| Message ID | 1431005924-21777-4-git-send-email-lee.jones@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Fri, 08 May 2015, Paul Bolle wrote: > On Thu, 2015-05-07 at 14:38 +0100, Lee Jones wrote: > > --- a/drivers/clocksource/Kconfig > > +++ b/drivers/clocksource/Kconfig > > > +config CLKSRC_ST_LPC_TIMER_SCHED_CLOCK > > + bool > > + depends on CLKSRC_ST_LPC > > + default y > > + help > > + Use Low Power controller timer clock source as sched_clock > > This adds, as far as I can see, a Kconfig symbol that will always be in > lockstep with CLKSRC_ST_LPC. Ie, CLKSRC_ST_LPC and > CLKSRC_ST_LPC_TIMER_SCHED_CLOCK will always both be 'n' or both be 'y'. > > Are there plans to break that lockstep in the future? What's stopping CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK=n?
On Fri, 08 May 2015, Paul Bolle wrote: > On Fri, 2015-05-08 at 10:36 +0100, Lee Jones wrote: > > On Fri, 08 May 2015, Paul Bolle wrote: > > > On Thu, 2015-05-07 at 14:38 +0100, Lee Jones wrote: > > > > --- a/drivers/clocksource/Kconfig > > > > +++ b/drivers/clocksource/Kconfig > > > > > > > +config CLKSRC_ST_LPC_TIMER_SCHED_CLOCK > > > > + bool > > > > + depends on CLKSRC_ST_LPC > > > > + default y > > > > + help > > > > + Use Low Power controller timer clock source as sched_clock > > > > > > This adds, as far as I can see, a Kconfig symbol that will always be in > > > lockstep with CLKSRC_ST_LPC. Ie, CLKSRC_ST_LPC and > > > CLKSRC_ST_LPC_TIMER_SCHED_CLOCK will always both be 'n' or both be 'y'. > > > > > > Are there plans to break that lockstep in the future? > > > > What's stopping CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK=n? > > If CLKSRC_ST_LPC=y you mean? The lack of a prompt, I'd say. Ie, you > would need > bool "A very short description" > > to be able to set these independently. > > But now I notice that I missed that there appears to be a problem with > CLKSRC_ST_LPC too. I'll reply to 2/12 shortly. Ah, you mean from menuconfig. I almost forgot what that was. ;) I can add a menu option, no problem.
On 05/08/2015 01:47 PM, Paul Bolle wrote: > On Fri, 2015-05-08 at 11:29 +0100, Lee Jones wrote: >> Ah, you mean from menuconfig. I almost forgot what that was. ;) >> >> I can add a menu option, no problem. > > It's not just menuconfig: > $ grep -e CONFIG_ARCH_STI -e CONFIG_CLKSRC_ST_LPC .config > CONFIG_ARCH_STI=y > CONFIG_CLKSRC_ST_LPC=y > CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK=y > $ vim .config > $ grep -e CONFIG_ARCH_STI -e CONFIG_CLKSRC_ST_LPC .config > CONFIG_ARCH_STI=y > # CONFIG_CLKSRC_ST_LPC is not set > # CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK is not set > $ make ARCH=arm silentoldconfig > scripts/kconfig/conf --silentoldconfig Kconfig > # > # configuration written to .config > # > $ grep -e CONFIG_ARCH_STI -e CONFIG_CLKSRC_ST_LPC .config > CONFIG_ARCH_STI=y > CONFIG_CLKSRC_ST_LPC=y > CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK=y > > So I think that, if you want to be able to set > CLKSRC_ST_LPC_TIMER_SCHED_CLOCK to 'n' even though CLKSRC_ST_LPC is 'y', > you need to add a prompt. Or have you found a way around this? The general policy is to have non-prompted options in the clocksource's Kconfig and let the platform's config to select the right components.
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index ac424cf..218daf8 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -258,4 +258,12 @@ config CLKSRC_ST_LPC help Enable this option to use the Low Power controller timer as clocksource. + +config CLKSRC_ST_LPC_TIMER_SCHED_CLOCK + bool + depends on CLKSRC_ST_LPC + default y + help + Use Low Power controller timer clock source as sched_clock + endmenu diff --git a/drivers/clocksource/clksrc_st_lpc.c b/drivers/clocksource/clksrc_st_lpc.c index 18a7dcd0..3d92b26 100644 --- a/drivers/clocksource/clksrc_st_lpc.c +++ b/drivers/clocksource/clksrc_st_lpc.c @@ -16,6 +16,7 @@ #include <linux/clocksource.h> #include <linux/init.h> #include <linux/of_address.h> +#include <linux/sched_clock.h> #include <linux/slab.h> #include <dt-bindings/mfd/st-lpc.h> @@ -38,6 +39,13 @@ static void st_clksrc_reset(void) writel_relaxed(1, ddata.base + LPC_LPT_START_OFF); } +#ifdef CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK +static u64 notrace st_clksrc_sched_clock_read(void) +{ + return (u64)readl_relaxed(ddata.base + LPC_LPT_LSB_OFF); +} +#endif + static int __init st_clksrc_init(void) { unsigned long rate; @@ -47,6 +55,9 @@ static int __init st_clksrc_init(void) rate = clk_get_rate(ddata.clk); +#ifdef CONFIG_CLKSRC_ST_LPC_TIMER_SCHED_CLOCK + sched_clock_register(st_clksrc_sched_clock_read, 32, rate); +#endif ret = clocksource_mmio_init(ddata.base + LPC_LPT_LSB_OFF, "clksrc-st-lpc", rate, 300, 32, clocksource_mmio_readl_up);
Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/clocksource/Kconfig | 8 ++++++++ drivers/clocksource/clksrc_st_lpc.c | 11 +++++++++++ 2 files changed, 19 insertions(+)