linux-kernel - [PATCH v4 2/2] mmc: block: Update ext_csd.cache

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Message-Id: <20210420134641.57343-3-avri.altman@wdc.com>
Date:   Tue, 20 Apr 2021 16:46:41 +0300
From:   Avri Altman <avri.altman@....com>
To:     Ulf Hansson <ulf.hansson@...aro.org>, linux-mmc@...r.kernel.org,
        Adrian Hunter <adrian.hunter@...el.com>
Cc:     linux-kernel@...r.kernel.org, Avri Altman <avri.altman@....com>
Subject: [PATCH v4 2/2] mmc: block: Update ext_csd.cache_ctrl if it was written

The cache function can be turned ON and OFF by writing to the CACHE_CTRL
byte (EXT_CSD byte [33]).  However,  card->ext_csd.cache_ctrl is only
set on init if cache size > 0.

Fix that by explicitly setting ext_csd.cache_ctrl on ext-csd write.

Signed-off-by: Avri Altman <avri.altman@....com>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
---
 drivers/mmc/core/block.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 24e1ecbdd510..7e70f11e85e2 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -572,6 +572,18 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
 		main_md->part_curr = value & EXT_CSD_PART_CONFIG_ACC_MASK;
 	}
 
+	/*
+	 * Make sure to update CACHE_CTRL in case it was changed. The cache
+	 * will get turned back on if the card is re-initialized, e.g.
+	 * suspend/resume or hw reset in recovery.
+	 */
+	if ((MMC_EXTRACT_INDEX_FROM_ARG(cmd.arg) == EXT_CSD_CACHE_CTRL) &&
+	    (cmd.opcode == MMC_SWITCH)) {
+		u8 value = MMC_EXTRACT_VALUE_FROM_ARG(cmd.arg) & 1;
+
+		card->ext_csd.cache_ctrl = value;
+	}
+
 	/*
 	 * According to the SD specs, some commands require a delay after
 	 * issuing the command.
-- 
2.25.1