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SubjectRe: [PATCH v2] mmc: host: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming
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On 16/07/19 10:31 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 v1:
> - Add a specific reset operation instead of changing the core to avoid
> affecting other hardware.
> ---
> drivers/mmc/host/sdhci-sprd.c | 38 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-sprd.c b/drivers/mmc/host/sdhci-sprd.c
> index 603a5d9..174b566 100644
> --- a/drivers/mmc/host/sdhci-sprd.c
> +++ b/drivers/mmc/host/sdhci-sprd.c
> @@ -373,6 +373,42 @@ 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;
> + ktime_t timeout;
> +
> + /*
> + * 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))
> + mask = SDHCI_RESET_CMD | SDHCI_RESET_DATA;
> +

Here you could just call sdhci_reset(host, mask) instead of below.

> + sdhci_writeb(host, mask, SDHCI_SOFTWARE_RESET);
> +
> + /* Wait max 100 ms */
> + timeout = ktime_add_ms(ktime_get(), 100);
> +
> + /* hw clears the bit when it's done */
> + while (1) {
> + bool timedout = ktime_after(ktime_get(), timeout);
> +
> + if (!(sdhci_readb(host, SDHCI_SOFTWARE_RESET) & mask))
> + break;
> + if (timedout) {
> + pr_err("%s: Reset 0x%x never completed.\n",
> + mmc_hostname(host->mmc), (int)mask);
> + sdhci_dumpregs(host);
> + return;
> + }
> + udelay(10);
> + }
> +}
> +
> static struct sdhci_ops sdhci_sprd_ops = {
> .read_l = sdhci_sprd_readl,
> .write_l = sdhci_sprd_writel,
> @@ -381,7 +417,7 @@ 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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