[PATCH 2/3] arm64: dts: juno: add arm, primecell-periphid override

[Liviu Dudau]

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 at arm.com>

Acked-by: Liviu Dudau <Liviu.Dudau at arm.com>

> Cc: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Cc: linux-arm-kernel at lists.infradead.org
> Cc: devicetree at vger.kernel.org
> Signed-off-by: Sudeep Holla <sudeep.holla at 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 at 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 at 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 at 20040000 {
>  		compatible = "arm,coresight-funnel", "arm,primecell";
> +		arm,primecell-periphid = <0x002bb908>;
>  		reg = <0 0x20040000 0 0x1000>;
> 
>  		clocks = <&soc_smc50mhz>;
> @@ -142,6 +152,7 @@
> 
>  	etr at 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 at 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 at 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
> 

-- 
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