Skip to content

Commit

Permalink
mmc_spi: do not check CID and CSD blocks with CRC16
Browse files Browse the repository at this point in the history
Some cards are not able to calculate a valid CRC16 value
for CID and CSD reads (CRC for 512 byte data blocks is OK).
By moving the CRC enable after the read of CID and CSD, these
cards can be used. This patch was tested with a faulty 8 GByte
takeMS Class 6 SDHC card. This patch was suggested by
Pierre Ossman.

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>
  • Loading branch information
Wolfgang Muees authored and Pierre Ossman committed Apr 8, 2009
1 parent 00adadc commit 9d9f25c
Showing 1 changed file with 12 additions and 9 deletions.
21 changes: 12 additions & 9 deletions drivers/mmc/core/sd.c
Original file line number Diff line number Diff line change
Expand Up @@ -362,15 +362,6 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
if (err)
goto err;

/*
* For SPI, enable CRC as appropriate.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_set_crc(host, use_spi_crc);
if (err)
goto err;
}

/*
* Fetch CID from card.
*/
Expand Down Expand Up @@ -457,6 +448,18 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
goto free_card;
}

/*
* For SPI, enable CRC as appropriate.
* This CRC enable is located AFTER the reading of the
* card registers because some SDHC cards are not able
* to provide valid CRCs for non-512-byte blocks.
*/
if (mmc_host_is_spi(host)) {
err = mmc_spi_set_crc(host, use_spi_crc);
if (err)
goto free_card;
}

/*
* Attempt to change to high-speed (if supported)
*/
Expand Down

0 comments on commit 9d9f25c

Please sign in to comment.