| Message ID | 20230517152513.27922-3-marex@denx.de |
|---|---|
| State | New |
| Headers | show |
| Series | None | expand |
On 5/17/23 17:25, Marek Vasut wrote: > Add nvmem-syscon subnode to expose TAMP_BKPxR register 19 to user space. > This register contains U-Boot boot counter, by exposing it to user space > the user space can reset the boot counter. > > Read access example: > " > $ hexdump -vC /sys/bus/nvmem/devices/5c00a000.tamp\:nvmem0/nvmem > 00000000 0c 00 c4 b0 > " > > Signed-off-by: Marek Vasut <marex@denx.de> > --- > Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> > Cc: Conor Dooley <conor+dt@kernel.org> > Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> > Cc: Marek Vasut <marex@denx.de> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > Cc: devicetree@vger.kernel.org > Cc: kernel@dh-electronics.com > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-stm32@st-md-mailman.stormreply.com > --- > V2: No change > --- > arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 11 +++++++++++ > arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 11 +++++++++++ > 2 files changed, 22 insertions(+) > > diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > index 74735552f4803..b2557bb718f52 100644 > --- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > +++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > @@ -537,6 +537,17 @@ &sdmmc3 { > status = "okay"; > }; > > +&tamp { > + #address-cells = <1>; > + #size-cells = <1>; > + > + /* Boot counter */ > + nvmem { nvmem@14c ? > + compatible = "nvmem-syscon"; > + reg = <0x14c 0x4>; > + }; > +}; > + > &uart4 { > pinctrl-names = "default"; > pinctrl-0 = <&uart4_pins_a>; > diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > index bba19f21e5277..864960387e634 100644 > --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > @@ -269,3 +269,14 @@ &rng1 { > &rtc { > status = "okay"; > }; > + > +&tamp { > + #address-cells = <1>; > + #size-cells = <1>; > + > + /* Boot counter */ > + nvmem { nvmem@14c ? > + compatible = "nvmem-syscon"; > + reg = <0x14c 0x4>; > + }; > +};
Hi Marek, > From: Marek Vasut <marex@denx.de> > Sent: Wednesday, May 17, 2023 5:25 PM > Subject: [PATCH v2 3/3] ARM: dts: stm32: Add nvmem-syscon node to TAMP to > expose boot count on DHSOM > > Add nvmem-syscon subnode to expose TAMP_BKPxR register 19 to user space. > This register contains U-Boot boot counter, by exposing it to user space the user > space can reset the boot counter. > > Read access example: > " > $ hexdump -vC /sys/bus/nvmem/devices/5c00a000.tamp\:nvmem0/nvmem > 00000000 0c 00 c4 b0 > " > > Signed-off-by: Marek Vasut <marex@denx.de> > --- > Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> > Cc: Conor Dooley <conor+dt@kernel.org> > Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> > Cc: Marek Vasut <marex@denx.de> > Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > Cc: devicetree@vger.kernel.org > Cc: kernel@dh-electronics.com > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-stm32@st-md-mailman.stormreply.com > --- > V2: No change > --- > arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 11 +++++++++++ > arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 11 +++++++++++ > 2 files changed, 22 insertions(+) > > diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > index 74735552f4803..b2557bb718f52 100644 > --- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > +++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi > @@ -537,6 +537,17 @@ &sdmmc3 { > status = "okay"; > }; > > +&tamp { > + #address-cells = <1>; > + #size-cells = <1>; > + > + /* Boot counter */ > + nvmem { > + compatible = "nvmem-syscon"; > + reg = <0x14c 0x4>; > + }; > +}; > + > &uart4 { > pinctrl-names = "default"; > pinctrl-0 = <&uart4_pins_a>; > diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > index bba19f21e5277..864960387e634 100644 > --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi > @@ -269,3 +269,14 @@ &rng1 { > &rtc { > status = "okay"; > }; > + > +&tamp { > + #address-cells = <1>; > + #size-cells = <1>; > + > + /* Boot counter */ > + nvmem { According binding you need to add "@<reg>" => nvmem@14c And you export only TAMP_BKP19R directly in a nvmem region ? > + compatible = "nvmem-syscon"; > + reg = <0x14c 0x4>; > + }; > +}; the boot counter could be a nvem cell so you could expose other backup registers For example : &tamp { #address-cells = <1>; #size-cells = <1>; nvmem@14c { compatible = "nvmem-syscon"; reg = <0x14c 0x4>; /* Data cells */ boot_counter: boot-counter@14c { reg = <0x14c 0x4>; }; }; }; Even if you export more backup register the cell will be correctly described in DT and could be accessible directly with sysfs without managed offset in userland with https://lore.kernel.org/lkml/202305240724.z3McDuYM-lkp@intel.com/T/ Or previous serie https://lore.kernel.org/lkml/20211220064730.28806-1-zajec5@gmail.com/ for example to export all the free register: Reference: https://wiki.st.com/stm32mpu/wiki/STM32MP15_backup_registers the cell " boot-counter" will be always available for users. &tamp { #address-cells = <1>; #size-cells = <1>; /* backup register: 10 to 21 */ nvmem@0x128 { compatible = "nvmem-syscon"; reg = <0x128 0x44>; /* Data cells */ boot_counter: boot-counter@14c { reg = <0x14c 0x4>; }; boot_mode: boot-mode@150 { reg = <0x150 0x4>; }; .... }; }; Patrick > -- > 2.39.2 ST Restricted
On 5/26/23 17:28, patrick.delaunay@foss.st.com wrote: > Hi Marek, Hi, >> From: Marek Vasut <marex@denx.de> >> Sent: Wednesday, May 17, 2023 5:25 PM >> Subject: [PATCH v2 3/3] ARM: dts: stm32: Add nvmem-syscon node to TAMP to >> expose boot count on DHSOM >> >> Add nvmem-syscon subnode to expose TAMP_BKPxR register 19 to user space. >> This register contains U-Boot boot counter, by exposing it to user space the user >> space can reset the boot counter. >> >> Read access example: >> " >> $ hexdump -vC /sys/bus/nvmem/devices/5c00a000.tamp\:nvmem0/nvmem >> 00000000 0c 00 c4 b0 >> " >> >> Signed-off-by: Marek Vasut <marex@denx.de> >> --- >> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> >> Cc: Conor Dooley <conor+dt@kernel.org> >> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> >> Cc: Marek Vasut <marex@denx.de> >> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> >> Cc: Rob Herring <robh+dt@kernel.org> >> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >> Cc: devicetree@vger.kernel.org >> Cc: kernel@dh-electronics.com >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-stm32@st-md-mailman.stormreply.com >> --- >> V2: No change >> --- >> arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 11 +++++++++++ >> arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 11 +++++++++++ >> 2 files changed, 22 insertions(+) >> >> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >> b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >> index 74735552f4803..b2557bb718f52 100644 >> --- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >> +++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >> @@ -537,6 +537,17 @@ &sdmmc3 { >> status = "okay"; >> }; >> >> +&tamp { >> + #address-cells = <1>; >> + #size-cells = <1>; >> + >> + /* Boot counter */ >> + nvmem { >> + compatible = "nvmem-syscon"; >> + reg = <0x14c 0x4>; >> + }; >> +}; >> + >> &uart4 { >> pinctrl-names = "default"; >> pinctrl-0 = <&uart4_pins_a>; >> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >> b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >> index bba19f21e5277..864960387e634 100644 >> --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >> +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >> @@ -269,3 +269,14 @@ &rng1 { >> &rtc { >> status = "okay"; >> }; >> + >> +&tamp { >> + #address-cells = <1>; >> + #size-cells = <1>; >> + >> + /* Boot counter */ >> + nvmem { > > According binding you need to add "@<reg>" => nvmem@14c > > And you export only TAMP_BKP19R directly in a nvmem region ? 4 bytes is more than plenty for boot counter , yes. >> + compatible = "nvmem-syscon"; >> + reg = <0x14c 0x4>; >> + }; >> +}; > > > the boot counter could be a nvem cell so you could expose other backup registers > > For example : > > &tamp { > #address-cells = <1>; > #size-cells = <1>; > > nvmem@14c { > compatible = "nvmem-syscon"; > reg = <0x14c 0x4>; > > /* Data cells */ > boot_counter: boot-counter@14c { > reg = <0x14c 0x4>; > }; > }; > }; > > Even if you export more backup register the cell will be correctly described in DT > and could be accessible directly with sysfs without managed offset in userland > > with https://lore.kernel.org/lkml/202305240724.z3McDuYM-lkp@intel.com/T/ > Or previous serie https://lore.kernel.org/lkml/20211220064730.28806-1-zajec5@gmail.com/ > > > for example to export all the free register: > > Reference: https://wiki.st.com/stm32mpu/wiki/STM32MP15_backup_registers > > the cell " boot-counter" will be always available for users. > > &tamp { > #address-cells = <1>; > #size-cells = <1>; > > /* backup register: 10 to 21 */ > nvmem@0x128 { > compatible = "nvmem-syscon"; > reg = <0x128 0x44>; > > /* Data cells */ > boot_counter: boot-counter@14c { > reg = <0x14c 0x4>; > }; > boot_mode: boot-mode@150 { > reg = <0x150 0x4>; > }; > .... > }; > }; Sure, thanks. I'm not sure I understood the message above.
Hi, On 6/1/23 01:09, Marek Vasut wrote: > On 5/26/23 17:28, patrick.delaunay@foss.st.com wrote: >> Hi Marek, > > Hi, > >>> From: Marek Vasut <marex@denx.de> >>> Sent: Wednesday, May 17, 2023 5:25 PM >>> Subject: [PATCH v2 3/3] ARM: dts: stm32: Add nvmem-syscon node to >>> TAMP to >>> expose boot count on DHSOM >>> >>> Add nvmem-syscon subnode to expose TAMP_BKPxR register 19 to user >>> space. >>> This register contains U-Boot boot counter, by exposing it to user >>> space the user >>> space can reset the boot counter. >>> >>> Read access example: >>> " >>> $ hexdump -vC /sys/bus/nvmem/devices/5c00a000.tamp\:nvmem0/nvmem >>> 00000000 0c 00 c4 b0 >>> " >>> >>> Signed-off-by: Marek Vasut <marex@denx.de> >>> --- >>> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> >>> Cc: Conor Dooley <conor+dt@kernel.org> >>> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> >>> Cc: Marek Vasut <marex@denx.de> >>> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> >>> Cc: Rob Herring <robh+dt@kernel.org> >>> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >>> Cc: devicetree@vger.kernel.org >>> Cc: kernel@dh-electronics.com >>> Cc: linux-arm-kernel@lists.infradead.org >>> Cc: linux-stm32@st-md-mailman.stormreply.com >>> --- >>> V2: No change >>> --- >>> arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 11 +++++++++++ >>> arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 11 +++++++++++ >>> 2 files changed, 22 insertions(+) >>> >>> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >>> b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >>> index 74735552f4803..b2557bb718f52 100644 >>> --- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >>> +++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi >>> @@ -537,6 +537,17 @@ &sdmmc3 { >>> status = "okay"; >>> }; >>> >>> +&tamp { >>> + #address-cells = <1>; >>> + #size-cells = <1>; >>> + >>> + /* Boot counter */ >>> + nvmem { >>> + compatible = "nvmem-syscon"; >>> + reg = <0x14c 0x4>; >>> + }; >>> +}; >>> + >>> &uart4 { >>> pinctrl-names = "default"; >>> pinctrl-0 = <&uart4_pins_a>; >>> diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >>> b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >>> index bba19f21e5277..864960387e634 100644 >>> --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >>> +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi >>> @@ -269,3 +269,14 @@ &rng1 { >>> &rtc { >>> status = "okay"; >>> }; >>> + >>> +&tamp { >>> + #address-cells = <1>; >>> + #size-cells = <1>; >>> + >>> + /* Boot counter */ >>> + nvmem { >> >> According binding you need to add "@<reg>" => nvmem@14c >> >> And you export only TAMP_BKP19R directly in a nvmem region ? > > 4 bytes is more than plenty for boot counter , yes. > >>> + compatible = "nvmem-syscon"; >>> + reg = <0x14c 0x4>; >>> + }; >>> +}; >> >> >> the boot counter could be a nvem cell so you could expose other >> backup registers >> >> For example : >> >> &tamp { >> #address-cells = <1>; >> #size-cells = <1>; >> >> nvmem@14c { >> compatible = "nvmem-syscon"; >> reg = <0x14c 0x4>; >> >> /* Data cells */ >> boot_counter: boot-counter@14c { >> reg = <0x14c 0x4>; >> }; >> }; >> }; >> >> Even if you export more backup register the cell will be correctly >> described in DT >> and could be accessible directly with sysfs without managed offset >> in userland >> >> with https://lore.kernel.org/lkml/202305240724.z3McDuYM-lkp@intel.com/T/ >> Or previous serie >> https://lore.kernel.org/lkml/20211220064730.28806-1-zajec5@gmail.com/ >> >> >> for example to export all the free register: >> >> Reference: https://wiki.st.com/stm32mpu/wiki/STM32MP15_backup_registers >> >> the cell " boot-counter" will be always available for users. >> >> &tamp { >> #address-cells = <1>; >> #size-cells = <1>; >> >> /* backup register: 10 to 21 */ >> nvmem@0x128 { >> compatible = "nvmem-syscon"; >> reg = <0x128 0x44>; >> >> /* Data cells */ >> boot_counter: boot-counter@14c { >> reg = <0x14c 0x4>; >> }; >> boot_mode: boot-mode@150 { >> reg = <0x150 0x4>; >> }; >> .... >> }; >> }; > > Sure, thanks. I'm not sure I understood the message above. sorry if it wasn't clear TAMP register a nvmem driver = NVRAM provider => it should export ALL the free backup registers as they can used by application / kernel for many purpose.... and not only for boot counterfor you use-case So limit the exported backup register to this 4 bytes is strange for me. and COUNTER is a nvem cell = a part of backup register = TAMP_BKP19R => I agree 4 byte for this count is fine for this cell NB: today we have no means to read only one nvmem cell with sysfs API but I see this feature is proposed to have something as /sys/bus/nvmem/devices/nvmem@0x128/ => all the backup registers /sys/bus/nvmem/devices/nvmem@0x128/cells/boot-mode => only the nvmem cell used as counter I think it is more safe for long term support to manage your counter as a nvmem cell. regards Patrick
diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi index 74735552f4803..b2557bb718f52 100644 --- a/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi +++ b/arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi @@ -537,6 +537,17 @@ &sdmmc3 { status = "okay"; }; +&tamp { + #address-cells = <1>; + #size-cells = <1>; + + /* Boot counter */ + nvmem { + compatible = "nvmem-syscon"; + reg = <0x14c 0x4>; + }; +}; + &uart4 { pinctrl-names = "default"; pinctrl-0 = <&uart4_pins_a>; diff --git a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi index bba19f21e5277..864960387e634 100644 --- a/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi +++ b/arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi @@ -269,3 +269,14 @@ &rng1 { &rtc { status = "okay"; }; + +&tamp { + #address-cells = <1>; + #size-cells = <1>; + + /* Boot counter */ + nvmem { + compatible = "nvmem-syscon"; + reg = <0x14c 0x4>; + }; +};
Add nvmem-syscon subnode to expose TAMP_BKPxR register 19 to user space. This register contains U-Boot boot counter, by exposing it to user space the user space can reset the boot counter. Read access example: " $ hexdump -vC /sys/bus/nvmem/devices/5c00a000.tamp\:nvmem0/nvmem 00000000 0c 00 c4 b0 " Signed-off-by: Marek Vasut <marex@denx.de> --- Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Cc: Conor Dooley <conor+dt@kernel.org> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org> Cc: Marek Vasut <marex@denx.de> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Cc: devicetree@vger.kernel.org Cc: kernel@dh-electronics.com Cc: linux-arm-kernel@lists.infradead.org Cc: linux-stm32@st-md-mailman.stormreply.com --- V2: No change --- arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi | 11 +++++++++++ arch/arm/boot/dts/stm32mp15xx-dhcor-som.dtsi | 11 +++++++++++ 2 files changed, 22 insertions(+)