From: Wolfgang Muees <[email protected]>
o some cards are not able to send the data token in time, but
miss the time frame for some bits(!). So synchronize to the
start of the token.
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_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c
--- 2_6_29_rc7_patch2_wait_16bytes_response/drivers/mmc/host/mmc_spi.c 2009-03-11 13:00:06.000000000 +0100
+++ 2_6_29_rc7_patch3_delayed_data_response/drivers/mmc/host/mmc_spi.c 2009-03-11 13:42:48.000000000 +0100
@@ -612,6 +612,7 @@ mmc_spi_writeblock(struct mmc_spi_host *
struct spi_device *spi = host->spi;
int status, i;
struct scratch *scratch = host->data;
+ u32 pattern;
if (host->mmc->use_spi_crc)
scratch->crc_val = cpu_to_be16(
@@ -639,8 +640,23 @@ mmc_spi_writeblock(struct mmc_spi_host *
* doesn't necessarily tell whether the write operation succeeded;
* it just says if the transmission was ok and whether *earlier*
* writes succeeded; see the standard.
- */
- switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) {
+ *
+ * In practice, there are (even modern SDHC-)Cards which need
+ * some bits to send the response, so we have to cope with this
+ * situation and check the response bit-by-bit. Arggh!!!
+ */
+ pattern = scratch->status[0] << 24;
+ pattern |= scratch->status[1] << 16;
+ pattern |= scratch->status[2] << 8;
+ pattern |= scratch->status[3];
+
+ /* left-adjust to leading 0 bit */
+ while (pattern & 0x80000000)
+ pattern <<= 1;
+ /* right-adjust for pattern matching. Code is in bit 4..0 now. */
+ pattern >>= 27;
+
+ switch (pattern) {
case SPI_RESPONSE_ACCEPTED:
status = 0;
break;
@@ -671,8 +687,8 @@ mmc_spi_writeblock(struct mmc_spi_host *
/* Return when not busy. If we didn't collect that status yet,
* we'll need some more I/O.
*/
- for (i = 1; i < sizeof(scratch->status); i++) {
- if (scratch->status[i] != 0)
+ for (i = 4; i < sizeof(scratch->status); i++) {
+ if (scratch->status[i] & 0x01)
return 0;
}
return mmc_spi_wait_unbusy(host, timeout);
---
regards
i. A. Wolfgang M?es
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On Wednesday 11 March 2009, Wolfgang M?es wrote:
> @@ -639,8 +640,23 @@ mmc_spi_writeblock(struct mmc_spi_host *
> * doesn't necessarily tell whether the write operation succeeded;
> * it just says if the transmission was ok and whether *earlier*
> * writes succeeded; see the standard.
> - */
> - switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) {
> + *
> + * In practice, there are (even modern SDHC-)Cards which need
> + * some bits to send the response, so we have to cope with this
All hardware needs some bits to send binary data!!
Do you mean "which don't send byte-aligned responses,
contrary to MMC/SD/SDIO specifications"?
> + * situation and check the response bit-by-bit. Arggh!!!
> + */
> + pattern = scratch->status[0] << 24;
> + pattern |= scratch->status[1] << 16;
> + pattern |= scratch->status[2] << 8;
> + pattern |= scratch->status[3];
> +
> + /* left-adjust to leading 0 bit */
> + while (pattern & 0x80000000)
> + pattern <<= 1;
> + /* right-adjust for pattern matching. Code is in bit 4..0 now. */
> + pattern >>= 27;
> +
> + switch (pattern) {
> case SPI_RESPONSE_ACCEPTED:
> status = 0;
> break;
> @@ -671,8 +687,8 @@ mmc_spi_writeblock(struct mmc_spi_host *
> /* Return when not busy. If we didn't collect that status yet,
> * we'll need some more I/O.
> */
> - for (i = 1; i < sizeof(scratch->status); i++) {
> - if (scratch->status[i] != 0)
> + for (i = 4; i < sizeof(scratch->status); i++) {
> + if (scratch->status[i] & 0x01)
I think I see why you skip four bytes, since you used
them above. But why change the "!= 0" test?
> return 0;
> }
> return mmc_spi_wait_unbusy(host, timeout);
>
> ---
> regards
>
David,
Am Mittwoch, 11. M?rz 2009 schrieb David Brownell:
> All hardware needs some bits to send binary data!!
>
> Do you mean "which don't send byte-aligned responses,
> contrary to MMC/SD/SDIO specifications"?
No. The specification states that the response from the card after a whole
data block is received is IMMEDIATELY, with 0 bits delay. Not every card is
able to do this all the time.
My comment is a little bit missleading, yes.
best 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 Thursday 12 March 2009, Wolfgang M?es wrote:
> David,
> Am Mittwoch, 11. M?rz 2009 schrieb David Brownell:
> > All hardware needs some bits to send binary data!!
> >
> > Do you mean "which don't send byte-aligned responses,
> > contrary to MMC/SD/SDIO specifications"?
>
> No. The specification states that the response from the card after a whole
> data block is received is IMMEDIATELY, with 0 bits delay. Not every card is
> able to do this all the time.
>
> My comment is a little bit missleading, yes.
Well, aligned to zero bytes is the same as "immediately". ;)
And that description matches up with your other patch. But
either way, the comment was confusing.
- Dave
On Thu, 12 Mar 2009 01:24:37 -0800
David Brownell <[email protected]> wrote:
>
> Well, aligned to zero bytes is the same as "immediately". ;)
>
> And that description matches up with your other patch. But
> either way, the comment was confusing.
>
I guess we need a new one then to avoid this happening again. ;)
And what about that changed if-clause?
Rgds
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