Re: [PATCH v6 0/3] Timer support for ARM Tegra

[Thierry Reding <thierry.reding@gmail.com>]

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On Thu, Jan 26, 2023 at 11:34:59AM +0100, Thierry Reding wrote:
> On Wed, Jan 25, 2023 at 05:41:08PM +0100, Thierry Reding wrote:
> > On Tue, Jan 24, 2023 at 08:57:48AM +0200, Svyatoslav Ryhel wrote:
> > > - ARM: tegra: remap clock_osc_freq for all Tegra family
> > > Enum clock_osc_freq was designed to use only with T20.
> > > This patch remaps it to use additional frequencies, added in
> > > T30+ SoC while maintaining backwards compatibility with T20.
> > > 
> > > - drivers: timer: add timer driver for ARMv7 based Tegra devices
> > > Add timer support for T20/T30/T114 and T124 based devices.
> > > Driver is based on DM, has device tree support and can be
> > > used on SPL and early boot stage.
> > > 
> > > - ARM: tegra: include timer as default option
> > > Enable TIMER as default option for all Tegra devices and
> > > enable TEGRA_TIMER for TEGRA_ARMV7_COMMON. Additionally
> > > enable SPL_TIMER if build as SPL part and drop deprecated
> > > configs from common header.
> > > 
> > > P. S. I have no arm64 Tegra and according to comment in 
> > > tegra-common.h
> > > Use the Tegra US timer on ARMv7, but the architected timer on ARMv8.
> > > 
> > > Svyatoslav Ryhel (3):
> > >   ARM: tegra: remap clock_osc_freq for all Tegra family
> > >   drivers: timer: add timer driver for ARMv7 based Tegra devices
> > >   ARM: tegra: include timer as default option
> > 
> > This causes a regression on Tegra210 (Jetson TX1). I'm trying to
> > investigate, but it's complicated by the fact that I'm not getting out
> > any debug prints, so I suspect the issue is happening quite early.
> 
> Alright, I managed to make this work on Tegra210 using the following
> patch on top of this series:
> 
> --- >8 ---
> diff --git a/arch/arm/dts/tegra210.dtsi b/arch/arm/dts/tegra210.dtsi
> index a521a43d6cfd..ccb5a927da89 100644
> --- a/arch/arm/dts/tegra210.dtsi
> +++ b/arch/arm/dts/tegra210.dtsi
> @@ -318,7 +318,7 @@
>  	};
>  
>  	timer@60005000 {
> -		compatible = "nvidia,tegra210-timer", "nvidia,tegra20-timer";
> +		compatible = "nvidia,tegra210-timer", "nvidia,tegra30-timer", "nvidia,tegra20-timer";
>  		reg = <0x0 0x60005000 0x0 0x400>;
>  		interrupts = <GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>,
>  			     <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>,
> diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
> index cc3f00e50128..b50eec5b8c9b 100644
> --- a/arch/arm/mach-tegra/Kconfig
> +++ b/arch/arm/mach-tegra/Kconfig
> @@ -136,6 +136,7 @@ config TEGRA210
>  	select TEGRA_PINCTRL
>  	select TEGRA_PMC
>  	select TEGRA_PMC_SECURE
> +	select TEGRA_TIMER
>  
>  config TEGRA186
>  	bool "Tegra186 family"
> diff --git a/drivers/timer/tegra-timer.c b/drivers/timer/tegra-timer.c
> index d2d163cf3fef..235532ba8926 100644
> --- a/drivers/timer/tegra-timer.c
> +++ b/drivers/timer/tegra-timer.c
> @@ -58,17 +58,26 @@ static notrace u64 tegra_timer_get_count(struct udevice *dev)
>  static int tegra_timer_probe(struct udevice *dev)
>  {
>  	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
> +	enum clock_osc_freq freq;
>  	u32 usec_config, value;
>  
>  	/* Timer rate has to be set unconditionally */
>  	uc_priv->clock_rate = TEGRA_TIMER_RATE;
>  
> +	/*
> +	 * The microsecond timer runs off of clk_m on Tegra210, and clk_m
> +	 * runs at half the OSC, so fake this up.
> +	 */
> +	freq = clock_get_osc_freq();
> +	if (freq == CLOCK_OSC_FREQ_38_4)
> +		freq = CLOCK_OSC_FREQ_19_2;
> +
>  	/*
>  	 * Configure microsecond timers to have 1MHz clock
>  	 * Config register is 0xqqww, where qq is "dividend", ww is "divisor"
>  	 * Uses n+1 scheme
>  	 */
> -	switch (clock_get_osc_freq()) {
> +	switch (freq) {
>  	case CLOCK_OSC_FREQ_13_0:
>  		usec_config = 0x000c; /* (12+1)/(0+1) */
>  		break;
> @@ -113,6 +122,7 @@ static const struct udevice_id tegra_timer_ids[] = {
>  	{ .compatible = "nvidia,tegra30-timer" },
>  	{ .compatible = "nvidia,tegra114-timer" },
>  	{ .compatible = "nvidia,tegra124-timer" },
> +	{ .compatible = "nvidia,tegra210-timer" },
>  	{ }
>  };
> --- >8 ---
> 
> I've also tested this on Tegra186, though no additional changes were
> needed since Tegra186 doesn't use the Tegra timer.
> 
> With the above folded in, the series is:
> 
> Tested-by: Thierry Reding <treding@nvidia.com>

I've also tested your series with the above on Tegra30 (Beaver) and
Tegra124 (Jetson TK1), both seem to work fine.

Thierry

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