linux-kernel - [PATCH] mmc: core: set read only with permanent write protect

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Message-Id: <20210222083156.19158-1-sh043.lee@samsung.com>
Date:   Mon, 22 Feb 2021 17:31:56 +0900
From:   Seunghui Lee <sh043.lee@...sung.com>
To:     ulf.hansson@...aro.org, pali@...nel.org, huyue2@...ong.com,
        tiantao6@...ilicon.com, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     grant.jung@...sung.com, jt77.jang@...sung.com,
        dh0421.hwang@...sung.com, junwoo80.lee@...sung.com,
        jangsub.yi@...sung.com, cw9316.lee@...sung.com,
        sh8267.baek@...sung.com, wkon.kim@...sung.com,
        Seunghui Lee <sh043.lee@...sung.com>
Subject: [PATCH] mmc: core: set read only with permanent write protect

Some of SD cards sets permanent write protection
due to lifespan or internal problem.
Host can find out it's protected permanantly during initialization.
Once set read only during initialization,
it could prevent unnecessary write operation in it.

Signed-off-by: Seunghui Lee <sh043.lee@...sung.com>
---
 drivers/mmc/core/sd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 6fa51a6ed058..2c48d6504101 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -135,6 +135,9 @@ static int mmc_decode_csd(struct mmc_card *card)
 			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_card *card)
 		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",
-- 
2.29.0