[PATCH 2/2] drivers: mmc: Add wait_dat0 support for sdhci driver

stcarlso
2021-08-17T19:48:22Z

Adds an implementation of the wait_dat0 MMC operation for the DM SDHCI
driver, allowing the driver to continue when the card is ready rather
than waiting for the worst case time on each MMC switch operation.

Signed-off-by: Stephen Carlson <stcarlso@linux.microsoft.com>
---
drivers/mmc/sdhci.c | 20 ++++++++++++++++++++
include/sdhci.h | 2 ++
2 files changed, 22 insertions(+)

diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index eea4701d8a..bb55e00ef5 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -775,6 +775,25 @@ static int sdhci_get_cd(struct udevice *dev)
return value;
}

+static int sdhci_wait_dat0(struct udevice *dev, int state,
+ int timeout_us)
+{
+ int tmp;
+ struct mmc *mmc = mmc_get_mmc_dev(dev);
+ struct sdhci_host *host = mmc->priv;
+ unsigned long timeout = timer_get_us() + timeout_us;
+
+ // readx_poll_timeout is unsuitable because sdhci_readl accepts
+ // two arguments
+ do {
+ tmp = sdhci_readl(host, SDHCI_PRESENT_STATE);
+ if (!!(tmp & SDHCI_DATA_0_LVL_MASK) == !!state)
+ return 0;
+ } while (!timeout_us || !time_after(timer_get_us(), timeout));
+
+ return -ETIMEDOUT;
+}
+
const struct dm_mmc_ops sdhci_ops = {
.send_cmd = sdhci_send_command,
.set_ios = sdhci_set_ios,
@@ -783,6 +802,7 @@ const struct dm_mmc_ops sdhci_ops = {
#ifdef MMC_SUPPORTS_TUNING
.execute_tuning = sdhci_execute_tuning,
#endif
+ .wait_dat0 = sdhci_wait_dat0,
};
#else
static const struct mmc_ops sdhci_ops = {
diff --git a/include/sdhci.h b/include/sdhci.h
index 0ae9471ad7..dd4eb41442 100644
--- a/include/sdhci.h
+++ b/include/sdhci.h
@@ -65,6 +65,8 @@
#define SDHCI_CARD_STATE_STABLE BIT(17)
#define SDHCI_CARD_DETECT_PIN_LEVEL BIT(18)
#define SDHCI_WRITE_PROTECT BIT(19)
+#define SDHCI_DATA_LVL_MASK 0x00F00000
+#define SDHCI_DATA_0_LVL_MASK BIT(20)

#define SDHCI_HOST_CONTROL 0x28
#define SDHCI_CTRL_LED BIT(0)
--
2.17.1