linux-kernel - [PATCH 5.4 022/184] mmc: core: Set read only for SD cards with permanent write protect bit

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Date:   Mon, 10 May 2021 12:18:36 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Seunghui Lee <sh043.lee@...sung.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 5.4 022/184] mmc: core: Set read only for SD cards with permanent write protect bit

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

--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -135,6 +135,9 @@ 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:
 		/*
@@ -169,6 +172,9 @@ 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",