On 12/8/2022 8:32 PM, Akhil P Oommen wrote: > 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. Btw, we can optimize this a bit more using 'completion' to minimize CPU overhead. But that can wait as this is supposed to be a rarely used path. We don't expect gpu faults often. I would like to see a simpler implementation upstream first. -Akhil. >> >>> 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
