| Message ID | 1510218917-1725-2-git-send-email-t-kristo@ti.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream, archived |
| Headers | show |
On 11/09, Tero Kristo wrote: > In certain cases it is possible that the timekeeping has been suspended > already when attempting to disable/enable a clkctrl clock. This will > happen at least on am43xx platform when attempting to enable / disable > the clockevent source itself, burping out a warning from timekeeping core. > > The sequence of events leading to this: > -> timekeeping_suspend() > -> clockevents_suspend() > -> omap_clkevt_idle() > -> omap_hwmod_idle() > -> _omap4_clkctrl_clk_disable() > -> _omap4_is_timeout() > > Avoid the issue by checking if the timekeeping is suspended and using > the fallback udelay approach for checking timeouts. > > Signed-off-by: Tero Kristo <t-kristo@ti.com> No Cc on timekeeping maintainers, but OK. Acked-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/ti/clkctrl.c b/drivers/clk/ti/clkctrl.c index 284ba449..38dbcc1 100644 --- a/drivers/clk/ti/clkctrl.c +++ b/drivers/clk/ti/clkctrl.c @@ -21,6 +21,7 @@ #include <linux/of_address.h> #include <linux/clk/ti.h> #include <linux/delay.h> +#include <linux/timekeeping.h> #include "clock.h" #define NO_IDLEST 0x1 @@ -90,7 +91,18 @@ static bool _omap4_is_ready(u32 val) static bool _omap4_is_timeout(union omap4_timeout *time, u32 timeout) { - if (unlikely(_early_timeout)) { + /* + * There are two special cases where ktime_to_ns() can't be + * used to track the timeouts. First one is during early boot + * when the timers haven't been initialized yet. The second + * one is during suspend-resume cycle while timekeeping is + * being suspended / resumed. Clocksource for the system + * can be from a timer that requires pm_runtime access, which + * will eventually bring us here with timekeeping_suspended, + * during both suspend entry and resume paths. This happens + * at least on am43xx platform. + */ + if (unlikely(_early_timeout || timekeeping_suspended)) { if (time->cycles++ < timeout) { udelay(1); return false;
In certain cases it is possible that the timekeeping has been suspended already when attempting to disable/enable a clkctrl clock. This will happen at least on am43xx platform when attempting to enable / disable the clockevent source itself, burping out a warning from timekeeping core. The sequence of events leading to this: -> timekeeping_suspend() -> clockevents_suspend() -> omap_clkevt_idle() -> omap_hwmod_idle() -> _omap4_clkctrl_clk_disable() -> _omap4_is_timeout() Avoid the issue by checking if the timekeeping is suspended and using the fallback udelay approach for checking timeouts. Signed-off-by: Tero Kristo <t-kristo@ti.com> --- drivers/clk/ti/clkctrl.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-)