Messages in this thread | | | Subject | Re: [PATCH v16 4/6] soc: qcom: rpmh: Invoke rpmh_flush() for dirty caches | From | Maulik Shah <> | Date | Sun, 12 Apr 2020 19:34:02 +0530 |
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Hi,
On 4/10/2020 9:45 AM, Stephen Boyd wrote: > Quoting Maulik Shah (2020-04-05 23:32:19) >> Add changes to invoke rpmh flush() from CPU PM notification. >> This is done when the last the cpu is entering power collapse and > 'power collapse' is a qcom-ism. Maybe say something like "deep CPU idle > states"? Okay, i updated in v17. > >> controller is not busy. >> >> Controllers that do have 'HW solver' mode do not need to register >> for CPU PM notification. They may be in autonomous mode executing >> low power mode and do not require rpmh_flush() to happen from CPU >> PM notification. > Can you provide an example of a HW solver mode controller? Presumably > the display RSC is one of these? Sure, Added in v17 to mention display RSC. >> Signed-off-by: Maulik Shah <mkshah@codeaurora.org> >> Reviewed-by: Douglas Anderson <dianders@chromium.org> >> diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c >> index b718221..fbe1f3e 100644 >> --- a/drivers/soc/qcom/rpmh-rsc.c >> +++ b/drivers/soc/qcom/rpmh-rsc.c >> @@ -521,8 +527,86 @@ int rpmh_rsc_write_ctrl_data(struct rsc_drv *drv, const struct tcs_request *msg) >> return tcs_ctrl_write(drv, msg); >> } >> >> +/** >> + * rpmh_rsc_ctrlr_is_busy() - Check if any of the AMCs are busy. >> + * >> + * @drv: The controller >> + * >> + * Checks if any of the AMCs are busy in handling ACTIVE sets. >> + * This is called from the last cpu powering down before flushing >> + * SLEEP and WAKE sets. If AMCs are busy, controller can not enter >> + * power collapse, so deny from the last cpu's pm notification. >> + * >> + * Return: >> + * * False - AMCs are idle >> + * * True - AMCs are busy >> + */ >> +static bool rpmh_rsc_ctrlr_is_busy(struct rsc_drv *drv) > Can drv be const? Would be nice to make it const in some places in this > driver.
It can, but it will require changing multiple places to make it const. some of those functions are
dropped/modified in doug's cleanup series. I can do in separate patch once this series is pulled in.
> >> +{ >> + int m; >> + struct tcs_group *tcs = get_tcs_of_type(drv, ACTIVE_TCS); >> + >> + /* >> + * If we made an active request on a RSC that does not have a >> + * dedicated TCS for active state use, then re-purposed wake TCSes >> + * should be checked for not busy. > not busy, because we use wake TCSes for active requests in this case. Ok, added in v17. > >> + * >> + * Since this is called from the last cpu, need not take drv or tcs >> + * lock before checking tcs_is_free(). >> + */ >> + if (!tcs->num_tcs) >> + tcs = get_tcs_of_type(drv, WAKE_TCS); >> + >> + for (m = tcs->offset; m < tcs->offset + tcs->num_tcs; m++) { >> + if (!tcs_is_free(drv, m)) >> + return true; >> + } >> + >> + return false; >> +} > [...] >> + >> diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c >> index a75f3df..88f8801 100644 >> --- a/drivers/soc/qcom/rpmh.c >> +++ b/drivers/soc/qcom/rpmh.c >> @@ -433,16 +430,17 @@ static int send_single(struct rpmh_ctrlr *ctrlr, enum rpmh_state state, >> } >> >> /** >> - * rpmh_flush: Flushes the buffered active and sleep sets to TCS >> + * rpmh_flush() - Flushes the buffered sleep and wake sets to TCSes >> * >> - * @ctrlr: controller making request to flush cached data >> + * @ctrlr: Controller making request to flush cached data >> * >> - * Return: -EBUSY if the controller is busy, probably waiting on a response >> - * to a RPMH request sent earlier. >> + * This function is called from sleep code on the last CPU >> + * (thus no spinlock needed). > Might be good to stick a lockdep_assert_irqs_disabled() in this function > then. That would document that this function should only be called when > irqs are disabled.
Okay. Added lockdep_assert_irqs_disabled(). But this may need to be dropped when
we add support for display RSC.
> >> * >> - * This function is always called from the sleep code from the last CPU >> - * that is powering down the entire system. Since no other RPMH API would be >> - * executing at this time, it is safe to run lockless. >> + * Return: >> + * * 0 - Success >> + * * -EAGAIN - Retry again >> + * * Error code - Otherwise >> */ >> int rpmh_flush(struct rpmh_ctrlr *ctrlr) > This function name keeps throwing me off. Can we please call it > something like rpmh_configure_tcs_sleep_wake()? The word "flush" seems > to imply there's some sort of cache going on, but that's not really the > case. We're programming a couple TCS FIFOs so that they can be used > across deep CPU sleep states. > >> { >> @@ -455,9 +453,7 @@ int rpmh_flush(struct rpmh_ctrlr *ctrlr) >> } >> >> /* Invalidate the TCSes first to avoid stale data */ >> - do { >> - ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr)); >> - } while (ret == -EAGAIN); >> + ret = rpmh_rsc_invalidate(ctrlr_to_drv(ctrlr)); >> if (ret) >> return ret;
Thanks,
Maulik
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