| Message ID | 1465228765-14038-3-git-send-email-sudeep.holla@arm.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Jun 06, 2016 at 04:59:24PM +0100, Sudeep Holla wrote: > The Linux AMBA framework probes the peripheral ids when adding the amba > devices very early on the boot. Generally they are on APB bus and just > require APB clocks to be on even when most of the core logic of the IP > is powered down. > > However on Juno, the entire debugsys domain needs to be ON to access > those CID/PID registers and hence broken by design. Accessing those > while debugsys power domain is off will lead to the bridge stalling the > transactions instead of returning the slave error. > > Since keeping the power domain on by default affects the core power(by > preventing cores entering deeper idle states), it's not feasible > solution. Instead we can provide arm,primecell-periphid override in the > device tree that prevents accessing the device early in the boot. > > However the power domains can be enabled whenever required using runtime > PM and associated power domains. > > Cc: Liviu Dudau <liviu.dudau@arm.com> Acked-by: Liviu Dudau <Liviu.Dudau@arm.com> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > Cc: linux-arm-kernel@lists.infradead.org > Cc: devicetree@vger.kernel.org > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > arch/arm64/boot/dts/arm/juno-base.dtsi | 13 +++++++++++++ > arch/arm64/boot/dts/arm/juno-r1.dts | 6 ++++++ > arch/arm64/boot/dts/arm/juno-r2.dts | 6 ++++++ > arch/arm64/boot/dts/arm/juno.dts | 6 ++++++ > 4 files changed, 31 insertions(+) > > diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi > index 90a8710f7032..49fa55cdc977 100644 > --- a/arch/arm64/boot/dts/arm/juno-base.dtsi > +++ b/arch/arm64/boot/dts/arm/juno-base.dtsi > @@ -63,6 +63,14 @@ > */ > etf@20010000 { > compatible = "arm,coresight-tmc", "arm,primecell"; > + /* > + * The primecell peripheral id is explicitly specified here with > + * the actual hardware value. It's not any override. It's > + * required to workaround an errata to avoid bus stalls early > + * in the boot when AMBA primecell ids are probed before the > + * actual power domain can be enabled using SCPI. > + */ > + arm,primecell-periphid = <0x001bb961>; > reg = <0 0x20010000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > @@ -92,6 +100,7 @@ > > tpiu@20030000 { > compatible = "arm,coresight-tpiu", "arm,primecell"; > + arm,primecell-periphid = <0x004bb912>; > reg = <0 0x20030000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > @@ -106,6 +115,7 @@ > > main_funnel@20040000 { > compatible = "arm,coresight-funnel", "arm,primecell"; > + arm,primecell-periphid = <0x002bb908>; > reg = <0 0x20040000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > @@ -142,6 +152,7 @@ > > etr@20070000 { > compatible = "arm,coresight-tmc", "arm,primecell"; > + arm,primecell-periphid = <0x001bb961>; > reg = <0 0x20070000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > @@ -192,6 +203,7 @@ > > cluster0_funnel@220c0000 { > compatible = "arm,coresight-funnel", "arm,primecell"; > + arm,primecell-periphid = <0x002bb908>; > reg = <0 0x220c0000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > @@ -227,6 +239,7 @@ > > cluster1_funnel@230c0000 { > compatible = "arm,coresight-funnel", "arm,primecell"; > + arm,primecell-periphid = <0x002bb908>; > reg = <0 0x230c0000 0 0x1000>; > > clocks = <&soc_smc50mhz>; > diff --git a/arch/arm64/boot/dts/arm/juno-r1.dts b/arch/arm64/boot/dts/arm/juno-r1.dts > index f4f8f54f8b85..c3c9fdff49bf 100644 > --- a/arch/arm64/boot/dts/arm/juno-r1.dts > +++ b/arch/arm64/boot/dts/arm/juno-r1.dts > @@ -184,24 +184,30 @@ > > &etm0 { > cpu = <&A57_0>; > + arm,primecell-periphid = <0x002bb95e>; > }; > > &etm1 { > cpu = <&A57_1>; > + arm,primecell-periphid = <0x002bb95e>; > }; > > &etm2 { > cpu = <&A53_0>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm3 { > cpu = <&A53_1>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm4 { > cpu = <&A53_2>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm5 { > cpu = <&A53_3>; > + arm,primecell-periphid = <0x003bb95d>; > }; > diff --git a/arch/arm64/boot/dts/arm/juno-r2.dts b/arch/arm64/boot/dts/arm/juno-r2.dts > index d903e545b64c..c672c978f89d 100644 > --- a/arch/arm64/boot/dts/arm/juno-r2.dts > +++ b/arch/arm64/boot/dts/arm/juno-r2.dts > @@ -184,24 +184,30 @@ > > &etm0 { > cpu = <&A72_0>; > + arm,primecell-periphid = <0x000bb95a>; > }; > > &etm1 { > cpu = <&A72_1>; > + arm,primecell-periphid = <0x000bb95a>; > }; > > &etm2 { > cpu = <&A53_0>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm3 { > cpu = <&A53_1>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm4 { > cpu = <&A53_2>; > + arm,primecell-periphid = <0x003bb95d>; > }; > > &etm5 { > cpu = <&A53_3>; > + arm,primecell-periphid = <0x003bb95d>; > }; > diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts > index a7270eff6939..0528e47e66d1 100644 > --- a/arch/arm64/boot/dts/arm/juno.dts > +++ b/arch/arm64/boot/dts/arm/juno.dts > @@ -176,24 +176,30 @@ > > &etm0 { > cpu = <&A57_0>; > + arm,primecell-periphid = <0x000bb95e>; > }; > > &etm1 { > cpu = <&A57_1>; > + arm,primecell-periphid = <0x000bb95e>; > }; > > &etm2 { > cpu = <&A53_0>; > + arm,primecell-periphid = <0x000bb95d>; > }; > > &etm3 { > cpu = <&A53_1>; > + arm,primecell-periphid = <0x000bb95d>; > }; > > &etm4 { > cpu = <&A53_2>; > + arm,primecell-periphid = <0x000bb95d>; > }; > > &etm5 { > cpu = <&A53_3>; > + arm,primecell-periphid = <0x000bb95d>; > }; > -- > 2.7.4 > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/06/16 16:59, Sudeep Holla wrote: > The Linux AMBA framework probes the peripheral ids when adding the amba > devices very early on the boot. Generally they are on APB bus and just > require APB clocks to be on even when most of the core logic of the IP > is powered down. > > However on Juno, the entire debugsys domain needs to be ON to access > those CID/PID registers and hence broken by design. Accessing those > while debugsys power domain is off will lead to the bridge stalling the > transactions instead of returning the slave error. > > Since keeping the power domain on by default affects the core power(by > preventing cores entering deeper idle states), it's not feasible > solution. Instead we can provide arm,primecell-periphid override in the > device tree that prevents accessing the device early in the boot. > OK, I recently found out that AMBA bus/infrastructure can deal with powered off domains even while adding the devices. That makes this patch redundant. I had missed it initially as I tested with !CONFIG_PM option. So I raised the issue with !CONFIG_PM option[1] and it was suggested to make platform select the same[2] as there's no simple way to deal with that. Hence I will drop this patch but will post patch to select PM from ARCH_VEXPRESS to ensure we always have it enabled to deal with this platform issue. -- Regards, Sudeep [1] http://marc.info/?l=linux-pm&m=146607608629880&w=2 [2] http://marc.info/?l=linux-pm&m=146608125731479&w=2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm64/boot/dts/arm/juno-base.dtsi b/arch/arm64/boot/dts/arm/juno-base.dtsi index 90a8710f7032..49fa55cdc977 100644 --- a/arch/arm64/boot/dts/arm/juno-base.dtsi +++ b/arch/arm64/boot/dts/arm/juno-base.dtsi @@ -63,6 +63,14 @@ */ etf@20010000 { compatible = "arm,coresight-tmc", "arm,primecell"; + /* + * The primecell peripheral id is explicitly specified here with + * the actual hardware value. It's not any override. It's + * required to workaround an errata to avoid bus stalls early + * in the boot when AMBA primecell ids are probed before the + * actual power domain can be enabled using SCPI. + */ + arm,primecell-periphid = <0x001bb961>; reg = <0 0x20010000 0 0x1000>; clocks = <&soc_smc50mhz>; @@ -92,6 +100,7 @@ tpiu@20030000 { compatible = "arm,coresight-tpiu", "arm,primecell"; + arm,primecell-periphid = <0x004bb912>; reg = <0 0x20030000 0 0x1000>; clocks = <&soc_smc50mhz>; @@ -106,6 +115,7 @@ main_funnel@20040000 { compatible = "arm,coresight-funnel", "arm,primecell"; + arm,primecell-periphid = <0x002bb908>; reg = <0 0x20040000 0 0x1000>; clocks = <&soc_smc50mhz>; @@ -142,6 +152,7 @@ etr@20070000 { compatible = "arm,coresight-tmc", "arm,primecell"; + arm,primecell-periphid = <0x001bb961>; reg = <0 0x20070000 0 0x1000>; clocks = <&soc_smc50mhz>; @@ -192,6 +203,7 @@ cluster0_funnel@220c0000 { compatible = "arm,coresight-funnel", "arm,primecell"; + arm,primecell-periphid = <0x002bb908>; reg = <0 0x220c0000 0 0x1000>; clocks = <&soc_smc50mhz>; @@ -227,6 +239,7 @@ cluster1_funnel@230c0000 { compatible = "arm,coresight-funnel", "arm,primecell"; + arm,primecell-periphid = <0x002bb908>; reg = <0 0x230c0000 0 0x1000>; clocks = <&soc_smc50mhz>; diff --git a/arch/arm64/boot/dts/arm/juno-r1.dts b/arch/arm64/boot/dts/arm/juno-r1.dts index f4f8f54f8b85..c3c9fdff49bf 100644 --- a/arch/arm64/boot/dts/arm/juno-r1.dts +++ b/arch/arm64/boot/dts/arm/juno-r1.dts @@ -184,24 +184,30 @@ &etm0 { cpu = <&A57_0>; + arm,primecell-periphid = <0x002bb95e>; }; &etm1 { cpu = <&A57_1>; + arm,primecell-periphid = <0x002bb95e>; }; &etm2 { cpu = <&A53_0>; + arm,primecell-periphid = <0x003bb95d>; }; &etm3 { cpu = <&A53_1>; + arm,primecell-periphid = <0x003bb95d>; }; &etm4 { cpu = <&A53_2>; + arm,primecell-periphid = <0x003bb95d>; }; &etm5 { cpu = <&A53_3>; + arm,primecell-periphid = <0x003bb95d>; }; diff --git a/arch/arm64/boot/dts/arm/juno-r2.dts b/arch/arm64/boot/dts/arm/juno-r2.dts index d903e545b64c..c672c978f89d 100644 --- a/arch/arm64/boot/dts/arm/juno-r2.dts +++ b/arch/arm64/boot/dts/arm/juno-r2.dts @@ -184,24 +184,30 @@ &etm0 { cpu = <&A72_0>; + arm,primecell-periphid = <0x000bb95a>; }; &etm1 { cpu = <&A72_1>; + arm,primecell-periphid = <0x000bb95a>; }; &etm2 { cpu = <&A53_0>; + arm,primecell-periphid = <0x003bb95d>; }; &etm3 { cpu = <&A53_1>; + arm,primecell-periphid = <0x003bb95d>; }; &etm4 { cpu = <&A53_2>; + arm,primecell-periphid = <0x003bb95d>; }; &etm5 { cpu = <&A53_3>; + arm,primecell-periphid = <0x003bb95d>; }; diff --git a/arch/arm64/boot/dts/arm/juno.dts b/arch/arm64/boot/dts/arm/juno.dts index a7270eff6939..0528e47e66d1 100644 --- a/arch/arm64/boot/dts/arm/juno.dts +++ b/arch/arm64/boot/dts/arm/juno.dts @@ -176,24 +176,30 @@ &etm0 { cpu = <&A57_0>; + arm,primecell-periphid = <0x000bb95e>; }; &etm1 { cpu = <&A57_1>; + arm,primecell-periphid = <0x000bb95e>; }; &etm2 { cpu = <&A53_0>; + arm,primecell-periphid = <0x000bb95d>; }; &etm3 { cpu = <&A53_1>; + arm,primecell-periphid = <0x000bb95d>; }; &etm4 { cpu = <&A53_2>; + arm,primecell-periphid = <0x000bb95d>; }; &etm5 { cpu = <&A53_3>; + arm,primecell-periphid = <0x000bb95d>; };
The Linux AMBA framework probes the peripheral ids when adding the amba devices very early on the boot. Generally they are on APB bus and just require APB clocks to be on even when most of the core logic of the IP is powered down. However on Juno, the entire debugsys domain needs to be ON to access those CID/PID registers and hence broken by design. Accessing those while debugsys power domain is off will lead to the bridge stalling the transactions instead of returning the slave error. Since keeping the power domain on by default affects the core power(by preventing cores entering deeper idle states), it's not feasible solution. Instead we can provide arm,primecell-periphid override in the device tree that prevents accessing the device early in the boot. However the power domains can be enabled whenever required using runtime PM and associated power domains. Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: devicetree@vger.kernel.org Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> --- arch/arm64/boot/dts/arm/juno-base.dtsi | 13 +++++++++++++ arch/arm64/boot/dts/arm/juno-r1.dts | 6 ++++++ arch/arm64/boot/dts/arm/juno-r2.dts | 6 ++++++ arch/arm64/boot/dts/arm/juno.dts | 6 ++++++ 4 files changed, 31 insertions(+) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html