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Date: Wed, 11 Mar 2009 13:56:04 +0000
From: Will Newton <will.newton@...il.com>
To: Wolfgang Mües <wolfgang.mues@...rswald.de>
Cc: Pierre Ossman <drzeus@...eus.cx>,
Andrew Morton <akpm@...ux-foundation.org>,
Matt Fleming <matt@...sole-pimps.org>,
David Brownell <dbrownell@...rs.sourceforge.net>,
Mike Frysinger <vapier.adi@...il.com>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 7/7] mmc_spi: support for non-byte-aligned cards
On Wed, Mar 11, 2009 at 1:40 PM, Wolfgang Mües
<wolfgang.mues@...rswald.de> wrote:
> From: Wolfgang Muees <wolfgang.mues@...rswald.de>
>
> o 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.
Are you sure about this? Do you have any further references for this
or examples of cards that exhibit this problem?
Are you sure your SPI host controller is operating correctly?
> Signed-off-by: Wolfgang Muees <wolfgang.mues@...rswald.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_patch6_jiffies_and_scheduling/drivers/mmc/host/mmc_spi.c 2_6_29_rc7_patch7_unaligned_responses/drivers/mmc/host/mmc_spi.c
> --- 2_6_29_rc7_patch6_jiffies_and_scheduling/drivers/mmc/host/mmc_spi.c 2009-03-11 13:49:53.000000000 +0100
> +++ 2_6_29_rc7_patch7_unaligned_responses/drivers/mmc/host/mmc_spi.c 2009-03-11 13:51:25.000000000 +0100
> @@ -254,6 +254,10 @@ static int mmc_spi_response_get(struct m
> 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 m
>
> /* 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 m
> }
>
> 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 */
> @@ -720,6 +770,8 @@ mmc_spi_readblock(struct mmc_spi_host *h
> 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.
> @@ -731,38 +783,60 @@ mmc_spi_readblock(struct mmc_spi_host *h
> 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);
> }
>
> /* Omitt the CRC check for CID and CSD reads. There are some SDHC
>
> ---
> 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@...rswald.de
> Web: http://www.auerswald.de
>
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