diff mbox series

[v2,7/8] mmc: zynq_sdhci: Wait till sd card detect state is stable

Message ID 20210727123642.2474-8-ashok.reddy.soma@xilinx.com
State Superseded
Delegated to: Michal Simek
Headers show
Series Arasan sdhci driver updates | expand

Commit Message

Ashok Reddy Soma July 27, 2021, 12:36 p.m. UTC 
From: T Karthik Reddy <t.karthik.reddy@xilinx.com>

As per SD spec when SD host controller is reset, it takes 1000msec
to detect the card state. In case, if we enable the sd bus voltage &
card detect state is not stable, then host controller will disable
the sd bus voltage.

In case of warm/subsystem reboot, due to unstable card detect state
host controller is disabling the sd bus voltage to sd card causing
sd card timeout error. So we wait for a maximum of 1000msec to get
the card detect state stable before we enable the sd bus voltage.

This current fix is workaround for now, this needs to be analysed
further. Zynqmp platform should behave the same as Versal, but we
did not encounter this issue as of now. So we are fixing it for
Versal only.

Signed-off-by: T Karthik Reddy <t.karthik.reddy@xilinx.com>
Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma@xilinx.com>
---

Changes in v2:
 - Changed return error from -EIO to -ETIMEDOUT in arasan_sdhci_probe()
   in card detect state stable workaround

 drivers/mmc/zynq_sdhci.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
diff mbox series

Patch

diff --git a/drivers/mmc/zynq_sdhci.c b/drivers/mmc/zynq_sdhci.c
index 81311d14ca..e71ba4eee0 100644
--- a/drivers/mmc/zynq_sdhci.c
+++ b/drivers/mmc/zynq_sdhci.c
@@ -689,6 +689,23 @@  static int arasan_sdhci_probe(struct udevice *dev)
 		return ret;
 	upriv->mmc = host->mmc;
 
+	/*
+	 * Wait for 1000msec till the card detect state gets stable
+	 * else host controller will set sd power bus voltage to 0.
+	 */
+	if (IS_ENABLED(CONFIG_ARCH_VERSAL)) {
+		u32 timeout = 1000;
+
+		while (((sdhci_readl(host, SDHCI_PRESENT_STATE) &
+			 SDHCI_CARD_STATE_STABLE) == 0) && timeout--) {
+			mdelay(1);
+		}
+		if (!timeout) {
+			dev_err(dev, "Sdhci card detect state not stable\n");
+			return -ETIMEDOUT;
+		}
+	}
+
 	return sdhci_probe(dev);
 }