Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6fe9febb authored by Pierre Ossman's avatar Pierre Ossman Committed by Russell King
Browse files

[MMC] Always use a sector size of 512 bytes 



Both MMC and SD specifications specify (although a bit unclearly in
the MMC case) that a sector size of 512 bytes must always be
supported by the card.

Cards can report larger "native" size than this, and cards >= 2 GB
even must do so. Most other readers use 512 bytes even for these
cards. We should do the same to be compatible.

Signed-off-by: default avatarPierre Ossman <drzeus@drzeus.cx>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent d773d725

drivers/mmc/mmc_block.c

+4 −45
Original line number Diff line number Diff line
@@ -319,52 +319,11 @@ static struct mmc_blk_data *mmc_blk_alloc(struct mmc_card *card) 
	md->read_only = mmc_blk_readonly(card);



	/*

	 * Figure out a workable block size.  MMC cards have:

	 *  - two block sizes, one for read and one for write.

	 *  - may support partial reads and/or writes

	 *    (allows block sizes smaller than specified)

	 * Both SD and MMC specifications state (although a bit

	 * unclearly in the MMC case) that a block size of 512

	 * bytes must always be supported by the card.

	 */

	md->block_bits = card->csd.read_blkbits;

	if (card->csd.write_blkbits != card->csd.read_blkbits) {

		if (card->csd.write_blkbits < card->csd.read_blkbits &&

		    card->csd.read_partial) {

			/*

			 * write block size is smaller than read block

			 * size, but we support partial reads, so choose

			 * the smaller write block size.

			 */

			md->block_bits = card->csd.write_blkbits;

		} else if (card->csd.write_blkbits > card->csd.read_blkbits &&

			   card->csd.write_partial) {

			/*

			 * read block size is smaller than write block

			 * size, but we support partial writes.  Use read

			 * block size.

			 */

		} else {

			/*

			 * We don't support this configuration for writes.

			 */

			printk(KERN_ERR "%s: unable to select block size for "

				"writing (rb%u wb%u rp%u wp%u)\n",

				mmc_card_id(card),

				1 << card->csd.read_blkbits,

				1 << card->csd.write_blkbits,

				card->csd.read_partial,

				card->csd.write_partial);

			md->read_only = 1;

		}

	}



	/*

	 * Refuse to allow block sizes smaller than 512 bytes.

	 */

	if (md->block_bits < 9) {

		printk(KERN_ERR "%s: unable to support block size %u\n",

			mmc_card_id(card), 1 << md->block_bits);

		ret = -EINVAL;

		goto err_kfree;

	}

	md->block_bits = 9;



	md->disk = alloc_disk(1 << MMC_SHIFT);

	if (md->disk == NULL) {