From: Wolfgang Muees <[email protected]>
o Some cards are not able to calculate a valid CRC16 value
for CID and CSD reads (CRC for 512 byte data blocks is OK).
So ommit the check for CRC16, as CID and CSD have a checksum
inside the block.
Signed-off-by: Wolfgang Muees <[email protected]>
---
This is one of a line of patches to enhance the usability of
the mmc spi host port driver from "don't work with most SD cards"
to "work with nearly all SD cards" (including those ugly cards
with non-byte-aligned responses).
diff -uprN 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c
--- 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2009-03-11 13:42:48.000000000 +0100
+++ 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c 2009-03-11 13:43:13.000000000 +0100
@@ -762,7 +762,11 @@ mmc_spi_readblock(struct mmc_spi_host *h
return -EIO;
}
- if (host->mmc->use_spi_crc) {
+ /* Omitt the CRC check for CID and CSD reads. There are some SDHC
+ * cards which don't supply a valid CRC after CID reads.
+ * Note that the CID has it's own CRC7 value inside the data block.
+ */
+ if (host->mmc->use_spi_crc && (t->len == MMC_SPI_BLOCKSIZE)) {
u16 crc = crc_itu_t(0, t->rx_buf, t->len);
be16_to_cpus(&scratch->crc_val);
---
regards
i. A. Wolfgang M?es
--
Auerswald GmbH & Co. KG
Hardware Development
Telefon: +49 (0)5306 9219 0
Telefax: +49 (0)5306 9219 94
E-Mail: [email protected]
Web: http://www.auerswald.de
?
--------------------------------------------------------------
Auerswald GmbH & Co. KG, Vor den Grash?fen 1, 38162 Cremlingen
Registriert beim AG Braunschweig HRA 13289
p.h.G Auerswald Gesch?ftsf?hrungsges. mbH
Registriert beim AG Braunschweig HRB 7463
Gesch?ftsf?hrer: Dipl-Ing. Gerhard Auerswald
On Wednesday 11 March 2009, Wolfgang M?es wrote:
> From: Wolfgang Muees <[email protected]>
>
> o Some cards are not able to calculate a valid CRC16 value
> for CID and CSD reads (CRC for 512 byte data blocks is OK).
> So ommit the check for CRC16, as CID and CSD have a checksum
> inside the block.
>
> Signed-off-by: Wolfgang Muees <[email protected]>
Acked-by: David Brownell <[email protected]>
>
> ---
> This is one of a line of patches to enhance the usability of
> the mmc spi host port driver from "don't work with most SD cards"
> to "work with nearly all SD cards" (including those ugly cards
> with non-byte-aligned responses).
>
> diff -uprN 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c
> --- 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2009-03-11 13:42:48.000000000 +0100
> +++ 2_6_29_rc7_patch4_no_crc_on_CID_CSD/drivers/mmc/host/mmc_spi.c 2009-03-11 13:43:13.000000000 +0100
> @@ -762,7 +762,11 @@ mmc_spi_readblock(struct mmc_spi_host *h
> return -EIO;
> }
>
> - if (host->mmc->use_spi_crc) {
> + /* Omitt the CRC check for CID and CSD reads. There are some SDHC
> + * cards which don't supply a valid CRC after CID reads.
> + * Note that the CID has it's own CRC7 value inside the data block.
> + */
> + if (host->mmc->use_spi_crc && (t->len == MMC_SPI_BLOCKSIZE)) {
> u16 crc = crc_itu_t(0, t->rx_buf, t->len);
>
> be16_to_cpus(&scratch->crc_val);
>
> ---
> regards
>
> i. A. Wolfgang M?es
> --
> Auerswald GmbH & Co. KG
> Hardware Development
> Telefon: +49 (0)5306 9219 0
> Telefax: +49 (0)5306 9219 94
> E-Mail: [email protected]
> Web: http://www.auerswald.de
> ?
> --------------------------------------------------------------
> Auerswald GmbH & Co. KG, Vor den Grash?fen 1, 38162 Cremlingen
> Registriert beim AG Braunschweig HRA 13289
> p.h.G Auerswald Gesch?ftsf?hrungsges. mbH
> Registriert beim AG Braunschweig HRB 7463
> Gesch?ftsf?hrer: Dipl-Ing. Gerhard Auerswald
>
>