diff mbox series

[2/7] mmc: bcm2835: Recover from MMC_SEND_EXT_CSD

Message ID 1541943930-23873-3-git-send-email-stefan.wahren@i2se.com (mailing list archive)
State New, archived
Headers show
Series mmc: Several fixes for bcm2835 driver | expand

Commit Message

Stefan Wahren Nov. 11, 2018, 1:45 p.m. UTC 
From: Phil Elwell <phil@raspberrypi.org>

If the user issues an "mmc extcsd read", the SD controller receives
what it thinks is a SEND_IF_COND command with an unexpected data block.
The resulting operations leave the FSM stuck in READWAIT, a state which
persists until the MMC framework resets the controller, by which point
the root filesystem is likely to have been unmounted.

A less heavyweight solution is to detect the condition and nudge the
FSM by asserting the (self-clearing) FORCE_DATA_MODE bit.

Link: https://github.com/raspberrypi/linux/issues/2728
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---
 drivers/mmc/host/bcm2835.c | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/drivers/mmc/host/bcm2835.c b/drivers/mmc/host/bcm2835.c
index f1712df..a251be2 100644
--- a/drivers/mmc/host/bcm2835.c
+++ b/drivers/mmc/host/bcm2835.c
@@ -773,6 +773,8 @@  static void bcm2835_finish_command(struct bcm2835_host *host)
 
 		if (!(sdhsts & SDHSTS_CRC7_ERROR) ||
 		    (host->cmd->opcode != MMC_SEND_OP_COND)) {
+			u32 edm, fsm;
+
 			if (sdhsts & SDHSTS_CMD_TIME_OUT) {
 				host->cmd->error = -ETIMEDOUT;
 			} else {
@@ -781,6 +783,13 @@  static void bcm2835_finish_command(struct bcm2835_host *host)
 				bcm2835_dumpregs(host);
 				host->cmd->error = -EILSEQ;
 			}
+			edm = readl(host->ioaddr + SDEDM);
+			fsm = edm & SDEDM_FSM_MASK;
+			if (fsm == SDEDM_FSM_READWAIT ||
+			    fsm == SDEDM_FSM_WRITESTART1)
+				/* Kick the FSM out of its wait */
+				writel(edm | SDEDM_FORCE_DATA_MODE,
+				       host->ioaddr + SDEDM);
 			bcm2835_finish_request(host);
 			return;
 		}