[RFC PATCH v3.1 12/27] mmc: sdhci-uhs2: add reset function

AKASHI Takahiro
2020-11-06T02:28:37Z

Sdhci_uhs2_reset() does a UHS-II specific reset operation.

Signed-off-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
---
drivers/mmc/host/sdhci-uhs2.c | 49 +++++++++++++++++++++++++++++++++++
drivers/mmc/host/sdhci-uhs2.h | 1 +
drivers/mmc/host/sdhci.c | 3 ++-
drivers/mmc/host/sdhci.h | 1 +
4 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
index 08905ed081fb..e2b9743fe17d 100644
--- a/drivers/mmc/host/sdhci-uhs2.c
+++ b/drivers/mmc/host/sdhci-uhs2.c
@@ -10,6 +10,7 @@
* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
*/

+#include <linux/delay.h>
#include <linux/module.h>

#include "sdhci.h"
@@ -49,6 +50,54 @@ void sdhci_uhs2_dump_regs(struct sdhci_host *host)
}
EXPORT_SYMBOL_GPL(sdhci_uhs2_dump_regs);

+/*****************************************************************************\
+ * *
+ * Low level functions *
+ * *
+\*****************************************************************************/
+
+/**
+ * sdhci_uhs2_reset - invoke SW reset
+ * @host: SDHCI host
+ * @mask: Control mask
+ *
+ * Invoke SW reset, depending on a bit in @mask and wait for completion.
+ */
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask)
+{
+ unsigned long timeout;
+
+ if (!(host->mmc->caps & MMC_CAP_UHS2))
+ return;
+
+ sdhci_writew(host, mask, SDHCI_UHS2_SW_RESET);
+
+ if (mask & SDHCI_UHS2_SW_RESET_FULL) {
+ host->clock = 0;
+ /* Reset-all turns off SD Bus Power */
+ if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
+ sdhci_runtime_pm_bus_off(host);
+ }
+
+ /* Wait max 100 ms */
+ timeout = 10000;
+
+ /* hw clears the bit when it's done */
+ while (sdhci_readw(host, SDHCI_UHS2_SW_RESET) & mask) {
+ if (timeout == 0) {
+ pr_err("%s: %s: Reset 0x%x never completed.\n",
+ __func__, mmc_hostname(host->mmc), (int)mask);
+ pr_err("%s: clean reset bit\n",
+ mmc_hostname(host->mmc));
+ sdhci_writeb(host, 0, SDHCI_UHS2_SW_RESET);
+ return;
+ }
+ timeout--;
+ udelay(10);
+ }
+}
+EXPORT_SYMBOL_GPL(sdhci_uhs2_reset);
+
/*****************************************************************************\
* *
* Driver init/exit *
diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
index b9529d32b58d..7bb7a0d67109 100644
--- a/drivers/mmc/host/sdhci-uhs2.h
+++ b/drivers/mmc/host/sdhci-uhs2.h
@@ -210,5 +210,6 @@
struct sdhci_host;

void sdhci_uhs2_dump_regs(struct sdhci_host *host);
+void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);

#endif /* __SDHCI_UHS2_H */
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index d4a57e8c9bb8..af336bdb4305 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -195,13 +195,14 @@ static void sdhci_runtime_pm_bus_on(struct sdhci_host *host)
pm_runtime_get_noresume(host->mmc->parent);
}

-static void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
+void sdhci_runtime_pm_bus_off(struct sdhci_host *host)
{
if (!host->bus_on)
return;
host->bus_on = false;
pm_runtime_put_noidle(host->mmc->parent);
}
+EXPORT_SYMBOL_GPL(sdhci_runtime_pm_bus_off);

void sdhci_reset(struct sdhci_host *host, u8 mask)
{
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index d9d7a76cedc1..b9932423db08 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -831,6 +831,7 @@ static inline void sdhci_read_caps(struct sdhci_host *host)
__sdhci_read_caps(host, NULL, NULL, NULL);
}

+void sdhci_runtime_pm_bus_off(struct sdhci_host *host);
u16 sdhci_calc_clk(struct sdhci_host *host, unsigned int clock,
unsigned int *actual_clock);
void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
--
2.28.0