| Message ID | 20231113185607.1756-1-james.quinlan@broadcom.com |
|---|---|
| Headers | show |
| Series | PCI: brcmstb: Configure appropriate HW CLKREQ# mode | expand |
On Mon, 13 Nov 2023 13:56:05 -0500, Jim Quinlan wrote: > The Broadcom STB/CM PCIe HW -- a core that is also used by RPi SOCs -- > requires the driver to deliberately place the RC HW one of three CLKREQ# > modes. The "brcm,clkreq-mode" property allows the user to override the > default setting. If this property is omitted, the default mode shall be > "default". > > Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com> > --- > .../devicetree/bindings/pci/brcm,stb-pcie.yaml | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > Reviewed-by: Rob Herring <robh@kernel.org>
On 11/26/23 12:19, Cyril Brulebois wrote: > Hi Jim, > > Jim Quinlan <james.quinlan@broadcom.com> (2023-11-13): >> V8 -- Un-advertise L1SS capability when in "no-l1ss" mode (Bjorn) >> -- Squashed last two commits of v7 (Bjorn) >> -- Fix DT binding description text wrapping (Bjorn) >> -- Fix incorrect Spec reference (Bjorn) >> s/PCIe Spec/PCIe Express Mini CEM 2.1 specification/ >> -- Text substitutions (Bjorn) >> s/WRT/With respect to/ >> s/Tclron/T_CLRon/ >> >> v7 -- Manivannan Sadhasivam suggested (a) making the property look like a >> network phy-mode and (b) keeping the code simple (not counting clkreq >> signal appearances, un-advertising capabilites, etc). This is >> what I have done. The property is now "brcm,clkreq-mode" and >> the values may be one of "safe", "default", and "no-l1ss". The >> default setting is to employ the most capable power savings mode. > > Still: > > Tested-by: Cyril Brulebois <cyril@debamax.com> Thanks Cyril! Bjorn, Lorenzo, any chance this can be applied soon? Thanks!
Hello, > V8 -- Un-advertise L1SS capability when in "no-l1ss" mode (Bjorn) > -- Squashed last two commits of v7 (Bjorn) > -- Fix DT binding description text wrapping (Bjorn) > -- Fix incorrect Spec reference (Bjorn) > s/PCIe Spec/PCIe Express Mini CEM 2.1 specification/ > -- Text substitutions (Bjorn) > s/WRT/With respect to/ > s/Tclron/T_CLRon/ > > v7 -- Manivannan Sadhasivam suggested (a) making the property look like a > network phy-mode and (b) keeping the code simple (not counting clkreq > signal appearances, un-advertising capabilites, etc). This is > what I have done. The property is now "brcm,clkreq-mode" and > the values may be one of "safe", "default", and "no-l1ss". The > default setting is to employ the most capable power savings mode. > > v6 -- No code has been changed. > -- Changed commit subject and comment in "#PERST" commit (Bjorn, Cyril) > -- Changed sign-off and author email address for all commits. > This was due to a change in Broadcom's upstreaming policy. > > v5 -- Remove DT property "brcm,completion-timeout-us" from > "DT bindings" commit. Although this error may be reported > as a completion timeout, its cause was traced to an > internal bus timeout which may occur even when there is > no PCIe access being processed. We set a timeout of four > seconds only if we are operating in "L1SS CLKREQ#" mode. > -- Correct CEM 2.0 reference provided by HW engineer, > s/3.2.5.2.5/3.2.5.2.2/ (Bjorn) > -- Add newline to dev_info() string (Stefan) > -- Change variable rval to unsigned (Stefan) > -- s/implementaion/implementation/ (Bjorn) > -- s/superpowersave/powersupersave/ (Bjorn) > -- Slightly modify message on "PERST#" commit. > -- Rebase to torvalds master > > v4 -- New commit that asserts PERST# for 2711/RPi SOCs at PCIe RC > driver probe() time. This is done in Raspian Linux and its > absence may be the cause of a failing test case. > -- New commit that removes stale comment. > > v3 -- Rewrote commit msgs and comments refering panics if L1SS > is enabled/disabled; the code snippet that unadvertises L1SS > eliminates the panic scenario. (Bjorn) > -- Add reference for "400ns of CLKREQ# assertion" blurb (Bjorn) > -- Put binding names in DT commit Subject (Bjorn) > -- Add a verb to a commit's subject line (Bjorn) > -- s/accomodat(\w+)/accommodat$1/g (Bjorn) > -- Rewrote commit msgs and comments refering panics if L1SS > is enabled/disabled; the code snippet that unadvertises L1SS > eliminates the panic scenario. (Bjorn) > > v2 -- Changed binding property 'brcm,completion-timeout-msec' to > 'brcm,completion-timeout-us'. (StefanW for standard suffix). > -- Warn when clamping timeout value, and include clamped > region in message. Also add min and max in YAML. (StefanW) > -- Qualify description of "brcm,completion-timeout-us" so that > it refers to PCIe transactions. (StefanW) > -- Remvove mention of Linux specifics in binding description. (StefanW) > -- s/clkreq#/CLKREQ#/g (Bjorn) > -- Refactor completion-timeout-us code to compare max and min to > value given by the property (as opposed to the computed value). > > v1 -- The current driver assumes the downstream devices can > provide CLKREQ# for ASPM. These commits accomodate devices > w/ or w/o clkreq# and also handle L1SS-capable devices. > > -- The Raspian Linux folks have already been using a PCIe RC > property "brcm,enable-l1ss". These commits use the same > property, in a backward-compatible manner, and the implementaion > adds more detail and also automatically identifies devices w/o > a clkreq# signal, i.e. most devices plugged into an RPi CM4 > IO board. Applied to controller/broadcom, thank you! [01/02] dt-bindings: PCI: brcmstb: Add property "brcm,clkreq-mode" https://git.kernel.org/pci/pci/c/14b15aeb3628 [02/02] PCI: brcmstb: Configure HW CLKREQ# mode appropriate for downstream device https://git.kernel.org/pci/pci/c/e2596dcf1e9d Krzysztof
V8 -- Un-advertise L1SS capability when in "no-l1ss" mode (Bjorn) -- Squashed last two commits of v7 (Bjorn) -- Fix DT binding description text wrapping (Bjorn) -- Fix incorrect Spec reference (Bjorn) s/PCIe Spec/PCIe Express Mini CEM 2.1 specification/ -- Text substitutions (Bjorn) s/WRT/With respect to/ s/Tclron/T_CLRon/ v7 -- Manivannan Sadhasivam suggested (a) making the property look like a network phy-mode and (b) keeping the code simple (not counting clkreq signal appearances, un-advertising capabilites, etc). This is what I have done. The property is now "brcm,clkreq-mode" and the values may be one of "safe", "default", and "no-l1ss". The default setting is to employ the most capable power savings mode. v6 -- No code has been changed. -- Changed commit subject and comment in "#PERST" commit (Bjorn, Cyril) -- Changed sign-off and author email address for all commits. This was due to a change in Broadcom's upstreaming policy. v5 -- Remove DT property "brcm,completion-timeout-us" from "DT bindings" commit. Although this error may be reported as a completion timeout, its cause was traced to an internal bus timeout which may occur even when there is no PCIe access being processed. We set a timeout of four seconds only if we are operating in "L1SS CLKREQ#" mode. -- Correct CEM 2.0 reference provided by HW engineer, s/3.2.5.2.5/3.2.5.2.2/ (Bjorn) -- Add newline to dev_info() string (Stefan) -- Change variable rval to unsigned (Stefan) -- s/implementaion/implementation/ (Bjorn) -- s/superpowersave/powersupersave/ (Bjorn) -- Slightly modify message on "PERST#" commit. -- Rebase to torvalds master v4 -- New commit that asserts PERST# for 2711/RPi SOCs at PCIe RC driver probe() time. This is done in Raspian Linux and its absence may be the cause of a failing test case. -- New commit that removes stale comment. v3 -- Rewrote commit msgs and comments refering panics if L1SS is enabled/disabled; the code snippet that unadvertises L1SS eliminates the panic scenario. (Bjorn) -- Add reference for "400ns of CLKREQ# assertion" blurb (Bjorn) -- Put binding names in DT commit Subject (Bjorn) -- Add a verb to a commit's subject line (Bjorn) -- s/accomodat(\w+)/accommodat$1/g (Bjorn) -- Rewrote commit msgs and comments refering panics if L1SS is enabled/disabled; the code snippet that unadvertises L1SS eliminates the panic scenario. (Bjorn) v2 -- Changed binding property 'brcm,completion-timeout-msec' to 'brcm,completion-timeout-us'. (StefanW for standard suffix). -- Warn when clamping timeout value, and include clamped region in message. Also add min and max in YAML. (StefanW) -- Qualify description of "brcm,completion-timeout-us" so that it refers to PCIe transactions. (StefanW) -- Remvove mention of Linux specifics in binding description. (StefanW) -- s/clkreq#/CLKREQ#/g (Bjorn) -- Refactor completion-timeout-us code to compare max and min to value given by the property (as opposed to the computed value). v1 -- The current driver assumes the downstream devices can provide CLKREQ# for ASPM. These commits accomodate devices w/ or w/o clkreq# and also handle L1SS-capable devices. -- The Raspian Linux folks have already been using a PCIe RC property "brcm,enable-l1ss". These commits use the same property, in a backward-compatible manner, and the implementaion adds more detail and also automatically identifies devices w/o a clkreq# signal, i.e. most devices plugged into an RPi CM4 IO board. Jim Quinlan (2): dt-bindings: PCI: brcmstb: Add property "brcm,clkreq-mode" PCI: brcmstb: Configure HW CLKREQ# mode appropriate for downstream device .../bindings/pci/brcm,stb-pcie.yaml | 18 ++++ drivers/pci/controller/pcie-brcmstb.c | 96 +++++++++++++++++-- 2 files changed, 104 insertions(+), 10 deletions(-) base-commit: 305230142ae0637213bf6e04f6d9f10bbcb74af8