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path: root/drivers/mmc/host/mmc_spi.c
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Diffstat (limited to 'drivers/mmc/host/mmc_spi.c')
-rw-r--r--drivers/mmc/host/mmc_spi.c40
1 files changed, 33 insertions, 7 deletions
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 87e211df68a..72f8bde4877 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -279,8 +279,11 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
* 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;
@@ -609,6 +612,7 @@ mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t,
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(
@@ -636,8 +640,27 @@ mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t,
* 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.
+ *
+ * In practice, there are (even modern SDHC-)cards which are late
+ * in sending the response, and miss the time frame by a few bits,
+ * so we have to cope with this situation and check the response
+ * bit-by-bit. Arggh!!!
*/
- switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) {
+ pattern = scratch->status[0] << 24;
+ pattern |= scratch->status[1] << 16;
+ pattern |= scratch->status[2] << 8;
+ pattern |= scratch->status[3];
+
+ /* First 3 bit of pattern are undefined */
+ pattern |= 0xE0000000;
+
+ /* 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;
@@ -668,8 +691,9 @@ mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t,
/* 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++) {
+ /* card is non-busy if the most recent bit is 1 */
+ if (scratch->status[i] & 0x01)
return 0;
}
return mmc_spi_wait_unbusy(host, timeout);
@@ -1204,10 +1228,12 @@ static int mmc_spi_probe(struct spi_device *spi)
/* MMC and SD specs only seem to care that sampling is on the
* rising edge ... meaning SPI modes 0 or 3. So either SPI mode
- * should be legit. We'll use mode 0 since it seems to be a
- * bit less troublesome on some hardware ... unclear why.
+ * should be legit. We'll use mode 0 since the steady state is 0,
+ * which is appropriate for hotplugging, unless the platform data
+ * specify mode 3 (if hardware is not compatible to mode 0).
*/
- spi->mode = SPI_MODE_0;
+ if (spi->mode != SPI_MODE_3)
+ spi->mode = SPI_MODE_0;
spi->bits_per_word = 8;
status = spi_setup(spi);