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@xxxxxxx>
Acked-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> ---
> 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@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
