Commit 07d40576 authored Nov 11, 2018 by Phil Elwell Committed by Ulf Hansson Dec 17, 2018

mmc: bcm2835: Recover from MMC_SEND_EXT_CSD

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>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

parent f6000a4e

drivers/mmc/host/bcm2835.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -762,6 +762,8 @@ 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 {
		@@ -770,6 +772,13 @@ 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;
		}

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