mmc_spi: support for non-byte-aligned cards (ab5a643c) · Commits · 戴 / test

drivers/mmc/host/mmc_spi.c

+112 −38

Original line number	Diff line number	Diff line
		@@ -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.
		@@ -298,14 +301,28 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
		}

		checkstatus:
		bitshift = 0;
		if (*cp & 0x80) {
		dev_dbg(&host->spi->dev, "%s: INVALID RESPONSE, %02x\n",
		tag, *cp);
		value = -EBADR;
		/* 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->error = 0;

		/* Status byte: the entire seven-bit R1 response. */
		@@ -339,12 +356,45 @@ checkstatus:
		* SPI R5 == R1 + data byte; IO_RW_DIRECT
		*/
		case MMC_RSP_SPI_R2:
		/* 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.
		@@ -736,7 +788,21 @@ 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 (status < 0) {
		dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status);
		return status;
		}

		/* 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_device(host->dma_dev,
		host->data_dma, sizeof(*scratch),
		@@ -757,17 +823,25 @@ mmc_spi_readblock(struct mmc_spi_host host, struct spi_transfer t,
		DMA_FROM_DEVICE);
		}

		} else {
		dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status);

		/* we've read extra garbage, timed out, etc */
		if (status < 0)
		return status;

		/* 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) {

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