Currently the driver will disable the clock and enable it one line later
if it is switching from periodic mode into one shot.
This can be avoided and causes a needless warning on -RT.
Tested-by: Alexandre Belloni <[email protected]>
Acked-by: Alexandre Belloni <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
---
drivers/clocksource/tcb_clksrc.c | 33 +++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)
diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
index 4da2af9694a2..ed1ae4445e8d 100644
--- a/drivers/clocksource/tcb_clksrc.c
+++ b/drivers/clocksource/tcb_clksrc.c
@@ -74,6 +74,7 @@ static struct clocksource clksrc = {
struct tc_clkevt_device {
struct clock_event_device clkevt;
struct clk *clk;
+ bool clk_enabled;
void __iomem *regs;
};
@@ -91,6 +92,24 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
*/
static u32 timer_clock;
+static void tc_clk_disable(struct clock_event_device *d)
+{
+ struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+
+ clk_disable(tcd->clk);
+ tcd->clk_enabled = false;
+}
+
+static void tc_clk_enable(struct clock_event_device *d)
+{
+ struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+
+ if (tcd->clk_enabled)
+ return;
+ clk_enable(tcd->clk);
+ tcd->clk_enabled = true;
+}
+
static int tc_shutdown(struct clock_event_device *d)
{
struct tc_clkevt_device *tcd = to_tc_clkevt(d);
@@ -98,8 +117,14 @@ static int tc_shutdown(struct clock_event_device *d)
__raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR));
__raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
+ return 0;
+}
+
+static int tc_shutdown_clk_off(struct clock_event_device *d)
+{
+ tc_shutdown(d);
if (!clockevent_state_detached(d))
- clk_disable(tcd->clk);
+ tc_clk_disable(d);
return 0;
}
@@ -112,7 +137,7 @@ static int tc_set_oneshot(struct clock_event_device *d)
if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
tc_shutdown(d);
- clk_enable(tcd->clk);
+ tc_clk_enable(d);
/* slow clock, count up to RC, then irq and stop */
__raw_writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
@@ -134,7 +159,7 @@ static int tc_set_periodic(struct clock_event_device *d)
/* By not making the gentime core emulate periodic mode on top
* of oneshot, we get lower overhead and improved accuracy.
*/
- clk_enable(tcd->clk);
+ tc_clk_enable(d);
/* slow clock, count up to RC, then irq and restart */
__raw_writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
@@ -168,7 +193,7 @@ static struct tc_clkevt_device clkevt = {
/* Should be lower than at91rm9200's system timer */
.rating = 125,
.set_next_event = tc_next_event,
- .set_state_shutdown = tc_shutdown,
+ .set_state_shutdown = tc_shutdown_clk_off,
.set_state_periodic = tc_set_periodic,
.set_state_oneshot = tc_set_oneshot,
},
--
2.8.0.rc3
Le 29/03/2016 15:26, Sebastian Andrzej Siewior a ?crit :
> Currently the driver will disable the clock and enable it one line later
> if it is switching from periodic mode into one shot.
> This can be avoided and causes a needless warning on -RT.
>
> Tested-by: Alexandre Belloni <[email protected]>
> Acked-by: Alexandre Belloni <[email protected]>
> Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Absolutely makes sense:
Acked-by: Nicolas Ferre <[email protected]>
Thanks.
> ---
> drivers/clocksource/tcb_clksrc.c | 33 +++++++++++++++++++++++++++++----
> 1 file changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
> index 4da2af9694a2..ed1ae4445e8d 100644
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -74,6 +74,7 @@ static struct clocksource clksrc = {
> struct tc_clkevt_device {
> struct clock_event_device clkevt;
> struct clk *clk;
> + bool clk_enabled;
> void __iomem *regs;
> };
>
> @@ -91,6 +92,24 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
> */
> static u32 timer_clock;
>
> +static void tc_clk_disable(struct clock_event_device *d)
> +{
> + struct tc_clkevt_device *tcd = to_tc_clkevt(d);
> +
> + clk_disable(tcd->clk);
> + tcd->clk_enabled = false;
> +}
> +
> +static void tc_clk_enable(struct clock_event_device *d)
> +{
> + struct tc_clkevt_device *tcd = to_tc_clkevt(d);
> +
> + if (tcd->clk_enabled)
> + return;
> + clk_enable(tcd->clk);
> + tcd->clk_enabled = true;
> +}
> +
> static int tc_shutdown(struct clock_event_device *d)
> {
> struct tc_clkevt_device *tcd = to_tc_clkevt(d);
> @@ -98,8 +117,14 @@ static int tc_shutdown(struct clock_event_device *d)
>
> __raw_writel(0xff, regs + ATMEL_TC_REG(2, IDR));
> __raw_writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
> + return 0;
> +}
> +
> +static int tc_shutdown_clk_off(struct clock_event_device *d)
> +{
> + tc_shutdown(d);
> if (!clockevent_state_detached(d))
> - clk_disable(tcd->clk);
> + tc_clk_disable(d);
>
> return 0;
> }
> @@ -112,7 +137,7 @@ static int tc_set_oneshot(struct clock_event_device *d)
> if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
> tc_shutdown(d);
>
> - clk_enable(tcd->clk);
> + tc_clk_enable(d);
>
> /* slow clock, count up to RC, then irq and stop */
> __raw_writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
> @@ -134,7 +159,7 @@ static int tc_set_periodic(struct clock_event_device *d)
> /* By not making the gentime core emulate periodic mode on top
> * of oneshot, we get lower overhead and improved accuracy.
> */
> - clk_enable(tcd->clk);
> + tc_clk_enable(d);
>
> /* slow clock, count up to RC, then irq and restart */
> __raw_writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
> @@ -168,7 +193,7 @@ static struct tc_clkevt_device clkevt = {
> /* Should be lower than at91rm9200's system timer */
> .rating = 125,
> .set_next_event = tc_next_event,
> - .set_state_shutdown = tc_shutdown,
> + .set_state_shutdown = tc_shutdown_clk_off,
> .set_state_periodic = tc_set_periodic,
> .set_state_oneshot = tc_set_oneshot,
> },
>
--
Nicolas Ferre
On 03/29/2016 03:26 PM, Sebastian Andrzej Siewior wrote:
> Currently the driver will disable the clock and enable it one line later
> if it is switching from periodic mode into one shot.
> This can be avoided and causes a needless warning on -RT.
I don't see the connection between the description and the content of
the patch.
It can be avoided by not disabling the clock when going to periodic /
oneshot.
The function below suggest clk_enable() is called twice, is that the
real issue ?
> Tested-by: Alexandre Belloni <[email protected]>
> Acked-by: Alexandre Belloni <[email protected]>
> Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
> ---
> drivers/clocksource/tcb_clksrc.c | 33 +++++++++++++++++++++++++++++----
> 1 file changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c
> index 4da2af9694a2..ed1ae4445e8d 100644
> --- a/drivers/clocksource/tcb_clksrc.c
> +++ b/drivers/clocksource/tcb_clksrc.c
> @@ -74,6 +74,7 @@ static struct clocksource clksrc = {
> struct tc_clkevt_device {
> struct clock_event_device clkevt;
> struct clk *clk;
> + bool clk_enabled;
> void __iomem *regs;
> };
>
> @@ -91,6 +92,24 @@ static struct tc_clkevt_device *to_tc_clkevt(struct clock_event_device *clkevt)
> */
> static u32 timer_clock;
>
> +static void tc_clk_disable(struct clock_event_device *d)
> +{
> + struct tc_clkevt_device *tcd = to_tc_clkevt(d);
> +
> + clk_disable(tcd->clk);
> + tcd->clk_enabled = false;
> +}
> +
> +static void tc_clk_enable(struct clock_event_device *d)
> +{
> + struct tc_clkevt_device *tcd = to_tc_clkevt(d);
> +
> + if (tcd->clk_enabled)
> + return;
> + clk_enable(tcd->clk);
> + tcd->clk_enabled = true;
> +}
This function.
--
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