mmc_spi: support for non-byte-aligned cards

A very large subset of SD cards in the market send their
responses and data non-byte-aligned. So add logic to the
mmc spi driver to handle this mess.

Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

1 files changed, 112 insertions, 38 deletions

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index ed02ebd899d1..f48349d18c92 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -254,6 +254,10 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
         u8      *cp = host->data->status;
         u8      *end = cp + host->t.len;
         int     value = 0;
+        int     bitshift;
+        u8      leftover = 0;
+        unsigned short rotator;
+        int     i;
         char    tag[32];
 
         snprintf(tag, sizeof(tag), "  ... CMD%d response SPI_%s",
@@ -271,9 +275,8 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
 
         /* Data block reads (R1 response types) may need more data... */
         if (cp == end) {
-                unsigned        i;
-
                 cp = host->data->status;
+                end = cp+1;
 
                 /* Card sends N(CR) (== 1..8) bytes of all-ones then one
                  * status byte ... and we already scanned 2 bytes.
@@ -298,20 +301,34 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
         }
 
 checkstatus:
-        if (*cp & 0x80) {
-                dev_dbg(&host->spi->dev, "%s: INVALID RESPONSE, %02x\n",
-                                        tag, *cp);
-                value = -EBADR;
-                goto done;
+        bitshift = 0;
+        if (*cp & 0x80) {
+                /* Houston, we have an ugly card with a bit-shifted response */
+                rotator = *cp++ << 8;
+                /* read the next byte */
+                if (cp == end) {
+                        value = mmc_spi_readbytes(host, 1);
+                        if (value < 0)
+                                goto done;
+                        cp = host->data->status;
+                        end = cp+1;
+                }
+                rotator |= *cp++;
+                while (rotator & 0x8000) {
+                        bitshift++;
+                        rotator <<= 1;
+                }
+                cmd->resp[0] = rotator >> 8;
+                leftover = rotator;
+        } else {
+                cmd->resp[0] = *cp++;
         }
-
-        cmd->resp[0] = *cp++;
         cmd->error = 0;
 
         /* Status byte: the entire seven-bit R1 response.  */
         if (cmd->resp[0] != 0) {
                 if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS
-                                        | R1_SPI_ILLEGAL_COMMAND)
+                                      | R1_SPI_ILLEGAL_COMMAND)
                                 & cmd->resp[0])
                         value = -EINVAL;
                 else if (R1_SPI_COM_CRC & cmd->resp[0])
@@ -339,12 +356,45 @@ checkstatus:
          * SPI R5 == R1 + data byte; IO_RW_DIRECT
          */
         case MMC_RSP_SPI_R2:
-                cmd->resp[0] |= *cp << 8;
+                /* read the next byte */
+                if (cp == end) {
+                        value = mmc_spi_readbytes(host, 1);
+                        if (value < 0)
+                                goto done;
+                        cp = host->data->status;
+                        end = cp+1;
+                }
+                if (bitshift) {
+                        rotator = leftover << 8;
+                        rotator |= *cp << bitshift;
+                        cmd->resp[0] |= (rotator & 0xFF00);
+                } else {
+                        cmd->resp[0] |= *cp << 8;
+                }
                 break;
 
         /* SPI R3, R4, or R7 == R1 + 4 bytes */
         case MMC_RSP_SPI_R3:
-                cmd->resp[1] = get_unaligned_be32(cp);
+                rotator = leftover << 8;
+                cmd->resp[1] = 0;
+                for (i = 0; i < 4; i++) {
+                        cmd->resp[1] <<= 8;
+                        /* read the next byte */
+                        if (cp == end) {
+                                value = mmc_spi_readbytes(host, 1);
+                                if (value < 0)
+                                        goto done;
+                                cp = host->data->status;
+                                end = cp+1;
+                        }
+                        if (bitshift) {
+                                rotator |= *cp++ << bitshift;
+                                cmd->resp[1] |= (rotator >> 8);
+                                rotator <<= 8;
+                        } else {
+                                cmd->resp[1] |= *cp++;
+                        }
+                }
                 break;
 
         /* SPI R1 == just one status byte */
@@ -725,6 +775,8 @@ mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t,
         struct spi_device       *spi = host->spi;
         int                     status;
         struct scratch          *scratch = host->data;
+        unsigned int            bitshift;
+        u8                      leftover;
 
         /* At least one SD card sends an all-zeroes byte when N(CX)
          * applies, before the all-ones bytes ... just cope with that.
@@ -736,38 +788,60 @@ mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t,
         if (status == 0xff || status == 0)
                 status = mmc_spi_readtoken(host, timeout);
 
-        if (status == SPI_TOKEN_SINGLE) {
-                if (host->dma_dev) {
-                        dma_sync_single_for_device(host->dma_dev,
-                                        host->data_dma, sizeof(*scratch),
-                                        DMA_BIDIRECTIONAL);
-                        dma_sync_single_for_device(host->dma_dev,
-                                        t->rx_dma, t->len,
-                                        DMA_FROM_DEVICE);
-                }
+        if (status < 0) {
+                dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status);
+                return status;
+        }
 
-                status = spi_sync(spi, &host->m);
+        /* The token may be bit-shifted...
+         * the first 0-bit precedes the data stream.
+         */
+        bitshift = 7;
+        while (status & 0x80) {
+                status <<= 1;
+                bitshift--;
+        }
+        leftover = status << 1;
 
-                if (host->dma_dev) {
-                        dma_sync_single_for_cpu(host->dma_dev,
-                                        host->data_dma, sizeof(*scratch),
-                                        DMA_BIDIRECTIONAL);
-                        dma_sync_single_for_cpu(host->dma_dev,
-                                        t->rx_dma, t->len,
-                                        DMA_FROM_DEVICE);
-                }
+        if (host->dma_dev) {
+                dma_sync_single_for_device(host->dma_dev,
+                                host->data_dma, sizeof(*scratch),
+                                DMA_BIDIRECTIONAL);
+                dma_sync_single_for_device(host->dma_dev,
+                                t->rx_dma, t->len,
+                                DMA_FROM_DEVICE);
+        }
 
-        } else {
-                dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status);
+        status = spi_sync(spi, &host->m);
 
-                /* we've read extra garbage, timed out, etc */
-                if (status < 0)
-                        return status;
+        if (host->dma_dev) {
+                dma_sync_single_for_cpu(host->dma_dev,
+                                host->data_dma, sizeof(*scratch),
+                                DMA_BIDIRECTIONAL);
+                dma_sync_single_for_cpu(host->dma_dev,
+                                t->rx_dma, t->len,
+                                DMA_FROM_DEVICE);
+        }
 
-                /* low four bits are an R2 subset, fifth seems to be
-                 * vendor specific ... map them all to generic error..
+        if (bitshift) {
+                /* Walk through the data and the crc and do
+                 * all the magic to get byte-aligned data.
                  */
-                return -EIO;
+                u8 *cp = t->rx_buf;
+                unsigned int len;
+                unsigned int bitright = 8 - bitshift;
+                u8 temp;
+                for (len = t->len; len; len--) {
+                        temp = *cp;
+                        *cp++ = leftover | (temp >> bitshift);
+                        leftover = temp << bitright;
+                }
+                cp = (u8 *) &scratch->crc_val;
+                temp = *cp;
+                *cp++ = leftover | (temp >> bitshift);
+                leftover = temp << bitright;
+                temp = *cp;
+                *cp = leftover | (temp >> bitshift);
         }
 
         if (host->mmc->use_spi_crc) {