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Subject[PATCH v4] mmc: host: sdhci-sprd: Fix the incorrect soft reset operation when runtime resuming
Date
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 will 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 adds one condition to validate
the power mode 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>
---
Changess from v3:
- Use ios.power_mode to validate if the card is power down or not.

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..94f9726 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->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,
--
1.7.9.5
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