[PATCH 4.9 013/240] mmc: core: Set read only for SD cards with permanent write protect bit

Greg Kroah-Hartman
2021-05-20T11:02:18Z

From: Seunghui Lee <sh043.lee@samsung.com>

commit 917a5336f2c27928be270226ab374ed0cbf3805d upstream.

Some of SD cards sets permanent write protection bit in their CSD register,
due to lifespan or internal problem. To avoid unnecessary I/O write
operations, let's parse the bits in the CSD during initialization and mark
the card as read only for this case.

Signed-off-by: Seunghui Lee <sh043.lee@samsung.com>
Link: https://lore.kernel.org/r/20210222083156.19158-1-sh043.lee@samsung.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/mmc/core/sd.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -136,6 +136,9 @@ static int mmc_decode_csd(struct mmc_car
csd->erase_size = UNSTUFF_BITS(resp, 39, 7) + 1;
csd->erase_size <<= csd->write_blkbits - 9;
}
+
+ if (UNSTUFF_BITS(resp, 13, 1))
+ mmc_card_set_readonly(card);
break;
case 1:
/*
@@ -170,6 +173,9 @@ static int mmc_decode_csd(struct mmc_car
csd->write_blkbits = 9;
csd->write_partial = 0;
csd->erase_size = 1;
+
+ if (UNSTUFF_BITS(resp, 13, 1))
+ mmc_card_set_readonly(card);
break;
default:
pr_err("%s: unrecognised CSD structure version %d\n",