On 09/03/2013 11:29 AM, Ulf Hansson wrote:
> If a corresponding power domain exists for the device and it manages
> to cut the domain regulator while the device is runtime suspended,
> the IP loses it's registers context. We restore the context in the
> .runtime_resume callback from the existing register caches to adapt
> to this siutuation.
>
> We also want to make sure the registers are in a known state while
> restoring context in the case when the power domain did not drop the
> power, since there are restrictions for the order of writing to these
> registers. To handle this, we clear the registers in the
> .runtime_suspend callback.
>
> Signed-off-by: Ulf Hansson <ulf.hans...@linaro.org>
> Acked-by: Rickard Andersson <rickard.anders...@stericsson.com>
> Cc: Daniel Lezcano <daniel.lezc...@linaro.org>
> ---
Reviewed-by: Daniel Lezcano <daniel.lezc...@linaro.org>
> drivers/mmc/host/mmci.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 82afcd3..97e541b 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -62,6 +62,7 @@ static unsigned int fmax = 515633;
> * @signal_direction: input/out direction of bus signals can be indicated
> * @pwrreg_clkgate: MMCIPOWER register must be used to gate the clock
> * @busy_detect: true if busy detection on dat0 is supported
> + * @pwrreg_nopower: bits in MMCIPOWER don't controls ext. power supply
> */
> struct variant_data {
> unsigned int clkreg;
> @@ -76,6 +77,7 @@ struct variant_data {
> bool signal_direction;
> bool pwrreg_clkgate;
> bool busy_detect;
> + bool pwrreg_nopower;
> };
>
> static struct variant_data variant_arm = {
> @@ -109,6 +111,7 @@ static struct variant_data variant_u300 = {
> .pwrreg_powerup = MCI_PWR_ON,
> .signal_direction = true,
> .pwrreg_clkgate = true,
> + .pwrreg_nopower = true,
> };
>
> static struct variant_data variant_nomadik = {
> @@ -121,6 +124,7 @@ static struct variant_data variant_nomadik = {
> .pwrreg_powerup = MCI_PWR_ON,
> .signal_direction = true,
> .pwrreg_clkgate = true,
> + .pwrreg_nopower = true,
> };
>
> static struct variant_data variant_ux500 = {
> @@ -135,6 +139,7 @@ static struct variant_data variant_ux500 = {
> .signal_direction = true,
> .pwrreg_clkgate = true,
> .busy_detect = true,
> + .pwrreg_nopower = true,
> };
>
> static struct variant_data variant_ux500v2 = {
> @@ -150,6 +155,7 @@ static struct variant_data variant_ux500v2 = {
> .signal_direction = true,
> .pwrreg_clkgate = true,
> .busy_detect = true,
> + .pwrreg_nopower = true,
> };
>
> static int mmci_card_busy(struct mmc_host *mmc)
> @@ -1759,6 +1765,41 @@ static int mmci_resume(struct device *dev)
> #endif
>
> #ifdef CONFIG_PM_RUNTIME
> +static void mmci_save(struct mmci_host *host)
> +{
> + unsigned long flags;
> +
> + if (host->variant->pwrreg_nopower) {
> + spin_lock_irqsave(&host->lock, flags);
> +
> + writel(0, host->base + MMCIMASK0);
> + writel(0, host->base + MMCIDATACTRL);
> + writel(0, host->base + MMCIPOWER);
> + writel(0, host->base + MMCICLOCK);
> + mmci_reg_delay(host);
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> + }
> +
> +}
> +
> +static void mmci_restore(struct mmci_host *host)
> +{
> + unsigned long flags;
> +
> + if (host->variant->pwrreg_nopower) {
> + spin_lock_irqsave(&host->lock, flags);
> +
> + writel(host->clk_reg, host->base + MMCICLOCK);
> + writel(host->datactrl_reg, host->base + MMCIDATACTRL);
> + writel(host->pwr_reg, host->base + MMCIPOWER);
> + writel(MCI_IRQENABLE, host->base + MMCIMASK0);
> + mmci_reg_delay(host);
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> + }
> +}
> +
> static int mmci_runtime_suspend(struct device *dev)
> {
> struct amba_device *adev = to_amba_device(dev);
> @@ -1767,6 +1808,7 @@ static int mmci_runtime_suspend(struct device *dev)
> if (mmc) {
> struct mmci_host *host = mmc_priv(mmc);
> pinctrl_pm_select_sleep_state(dev);
> + mmci_save(host);
> clk_disable_unprepare(host->clk);
> }
>
> @@ -1781,6 +1823,7 @@ static int mmci_runtime_resume(struct device *dev)
> if (mmc) {
> struct mmci_host *host = mmc_priv(mmc);
> clk_prepare_enable(host->clk);
> + mmci_restore(host);
> pinctrl_pm_select_default_state(dev);
> }
>
>
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