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SubjectRe: [PATCH v3] mmc: host: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming
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On 16/07/19 11:39 AM, Baolin Wang wrote:
> In sdhci_runtime_resume_host() function, we will always do software reset
> for all, which will cause Spreadtrum host controller work abnormally after
> resuming.
>
> Thus for Spreadtrum platform that do not power down the SD/eMMC card during
> runtime suspend, we should not do software reset for all. To fix this
> issue, adding a specific reset operation that add one condition to validate
> the MMC_CAP_AGGRESSIVE_PM to decide if we can do software reset for all or
> just reset command and data lines.
>
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
> Changes from v2:
> - Simplify the sdhci_sprd_reset() by issuing sdhci_reset().
>
> Changes from v1:
> - Add a specific reset operation instead of changing the core to avoid
> affecting other hardware.
> ---
> drivers/mmc/host/sdhci-sprd.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
> index 603a5d9..bc9393c 100644
> --- a/drivers/mmc/host/sdhci-sprd.c
> +++ b/drivers/mmc/host/sdhci-sprd.c
> @@ -373,6 +373,23 @@ static unsigned int sdhci_sprd_get_max_timeout_count(struct sdhci_host *host)
> return 1 << 31;
> }
>
> +static void sdhci_sprd_reset(struct sdhci_host *host, u8 mask)
> +{
> + struct mmc_host *mmc = host->mmc;
> +
> + /*
> + * When try to reset controller after runtime suspend, we should not
> + * reset for all if the SD/eMMC card is not power down, just reset
> + * command and data lines instead. Otherwise will meet some strange
> + * behaviors for Spreadtrum host controller.
> + */
> + if (host->runtime_suspended && (mask & SDHCI_RESET_ALL) &&
> + !(mmc->caps & MMC_CAP_AGGRESSIVE_PM))

MMC_CAP_AGGRESSIVE_PM does not necessarily mean that the card will have been
runtime suspended.

What about checking if the card power is on? i.e.

if (host->runtime_suspended && (mask & SDHCI_RESET_ALL) &&
mmc->ios.power_mode == MMC_POWER_ON)

> + mask = SDHCI_RESET_CMD | SDHCI_RESET_DATA;
> +
> + sdhci_reset(host, mask);
> +}
> +
> static struct sdhci_ops sdhci_sprd_ops = {
> .read_l = sdhci_sprd_readl,
> .write_l = sdhci_sprd_writel,
> @@ -381,7 +398,7 @@ static unsigned int sdhci_sprd_get_max_timeout_count(struct sdhci_host *host)
> .get_max_clock = sdhci_sprd_get_max_clock,
> .get_min_clock = sdhci_sprd_get_min_clock,
> .set_bus_width = sdhci_set_bus_width,
> - .reset = sdhci_reset,
> + .reset = sdhci_sprd_reset,
> .set_uhs_signaling = sdhci_sprd_set_uhs_signaling,
> .hw_reset = sdhci_sprd_hw_reset,
> .get_max_timeout_count = sdhci_sprd_get_max_timeout_count,
>

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