On 12/7/2022 9:15 PM, Ulf Hansson wrote: > On Wed, 5 Oct 2022 at 11:08, Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> wrote: >> Add a reset op compatible function to poll for gdsc collapse. This is >> required because: >> 1. We don't wait for it to turn OFF at hardware for VOTABLE GDSCs. >> 2. There is no way for client drivers (eg. gpu driver) to do >> put-with-wait for these gdscs which is required in some scenarios >> (eg. GPU recovery). > What puzzles me a bit, who is the typical consumer of the reset. > > I looked at patch4 and tried to figure it out, but let's discuss that > in that thread instead. Some more comments, see below. https://patchwork.freedesktop.org/patch/498397/ gpu driver side changes are already merged in upstream. We call this interface during a GPU recovery which is supposed to be a rare event. > >> Signed-off-by: Akhil P Oommen <quic_akhilpo@xxxxxxxxxxx> >> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> >> --- >> >> Changes in v7: >> - Update commit message (Bjorn) >> >> Changes in v2: >> - Minor update to function prototype >> >> drivers/clk/qcom/gdsc.c | 23 +++++++++++++++++++---- >> drivers/clk/qcom/gdsc.h | 7 +++++++ >> 2 files changed, 26 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c >> index 7cf5e13..ccef742 100644 >> --- a/drivers/clk/qcom/gdsc.c >> +++ b/drivers/clk/qcom/gdsc.c >> @@ -17,6 +17,7 @@ >> #include <linux/reset-controller.h> >> #include <linux/slab.h> >> #include "gdsc.h" >> +#include "reset.h" >> >> #define PWR_ON_MASK BIT(31) >> #define EN_REST_WAIT_MASK GENMASK_ULL(23, 20) >> @@ -116,7 +117,8 @@ static int gdsc_hwctrl(struct gdsc *sc, bool en) >> return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val); >> } >> >> -static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status) >> +static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status, >> + s64 timeout_us, unsigned int interval_ms) >> { >> ktime_t start; >> >> @@ -124,7 +126,9 @@ static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status) >> do { >> if (gdsc_check_status(sc, status)) >> return 0; >> - } while (ktime_us_delta(ktime_get(), start) < TIMEOUT_US); >> + if (interval_ms) >> + msleep(interval_ms); >> + } while (ktime_us_delta(ktime_get(), start) < timeout_us); > Rather than continue to open code this polling loop, would it not make > sense to convert the code into using readx_poll_timeout() (or some of > its friends). I was going for a minimal code churn to get this mainlined easily. I like the idea, perhaps we can have a refactor patch if there is consensus. -Akhil. > > Down the road, this leads to that the msleep() above should become > usleep_range() instead, which seems more correct to me. > >> if (gdsc_check_status(sc, status)) >> return 0; >> @@ -189,7 +193,7 @@ static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status) >> udelay(1); >> } >> >> - ret = gdsc_poll_status(sc, status); >> + ret = gdsc_poll_status(sc, status, TIMEOUT_US, 0); >> WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n"); >> >> if (!ret && status == GDSC_OFF && sc->rsupply) { >> @@ -360,7 +364,7 @@ static int _gdsc_disable(struct gdsc *sc) >> */ >> udelay(1); >> >> - ret = gdsc_poll_status(sc, GDSC_ON); >> + ret = gdsc_poll_status(sc, GDSC_ON, TIMEOUT_US, 0); >> if (ret) >> return ret; >> } >> @@ -608,3 +612,14 @@ int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain) >> return 0; >> } >> EXPORT_SYMBOL_GPL(gdsc_gx_do_nothing_enable); >> + >> +int gdsc_wait_for_collapse(void *priv) >> +{ >> + struct gdsc *sc = priv; >> + int ret; >> + >> + ret = gdsc_poll_status(sc, GDSC_OFF, 500000, 5); >> + WARN(ret, "%s status stuck at 'on'", sc->pd.name); >> + return ret; >> +} >> +EXPORT_SYMBOL_GPL(gdsc_wait_for_collapse); >> diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h >> index 981a12c..5395f69 100644 >> --- a/drivers/clk/qcom/gdsc.h >> +++ b/drivers/clk/qcom/gdsc.h >> @@ -12,6 +12,7 @@ >> struct regmap; >> struct regulator; >> struct reset_controller_dev; >> +struct qcom_reset_map; >> >> /** >> * struct gdsc - Globally Distributed Switch Controller >> @@ -88,6 +89,7 @@ int gdsc_register(struct gdsc_desc *desc, struct reset_controller_dev *, >> struct regmap *); >> void gdsc_unregister(struct gdsc_desc *desc); >> int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain); >> +int gdsc_wait_for_collapse(void *priv); >> #else >> static inline int gdsc_register(struct gdsc_desc *desc, >> struct reset_controller_dev *rcdev, >> @@ -97,5 +99,10 @@ static inline int gdsc_register(struct gdsc_desc *desc, >> } >> >> static inline void gdsc_unregister(struct gdsc_desc *desc) {}; >> + >> +static int gdsc_wait_for_collapse(void *priv) >> +{ >> + return -ENOSYS; >> +} >> #endif /* CONFIG_QCOM_GDSC */ >> #endif /* __QCOM_GDSC_H__ */ > Kind regards > Uffe
