diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.14/950-0434-mmc-bcm2835-Recover-from-MMC_SEND_EXT_CSD.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.14/950-0434-mmc-bcm2835-Recover-from-MMC_SEND_EXT_CSD.patch | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.14/950-0434-mmc-bcm2835-Recover-from-MMC_SEND_EXT_CSD.patch b/target/linux/brcm2708/patches-4.14/950-0434-mmc-bcm2835-Recover-from-MMC_SEND_EXT_CSD.patch new file mode 100644 index 0000000000..9a9e811038 --- /dev/null +++ b/target/linux/brcm2708/patches-4.14/950-0434-mmc-bcm2835-Recover-from-MMC_SEND_EXT_CSD.patch @@ -0,0 +1,50 @@ +From c2eae29f6503cf29ac6a204c51132cfed33d203e Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 26 Oct 2018 17:40:44 +0100 +Subject: [PATCH 434/454] 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. + +N.B. This workaround was essentially discovered by accident and without +a full understanding the inner workings of the controller, so it is +fortunate that the "fix" only modifies error paths. + +See: 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(+) + +--- a/drivers/mmc/host/bcm2835.c ++++ b/drivers/mmc/host/bcm2835.c +@@ -772,6 +772,8 @@ static void bcm2835_finish_command(struc + + 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 { +@@ -780,6 +782,13 @@ static void bcm2835_finish_command(struc + 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; + } |