Re: [PATCH V5 2/7] clocksource: tegra: add Tegra210 timer support

Jon Hunter
2019-02-01T12:44:10Z

On 01/02/2019 03:36, Joseph Lo wrote:
> Add support for the Tegra210 timer that runs at oscillator clock
> (TMR10-TMR13). We need these timers to work as clock event device and to
> replace the ARMv8 architected timer due to it can't survive across the
> power cycle of the CPU core or CPUPORESET signal. So it can't be a wake-up
> source when CPU suspends in power down state.
>
> Also convert the original driver to use timer-of API.

It may have been nice to split this into 2 patches to make it easier to
see what is going on but not a big deal.

> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Joseph Lo <josephl@nvidia.com>
> Acked-by: Thierry Reding <treding@nvidia.com>
> ---
> v5:
> * add ack tag from Thierry
> v4:
> * merge timer-tegra210.c in previous version into timer-tegra20.c
> v3:
> * use timer-of API
> v2:
> * add error clean-up code
> ---
> drivers/clocksource/Kconfig | 2 +-
> drivers/clocksource/timer-tegra20.c | 369 ++++++++++++++++++++--------
> include/linux/cpuhotplug.h | 1 +
> 3 files changed, 272 insertions(+), 100 deletions(-)
>
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index a9e26f6a81a1..6af78534a285 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -131,7 +131,7 @@ config SUN5I_HSTIMER
> config TEGRA_TIMER
> bool "Tegra timer driver" if COMPILE_TEST
> select CLKSRC_MMIO
> - depends on ARM
> + select TIMER_OF
> help
> Enables support for the Tegra driver.
>
> diff --git a/drivers/clocksource/timer-tegra20.c b/drivers/clocksource/timer-tegra20.c
> index 4293943f4e2b..96a809341c9b 100644
> --- a/drivers/clocksource/timer-tegra20.c
> +++ b/drivers/clocksource/timer-tegra20.c
> @@ -15,21 +15,24 @@
> *
> */
>
> -#include <linux/init.h>
> +#include <linux/clk.h>
> +#include <linux/clockchips.h>
> +#include <linux/cpu.h>
> +#include <linux/cpumask.h>
> +#include <linux/delay.h>
> #include <linux/err.h>
> -#include <linux/time.h>
> #include <linux/interrupt.h>
> -#include <linux/irq.h>
> -#include <linux/clockchips.h>
> -#include <linux/clocksource.h>
> -#include <linux/clk.h>
> -#include <linux/io.h>
> #include <linux/of_address.h>
> #include <linux/of_irq.h>
> -#include <linux/sched_clock.h>
> -#include <linux/delay.h>
> +#include <linux/percpu.h>
> +#include <linux/syscore_ops.h>
> +#include <linux/time.h>
> +
> +#include "timer-of.h"
>
> +#ifdef CONFIG_ARM
> #include <asm/mach/time.h>
> +#endif
>
> #define RTC_SECONDS 0x08
> #define RTC_SHADOW_SECONDS 0x0c
> @@ -43,70 +46,147 @@
> #define TIMER2_BASE 0x8
> #define TIMER3_BASE 0x50
> #define TIMER4_BASE 0x58
> -
> -#define TIMER_PTV 0x0
> -#define TIMER_PCR 0x4
> -
> +#define TIMER10_BASE 0x90
> +
> +#define TIMER_PTV 0x0
> +#define TIMER_PTV_EN BIT(31)
> +#define TIMER_PTV_PER BIT(30)
> +#define TIMER_PCR 0x4
> +#define TIMER_PCR_INTR_CLR BIT(30)
> +
> +#ifdef CONFIG_ARM
> +#define TIMER_BASE TIMER3_BASE
> +#else
> +#define TIMER_BASE TIMER10_BASE
> +#endif
> +#define TIMER10_IRQ_IDX 10
> +#define TIMER_FOR_CPU(cpu) (TIMER_BASE + (cpu) * 8)
> +#define IRQ_IDX_FOR_CPU(cpu) (TIMER10_IRQ_IDX + cpu)

TIMER10_IRQ_IDX and IRQ_IDX_FOR_CPU are only applicable to ARM64 and so
we should probably not defined for ARM to avoid any confusion.

Furthermore, a lot of these TIMERx_BASE definitions are unused AFAICT.
Would be good to get rid of these.

Maybe we could just have ...

+#ifdef CONFIG_ARM
+#define TIMER_CPU0 3
+#else
+#define TIMER_CPU0 10
+#endif
+#define TIMER_BASE_FOR_CPU(cpu) ((TIMER_CPU0 + cpu) * 8)
+#define TIMER_FOR_CPU(cpu) (TIMER_CPU0 + cpu)

Otherwise looks good to me.

Cheers
Jon

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