[PATCH 2/7] mmc_spi: wait more bytes for card response

[PATCH 2/7] mmc_spi: wait more bytes for card response

[Wolfgang Mües]

From: Wolfgang Muees <wolfgang.mues@auerswald.de>

o some cards are slower than the standard allows and need more
  time to respond to a command. Max. observed number of bytes
  was 12.

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>

---
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_patch1_spi_mode_3/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c
--- 2_6_29_rc7_patch1_spi_mode_3/drivers/mmc/host/mmc_spi.c	2009-03-11 12:58:47.000000000 +0100
+++ 2_6_29_rc7_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c	2009-03-11 13:00:06.000000000 +0100
@@ -279,8 +279,11 @@ static int mmc_spi_response_get(struct m
 		 * so it can always DMA directly into the target buffer.
 		 * It'd probably be better to memcpy() the first chunk and
 		 * avoid extra i/o calls...
+		 *
+		 * Note we check for more than 8 bytes, because in practice,
+		 * some SD cards are slow...
 		 */
-		for (i = 2; i < 9; i++) {
+		for (i = 2; i < 16; i++) {
 			value = mmc_spi_readbytes(host, 1);
 			if (value < 0)
 				goto done;

---
regards

i. A. Wolfgang Mües
-- 
Auerswald GmbH & Co. KG
Hardware Development
Telefon: +49 (0)5306 9219 0
Telefax: +49 (0)5306 9219 94 
E-Mail: Wolfgang.Mues@Auerswald.de
Web: http://www.auerswald.de
 
--------------------------------------------------------------
Auerswald GmbH & Co. KG, Vor den Grashöfen 1, 38162 Cremlingen
Registriert beim AG Braunschweig HRA 13289
p.h.G Auerswald Geschäftsführungsges. mbH
Registriert beim AG Braunschweig HRB 7463
Geschäftsführer: Dipl-Ing. Gerhard Auerswald

Re: [PATCH 2/7] mmc_spi: wait more bytes for card response

[David Brownell]

On Wednesday 11 March 2009, Wolfgang Mües wrote:
> From: Wolfgang Muees <wolfgang.mues@auerswald.de>
> 
> o some cards are slower than the standard allows and need more
>   time to respond to a command. Max. observed number of bytes
>   was 12.
> 
> Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>

Acked-by: David Brownell <dbrownell@users.sourceforge.net>

> 
> ---
> 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_patch1_spi_mode_3/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c
> --- 2_6_29_rc7_patch1_spi_mode_3/drivers/mmc/host/mmc_spi.c	2009-03-11 12:58:47.000000000 +0100
> +++ 2_6_29_rc7_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c	2009-03-11 13:00:06.000000000 +0100
> @@ -279,8 +279,11 @@ static int mmc_spi_response_get(struct m
>  		 * so it can always DMA directly into the target buffer.
>  		 * It'd probably be better to memcpy() the first chunk and
>  		 * avoid extra i/o calls...
> +		 *
> +		 * Note we check for more than 8 bytes, because in practice,
> +		 * some SD cards are slow...
>  		 */
> -		for (i = 2; i < 9; i++) {
> +		for (i = 2; i < 16; i++) {
>  			value = mmc_spi_readbytes(host, 1);
>  			if (value < 0)
>  				goto done;
> 
> ---
> regards
> 
> i. A. Wolfgang Mües
> -- 
> Auerswald GmbH & Co. KG
> Hardware Development
> Telefon: +49 (0)5306 9219 0
> Telefax: +49 (0)5306 9219 94 
> E-Mail: Wolfgang.Mues@Auerswald.de
> Web: http://www.auerswald.de
>  
> --------------------------------------------------------------
> Auerswald GmbH & Co. KG, Vor den Grashöfen 1, 38162 Cremlingen
> Registriert beim AG Braunschweig HRA 13289
> p.h.G Auerswald Geschäftsführungsges. mbH
> Registriert beim AG Braunschweig HRB 7463
> Geschäftsführer: Dipl-Ing. Gerhard Auerswald
> 
>