[v6,0/5] Add system timer driver for Mediatek SoCs

Changes since v5:
- Optimize driver and remove redundant register operations.
- Docuement registers.
- Fix system timer base address.

Changes since v4:
- Simplify dt-bindings.
- Add error handling for mtk_syst_init().

Changes since v3:
- Use the same binding style for both GPT and System Timer.
- Use timer_of.of_clk->period instead of private structure.
- Arrange patches to contain system timer changes in patch 5/5 only.

Changes since v2:
- Rename existed mtk_timer.c to timer-mediatek.c.
- Add system timer support into timer-mediatek.c instead of creating a new file.
- Use _gpt_ and _syst_ to identify different timers.
- Convert gpt driver to use timer_of.
- Fix system timer driver: irq flags.
- Fix bindings of both gpt and system timer.

Changes since v1:
- Use timer_of structure and APIs to make driver more clean.
- Remove unnecessary headers.
- Use fixed-clock.
- Fix indent.


Stanley Chu (5):
  clocksource/drivers/timer-mediatek: Add system timer bindings
  clocksource/drivers/timer-mediatek: Rename mtk_timer to timer-mediatek
  clocksource/drivers/timer-mediatek: Use specific prefix for GPT
  clocksource/drivers/timer-mediatek: Convert the driver to timer-of
  clocksource/drivers/timer-mediatek: Add support for system timer

 .../bindings/timer/mediatek,mtk-timer.txt          |  36 ++-
 drivers/clocksource/Makefile                       |   2 +-
 drivers/clocksource/mtk_timer.c                    | 268 -----------------
 drivers/clocksource/timer-mediatek.c               | 334 +++++++++++++++++++++
 4 files changed, 356 insertions(+), 284 deletions(-)
 delete mode 100644 drivers/clocksource/mtk_timer.c
 create mode 100644 drivers/clocksource/timer-mediatek.c

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On 04/07/2018 16:50, Stanley Chu wrote:
> This patch adds a new "System Timer" on the Mediatek SoCs.
> 
> The System Timer is introduced as an always-on timer being
> clockevent device for tick-broadcasting.
> 
> For clock, it is driven by 13 MHz system clock.
> The implementation uses the system clock with no clock
> source divider.
> 
> For interrupt, the clock event timer can be used by all cores.
> 
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> ---
>  drivers/clocksource/timer-mediatek.c |  110 +++++++++++++++++++++++++++++++++-
>  1 file changed, 109 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clocksource/timer-mediatek.c b/drivers/clocksource/timer-mediatek.c
> index e57c4d7..e98244a 100644
> --- a/drivers/clocksource/timer-mediatek.c
> +++ b/drivers/clocksource/timer-mediatek.c
> @@ -58,6 +58,86 @@
>  
>  static void __iomem *gpt_sched_reg __read_mostly;
>  
> +/* system timer */
> +#define SYST_BASE               (0x40)
> +
> +#define SYST_CON                (SYST_BASE + 0x0)
> +#define SYST_VAL                (SYST_BASE + 0x4)
> +
> +#define SYST_CON_REG(to)        (timer_of_base(to) + SYST_CON)
> +#define SYST_VAL_REG(to)        (timer_of_base(to) + SYST_VAL)
> +
> +/*
> + * SYST_CON_EN: Clock enable. Shall be set to
> + *   - Start timer countdown.
> + *   - Allow timeout ticks being updated.
> + *   - Allow changing interrupt functions.
> + *
> + * SYST_CON_IRQ_EN: Set to allow interrupt.
> + *
> + * SYST_CON_IRQ_CLR: Set to clear interrupt.
> + */
> +#define SYST_CON_EN              BIT(0)
> +#define SYST_CON_IRQ_EN          BIT(1)
> +#define SYST_CON_IRQ_CLR         BIT(4)
> +
> +static void __iomem *gpt_sched_reg __read_mostly;

duplicate 'gpt_sched_reg' variable.


> +static void mtk_syst_ack_irq(struct timer_of *to)
> +{
> +	/* Clear and disable interrupt */
> +	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
> +}
> +
> +static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
> +{
> +	struct clock_event_device *clkevt = dev_id;
> +	struct timer_of *to = to_timer_of(clkevt);
> +
> +	mtk_syst_ack_irq(to);
> +	clkevt->event_handler(clkevt);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int mtk_syst_clkevt_next_event(unsigned long ticks,
> +				      struct clock_event_device *clkevt)
> +{
> +	struct timer_of *to = to_timer_of(clkevt);
> +
> +	/* Enable clock to allow timeout tick update later */
> +	writel(SYST_CON_EN, SYST_CON_REG(to));
> +
> +	/*
> +	 * Write new timeout ticks. Timer shall start countdown
> +	 * after timeout ticks are updated.
> +	 */
> +	writel(ticks, SYST_VAL_REG(to));
> +
> +	/* Enable interrupt */
> +	writel(SYST_CON_EN | SYST_CON_IRQ_EN, SYST_CON_REG(to));
> +
> +	return 0;
> +}
> +
> +static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
> +{
> +	/* Disable timer */
> +	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
> +
> +	return 0;
> +}
> +
> +static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
> +{
> +	return mtk_syst_clkevt_shutdown(clkevt);
> +}
> +
> +static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
> +{
> +	return 0;
> +}
> +
>  static u64 notrace mtk_gpt_read_sched_clock(void)
>  {
>  	return readl_relaxed(gpt_sched_reg);
> @@ -186,6 +266,34 @@ static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
>  	},
>  };
>  
> +static int __init mtk_syst_init(struct device_node *node)
> +{
> +	int ret;
> +
> +	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
> +	to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
> +	to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
> +	to.clkevt.tick_resume = mtk_syst_clkevt_resume;
> +	to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
> +	to.of_irq.handler = mtk_syst_handler;
> +
> +	ret = timer_of_init(node, &to);
> +	if (ret)
> +		goto err;
> +
> +	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
> +					TIMER_SYNC_TICKS, 0xffffffff);
> +
> +	pr_info("irq=%d, rate=%lu, max_ns: %llu, min_ns: %llu\n",
> +		timer_of_irq(&to), timer_of_rate(&to),
> +		to.clkevt.max_delta_ns, to.clkevt.min_delta_ns);

Please remove this trace. Most of this information is already available
in /proc/timer_list.

However, if you think it is worth to add this trace, do a proposition in
the time framework directly so all drivers can benefit this change.

> +	return 0;
> +err:
> +	timer_of_cleanup(&to);
> +	return ret;
> +}
> +
>  static int __init mtk_gpt_init(struct device_node *node)
>  {
>  	int ret;
> @@ -218,9 +326,9 @@ static int __init mtk_gpt_init(struct device_node *node)
>  	mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);
>  
>  	return 0;
> -
>  err:
>  	timer_of_cleanup(&to);
>  	return ret;
>  }
>  TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
> +TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
>

On Thu, 2018-07-05 at 02:13 +0200, Daniel Lezcano wrote:
> On 04/07/2018 16:50, Stanley Chu wrote:

Hi Daniel,

Well remove duplicate one in v7.

> > +
> > +static void __iomem *gpt_sched_reg __read_mostly;
> 
> duplicate 'gpt_sched_reg' variable.
> 
> 
> > +static void mtk_syst_ack_irq(struct timer_of *to)
> > +{
> > +	/* Clear and disable interrupt */
> > +	writel(SYST_CON_IRQ_CLR | SYST_CON_EN, SYST_CON_REG(to));
> > +}
> > +
> > +static irqreturn_t mtk_syst_handler(int irq, void *dev_id)
> > +{
> > +	struct clock_event_device *clkevt = dev_id;
> > +	struct timer_of *to = to_timer_of(clkevt);
> > +
> > +	mtk_syst_ack_irq(to);
> > +	clkevt->event_handler(clkevt);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int mtk_syst_clkevt_next_event(unsigned long ticks,
> > +				      struct clock_event_device *clkevt)
> > +{
> > +	struct timer_of *to = to_timer_of(clkevt);
> > +
> > +	/* Enable clock to allow timeout tick update later */
> > +	writel(SYST_CON_EN, SYST_CON_REG(to));
> > +
> > +	/*
> > +	 * Write new timeout ticks. Timer shall start countdown
> > +	 * after timeout ticks are updated.
> > +	 */
> > +	writel(ticks, SYST_VAL_REG(to));
> > +
> > +	/* Enable interrupt */
> > +	writel(SYST_CON_EN | SYST_CON_IRQ_EN, SYST_CON_REG(to));
> > +
> > +	return 0;
> > +}
> > +
> > +static int mtk_syst_clkevt_shutdown(struct clock_event_device *clkevt)
> > +{
> > +	/* Disable timer */
> > +	writel(0, SYST_CON_REG(to_timer_of(clkevt)));
> > +
> > +	return 0;
> > +}
> > +
> > +static int mtk_syst_clkevt_resume(struct clock_event_device *clkevt)
> > +{
> > +	return mtk_syst_clkevt_shutdown(clkevt);
> > +}
> > +
> > +static int mtk_syst_clkevt_oneshot(struct clock_event_device *clkevt)
> > +{
> > +	return 0;
> > +}
> > +
> >  static u64 notrace mtk_gpt_read_sched_clock(void)
> >  {
> >  	return readl_relaxed(gpt_sched_reg);
> > @@ -186,6 +266,34 @@ static void mtk_gpt_enable_irq(struct timer_of *to, u8 timer)
> >  	},
> >  };
> >  
> > +static int __init mtk_syst_init(struct device_node *node)
> > +{
> > +	int ret;
> > +
> > +	to.clkevt.features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_ONESHOT;
> > +	to.clkevt.set_state_shutdown = mtk_syst_clkevt_shutdown;
> > +	to.clkevt.set_state_oneshot = mtk_syst_clkevt_oneshot;
> > +	to.clkevt.tick_resume = mtk_syst_clkevt_resume;
> > +	to.clkevt.set_next_event = mtk_syst_clkevt_next_event;
> > +	to.of_irq.handler = mtk_syst_handler;
> > +
> > +	ret = timer_of_init(node, &to);
> > +	if (ret)
> > +		goto err;
> > +
> > +	clockevents_config_and_register(&to.clkevt, timer_of_rate(&to),
> > +					TIMER_SYNC_TICKS, 0xffffffff);
> > +
> > +	pr_info("irq=%d, rate=%lu, max_ns: %llu, min_ns: %llu\n",
> > +		timer_of_irq(&to), timer_of_rate(&to),
> > +		to.clkevt.max_delta_ns, to.clkevt.min_delta_ns);
> 
> Please remove this trace. Most of this information is already available
> in /proc/timer_list.
> 
> However, if you think it is worth to add this trace, do a proposition in
> the time framework directly so all drivers can benefit this change.
> 

OK! Will remove this log in v7.

> > +	return 0;
> > +err:
> > +	timer_of_cleanup(&to);
> > +	return ret;
> > +}
> > +
> >  static int __init mtk_gpt_init(struct device_node *node)
> >  {
> >  	int ret;
> > @@ -218,9 +326,9 @@ static int __init mtk_gpt_init(struct device_node *node)
> >  	mtk_gpt_enable_irq(&to, TIMER_CLK_EVT);
> >  
> >  	return 0;
> > -
> >  err:
> >  	timer_of_cleanup(&to);
> >  	return ret;
> >  }
> >  TIMER_OF_DECLARE(mtk_mt6577, "mediatek,mt6577-timer", mtk_gpt_init);
> > +TIMER_OF_DECLARE(mtk_mt6765, "mediatek,mt6765-timer", mtk_syst_init);
> > 
> 
> 


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