From: Adrian Hunter adrian.hunter@intel.com
commit c981cdfb9925f64a364f13c2b4f98f877308a408 upstream.
Commit 20b92a30b561 ("mmc: sdhci: update signal voltage switch code") removed voltage switch delays from sdhci because mmc core had been enhanced to support them. However that assumed that sdhci_set_ios() did a single clock change, which it did not, and so the delays in mmc core, which should have come after the first clock change, were not effective.
Fix by avoiding re-configuring UHS and preset settings when the clock is turning on and the settings have not changed. That then also avoids the associated clock changes, so that then sdhci_set_ios() does a single clock change when voltage switching, and the mmc core delays become effective.
To do that has meant keeping track of driver strength (host->drv_type), and cases of reinitialization (host->reinit_uhs).
Note also, the 'turning_on_clk' restriction should not be necessary but is done to minimize the impact of the change on stable kernels.
Fixes: 20b92a30b561 ("mmc: sdhci: update signal voltage switch code") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter adrian.hunter@intel.com Link: https://lore.kernel.org/r/20221128133259.38305-2-adrian.hunter@intel.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mmc/host/sdhci.c | 61 +++++++++++++++++++++++++++++++++++++++++------ drivers/mmc/host/sdhci.h | 2 + 2 files changed, 56 insertions(+), 7 deletions(-)
--- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -339,6 +339,7 @@ static void sdhci_init(struct sdhci_host if (soft) { /* force clock reconfiguration */ host->clock = 0; + host->reinit_uhs = true; mmc->ops->set_ios(mmc, &mmc->ios); } } @@ -2258,11 +2259,46 @@ void sdhci_set_uhs_signaling(struct sdhc } EXPORT_SYMBOL_GPL(sdhci_set_uhs_signaling);
+static bool sdhci_timing_has_preset(unsigned char timing) +{ + switch (timing) { + case MMC_TIMING_UHS_SDR12: + case MMC_TIMING_UHS_SDR25: + case MMC_TIMING_UHS_SDR50: + case MMC_TIMING_UHS_SDR104: + case MMC_TIMING_UHS_DDR50: + case MMC_TIMING_MMC_DDR52: + return true; + }; + return false; +} + +static bool sdhci_preset_needed(struct sdhci_host *host, unsigned char timing) +{ + return !(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN) && + sdhci_timing_has_preset(timing); +} + +static bool sdhci_presetable_values_change(struct sdhci_host *host, struct mmc_ios *ios) +{ + /* + * Preset Values are: Driver Strength, Clock Generator and SDCLK/RCLK + * Frequency. Check if preset values need to be enabled, or the Driver + * Strength needs updating. Note, clock changes are handled separately. + */ + return !host->preset_enabled && + (sdhci_preset_needed(host, ios->timing) || host->drv_type != ios->drv_type); +} + void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) { struct sdhci_host *host = mmc_priv(mmc); + bool reinit_uhs = host->reinit_uhs; + bool turning_on_clk = false; u8 ctrl;
+ host->reinit_uhs = false; + if (ios->power_mode == MMC_POWER_UNDEFINED) return;
@@ -2288,6 +2324,8 @@ void sdhci_set_ios(struct mmc_host *mmc, sdhci_enable_preset_value(host, false);
if (!ios->clock || ios->clock != host->clock) { + turning_on_clk = ios->clock && !host->clock; + host->ops->set_clock(host, ios->clock); host->clock = ios->clock;
@@ -2314,6 +2352,17 @@ void sdhci_set_ios(struct mmc_host *mmc,
host->ops->set_bus_width(host, ios->bus_width);
+ /* + * Special case to avoid multiple clock changes during voltage + * switching. + */ + if (!reinit_uhs && + turning_on_clk && + host->timing == ios->timing && + host->version >= SDHCI_SPEC_300 && + !sdhci_presetable_values_change(host, ios)) + return; + ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
if (!(host->quirks & SDHCI_QUIRK_NO_HISPD_BIT)) { @@ -2357,6 +2406,7 @@ void sdhci_set_ios(struct mmc_host *mmc, }
sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2); + host->drv_type = ios->drv_type; } else { /* * According to SDHC Spec v3.00, if the Preset Value @@ -2384,19 +2434,14 @@ void sdhci_set_ios(struct mmc_host *mmc, host->ops->set_uhs_signaling(host, ios->timing); host->timing = ios->timing;
- if (!(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN) && - ((ios->timing == MMC_TIMING_UHS_SDR12) || - (ios->timing == MMC_TIMING_UHS_SDR25) || - (ios->timing == MMC_TIMING_UHS_SDR50) || - (ios->timing == MMC_TIMING_UHS_SDR104) || - (ios->timing == MMC_TIMING_UHS_DDR50) || - (ios->timing == MMC_TIMING_MMC_DDR52))) { + if (sdhci_preset_needed(host, ios->timing)) { u16 preset;
sdhci_enable_preset_value(host, true); preset = sdhci_get_preset_value(host); ios->drv_type = FIELD_GET(SDHCI_PRESET_DRV_MASK, preset); + host->drv_type = ios->drv_type; }
/* Re-enable SD Clock */ @@ -3707,6 +3752,7 @@ int sdhci_resume_host(struct sdhci_host sdhci_init(host, 0); host->pwr = 0; host->clock = 0; + host->reinit_uhs = true; mmc->ops->set_ios(mmc, &mmc->ios); } else { sdhci_init(host, (host->mmc->pm_flags & MMC_PM_KEEP_POWER)); @@ -3769,6 +3815,7 @@ int sdhci_runtime_resume_host(struct sdh /* Force clock and power re-program */ host->pwr = 0; host->clock = 0; + host->reinit_uhs = true; mmc->ops->start_signal_voltage_switch(mmc, &mmc->ios); mmc->ops->set_ios(mmc, &mmc->ios);
--- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -520,6 +520,8 @@ struct sdhci_host {
unsigned int clock; /* Current clock (MHz) */ u8 pwr; /* Current voltage */ + u8 drv_type; /* Current UHS-I driver type */ + bool reinit_uhs; /* Force UHS-related re-initialization */
bool runtime_suspended; /* Host is runtime suspended */ bool bus_on; /* Bus power prevents runtime suspend */