linux-kernel - Re: [PATCH] clocksource/drivers/timer-ti-dm: fix regression from errata i940 fix

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Date:   Wed, 2 Feb 2022 15:33:45 -0600
From:   Suman Anna <s-anna@...com>
To:     Drew Fustini <dfustini@...libre.com>,
        Tony Lindgren <tony@...mide.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Keerthy <j-keerthy@...com>, <linux-kernel@...r.kernel.org>,
        <linux-omap@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Tero Kristo <kristo@...nel.org>, <khilman@...libre.com>
Subject: Re: [PATCH] clocksource/drivers/timer-ti-dm: fix regression from
 errata i940 fix

On 2/2/22 15:25, Drew Fustini wrote:
> The existing fix for errata i940 causes a conflict for IPU2 which is
> using timer 3 and 4. From arch/arm/boot/dts/dra7-ipu-dsp-common.dtsi:
> 
>   &ipu2 {
>           mboxes = <&mailbox6 &mbox_ipu2_ipc3x>;
>           ti,timers = <&timer3>;
>           ti,watchdog-timers = <&timer4>, <&timer9>;
>   };
> 
> I discovered the timer conflict from when booting mainline on a
> BeagleBoard X15 (AM5728):
> 
>   remoteproc remoteproc1: 55020000.ipu is available
>   remoteproc remoteproc1: powering up 55020000.ipu
>   remoteproc remoteproc1: Booting fw image dra7-ipu2-fw.xem4
>   omap-rproc 55020000.ipu: could not get timer platform device
>   omap-rproc 55020000.ipu: omap_rproc_enable_timers failed: -19
>   remoteproc remoteproc1: can't start rproc 55020000.ipu: -19
> 
> I modified the errata fix to use timer 15 and 16 instead which resolves
> the timer conflict.
> 
> Fixes: 25de4ce5ed02 ("clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940")
> Link: https://lore.kernel.org/linux-omap/YfWsG0p6to3IJuvE@x1/

Suggested-by: Suman Anna <s-anna@...com>

regards
Suman

> Signed-off-by: Drew Fustini <dfustini@...libre.com>
> ---
> Note: I am keeping the device tree and driver change together in one
> patch as that is how the original errata fix commit was structured.
> 
>  arch/arm/boot/dts/dra7-l4.dtsi             | 5 ++---
>  arch/arm/boot/dts/dra7.dtsi                | 8 ++++----
>  drivers/clocksource/timer-ti-dm-systimer.c | 4 ++--
>  3 files changed, 8 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/dra7-l4.dtsi b/arch/arm/boot/dts/dra7-l4.dtsi
> index 956a26d52a4c..0a11bacffc1f 100644
> --- a/arch/arm/boot/dts/dra7-l4.dtsi
> +++ b/arch/arm/boot/dts/dra7-l4.dtsi
> @@ -3482,8 +3482,7 @@ timer14: timer@0 {
>  				ti,timer-pwm;
>  			};
>  		};
> -
> -		target-module@...00 {			/* 0x4882c000, ap 17 02.0 */
> +		timer15_target: target-module@...00 {	/* 0x4882c000, ap 17 02.0 */
>  			compatible = "ti,sysc-omap4-timer", "ti,sysc";
>  			reg = <0x2c000 0x4>,
>  			      <0x2c010 0x4>;
> @@ -3511,7 +3510,7 @@ timer15: timer@0 {
>  			};
>  		};
>  
> -		target-module@...00 {			/* 0x4882e000, ap 19 14.0 */
> +		timer16_target: target-module@...00 {	/* 0x4882e000, ap 19 14.0 */
>  			compatible = "ti,sysc-omap4-timer", "ti,sysc";
>  			reg = <0x2e000 0x4>,
>  			      <0x2e010 0x4>;
> diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi
> index 6b485cbed8d5..8f7ffe2f66e9 100644
> --- a/arch/arm/boot/dts/dra7.dtsi
> +++ b/arch/arm/boot/dts/dra7.dtsi
> @@ -1339,20 +1339,20 @@ timer@0 {
>  };
>  
>  /* Local timers, see ARM architected timer wrap erratum i940 */
> -&timer3_target {
> +&timer15_target {
>  	ti,no-reset-on-init;
>  	ti,no-idle;
>  	timer@0 {
> -		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER3_CLKCTRL 24>;
> +		assigned-clocks = <&l4per3_clkctrl DRA7_L4PER3_TIMER15_CLKCTRL 24>;
>  		assigned-clock-parents = <&timer_sys_clk_div>;
>  	};
>  };
>  
> -&timer4_target {
> +&timer16_target {
>  	ti,no-reset-on-init;
>  	ti,no-idle;
>  	timer@0 {
> -		assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER4_CLKCTRL 24>;
> +		assigned-clocks = <&l4per3_clkctrl DRA7_L4PER3_TIMER16_CLKCTRL 24>;
>  		assigned-clock-parents = <&timer_sys_clk_div>;
>  	};
>  };
> diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c
> index b6f97960d8ee..c706d63e9f5c 100644
> --- a/drivers/clocksource/timer-ti-dm-systimer.c
> +++ b/drivers/clocksource/timer-ti-dm-systimer.c
> @@ -695,9 +695,9 @@ static int __init dmtimer_percpu_quirk_init(struct device_node *np, u32 pa)
>  		return 0;
>  	}
>  
> -	if (pa == 0x48034000)		/* dra7 dmtimer3 */
> +	if (pa == 0x4882C000)           /* dra7 dmtimer15 */
>  		return dmtimer_percpu_timer_init(np, 0);
> -	else if (pa == 0x48036000)	/* dra7 dmtimer4 */
> +	else if (pa == 0x4882E000)      /* dra7 dmtimer16 */
>  		return dmtimer_percpu_timer_init(np, 1);
>  
>  	return 0;