWCR0 - RCWCR15 (Reset Control Word Control Register) registers which are also writable. There is a one-to-one mapping between each register (and field) in RCWSR and RCWCR, so I won't detail the contents of the RCWCR registers, because we document RCWSR fully. RCW override means modifying some of the RCWCR registers. In this particular case, finalizing the major SerDes reconfiguration requires overriding SRDS_PRTCL_S1 in RCWCR5 with the new per-lane settings, to mux the correct PCS to the MAC. In the general case, random RCW overrides that don't come from the hardware validation team are unsupported by NXP, and you should expect the procedure to yield unpredictable results. I don't know how much of the above steps is applicable to the other 10G Lynx SoCs (LS1088, LS2088 etc). Not all SoCs may require RCW override, and the RCW override procedure may not be the same. That is TBD, and we'd appreciate if support for other SoCs than the LS1046 to be added no earlier than when we have a validated SerDes reconfiguration procedure. I believe this is enough information to permit the creation of a Linux driver on the DCFG_DCSR registers which permits RCW override at runtime. It seems this will be necessary at least on LS1046. We should discuss who and when picks up your patches, removes the unsupported, untested and unnecessary code and adds the RCW override procedure. It can be you, it can also be someone from NXP. If it will be you, please let me know, because there are concrete implementation choices I want to leave comments on. There is also the previous observation from Ioana that you should not delete PHY interrupts without finding out why they don't work. Only what was thoroughly tested and is based on a hardware validated procedure should be submitted. This means only a 1G <-> 10G transition on LS1046 for now. Nonetheless, below is a functional example of how NXP would recommend you to achieve the desired PLL mapping for any RCW-based SerDes protocol. My testing platform was the LS1046A-QDS with PLL1 at 100 MHz and PLL2 at 156.25 MHz. I believe that this should eliminate the need for a clk driver for the PLLs, and should make your Ethernet lanes usable much earlier than Linux. That being said, our position at NXP is that you don't need a clk driver for the PLLs, and I would like to see the clk portion removed from future patch revisions. This patch is on top of https://github.com/nxp-qoriq/rcw/tree/lf-6.1.22-2.0.0
Hi Vladimir, On 8/10/23 06:26, Vladimir Oltean wrote: > Hi Sean, > > On Tue, Jun 13, 2023 at 05:27:54PM +0300, Vladimir Oltean wrote: >> The way things are supposed to work (*if* this works at all) is that the >> reset state machine starts with a supported PLL / refclk configuration >> that permits a certain subset of protocols, and the SERDES protocols can >> be changed from the reset state, as desired, for the individual lanes. >> >> What is self-inflicted is that the refclks on your board design are not >> supportable by any reset state machine configuration, and wiring them >> that way was a conscious decision. Did your company's board designers >> receive the recommendation to disconnect RESET_REQ from NXP, and has NXP >> said that the end result will be something that continues to be supportable? >> I've searched the customer support database and the answer seems to be no. >> In any case, if you have to disconnect RESET_REQ from the SoC to make >> the driver in this form useful, then... yeah, no. You're obviously free >> to do whatever you want with your products, but that's not how mainline >> Linux works, it needs to be useful beyond you. As explained previously (and noted by yourself below) 1G and 10G RCWs have mutally-incompatible clocking requirements. Now that you have documented an alternate solution, it is possible to boot up with one RCW and switch to another. But without that it was not possible to have one board support both RCWs (without e.g. a microcontroller or FPGA to configure the clock generator before releasing the processor reset). I do not think that the silicon should assert the reset request line if the serdes doesn't lock, but it does and it can't really be disabled. As it happens, our board is set up so that the reference clocks are configured for 10G by default. During this boot, reset request is never requested. If we did not have to support software configuration of the serdes speed (to support 1G SFPs) we would not have to disconnect reset request. That said, I have evaluated the various reasons that reset request can be asserted, and I have determined that for our product they are not necessary. The only major limitation is the lack of a watchdog, but that was not a requirement for us. Because of this, using a GPIO for reset is sufficient and neatly avoids the issue. We did not see the need to contact NXP support because we internally came up with a reliable solution. I suspect that they would not have suggested the solution you present below, but if you think otherwise I will try them in the future :) I would appreciate if you are not so derisive in your comments. I do not like reading your emails because they are very abrasive. >> If protocol switching works, I will maintain that your board should have >> wired the refclks to PLLs the other way around (which is supported by >> the RCW), and then proceed to do protocol switching to reach the desired >> configuration. > > It was quite a journey to piece everything together. > > There is one thing to be mentioned right from the start, and that is > that on some SoCs (including the LS1043A and LS1046A), the SerDes data > path is partially controlled by the RCW, and thus, dynamically performing > a major SerDes protocol reconfiguration requires a RCW override procedure > (undocumented in the SerDes reconfiguration steps, but all the info you > need is summarized below). > > The DCFG block has a set of RCWSR0 - RCWSR15 read-only status registers > relative to DCFG_CCSR. What we don't document in the SoC RM, but I got > permission to say here, is that the DCFG block exposes a second set of > Expert Mode registers in the DCSR address space (base address 2000_0000h). > The DCFG_DCSR register region spans from offset 2_0000h to 2_05AC into > the DCSR base address. At the exact same offsets into DCFG_DCSR as > RCWSR0 - RCWSR15 are into DCFG_CCSR (aka 100h-13ch), one can find the > shadow RCWCR0 - RCWCR15 (Reset Control Word Control Register) registers > which are also writable. There is a one-to-one mapping between each > register (and field) in RCWSR and RCWCR, so I won't detail the > contents of the RCWCR registers, because we document RCWSR fully. > > RCW override means modifying some of the RCWCR registers. In this > particular case, finalizing the major SerDes reconfiguration requires > overriding SRDS_PRTCL_S1 in RCWCR5 with the new per-lane settings, to mux > the correct PCS to the MAC. In the general case, random RCW overrides > that don't come from the hardware validation team are unsupported by > NXP, and you should expect the procedure to yield unpredictable results. Good to see these finally documented (in some form or other). Perhaps these could also be used to enable e.g. a UART in the hard-coded RCW without requiring e.g. JTAG... > I don't know how much of the above steps is applicable to the other 10G Lynx > SoCs (LS1088, LS2088 etc). Not all SoCs may require RCW override, and > the RCW override procedure may not be the same. That is TBD, and we'd > appreciate if support for other SoCs than the LS1046 to be added no > earlier than when we have a validated SerDes reconfiguration procedure. > > I believe this is enough information to permit the creation of a Linux > driver on the DCFG_DCSR registers which permits RCW override at runtime. > It seems this will be necessary at least on LS1046. > > We should discuss who and when picks up your patches, removes the > unsupported, untested and unnecessary code and adds the RCW override > procedure. Well, while I don't agree with your characterization (since this code was indeed tested by me and was indeed necessary), I am glad to see that you think there is a path forward. > It can be you, it can also be someone from NXP. If it will be > you, please let me know, because there are concrete implementation > choices I want to leave comments on. I can look into doing this. It will be in my free time, so it will likely be a bit before I can update this series. > There is also the previous observation from Ioana that you should not > delete PHY interrupts without finding out why they don't work. Well, if you have a better solution, please let me know. The interrupt does not work in real hardware. I was hampered in my efforts to determine the cause because the interrupt passes through an FPGA to which I lack the HDL. So far, I have not seen any argument against polling except that we do not understand the problem yet. However, I have not seen any other analysis of the problem either. > Only what was thoroughly tested and is based on a hardware validated > procedure should be submitted. This means only a 1G <-> 10G transition > on LS1046 for now. > > Nonetheless, below is a functional example of how NXP would recommend > you to achieve the desired PLL mapping for any RCW-based SerDes protocol. > My testing platform was the LS1046A-QDS with PLL1 at 100 MHz and PLL2 at > 156.25 MHz. I believe that this should eliminate the need for a clk > driver for the PLLs, and should make your Ethernet lanes usable much > earlier than Linux. That being said, our position at NXP is that you > don't need a clk driver for the PLLs, and I would like to see the clk > portion removed from future patch revisions. I have not had any issues with clocking. This is actually one of the areas where the reference manual is sufficient to create a working driver. Adding flexibility here is very useful, because we can solve hardware problems in software. This can reduce e.g. board respins, and allow for more interesting clocking solutions (such as allowing clock generators which must be configured before use). > This patch is on top of https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fgithub.com%2fnxp%2dqoriq%2frcw%2ftree%2flf%2d6.1.22%2d2.0.0&umid=9173333f-cda0-48a2-a652-ccb5b892d77e&auth=d807158c60b7d2502abde8a2fc01f40662980862-d3ec43c9e78658dbb409cef29887d136eca21c6a > > From 9f90d6805883f23a898f9d66826f89b7ba73afe3 Mon Sep 17 00:00:00 2001 > From: Vladimir Oltean <vladimir.oltean@nxp.com> > Date: Thu, 25 May 2023 11:23:41 +0300 > Subject: [PATCH] LS1046A: implement a PBI-based SerDes protocol switching > mechanism > > The LS1046A reset state machine is a bit limited in the SRDS_PRTCL_S1 > protocol combinations that it offers. For example, it offers protocol > 0x3333 (4x SGMII) only with PLL mapping 2222, and that is good as long > as dynamic protocol switching between 1G (SGMII) and 10G (XFI) isn't > desired at runtime. > > If that is taken into account as an additional constraint, then we need > PLL2 (yes, specifically 2) to have a refclk of 156.25 MHz, and that is > in conflict with the PLL mapping of the aforementioned 0x3333, because > 1G (SGMII) can only work with a PLL refclk of 100 or 125 MHz, so that's > what has to be fed into PLL 2. > > Dynamic frequency switching of PLLs is hard and out of question. > > It is desirable to be able to use PLL2 for the 156.25 MHz refclk > frequency (for the 10G link modes), and PLL1 for the 100 MHz refclk > frequency (for the 1G link modes). It turns out, this is possible, even > if not 100% natively through the reset state machine built-in options. > > The strategy is to pick a pair of SerDes refclk frequencies in the RCW > that is correct for the given board (thus allowing the SerDes PLLs to > lock, and the SoC to boot) as a first step. The SerDes protocol can be > absolutely anything as long as the PLL frequencies are right, because as > a second step, we'll be fixing up the SerDes lane registers for the > desired final protocol, to appear as if we had that protocol natively. > > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> > --- > .../rcw_1600.rcw | 99 +++++++++++++++++ > ls1046ardb/serdes_1133_to_3333.rcw | 73 +++++++++++++ > serdes_10g.rcw | 102 ++++++++++++++++++ > 3 files changed, 274 insertions(+) > create mode 100644 ls1046aqds/RR_FFSNPPPH_1133_5559_to_3333_5559/rcw_1600.rcw > create mode 100644 ls1046ardb/serdes_1133_to_3333.rcw > create mode 100644 serdes_10g.rcw > > diff --git a/ls1046aqds/RR_FFSNPPPH_1133_5559_to_3333_5559/rcw_1600.rcw b/ls1046aqds/RR_FFSNPPPH_1133_5559_to_3333_5559/rcw_1600.rcw > new file mode 100644 > index 000000000000..2bbc0163392d > --- /dev/null > +++ b/ls1046aqds/RR_FFSNPPPH_1133_5559_to_3333_5559/rcw_1600.rcw > @@ -0,0 +1,99 @@ > +/* > + * LS1046AQDS RCW for SerDes Protocol 0x3333_5559 derived from 0x1133_5559 > + * > + * 42G configuration -- 2 RGMII + 4 SGMII (reconfigurable to XFI) + 3 PCIe + SATA > + * > + * Frequencies: > + * > + * Sys Clock: 100 MHz > + * DDR_Refclock: 100 MHz > + * > + * Core -- 1600 MHz (Mul 16) > + * Platform -- 600 MHz (Mul 6) > + * DDR -- 2100 MT/s (Mul 21) > + * FMan -- 700 MHz (CGA2 /2) > + * XFI -- 156.25 MHz (10.3125G) > + * SGMII -- 100 MHz (5G) > + * PCIE -- 100 MHz (5G) > + * eSDHC -- 1400 MHz (CGA2 /1) > + * > + * Hardware Accelerator Block Cluster Group A Mux Clock: > + * FMan - HWA_CGA_M1_CLK_SEL = 6 - Async mode, CGA PLL 2 /2 is clock > + * eSDHC, QSPI - HWA_CGA_M2_CLK_SEL = 1 - Async mode, CGA PLL 2 /1 is clock > + * > + * Serdes Lanes vs Slot information > + * Serdes1 Lane 0 (D) - Starts as XFI9, switches to SGMII9 > + * Serdes1 Lane 1 (C) - Starts as XFI10, switches to SGMII10 > + * Serdes1 Lane 2 (B) - SGMII5, Slot 1 > + * Serdes1 Lane 3 (A) - SGMII6, Slot 1 > + * > + * Serdes2 Lane 0 (A) - PCIe1 Gen2 x1, Slot 3 > + * Serdes2 Lane 1 (B) - PCIe2 Gen2 x1, Slot 4 > + * Serdes2 Lane 2 (C) - PCIe3 Gen2 x1, Slot 5 > + * Serdes2 Lane 3 (D) - SATA > + * > + * PLL mapping: starts as 2211_2221, ends as 1111_2221 > + * > + * Serdes 1: > + * PLL mapping: 1111 > + * SRDS_PLL_REF_CLK_SEL_S1 : 0b'01 > + * SerDes 1, PLL1[160] : 0 - 100MHz for SGMII and PCIe > + * SerDes 1, PLL2[161] : 1 - 156.25MHz for XFI > + * SRDS_PLL_PD_S1 : 0b'0 > + * SerDes 1, PLL1 : 0 - not powered down > + * SerDes 1, PLL2 : 0 - not powered down > + * SRDS_DIV_PEX_S1 : > + * Only used for PEX, not used. > + * > + * Serdes 2: > + * PLL mapping: 2221 > + * SRDS_PLL_REF_CLK_SEL_S2 : 0b'00 > + * SerDes 2, PLL1[162] : 0 - 100MHz for SATA > + * SerDes 2, PLL2[163] : 0 - 100MHz for PCIe > + * SRDS_PLL_PD_S2 : 0b'00 > + * SerDes 2, PLL1 : 0 - not powered down > + * SerDes 2, PLL2 : 0 - not powered down > + * SRDS_DIV_PEX_S2 : 0b'01 > + * 00 - train up to max rate of 8G > + * 01 - train up to max rate of 5G > + * 10 - train up to max rate of 2.5G > + * > + * DDR clock: > + * DDR_REFCLK_SEL : 1 - DDRCLK pin provides the reference clock to the DDR PLL > + * > + */ > + > +#include <../ls1046ardb/ls1046a.rcwi> > + > +SYS_PLL_RAT=6 > +MEM_PLL_RAT=21 > +CGA_PLL1_RAT=16 > +CGA_PLL2_RAT=14 > +SRDS_PRTCL_S1=4403 > +SRDS_PRTCL_S2=21849 I know it is not typical for NXP RCWs, but your rcw tool supports using hex/binary prefixes. Thus, you could rewrite the above lines as SRDS_PRTCL_S1=0x1133 SRDS_PRTCL_S2=0x5559 IMO this is much easier to read, since it matches the documentation. > +SRDS_PLL_REF_CLK_SEL_S1=1 > +SRDS_PLL_REF_CLK_SEL_S2=0 > +SRDS_DIV_PEX_S1=1 > +SRDS_DIV_PEX_S2=1 > +DDR_FDBK_MULT=2 > +DDR_REFCLK_SEL=1 > +PBI_SRC=14 As another example, here you can do e.g. PBI_SRC=0b1110 which better matches the documentation. > +IFC_MODE=37 > +HWA_CGA_M1_CLK_SEL=6 > +DRAM_LAT=1 > +UART_BASE=7 > +IRQ_OUT=1 > +LVDD_VSEL=1 > +TVDD_VSEL=0 > +DVDD_VSEL=2 > +EVDD_VSEL=2 > +IIC2_EXT=1 > +SYSCLK_FREQ=600 > +HWA_CGA_M2_CLK_SEL=1 > + > +#include <../ls1046ardb/cci_barrier_disable.rcw> > +#include <../ls1046ardb/usb_phy_freq.rcw> > +#include <../ls1046ardb/uboot_address.rcw> > +#include <../ls1046ardb/serdes_sata.rcw> > +#include <../ls1046ardb/a009531.rcw> > +#include <../ls1046ardb/serdes_1133_to_3333.rcw> > diff --git a/ls1046ardb/serdes_1133_to_3333.rcw b/ls1046ardb/serdes_1133_to_3333.rcw > new file mode 100644 > index 000000000000..ffd548a73675 > --- /dev/null > +++ b/ls1046ardb/serdes_1133_to_3333.rcw > @@ -0,0 +1,73 @@ > +/* > + * Change protocols on SerDes1 from 1133 to 3333, and their PLL mappings from > + * 2211 to 1111. This is useful because, although the reset state machine has a > + * native 0x3333 SerDes protocol option, the PLL mapping of that is 2222. > + * This non-native option frees up PLL 2, and it can be provisioned e.g. with a > + * 156.25 MHz for any lanes that might want to switch to XFI at runtime. > + */ > + > +#define SRDS_BASE 0xea0000 /* SerDes 1 relative to CCSR_BASE */ > +#include <../serdes_10g.rcw> > + > +/* For writing outside the CCSR space (in DCSR), an indirect access method is > + * used. The SCFG_ALTCBAR register (field ALTCFG) holds the upper 24 bits of > + * the 48-bit address, and the awrite PBL instruction gets the lower 24 bits of > + * the address that is relative to that. Here we work with 32-bit addresses, > + * so we only care about the upper 8 bits. > + */ > +#define SCFG_ALTCBAR 0x570158 > +#define ALTCFG(x) (((x) << 8) & 0xffffff00) > +#define DCFG_DCSR_RCWCR5 0x20140110 > +#define RCWCR5_SRDS_PRTCL_S1(x) (((x) << 16) & 0xffff0000) > +#define RCWCR5_SRDS_PRTCL_S2(x) ((x) & 0xffff) > +#define upper_8_bits(x) (((x) & 0xff000000) >> 24) > +#define lower_24_bits(x) ((x) & 0xffffff) > + > +#define GCR0_SGMII_FROM_PLL1 RPLL_LES(1) | RRAT_SEL(2) | \ > + TPLL_LES(1) | TRAT_SEL(2) | \ > + FIRST_LANE(1) | PROTS(1) > + > +.pbi > + > +write LNmGCR0(2), RRST_B(0) | TRST_B(0) > +write LNmGCR0(3), RRST_B(0) | TRST_B(0) > + > +wait 50 > + > +write LNmGCR0(2), GCR0_SGMII_FROM_PLL1 > +write LNmGCR0(3), GCR0_SGMII_FROM_PLL1 > + > +write LNmGCR1(2), REIDL_TH(1) | REIDL_EX_SEL(3) | REIDL_ET_MSB(1) | \ > + ISLEW_RCTL(1) | OSLEW_RCTL(1) > +write LNmGCR1(3), REIDL_TH(1) | REIDL_EX_SEL(3) | REIDL_ET_MSB(1) | \ > + ISLEW_RCTL(1) | OSLEW_RCTL(1) > + > +write LNmRECR0(2), GK2OVD_EN(1) | GK2OVD(15) | GK3OVD_EN(1) | GK3OVD(15) > +write LNmRECR0(3), GK2OVD_EN(1) | GK2OVD(15) | GK3OVD_EN(1) | GK3OVD(15) > + > +write LNmTECR0(2), ADPT_EQ(48) | AMP_RED(6) > +write LNmTECR0(3), ADPT_EQ(48) | AMP_RED(6) > + > +/* LS1046A requires RCW override to reconfigure the mux between > + * the PCS and the MAC. > + */ > +write SCFG_ALTCBAR, ALTCFG(upper_8_bits(DCFG_DCSR_RCWCR5)) > +flush > +awrite lower_24_bits(DCFG_DCSR_RCWCR5), RCWCR5_SRDS_PRTCL_S1(0x3333) | \ > + RCWCR5_SRDS_PRTCL_S2(0x5559) > + > +/* PCCRB: 0x21000000 -> 0x00000000 */ > +write PCCRB, XFIA_CFG(0) | XFIB_CFG(0) > + > +/* PCCR8: 0x11000000 -> 0x11110000 */ > +write PCCR8, SGMIIA_CFG(1) | SGMIIB_CFG(1) | SGMIIC_CFG(1) | SGMIID_CFG(1) > + > +write SGMIIaCR1(2), SGMII_MDEV_PORT(0) | SGPCS_EN(1) > +write SGMIIaCR1(3), SGMII_MDEV_PORT(0) | SGPCS_EN(1) > + > +wait 120 > + > +write LNmGCR0(2), GCR0_SGMII_FROM_PLL1 | RRST_B(1) | TRST_B(1) > +write LNmGCR0(3), GCR0_SGMII_FROM_PLL1 | RRST_B(1) | TRST_B(1) > + > +.end > diff --git a/serdes_10g.rcw b/serdes_10g.rcw > new file mode 100644 > index 000000000000..714d53fde8af > --- /dev/null > +++ b/serdes_10g.rcw > @@ -0,0 +1,102 @@ > +/* > + * Registers for the Lynx 10G SerDes block. > + * > + * Must be included by an SoC-specific header that defines the > + * SRDS_BASE value. > + */ > + > +#define PLLnRSTCTL(n) (SRDS_BASE + (0x20 * (n))) > +#define PLLnCR0(n) (SRDS_BASE + (0x20 * (n)) + 0x0004) > +#define POFF(x) (((x) << 31) & 0x80000000) > +#define REFCLK_SEL(x) (((x) << 28) & 0x70000000) > +#define REFCLK_EN(x) (((x) << 27) & 0x08000000) > +#define FRATE_SEL(x) (((x) << 16) & 0x000f0000) > +#define DLYDIV_SEL(x) ((x) & 0x00000003) > +#define PCCR8 (SRDS_BASE + 0x0220) > +#define SGMIIA_KX(x) (((x) << 31) & 0x80000000) > +#define SGMIIA_CFG(x) (((x) << 28) & 0x70000000) > +#define SGMIIB_KX(x) (((x) << 27) & 0x08000000) > +#define SGMIIB_CFG(x) (((x) << 24) & 0x07000000) > +#define SGMIIC_KX(x) (((x) << 23) & 0x00800000) > +#define SGMIIC_CFG(x) (((x) << 20) & 0x00700000) > +#define SGMIID_KX(x) (((x) << 19) & 0x00080000) > +#define SGMIID_CFG(x) (((x) << 16) & 0x00070000) > +#define SGMIIE_KX(x) (((x) << 15) & 0x00008000) > +#define SGMIIE_CFG(x) (((x) << 12) & 0x00007000) > +#define SGMIIF_KX(x) (((x) << 11) & 0x00000800) > +#define SGMIIF_CFG(x) (((x) << 8) & 0x00000700) > +#define SGMIIG_KX(x) (((x) << 7) & 0x00000080) > +#define SGMIIG_CFG(x) (((x) << 4) & 0x00000070) > +#define SGMIIH_KX(x) (((x) << 3) & 0x00000008) > +#define SGMIIH_CFG(x) ((x) & 0x00000007) > +#define PCCRB (SRDS_BASE + 0x022c) > +#define XFIA_CFG(x) (((x) << 28) & 0x70000000) > +#define XFIB_CFG(x) (((x) << 24) & 0x07000000) > +#define XFIC_CFG(x) (((x) << 20) & 0x00700000) > +#define XFID_CFG(x) (((x) << 16) & 0x00070000) > +#define XFIE_CFG(x) (((x) << 12) & 0x00007000) > +#define XFIF_CFG(x) (((x) << 8) & 0x00000700) > +#define XFIG_CFG(x) (((x) << 4) & 0x00000070) > +#define XFIH_CFG(x) ((x) & 0x00000007) > +#define LNmGCR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0800) > +#define RPLL_LES(x) (((x) << 31) & 0x80000000) > +#define RRAT_SEL(x) (((x) << 28) & 0x30000000) > +#define TPLL_LES(x) (((x) << 27) & 0x08000000) > +#define TRAT_SEL(x) (((x) << 24) & 0x03000000) > +#define RRST_B(x) (((x) << 22) & 0x00400000) > +#define TRST_B(x) (((x) << 21) & 0x00200000) > +#define RX_PD(x) (((x) << 20) & 0x00100000) > +#define TX_PD(x) (((x) << 19) & 0x00080000) > +#define IF20BIT_EN(x) (((x) << 18) & 0x00040000) > +#define FIRST_LANE(x) (((x) << 16) & 0x00010000) > +#define GCR0_RSV 0x1000 > +#define PROTS(x) (((x) << 7) & 0x00000f80) > +#define LNmGCR1(m) (SRDS_BASE + (0x40 * (m)) + 0x0804) > +#define RDAT_INV(x) (((x) << 31) & 0x80000000) > +#define TDAT_INV(x) (((x) << 30) & 0x40000000) > +#define OPAD_CTL(x) (((x) << 26) & 0x04000000) > +#define REIDL_TH(x) (((x) << 20) & 0x00700000) > +#define REIDL_EX_SEL(x) (((x) << 18) & 0x000C0000) > +#define REIDL_ET_SEL(x) (((x) << 16) & 0x00030000) > +#define REIDL_EX_MSB(x) (((x) << 15) & 0x00008000) > +#define REIDL_ET_MSB(x) (((x) << 14) & 0x00004000) > +#define REQ_CTL_SNP(x) (((x) << 13) & 0x00002000) > +#define REQ_CDR_SNP(x) (((x) << 12) & 0x00001000) > +#define TRSTDIR(x) (((x) << 7) & 0x00000080) > +#define REQ_BIN_SNP(x) (((x) << 6) & 0x00000040) > +#define ISLEW_RCTL(x) (((x) << 4) & 0x00000030) > +#define GCR1_RSV 0x8 > +#define OSLEW_RCTL(x) ((x) & 0x3) > +#define LNmRECR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0810) > +#define RXEQ_BST(x) (((x) << 28) & 0x10000000) > +#define GK2OVD(x) (((x) << 24) & 0x0f000000) > +#define GK3OVD(x) (((x) << 16) & 0x000f0000) > +#define GK2OVD_EN(x) (((x) << 15) & 0x00008000) > +#define GK3OVD_EN(x) (((x) << 14) & 0x00004000) > +#define OSETOVD_EN(x) (((x) << 13) & 0x00002000) > +#define BASE_WAND(x) (((x) << 10) & 0x00000c00) > +#define OSETOVD(x) ((x) & 0x0000007F) > +#define LNmTECR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0818) > +#define TEQ_TYPE(x) (((x) << 28) & 0x30000000) > +#define SGN_PREQ(x) (((x) << 26) & 0x04000000) > +#define RATIO_PREQ(x) (((x) << 22) & 0x03C00000) > +#define SGN_POST1Q(x) (((x) << 21) & 0x00200000) > +#define RATIO_PST1Q(x) (((x) << 16) & 0x001F0000) > +#define ADPT_EQ(x) (((x) << 8) & 0x00003F00) > +#define AMP_RED(x) ((x) & 0x0000003f) > +#define LNmTTLCR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0820) > +#define LNmTCSR0(m) (SRDS_BASE + (0x40 * (m)) + 0x0830) > +#define LNmTCSR1(m) (SRDS_BASE + (0x40 * (m)) + 0x0834) > +#define LNmTCSR2(m) (SRDS_BASE + (0x40 * (m)) + 0x0838) > +#define LNmTCSR3(m) (SRDS_BASE + (0x40 * (m)) + 0x083c) > +#define SGMIIaCR0(a) (SRDS_BASE + (0x10 * (a)) + 0x1800) > +#define RST_SGM(x) (((x) << 31) & 0x80000000) > +#define PD_SGM(x) (((x) << 30) & 0x40000000) > +#define SGMIIaCR1(a) (SRDS_BASE + (0x10 * (a)) + 0x1804) > +#define SGMII_MDEV_PORT(x) (((x) << 27) & 0xf8000000) > +#define SGPCS_EN(x) (((x) << 11) & 0x00000800) > +#define XFIaCR0(a) (SRDS_BASE + (0x10 * (a)) + 0x1980) > +#define RST_XFI(x) (((x) << 31) & 0x80000000) > +#define PD_XFI(x) (((x) << 30) & 0x40000000) > +#define XFIaCR1(a) (SRDS_BASE + (0x10 * (a)) + 0x1984) > +#define XFI_MDEV_PORT(x) (((x) << 27) & 0xf8000000) > -- > 2.34.1 > >> > This driver would also be a good place to add the KR link training with >> > NXP tried to upstream a few years ago. >> >> Well, speaking as someone who is now also tasked with the copper backplane >> support, believe me that I know that, and this is why I'm so desperate >> with the logic you're trying to push forward. It's clear that we should >> try to collaborate rather than try to push individualistic non-tested >> non-solutions. > > Speaking of this, I will send an RFC in the upcoming days which proposes > a model for the copper backplane PHY support on LX2160A and its already > existing Lynx 28G SerDes driver. > > I will concern myself with porting that support on Lynx 10G only once > the model I propose turns out to be acceptable for both the network PHY > as well as the generic PHY maintainers. Well, as far as I know this driver is only a few changes from being acceptable to these maintainers as well :) --Sean
Hi Sean, On Tue, Jun 13, 2023 at 05:27:54PM +0300, Vladimir Oltean wrote: > > > At first sight you might appear to have a point related to the fact that > > > PLL register writes are necessary, and thus this whole shebang is necessary. > > > But this can all be done using PBI commands, with the added benefit that > > > U-Boot can also use those SERDES networking ports, and not just Linux. > > > You can use the RCW+PBL specific to your board to inform the SoC that > > > your platform's refclk 1 is 156 MHz (something which the reset state > > > machine seems unable to learn, with protocol 0x3333). You don't have to > > > put that in the device tree. You don't have to push code to any open > > > source project to expose your platform specific details. Then, just like > > > in the case of the Lynx 28G driver on LX2160, the SERDES driver could > > > just treat the PLL configuration as read-only, which would greatly > > > simplify things and eliminate the need for a clk driver. > > > > > > Here is an illustrative example (sorry, I don't have a board with the > > > right refclk on that PLL, to verify all the way): > > > > > > ... snip ... > > > > (which of course complicates the process of building the PBIs...) > > Maybe this is the language barrier, but what are you trying to say here? I said that I don't understand. Can you please clarify what you were trying to transmit with this comment?
Hi Sean, On Thu, Aug 10, 2023 at 03:58:36PM -0400, Sean Anderson wrote: > As explained previously (and noted by yourself below) 1G and 10G RCWs > have mutally-incompatible clocking requirements. Now that you have > documented an alternate solution, it is possible to boot up with one RCW > and switch to another. But without that it was not possible to have one > board support both RCWs (without e.g. a microcontroller or FPGA to > configure the clock generator before releasing the processor reset). I > do not think that the silicon should assert the reset request line if > the serdes doesn't lock, but it does and it can't really be disabled. > > As it happens, our board is set up so that the reference clocks are > configured for 10G by default. During this boot, reset request is never > requested. If we did not have to support software configuration of the > serdes speed (to support 1G SFPs) we would not have to disconnect reset > request. > > That said, I have evaluated the various reasons that reset request can > be asserted, and I have determined that for our product they are not > necessary. The only major limitation is the lack of a watchdog, but that > was not a requirement for us. Because of this, using a GPIO for reset is > sufficient and neatly avoids the issue. I would like to pause here and highlight the existence of the so-called XY problem: https://en.wikipedia.org/wiki/XY_problem | The XY problem is a communication problem encountered in help desk, | technical support, software engineering, or customer service situations | where the question is about an end user's attempted solution (Y) rather | than the root problem itself (X). You admitted that you needed to solve problem X (software reconfiguration of the SerDes speed between 1G and 10G), and that has led you to problem Y (giving the PLLs some refclk frequencies which aren't supported at power-on reset, and thus, are also not validated by NXP). You've presented to the Linux mailing lists a driver which solves problem Y, but not X. I gave you a solution to problem X which doesn't even trigger problem Y. Furthermore, I gave you a solution to problem Y which is much simpler than yours. On the 12th of June, in Message-ID: 20230612163353.dwouatvqbuo6h4ea@skbuf, I explained that if you absolutely insist to use the unsupported PLL refclks, you can use PBL commands to change the PLL settings (so that they lock) at power-on reset time. The advantage is that both U-Boot and Linux will work without having to make any modification to the PLLs, just treat them as read-only. As it happens, at NXP we also want to solve problem X in a generic way (aka we need a procedure that works for all customers, and not just for your board), and we want to do so in a way that the hardware validation team agrees with. Thus, the SoC needs to accept the PLL refclks at power-on reset time. The solution we came up with is the one presented to you yesterday. It makes your PLL clk driver unnecessary. No one will come after you if you keep it in your Linux tree and use it, but it is unnecessary. > > Nonetheless, below is a functional example of how NXP would recommend > > you to achieve the desired PLL mapping for any RCW-based SerDes protocol. > > My testing platform was the LS1046A-QDS with PLL1 at 100 MHz and PLL2 at > > 156.25 MHz. I believe that this should eliminate the need for a clk > > driver for the PLLs, and should make your Ethernet lanes usable much > > earlier than Linux. That being said, our position at NXP is that you > > don't need a clk driver for the PLLs, and I would like to see the clk > > portion removed from future patch revisions. > > I have not had any issues with clocking. This is actually one of the > areas where the reference manual is sufficient to create a working > driver. Adding flexibility here is very useful, because we can solve > hardware problems in software. This can reduce e.g. board respins, and > allow for more interesting clocking solutions (such as allowing clock > generators which must be configured before use). I am waiting for someone to come up with a real life use case that justifies those "more interesting clocking solutions". Please correct me if you think I am wrong, but as things stand, the SerDes PLL clk driver is now a solution waiting for a problem. It can wait for that problem out of tree. > > There is also the previous observation from Ioana that you should not > > delete PHY interrupts without finding out why they don't work. > > Well, if you have a better solution, please let me know. The interrupt > does not work in real hardware. > > I was hampered in my efforts to determine the cause because the interrupt > passes through an FPGA to which I lack the HDL. So far, I have not seen > any argument against polling except that we do not understand the > problem yet. However, I have not seen any other analysis of the problem > either. Out of respect for the topic at hand, ask for help in a separate thread, open an NXP support ticket - do something to split it from the SerDes work which it is unrelated with. You were told that part of the reason for the NACK is the fact that you are grouping unrelated things together, and you did nothing about it. > > +SRDS_PRTCL_S1=4403 > > +SRDS_PRTCL_S2=21849 > > I know it is not typical for NXP RCWs, but your rcw tool supports using > hex/binary prefixes. Thus, you could rewrite the above lines as > > SRDS_PRTCL_S1=0x1133 > SRDS_PRTCL_S2=0x5559 > > IMO this is much easier to read, since it matches the documentation. Ok, thanks.
Hi Sean, On Fri, Aug 11, 2023 at 07:36:37PM +0300, Vladimir Oltean wrote: > Let me explain that approach, because your mention of "swapping out the > bootloaders" makes it appear as if you are not visualising what I am > proposing. > > The Lynx SerDes family has 2 PLLs, and more lanes (4 or 8). Each lane > uses one PLL or the other, to derive its protocol frequency. Through the > RCW, you provision the 2 PLL frequencies that may be used by the lanes > at runtime. > > The Lynx 28G SerDes driver reads the PLL frequencies in > lynx_28g_pll_read_configuration(), and determines the interface modes > supportable by each PLL (this is used by phylink). But it never changes > those PLL frequencies, since that operation is practically impossible in > the general sense (PLLs are shared by multiple lanes, so changing a PLL > frequency disrupts all lanes that use it). Is my high-level feedback clear and actionable to you? I am suggesting to keep the look and feel the same between the lynx-10g and lynx-28g drivers, and to not use "fsl,type" protocols listed in the device tree as the immutable source of information for populating mode->protos, but instead the current PLL frequency configuration. So this implies that I am requesting that the dt-bindings should not contain a listing of the supported protocols.
On 8/21/23 08:49, Vladimir Oltean wrote: > Hi Sean, > > On Fri, Aug 11, 2023 at 07:36:37PM +0300, Vladimir Oltean wrote: >> Let me explain that approach, because your mention of "swapping out the >> bootloaders" makes it appear as if you are not visualising what I am >> proposing. >> >> The Lynx SerDes family has 2 PLLs, and more lanes (4 or 8). Each lane >> uses one PLL or the other, to derive its protocol frequency. Through the >> RCW, you provision the 2 PLL frequencies that may be used by the lanes >> at runtime. >> >> The Lynx 28G SerDes driver reads the PLL frequencies in >> lynx_28g_pll_read_configuration(), and determines the interface modes >> supportable by each PLL (this is used by phylink). But it never changes >> those PLL frequencies, since that operation is practically impossible in >> the general sense (PLLs are shared by multiple lanes, so changing a PLL >> frequency disrupts all lanes that use it). > > Is my high-level feedback clear and actionable to you? I am suggesting > to keep the look and feel the same between the lynx-10g and lynx-28g > drivers, and to not use "fsl,type" protocols listed in the device tree > as the immutable source of information for populating mode->protos, but > instead the current PLL frequency configuration. So this implies that I > am requesting that the dt-bindings should not contain a listing of the > supported protocols. Well, we have two pieces of information we need - What values do we need to program in the PCCRs to select a particular mode? This includes whether to e.g. set the KX bits. - Implied by the above, what protocols are supported on which lanes? This is not strictly necessary, but will certainly solve a lot of headscratching. This information varies between different socs, and different serdes on the same socs. We can't really look at the RCW or the clocks and figure out what we need to program. So what are our options? - We can have a separate compatible for each serdes on each SoC (e.g. "fsl,lynx-10g-a"). This was rejected by the devicetree maintainers. - We can have one compatible for each SoC, and determine the serdes based on the address. I would like to avoid this... - We can stick all the details which vary between serdes/socs into the device tree. This is very flexible, since supporting new SoCs is mostly a matter of adding a new compatible and writing a new devicetree. On the other hand, if you have a bug in your devicetree, it's not easy to fix it in the kernel. - Just don't support protocol switching. The 28G driver does this, which is why it only has one compatible. However, supporting protocol switching is a core goal of this driver, so dropping support is not an option. I'm open to any other suggestions you have, but this was the best way I could figure out to get this information to the driver in a way which would be acceptable to the devicetree folks. --Sean
On Mon, Aug 21, 2023 at 01:45:44PM -0400, Sean Anderson wrote: > Well, we have two pieces of information we need > > - What values do we need to program in the PCCRs to select a particular > mode? This includes whether to e.g. set the KX bits. > - Implied by the above, what protocols are supported on which lanes? > This is not strictly necessary, but will certainly solve a lot of > headscratching. > > This information varies between different socs, and different serdes on > the same socs. We can't really look at the RCW or the clocks and figure > out what we need to program. So what are our options? > > - We can have a separate compatible for each serdes on each SoC (e.g. > "fsl,lynx-10g-a"). This was rejected by the devicetree maintainers. > - We can have one compatible for each SoC, and determine the serdes > based on the address. I would like to avoid this... To me this really seems like a straightforward approach. > - We can stick all the details which vary between serdes/socs into the > device tree. This is very flexible, since supporting new SoCs is > mostly a matter of adding a new compatible and writing a new > devicetree. On the other hand, if you have a bug in your devicetree, > it's not easy to fix it in the kernel. > - Just don't support protocol switching. The 28G driver does this, which > is why it only has one compatible. However, supporting protocol > switching is a core goal of this driver, so dropping support is not an > option. > The Lynx 28G SerDes driver does support protocol switching. How did you arrive at the opposite conclusion? The initial commit on the driver is even part of a patch set named "dpaa2-mac: add support for changing the protocol at runtime". In upstream it only supports the 1G <-> 10G transition but I have some patches on the way to also support 25G. Ioana
On Mon, Aug 21, 2023 at 09:13:49PM +0300, Ioana Ciornei wrote: > > - We can have one compatible for each SoC, and determine the serdes > > based on the address. I would like to avoid this... > > To me this really seems like a straightforward approach. +1
On 8/21/23 14:13, Ioana Ciornei wrote: > On Mon, Aug 21, 2023 at 01:45:44PM -0400, Sean Anderson wrote: >> Well, we have two pieces of information we need >> >> - What values do we need to program in the PCCRs to select a particular >> mode? This includes whether to e.g. set the KX bits. >> - Implied by the above, what protocols are supported on which lanes? >> This is not strictly necessary, but will certainly solve a lot of >> headscratching. >> >> This information varies between different socs, and different serdes on >> the same socs. We can't really look at the RCW or the clocks and figure >> out what we need to program. So what are our options? >> >> - We can have a separate compatible for each serdes on each SoC (e.g. >> "fsl,lynx-10g-a"). This was rejected by the devicetree maintainers. >> - We can have one compatible for each SoC, and determine the serdes >> based on the address. I would like to avoid this... > > To me this really seems like a straightforward approach. Indeed it would be straightforward, but what's the point of having a devicetree in the first place then? We could just go back to being a (non-dt) platform device. >> - We can stick all the details which vary between serdes/socs into the >> device tree. This is very flexible, since supporting new SoCs is >> mostly a matter of adding a new compatible and writing a new >> devicetree. On the other hand, if you have a bug in your devicetree, >> it's not easy to fix it in the kernel. >> - Just don't support protocol switching. The 28G driver does this, which >> is why it only has one compatible. However, supporting protocol >> switching is a core goal of this driver, so dropping support is not an >> option. >> > > The Lynx 28G SerDes driver does support protocol switching. > How did you arrive at the opposite conclusion? Sorry, it's been a while and I just did a quick look-over, and noticed there was no configuration for different SoCs. After further review, it seems the reason 28g can get away without this is because there's a one-to-one mapping between protocol controllers and lanes. Unfortunately, that regularity is not present for 10g. --Sean > The initial commit on the driver is even part of a patch set named > "dpaa2-mac: add support for changing the protocol at runtime". In > upstream it only supports the 1G <-> 10G transition but I have some > patches on the way to also support 25G. > > Ioana
On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: > After further review, it seems the reason 28g can get away without this > is because there's a one-to-one mapping between protocol controllers and > lanes. Unfortunately, that regularity is not present for 10g. > > --Sean There are some things I saw in your phy-fsl-lynx-10g.c driver and device tree bindings that I don't understand (the concept of lane groups), and I'm not sure if they're related with what you're saying here, so if you could elaborate a bit more (ideally with an example) on the one-to-one mapping and the specific problems it causes, it would be great. I may be off with my understanding of the regularity you are talking about, but the LX2160 (and Lynx 28G block) also has multi-lane protocols like 40G, 100G, assuming that's what you are talking about. I haven't started yet working on those for the mtip_backplane driver, but I'm not currently seeing a problem with the architecture where a phy_device represents a single lane that's part of a multi-lane port, and not an entire group. In my imagination, there are 2 cases: - all 4 lanes are managed by the single dpaa2-mac consumer (which has 4 phandles, and iterates over them with a "for" loop) - each of the 4 lanes is managed by the respective backplane AN/LT core, and thus, there's one phandle to each lane I sketched some dt-bindings for the second case here, so I guess it must be the first scenario that's somehow problematic? https://patchwork.kernel.org/project/netdevbpf/patch/20230817150644.3605105-9-vladimir.oltean@nxp.com/
On 8/21/23 15:58, Vladimir Oltean wrote: > On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: >> After further review, it seems the reason 28g can get away without this >> is because there's a one-to-one mapping between protocol controllers and >> lanes. Unfortunately, that regularity is not present for 10g. >> >> --Sean > > There are some things I saw in your phy-fsl-lynx-10g.c driver and device > tree bindings that I don't understand (the concept of lane groups) Each lane group corresponds to a phy device (struct phy). For protocols like PCIe or XAUI which can use multiple lanes, this lets the driver coordinate configuring all lanes at once in the correct order. > and > I'm not sure if they're related with what you're saying here, so if you > could elaborate a bit more (ideally with an example) on the one-to-one > mapping and the specific problems it causes, it would be great. For e.g. the LS2088A, SerDes1 lanes H-A use SG1-8 and XFI1-8. SerDes2 lanes A-H use SG9-16 and XFI9-16. Each lane has its own controller, and the mapping is 1-to-1. In the PCCRs, each controller uses the same value, and is mapped in a regular way. So you can go directly from the lane number to the right value to mask in the PCCR, with a very simple translation scheme. For e.g. the LS1046A, SerDes1 lane D uses XFI.9 (aka XFIA) and lane C uses XFI.10 (aka XFIB). This is the opposite of how SerDes1 lanes A-D use SGMII.9, .10, .5, and .6 (aka SGMIIA-D). For e.g. the T4240, SerDes1 lanes A-H use sg1.5, .6, .10, .9, .1, .2, .3, .4 (aka SGMII E, F, H, G, A, B, C, D). For e.g. the B4860, SerDes lanes A uses sgmii1 or sgmii5 and B uses sgmii2 or sgmii6. The MAC selected is determined based on the value programmed into PCCR2. While I appreciate that your hardware engineers did a better job for 28g, many 10g serdes arbitrarily map lanes to protocol controllers. I think the mapping is too irregular to tame, and it is better to say "if you want this configuration, program this value". > I may be off with my understanding of the regularity you are talking about, > but the LX2160 (and Lynx 28G block) also has multi-lane protocols like 40G, > 100G, assuming that's what you are talking about. I haven't started yet > working on those for the mtip_backplane driver, but I'm not currently > seeing a problem with the architecture where a phy_device represents a > single lane that's part of a multi-lane port, and not an entire group. Resetting one lane in a group will reset the rest, which could confuse the driver. Additionally, treating the lanes as one phy lets us set the reset direction and first lane bits correctly. > In my imagination, there are 2 cases: > - all 4 lanes are managed by the single dpaa2-mac consumer (which has 4 > phandles, and iterates over them with a "for" loop) > - each of the 4 lanes is managed by the respective backplane AN/LT core, > and thus, there's one phandle to each lane By doing the grouping in the driver, we also simplify the consumer implementation. The MAC can always use a single phy, without worrying about the actual number of lanes. This matches the hardware, since the MAC is going to talk XGMII (or whatever) to the protocol controller anyway. I think it will be a lot easier to add multi-lane support with this method because it gives the driver more information about what's going on. The driver can control the whole configuration/reset process and the timing. > I sketched some dt-bindings for the second case here, so I guess it must > be the first scenario that's somehow problematic? > https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fpatchwork.kernel.org%2fproject%2fnetdevbpf%2fpatch%2f20230817150644.3605105%2d9%2dvladimir.oltean%40nxp.com%2f&umid=9e644233-009e-4197-a266-5d9a85eb1148&auth=d807158c60b7d2502abde8a2fc01f40662980862-cc1d5330d84af8fa40745b165a44849db50f8a67 Yes, no issues with the second case. --Sean
On Mon, Aug 21, 2023 at 05:06:46PM -0400, Sean Anderson wrote: > On 8/21/23 15:58, Vladimir Oltean wrote: > > On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: > >> After further review, it seems the reason 28g can get away without this > >> is because there's a one-to-one mapping between protocol controllers and > >> lanes. Unfortunately, that regularity is not present for 10g. > >> > >> --Sean > > > > There are some things I saw in your phy-fsl-lynx-10g.c driver and device > > tree bindings that I don't understand (the concept of lane groups) > > Each lane group corresponds to a phy device (struct phy). For protocols > like PCIe or XAUI which can use multiple lanes, this lets the driver > coordinate configuring all lanes at once in the correct order. For PCIe I admit that I don't know. I don't even know if there's any valid (current or future) use case for having the PCIe controller have a phandle to the SerDes. Everything else below in my reply assumes Ethernet. > > and > > I'm not sure if they're related with what you're saying here, so if you > > could elaborate a bit more (ideally with an example) on the one-to-one > > mapping and the specific problems it causes, it would be great. > > For e.g. the LS2088A, SerDes1 lanes H-A use SG1-8 and XFI1-8. SerDes2 > lanes A-H use SG9-16 and XFI9-16. Each lane has its own controller, and > the mapping is 1-to-1. In the PCCRs, each controller uses the same > value, and is mapped in a regular way. So you can go directly from the > lane number to the right value to mask in the PCCR, with a very simple > translation scheme. > > For e.g. the LS1046A, SerDes1 lane D uses XFI.9 (aka XFIA) and lane C > uses XFI.10 (aka XFIB). This is the opposite of how SerDes1 lanes A-D > use SGMII.9, .10, .5, and .6 (aka SGMIIA-D). > > For e.g. the T4240, SerDes1 lanes A-H use sg1.5, .6, .10, .9, .1, .2, > .3, .4 (aka SGMII E, F, H, G, A, B, C, D). > > For e.g. the B4860, SerDes lanes A uses sgmii1 or sgmii5 and B uses > sgmii2 or sgmii6. The MAC selected is determined based on the value > programmed into PCCR2. It's so exceedingly unlikely that B4860 will gain support for anything new, that it's not even worth talking about it, or even considering it in the design of a new driver. Just forget about it. Let's concentrate on the Layerscapes, and on the T series to the extent that we're not going out of our way to support them with a fairly simple design. In the Lynx 10G block guide that I have, PCCR2 is a register that does something completely different from Ethernet. I'm not sure if B4860 has a Lynx 10G block and not something else. > While I appreciate that your hardware engineers did a better job for > 28g, many 10g serdes arbitrarily map lanes to protocol controllers. > I think the mapping is too irregular to tame, and it is better to say > "if you want this configuration, program this value". Ok, but that's a lateral argument (or I'm not understanding the connection). Some maintainers (Mark Brown for sure, from my personal experience) prefer that expert-level knowledge of hardware should be hardcoded into the kernel driver based on known stuff such as the SoC-specific compatible string. I certainly share the same view. With your case, I think that argument is even more pertinent, because IIUC, the lane group protocols won't be put in the SoC .dtsi (so as to be written only once), but in the board device trees (since the available protocols invariably depend upon the board provisioning). So, non-expert board device tree writers will have to know what's with the PCCR stuff. Pretty brain-intensive. > > I may be off with my understanding of the regularity you are talking about, > > but the LX2160 (and Lynx 28G block) also has multi-lane protocols like 40G, > > 100G, assuming that's what you are talking about. I haven't started yet > > working on those for the mtip_backplane driver, but I'm not currently > > seeing a problem with the architecture where a phy_device represents a > > single lane that's part of a multi-lane port, and not an entire group. > > Resetting one lane in a group will reset the rest, which could confuse > the driver. Additionally, treating the lanes as one phy lets us set the > reset direction and first lane bits correctly. Yeah, in theory that is probably correct, but in practice can't we hide our head in the sand and say that the "phys" phandles have to have the lanes in the same order as LNmGCR0[1STLANE] expects them (which is also the "natural" order as the SoC RM describes it)? With a "for" loop implementation in the MAC, that would work just fine 100% of the time. Doing more intricate massaging of the "phys" in the consumer, and you're just asking for trouble. My 2 cents. Sure, it's the same kind of ask of a board device tree writer as "hey, please give me a good PCCR value", but I honestly think that the head scratching will be much less severe. > > In my imagination, there are 2 cases: > > - all 4 lanes are managed by the single dpaa2-mac consumer (which has 4 > > phandles, and iterates over them with a "for" loop) > > - each of the 4 lanes is managed by the respective backplane AN/LT core, > > and thus, there's one phandle to each lane > > By doing the grouping in the driver, we also simplify the consumer > implementation. The MAC can always use a single phy, without worrying > about the actual number of lanes. This matches the hardware, since the > MAC is going to talk XGMII (or whatever) to the protocol controller > anyway. XGMII is the link between the MAC and the PCS, but the "phys" phandle to the SerDes gives insight to the MAC driver way beyond the PCS layer. That kinda invalidates the idea that "you don't need to worry about the actual number of lanes". When you're a MAC driver with an XLAUI link and you need insight into the PMA/PMD layer, you'd better not be surprised about the fact that there are 4 lanes, at the very least? > I think it will be a lot easier to add multi-lane support with this > method because it gives the driver more information about what's going > on. The driver can control the whole configuration/reset process and the > timing. Also, I'm thinking that if you support multi-lane (which dpaa2-mac currently doesn't, even in LSDK), you can't avoid multiple "phys" phandles in dpaa2-mac, and a "for" loop, eventually, anyway. That's because if your lanes have protocol retimers on them, those are going to be modeled as generic PHYs too. And those will not be bundled in these "groups", because they might be one chip per lane. The retimer thing isn't theoretical, but, due to reasons independent of NXP, we lack the ability to provide an upstream user of the "lane retimer as generic PHY" functionality in dpaa2-mac. So it stays downstream for now. https://github.com/nxp-qoriq/linux/commit/627c5f626a13657f46f68b90882f329310e0e22f So, if you're thinking of easing the work of the consumer side, I'm not sure that the gains will be that high. Otherwise, I will repeat the idea that lynx-10g and lynx-28g should be treated in unison, because some drivers (dpaa2-mac, mtip_backplane) will have to interface with both, and I don't really believe that major deviations in software architecture between the 2 SerDes drivers are justifiable in any way (multi-protocol handled differently, for example).
On 8/21/23 18:48, Vladimir Oltean wrote: > On Mon, Aug 21, 2023 at 05:06:46PM -0400, Sean Anderson wrote: >> On 8/21/23 15:58, Vladimir Oltean wrote: >> > On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: >> >> After further review, it seems the reason 28g can get away without this >> >> is because there's a one-to-one mapping between protocol controllers and >> >> lanes. Unfortunately, that regularity is not present for 10g. >> >> >> >> --Sean >> > >> > There are some things I saw in your phy-fsl-lynx-10g.c driver and device >> > tree bindings that I don't understand (the concept of lane groups) >> >> Each lane group corresponds to a phy device (struct phy). For protocols >> like PCIe or XAUI which can use multiple lanes, this lets the driver >> coordinate configuring all lanes at once in the correct order. > > For PCIe I admit that I don't know. I don't even know if there's any > valid (current or future) use case for having the PCIe controller have a > phandle to the SerDes. Everything else below in my reply assumes Ethernet. One use case could be selecting PCIe/SATA as appropriate for an M.2 card. Another use case could be allocating lanes to different slots based on card presence (e.g. 1 card use x4, 2+ cards use x1). I recently bought a motherboard whose manual says | PCI_E4 [normally x4] will run x1 speed when installing devices in PCI_E2/ | PCI_E3/ PCI_E5 slot [all x1]. which implies exactly this sort of design. >> > and >> > I'm not sure if they're related with what you're saying here, so if you >> > could elaborate a bit more (ideally with an example) on the one-to-one >> > mapping and the specific problems it causes, it would be great. >> >> For e.g. the LS2088A, SerDes1 lanes H-A use SG1-8 and XFI1-8. SerDes2 >> lanes A-H use SG9-16 and XFI9-16. Each lane has its own controller, and >> the mapping is 1-to-1. In the PCCRs, each controller uses the same >> value, and is mapped in a regular way. So you can go directly from the >> lane number to the right value to mask in the PCCR, with a very simple >> translation scheme. >> >> For e.g. the LS1046A, SerDes1 lane D uses XFI.9 (aka XFIA) and lane C >> uses XFI.10 (aka XFIB). This is the opposite of how SerDes1 lanes A-D >> use SGMII.9, .10, .5, and .6 (aka SGMIIA-D). >> >> For e.g. the T4240, SerDes1 lanes A-H use sg1.5, .6, .10, .9, .1, .2, >> .3, .4 (aka SGMII E, F, H, G, A, B, C, D). >> >> For e.g. the B4860, SerDes lanes A uses sgmii1 or sgmii5 and B uses >> sgmii2 or sgmii6. The MAC selected is determined based on the value >> programmed into PCCR2. > > It's so exceedingly unlikely that B4860 will gain support for anything > new, that it's not even worth talking about it, or even considering it > in the design of a new driver. Just forget about it. > > Let's concentrate on the Layerscapes, and on the T series to the extent > that we're not going out of our way to support them with a fairly simple > design. Well, these are just easy ways to show the oddities in the PCCRs. I could have made the same points with the various Layerscapes. > In the Lynx 10G block guide that I have, PCCR2 is a register that does > something completely different from Ethernet. I'm not sure if B4860 has > a Lynx 10G block and not something else. T-series SoCs use a different PCCR layout than Layerscape, despite using the same registers in the rest of the SerDes. The LS1021 also uses this scheme, so it's not just T-series (but it's close enough). This is why I had an option for different PCCR configuration functions in earlier versions of this series, so if someone wanted they could easily add T-series support. >> While I appreciate that your hardware engineers did a better job for >> 28g, many 10g serdes arbitrarily map lanes to protocol controllers. >> I think the mapping is too irregular to tame, and it is better to say >> "if you want this configuration, program this value". > > Ok, but that's a lateral argument (or I'm not understanding the connection). To restate, there's no systemic organization to the PCCRs. The driver configuration should reflect this and allow arbitrary mappings. > Some maintainers (Mark Brown for sure, from my personal experience) prefer > that expert-level knowledge of hardware should be hardcoded into the kernel > driver based on known stuff such as the SoC-specific compatible string. > I certainly share the same view. > > With your case, I think that argument is even more pertinent, because > IIUC, the lane group protocols won't be put in the SoC .dtsi (so as to > be written only once), but in the board device trees (since the > available protocols invariably depend upon the board provisioning). > So, non-expert board device tree writers will have to know what's with > the PCCR stuff. Pretty brain-intensive. The idea is to stick all the PCCR stuff in the SoC devicetree, and the board-level devicetrees just set up the clocks and pick which MACs use which phys. Have a look at patches 10 and 15 of this series for some typical board configurations. I think it's pretty simple, since all the complexity is in the SoC dt. That said, I originally had the driver set up so that everything was based on the compatible, but I had to change that because it was nacked by the devicetree people. >> > I may be off with my understanding of the regularity you are talking about, >> > but the LX2160 (and Lynx 28G block) also has multi-lane protocols like 40G, >> > 100G, assuming that's what you are talking about. I haven't started yet >> > working on those for the mtip_backplane driver, but I'm not currently >> > seeing a problem with the architecture where a phy_device represents a >> > single lane that's part of a multi-lane port, and not an entire group. >> >> Resetting one lane in a group will reset the rest, which could confuse >> the driver. Additionally, treating the lanes as one phy lets us set the >> reset direction and first lane bits correctly. > > Yeah, in theory that is probably correct, but in practice can't we hide > our head in the sand and say that the "phys" phandles have to have the > lanes in the same order as LNmGCR0[1STLANE] expects them (which is also > the "natural" order as the SoC RM describes it)? With a "for" loop > implementation in the MAC, that would work just fine 100% of the time. > Doing more intricate massaging of the "phys" in the consumer, and you're > just asking for trouble. My 2 cents. Yeah, but from the perspective of the driver, if we have one phy per lane we don't get any indication from the subsystem that we are doing a multi-lane configuration. So we need to stick this sort of thing into the phy handle. But IMO we can do all this in the driver and the board integrator never has to worry about it. > Sure, it's the same kind of ask of a board device tree writer as "hey, > please give me a good PCCR value", but I honestly think that the head > scratching will be much less severe. > >> > In my imagination, there are 2 cases: >> > - all 4 lanes are managed by the single dpaa2-mac consumer (which has 4 >> > phandles, and iterates over them with a "for" loop) >> > - each of the 4 lanes is managed by the respective backplane AN/LT core, >> > and thus, there's one phandle to each lane >> >> By doing the grouping in the driver, we also simplify the consumer >> implementation. The MAC can always use a single phy, without worrying >> about the actual number of lanes. This matches the hardware, since the >> MAC is going to talk XGMII (or whatever) to the protocol controller >> anyway. > > XGMII is the link between the MAC and the PCS, but the "phys" phandle to > the SerDes gives insight to the MAC driver way beyond the PCS layer. > That kinda invalidates the idea that "you don't need to worry about the > actual number of lanes". When you're a MAC driver with an XLAUI link and > you need insight into the PMA/PMD layer, you'd better not be surprised > about the fact that there are 4 lanes, at the very least? Well, this is why they are condensed into a "lane group". From the MAC's perspective the whole thing is opaque, and gets handled by the phy subsystem. >> I think it will be a lot easier to add multi-lane support with this >> method because it gives the driver more information about what's going >> on. The driver can control the whole configuration/reset process and the >> timing. > > Also, I'm thinking that if you support multi-lane (which dpaa2-mac currently > doesn't, even in LSDK), you can't avoid multiple "phys" phandles in dpaa2-mac, > and a "for" loop, eventually, anyway. That's because if your lanes have protocol > retimers on them, those are going to be modeled as generic PHYs too. And those > will not be bundled in these "groups", because they might be one chip per lane. > > The retimer thing isn't theoretical, but, due to reasons independent of NXP, > we lack the ability to provide an upstream user of the "lane retimer as > generic PHY" functionality in dpaa2-mac. So it stays downstream for now. > https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2fgithub.com%2fnxp%2dqoriq%2flinux%2fcommit%2f627c5f626a13657f46f68b90882f329310e0e22f&umid=54bd2b00-07e7-4f55-8e2a-ed7b7cf7d142&auth=d807158c60b7d2502abde8a2fc01f40662980862-a6780f8e227e850b7785d5afbae1abed18ded9d9 > > So, if you're thinking of easing the work of the consumer side, I'm not > sure that the gains will be that high. Well, FWIW those serdes don't need good coordination. That said, I think it might be interesting to have some subsystem-level support for this, much like clock groups. > Otherwise, I will repeat the idea that lynx-10g and lynx-28g should be > treated in unison, because some drivers (dpaa2-mac, mtip_backplane) will > have to interface with both, and I don't really believe that major deviations > in software architecture between the 2 SerDes drivers are justifiable in > any way (multi-protocol handled differently, for example). Well, I think we should take the opportunity to think about the hardware which exists and how we plan to model it. IMO grouping lanes into a single phy simplifies both the phy driver and the mac driver. --Sean
On Mon, Aug 21, 2023 at 07:39:15PM -0400, Sean Anderson wrote: > Well, I think we should take the opportunity to think about the hardware > which exists and how we plan to model it. IMO grouping lanes into a > single phy simplifies both the phy driver and the mac driver. Ok, but ungrouped for backplane and grouped for !backplane? For the KR link modes, parallel link training, with separate consumers per lanes in a group, will be needed per lane.
On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: > On 8/21/23 14:13, Ioana Ciornei wrote: > > On Mon, Aug 21, 2023 at 01:45:44PM -0400, Sean Anderson wrote: > >> Well, we have two pieces of information we need > >> > >> - What values do we need to program in the PCCRs to select a particular > >> mode? This includes whether to e.g. set the KX bits. > >> - Implied by the above, what protocols are supported on which lanes? > >> This is not strictly necessary, but will certainly solve a lot of > >> headscratching. > >> > >> This information varies between different socs, and different serdes on > >> the same socs. We can't really look at the RCW or the clocks and figure > >> out what we need to program. So what are our options? > >> > >> - We can have a separate compatible for each serdes on each SoC (e.g. > >> "fsl,lynx-10g-a"). This was rejected by the devicetree maintainers. I previously took this statement at face value and didn't further investigate. After a bit of digging through the first versions of this patch set it's evident that you left out a big piece of information. The devicetree maintainers have indeed rejected compatible strings of the "fsl,<soc-name>-serdes-<instance>" form but they also suggested to move the numbering to a property instead: https://lore.kernel.org/all/db9d9455-37af-1616-8f7f-3d752e7930f1@linaro.org/ But instead of doing that, you chose to move all the different details that vary between SerDes blocks/SoCs from the driver to the DTS. I don't see that this was done in response to explicit feedback. > >> - We can have one compatible for each SoC, and determine the serdes > >> based on the address. I would like to avoid this... > > > > To me this really seems like a straightforward approach. > > Indeed it would be straightforward, but what's the point of having a > devicetree in the first place then? We could just go back to being a > (non-dt) platform device. > I am confused why you are now so adamant to have these details into the DTS. Your first approach was to put them into the driver, not the DTS: https://lore.kernel.org/netdev/20220628221404.1444200-5-sean.anderson@seco.com/ And this approach could still work now and get accepted by the device tree maintainers. The only change that would be needed is to add a property like "fsl,serdes-block-id = <1>". > >> - We can stick all the details which vary between serdes/socs into the > >> device tree. This is very flexible, since supporting new SoCs is > >> mostly a matter of adding a new compatible and writing a new > >> devicetree. On the other hand, if you have a bug in your devicetree, > >> it's not easy to fix it in the kernel. > >> - Just don't support protocol switching. The 28G driver does this, which > >> is why it only has one compatible. However, supporting protocol > >> switching is a core goal of this driver, so dropping support is not an > >> option. > >> Ioana
On 8/22/23 10:55, Ioana Ciornei wrote: > On Mon, Aug 21, 2023 at 02:46:53PM -0400, Sean Anderson wrote: >> On 8/21/23 14:13, Ioana Ciornei wrote: >> > On Mon, Aug 21, 2023 at 01:45:44PM -0400, Sean Anderson wrote: >> >> Well, we have two pieces of information we need >> >> >> >> - What values do we need to program in the PCCRs to select a particular >> >> mode? This includes whether to e.g. set the KX bits. >> >> - Implied by the above, what protocols are supported on which lanes? >> >> This is not strictly necessary, but will certainly solve a lot of >> >> headscratching. >> >> >> >> This information varies between different socs, and different serdes on >> >> the same socs. We can't really look at the RCW or the clocks and figure >> >> out what we need to program. So what are our options? >> >> >> >> - We can have a separate compatible for each serdes on each SoC (e.g. >> >> "fsl,lynx-10g-a"). This was rejected by the devicetree maintainers. > > I previously took this statement at face value and didn't further > investigate. After a bit of digging through the first versions of this > patch set it's evident that you left out a big piece of information. > > The devicetree maintainers have indeed rejected compatible strings of > the "fsl,<soc-name>-serdes-<instance>" form but they also suggested to > move the numbering to a property instead: > > https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2flore.kernel.org%2fall%2fdb9d9455%2d37af%2d1616%2d8f7f%2d3d752e7930f1%40linaro.org%2f&umid=2d629417-3b95-49e4-8cdb-34737cc93582&auth=d807158c60b7d2502abde8a2fc01f40662980862-895c2dfe1c33719569d44ae2b51e21f626f39d39 > > But instead of doing that, you chose to move all the different details > that vary between SerDes blocks/SoCs from the driver to the DTS. I don't > see that this was done in response to explicit feedback. > >> >> - We can have one compatible for each SoC, and determine the serdes >> >> based on the address. I would like to avoid this... >> > >> > To me this really seems like a straightforward approach. >> >> Indeed it would be straightforward, but what's the point of having a >> devicetree in the first place then? We could just go back to being a >> (non-dt) platform device. >> > > I am confused why you are now so adamant to have these details into the > DTS. Your first approach was to put them into the driver, not the DTS: > > https://cas5-0-urlprotect.trendmicro.com:443/wis/clicktime/v1/query?url=https%3a%2f%2flore.kernel.org%2fnetdev%2f20220628221404.1444200%2d5%2dsean.anderson%40seco.com%2f&umid=2d629417-3b95-49e4-8cdb-34737cc93582&auth=d807158c60b7d2502abde8a2fc01f40662980862-64ea8fa45172282f676b7463a5401e8a7c5bdcbf > > And this approach could still work now and get accepted by the device > tree maintainers. The only change that would be needed is to add a > property like "fsl,serdes-block-id = <1>". https://lore.kernel.org/linux-phy/1c2bbc12-0aa5-6d2a-c701-577ce70f7502@linaro.org/ Despite what he says in your link, I explicitly proposed doing exactly that and he rejected it. I suspect that despite accusing me of "twisting" the conversation, he did not clearly remember that exchange... That said, maybe we could do something like serdes: phy@1ea0000 { compatible = "fsl,ls1046a-serdes"; reg = <0x1ea0000 0x1000>, <0x1eb0000 0x1000>; }; --Sean
On 8/21/23 19:59, Vladimir Oltean wrote: > On Mon, Aug 21, 2023 at 07:39:15PM -0400, Sean Anderson wrote: >> Well, I think we should take the opportunity to think about the hardware >> which exists and how we plan to model it. IMO grouping lanes into a >> single phy simplifies both the phy driver and the mac driver. > > Ok, but ungrouped for backplane and grouped for !backplane? For the KR > link modes, parallel link training, with separate consumers per lanes in > a group, will be needed per lane. Hm, this is the sort of thing I hadn't considered since separate link training isn't necessary for lynx 10g. But couldn't this be done by adding a "lane" parameter to phy_configure_opts_xgkr? Although, I am not sure how the driver is supposed to figure out what coefficients to use. c73 implies that the training frame should be sent on each lane. So I expected that there would be four copies of the link coefficient registers. However, when reading the LX2160ARM, I only saw one set of registers (e.g. 26.6.3.3). So is link training done serially? I didn't see anything like a "lane select" field. --Sean
On Thu, Aug 24, 2023 at 06:09:52PM -0400, Sean Anderson wrote: > On 8/21/23 19:59, Vladimir Oltean wrote: > > On Mon, Aug 21, 2023 at 07:39:15PM -0400, Sean Anderson wrote: > >> Well, I think we should take the opportunity to think about the hardware > >> which exists and how we plan to model it. IMO grouping lanes into a > >> single phy simplifies both the phy driver and the mac driver. > > > > Ok, but ungrouped for backplane and grouped for !backplane? For the KR > > link modes, parallel link training, with separate consumers per lanes in > > a group, will be needed per lane. > > Hm, this is the sort of thing I hadn't considered since separate link > training isn't necessary for lynx 10g. But couldn't this be done by > adding a "lane" parameter to phy_configure_opts_xgkr? > > Although, I am not sure how the driver is supposed to figure out what > coefficients to use. c73 implies that the training frame should be sent > on each lane. So I expected that there would be four copies of the > link coefficient registers. However, when reading the LX2160ARM, I only > saw one set of registers (e.g. 26.6.3.3). So is link training done > serially? I didn't see anything like a "lane select" field. > > --Sean There is one AN/LT block replicated for each lane, even for multi-lane backplane protocols. The primary (first) AN/LT block handles C73 autoneg + C73 link training on that lane, and the secondary AN/LT blocks handle just link training on their respective lanes. In other words, each AN/LT block needs to interact with just its lane (SerDes PHY). A "lane" parameter could be added to phy_configure_opts_xgkr to work around the "grouped lanes" design, but it would complicate the consumer implementation, since the AN/LT block does not otherwise need to know what is the index of the SerDes lane it is attached to (so it would need something like an extra device tree property). C72 link training is independent on each lane, has independent AN/LT block MDIO registers, independent SerDes lane registers, and independent training frame exchanges. There is no "lane select" field. You can see the "LX2160A lanes A, B, C, D with SerDes 1 protocol 19: dpmac2 uses 40GBase-KR4" example in my backplane dt-bindings patch, which shows how on dpmac2's internal MDIO bus, there are AN/LT devices at MDIO addresses 7, 6, 5 and 4, one for each lane. I know that Lynx 10G doesn't do multi-lane backplane, but I wouldn't want Lynx 10G and Lynx 28G to have different designs when it comes to their handling of multi-lane. A single design that works for both would be great.
Hi Sean, On Thu, Aug 10, 2023 at 03:58:36PM -0400, Sean Anderson wrote: > I can look into doing this. It will be in my free time, so it will > likely be a bit before I can update this series. I was expecting you'd ask some clarification questions about the RCW override procedure that I've informally described over email, so I guess you haven't spent any more time on this. I'm letting you know that very soon, I will have to start my work on porting the backplane driver posted here: https://patchwork.kernel.org/project/netdevbpf/cover/20230817150644.3605105-1-vladimir.oltean@nxp.com/ to the Lynx 10G SoCs. And for that, I need a SerDes driver as a base :) I was wondering how inclined are you to respond positively to the feedback that the lynx-10g driver should have a look and feel as close as possible to lynx-28g, given that they're very similar. Because internally within NXP, we do have a version of the lynx-10g driver which is contemporary with lynx-28g from mainline, but we didn't publish it because protocol changes didn't work (for the same reason that they don't work with your driver). With that driver, you can think of the feedback about the similar look and feel as being "implicitly applied" (being written by the same author), so I'm starting to consider more and more seriously the option of basing my work on that instead of your v14 (on which I'd need to spend extra time to modify the dt-bindings with PCCRs, concept of lane groups, concept of PLL CCF driver, etc). What are your thoughts?