From f7cfcd2f7e3678f199306894dd8eaaf195cc998e Mon Sep 17 00:00:00 2001 From: Dmitry Baryshkov Date: Wed, 30 Aug 2023 03:21:57 +0300 Subject: [PATCH 3/4] clk: qcom: mmcc-msm8996: introduce turnaround time In order to prevent the GX GDSC from toggling too fast, introduce the turnaround time. Delay turning GDSC on if it was turned off lately enough. Signed-off-by: Dmitry Baryshkov --- kernel/drivers/clk/qcom/gdsc.c | 39 ++++++++++++++++++++++++++ kernel/drivers/clk/qcom/gdsc.h | 3 ++ kernel/drivers/clk/qcom/mmcc-msm8996.c | 1 + 3 files changed, 43 insertions(+) diff --git a/kernel/drivers/clk/qcom/gdsc.c b/kernel/drivers/clk/qcom/gdsc.c index cf23cfd7e467..6c4349336b0c 100644 --- a/kernel/drivers/clk/qcom/gdsc.c +++ b/kernel/drivers/clk/qcom/gdsc.c @@ -237,11 +237,47 @@ static void gdsc_retain_ff_on(struct gdsc *sc) regmap_update_bits(sc->regmap, sc->gdscr, mask, mask); } +static void gdsc_enable_delay(unsigned int delay) +{ + unsigned int ms = delay / 1000; + unsigned int us = delay % 1000; + + if (ms > 0) { + /* + * For small enough values, handle super-millisecond + * delays in the usleep_range() call below. + */ + if (ms < 20) + us += ms * 1000; + else + msleep(ms); + } + + /* + * Give the scheduler some room to coalesce with any other + * wakeup sources. For delays shorter than 10 us, don't even + * bother setting up high-resolution timers and just busy- + * loop. + */ + if (us >= 10) + usleep_range(us, us + 100); + else + udelay(us); +} + static int gdsc_enable(struct generic_pm_domain *domain) { struct gdsc *sc = domain_to_gdsc(domain); int ret; + if (sc->off_on_delay && sc->last_off) { + ktime_t end = ktime_add_us(sc->last_off, sc->off_on_delay); + s64 remain = ktime_us_delta(end, ktime_get()); + + if (remain > 0) + gdsc_enable_delay(remain); + } + if (sc->pwrsts == PWRSTS_ON) return gdsc_deassert_reset(sc); @@ -331,6 +367,9 @@ static int gdsc_disable(struct generic_pm_domain *domain) if (sc->flags & CLAMP_IO) gdsc_assert_clamp_io(sc); + if (sc->off_on_delay) + sc->last_off = ktime_get(); + return 0; } diff --git a/kernel/drivers/clk/qcom/gdsc.h b/kernel/drivers/clk/qcom/gdsc.h index 762f1b5e1ec5..196b6d22a069 100644 --- a/kernel/drivers/clk/qcom/gdsc.h +++ b/kernel/drivers/clk/qcom/gdsc.h @@ -64,6 +64,9 @@ struct gdsc { const char *supply; struct regulator *rsupply; + + u64 off_on_delay; + ktime_t last_off; }; struct gdsc_desc { diff --git a/kernel/drivers/clk/qcom/mmcc-msm8996.c b/kernel/drivers/clk/qcom/mmcc-msm8996.c index 24843e4f2599..985fa34ca23c 100644 --- a/kernel/drivers/clk/qcom/mmcc-msm8996.c +++ b/kernel/drivers/clk/qcom/mmcc-msm8996.c @@ -3074,6 +3074,7 @@ static struct gdsc gpu_gx_gdsc = { .parent = &gpu_gdsc.pd, .flags = CLAMP_IO, .supply = "vdd-gfx", + .off_on_delay = 250 * 1000, }; static struct clk_regmap *mmcc_msm8996_clocks[] = { -- 2.39.2