On 30/08/17 15:51, Vijay Viswanath wrote: > Register writes which change voltage of IO lines or turn the IO bus > on/off require controller to be ready before progressing further. When > the controller is ready, it will generate a power irq which needs to be > handled. The thread which initiated the register write should wait for > power irq to complete. This will be done through the new sdhc msm write > APIs which will check whether the particular write can trigger a power > irq and wait for it with a timeout if it is expected. > The SDHC core power control IRQ gets triggered when - > * There is a state change in power control bit (bit 0) > of SDHCI_POWER_CONTROL register. > * There is a state change in 1.8V enable bit (bit 3) of > SDHCI_HOST_CONTROL2 register. > * Bit 1 of SDHCI_SOFTWARE_RESET is set. > > Signed-off-by: Vijay Viswanath <vviswana@xxxxxxxxxxxxxx> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > --- > drivers/mmc/host/sdhci-msm.c | 69 +++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 68 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c > index e3e385e..a4a78b5 100644 > --- a/drivers/mmc/host/sdhci-msm.c > +++ b/drivers/mmc/host/sdhci-msm.c > @@ -1070,7 +1070,6 @@ static void sdhci_msm_check_power_status(struct sdhci_host *host, u32 req_type) > __WARN_printf("%s: pwr_irq for req: (%d) timed out\n", > mmc_hostname(host->mmc), req_type); > } > - msm_host->pwr_irq_flag = 0; > pr_debug("%s: %s: request %d done\n", mmc_hostname(host->mmc), > __func__, req_type); > } > @@ -1250,6 +1249,70 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) > __sdhci_msm_set_clock(host, clock); > } > > +#ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS > +/* > + * Platform specific register write functions. This is so that, if any > + * register write needs to be followed up by platform specific actions, > + * they can be added here. These functions can go to sleep when writes > + * to certain registers are done. > + * These functions are relying on sdhci_set_ios not using spinlock. > + */ > +static int __sdhci_msm_check_write(struct sdhci_host *host, u16 val, int reg) > +{ > + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); > + u32 req_type = 0; > + > + switch (reg) { > + case SDHCI_HOST_CONTROL2: > + req_type = (val & SDHCI_CTRL_VDD_180) ? REQ_IO_LOW : > + REQ_IO_HIGH; > + break; > + case SDHCI_SOFTWARE_RESET: > + if (host->pwr && (val & SDHCI_RESET_ALL)) > + req_type = REQ_BUS_OFF; > + break; > + case SDHCI_POWER_CONTROL: > + req_type = !val ? REQ_BUS_OFF : REQ_BUS_ON; > + break; > + } > + > + if (req_type) { > + msm_host->pwr_irq_flag = 0; > + /* > + * Since this register write may trigger a power irq, ensure > + * all previous register writes are complete by this point. > + */ > + mb(); > + } > + return req_type; > +} > + > +/* This function may sleep*/ > +static void sdhci_msm_writew(struct sdhci_host *host, u16 val, int reg) > +{ > + u32 req_type = 0; > + > + req_type = __sdhci_msm_check_write(host, val, reg); > + writew_relaxed(val, host->ioaddr + reg); > + > + if (req_type) > + sdhci_msm_check_power_status(host, req_type); > +} > + > +/* This function may sleep*/ > +static void sdhci_msm_writeb(struct sdhci_host *host, u8 val, int reg) > +{ > + u32 req_type = 0; > + > + req_type = __sdhci_msm_check_write(host, val, reg); > + > + writeb_relaxed(val, host->ioaddr + reg); > + > + if (req_type) > + sdhci_msm_check_power_status(host, req_type); > +} > +#endif > static const struct of_device_id sdhci_msm_dt_match[] = { > { .compatible = "qcom,sdhci-msm-v4" }, > {}, > @@ -1264,6 +1327,10 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) > .get_max_clock = sdhci_msm_get_max_clock, > .set_bus_width = sdhci_set_bus_width, > .set_uhs_signaling = sdhci_msm_set_uhs_signaling, > +#ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS > + .write_w = sdhci_msm_writew, > + .write_b = sdhci_msm_writeb, > +#endif > }; > > static const struct sdhci_pltfm_data sdhci_msm_pdata = { > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html