[PATCH 1/2] drivers: mmc: Add wait_dat0 support for Freescale eSDHC driver

[stcarlso]

From: Stephen Carlson <stcar...@linux.microsoft.com>

Adds an implementation of the wait_dat0 MMC operation for the Freescale
eSHDC 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 <stcar...@linux.microsoft.com>
---
 drivers/mmc/fsl_esdhc.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 1d98fa65c4..f74289a677 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -27,6 +27,7 @@
 #include <dm/device_compat.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
+#include <linux/iopoll.h>
 #include <linux/dma-mapping.h>
 #include <sdhci.h>
 
@@ -1145,6 +1146,20 @@ int fsl_esdhc_hs400_prepare_ddr(struct udevice *dev)
        return 0;
 }
 
+static int fsl_esdhc_wait_dat0(struct udevice *dev, int state,
+                              int timeout_us)
+{
+       int ret;
+       u32 tmp;
+       struct fsl_esdhc_priv *priv = dev_get_priv(dev);
+       struct fsl_esdhc *regs = priv->esdhc_regs;
+
+       ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp,
+                                !!(tmp & PRSSTAT_DAT0) == !!state,
+                                timeout_us);
+       return ret;
+}
+
 static const struct dm_mmc_ops fsl_esdhc_ops = {
        .get_cd         = fsl_esdhc_get_cd,
        .send_cmd       = fsl_esdhc_send_cmd,
@@ -1154,6 +1169,7 @@ static const struct dm_mmc_ops fsl_esdhc_ops = {
 #endif
        .reinit = fsl_esdhc_reinit,
        .hs400_prepare_ddr = fsl_esdhc_hs400_prepare_ddr,
+       .wait_dat0 = fsl_esdhc_wait_dat0,
 };
 
 static const struct udevice_id fsl_esdhc_ids[] = {
-- 
2.17.1