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mmc: core: Add cache control for eMMC4.5 device

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This patch adds cache feature of eMMC4.5 Spec.
If device supports cache capability, host can utilize some specific
operations.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Seungwon Jeon
2011-10-14 14:03:21 +09:00
committed by Chris Ball
parent 71fe3eb0d0
commit 881d1c25f7
7 changed files with 104 additions and 6 deletions
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23
drivers/mmc/core/mmc.c
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@@ -470,6 +470,12 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
} else
card->ext_csd.generic_cmd6_time = 0;
card->ext_csd.cache_size =
ext_csd[EXT_CSD_CACHE_SIZE + 0] << 0 |
ext_csd[EXT_CSD_CACHE_SIZE + 1] << 8 |
ext_csd[EXT_CSD_CACHE_SIZE + 2] << 16 |
ext_csd[EXT_CSD_CACHE_SIZE + 3] << 24;
out:
return err;
}
@@ -1020,6 +1026,23 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
}
}
/*
* If cache size is higher than 0, this indicates
* the existence of cache and it can be turned on.
*/
if ((host->caps2 & MMC_CAP2_CACHE_CTRL) &&
card->ext_csd.cache_size > 0) {
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_CACHE_CTRL, 1, 0);
if (err && err != -EBADMSG)
goto free_card;
/*
* Only if no error, cache is turned on successfully.
*/
card->ext_csd.cache_ctrl = err ? 0 : 1;
}
if (!oldcard)
host->card = card;