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

[Joseph Lo]

On 2/1/19 8:44 PM, Jon Hunter wrote:
> 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@xxxxxxxxxx>
> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Joseph Lo <josephl@xxxxxxxxxx>
> > Acked-by: Thierry Reding <treding@xxxxxxxxxx>
> > ---
> > 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.
Okay, will do.
> Furthermore, a lot of these TIMERx_BASE definitions are unused AFAICT.
> Would be good to get rid of these.

Okay.
> 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)
This can't get the timer base address. I think you mean ...

+#ifdef CONFIG_ARM
+#define TIMER_CPU0 0x50 /* TIMER3 */
+#else
+#define TIMER_CPU0 0x90 /* TIMER10 */
+#endif
+#define TIMER_BASE_FOR_CPU(cpu) (TIMER_CPU0 + (cpu) * 8)

This doesn't need.
+#define TIMER_FOR_CPU(cpu) (TIMER_CPU0 + cpu)

Will fix above accordingly and adding your ack tag.

Thanks,
Joseph

> Otherwise looks good to me.
>
> Cheers
> Jon