[PATCH 4.4 013/190] mmc: core: Set read only for SD cards with permanent write protect bit

[Greg Kroah-Hartman]

From: Seunghui Lee <sh043.lee@xxxxxxxxxxx>

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

--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -138,6 +138,9 @@ 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:
 		/*
@@ -172,6 +175,9 @@ 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",