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    Subjectsdio: extend sdio_readsb() and friends to handle any length of buffer
    Date
    Extend sdio_readsb(), sdio_writesb(), sdio_memcpy_fromio(), and
    sdio_memcpy_toio() to handle any length of buffer by splitting the transfer
    into several IO_RW_EXTENDED commands. Typically, a transfer would be split
    into a single block mode transfer followed by a byte mode transfer for the
    remainder.

    For this to work the block size must be limited to the maximum size of a
    byte mode transfer (512 bytes). This limitation could be revisited if
    there are any cards out there that require a block size > 512.

    Signed-off-by: David Vrabel <david.vrabel@csr.com>

    ---
    commit 1c701a6566f373ede250b51c99216227fd881535
    tree 2bbc5005de65bbdc497c8603e8a68486465065dc
    parent 6d367fd822cbb2b8089ab7ef83f706f1984ab25b
    author David Vrabel <david.vrabel@csr.com> Tue, 31 Jul 2007 11:08:49 +0100
    committer David Vrabel <dvrabel@cantab.net> Tue, 31 Jul 2007 11:44:44 +0100

    drivers/mmc/core/sdio_io.c | 63 ++++++++++++++++++++++++++++++++++---------
    drivers/mmc/core/sdio_ops.c | 17 +++++++-----
    drivers/mmc/core/sdio_ops.h | 2 +
    3 files changed, 61 insertions(+), 21 deletions(-)

    diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
    index e74e605..8fb1880 100644
    --- a/drivers/mmc/core/sdio_io.c
    +++ b/drivers/mmc/core/sdio_io.c
    @@ -156,6 +156,13 @@ int sdio_set_block_size(struct sdio_func *func, unsigned short blksz)
    {
    int ret;

    + /* The standard permits block sizes up to 2048 bytes, but
    + * sdio_readsb() etc. can only work with block size <= 512. */
    + if (blksz > 512) {
    + blksz = 512;
    + dev_warn(&func->dev, "block size limited to 512 bytes\n");
    + }
    +
    ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_FBR_BLKSIZE(func->num),
    blksz & 0xff, NULL);
    if (ret)
    @@ -228,6 +235,39 @@ void sdio_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,

    EXPORT_SYMBOL_GPL(sdio_writeb);

    +/* Split an arbitrarily sized data transfer into several
    + * IO_RW_EXTENDED commands. */
    +static int sdio_io_rw_ext_helper(struct sdio_func *func, int write,
    + unsigned fn, unsigned addr, int incr_addr, u8 *buf, unsigned size)
    +{
    + unsigned remainder = size;
    + int ret;
    +
    + while (remainder > func->block_size) {
    + unsigned blocks;
    +
    + blocks = remainder % func->block_size;
    + if (blocks > 511)
    + blocks = 511;
    + size = blocks * func->block_size;
    +
    + ret = mmc_io_rw_extended(func->card, write, fn, addr,
    + incr_addr, buf, blocks, func->block_size);
    + if (ret)
    + return ret;
    +
    + remainder -= size;
    + buf += size;
    + if (incr_addr)
    + addr += size;
    + }
    +
    + if (remainder)
    + ret = mmc_io_rw_extended(func->card, write, fn, addr,
    + incr_addr, buf, 1, remainder);
    + return ret;
    +}
    +
    /**
    * sdio_memcpy_fromio - read a chunk of memory from a SDIO function
    * @func: SDIO function to access
    @@ -235,14 +275,13 @@ EXPORT_SYMBOL_GPL(sdio_writeb);
    * @addr: address to begin reading from
    * @count: number of bytes to read
    *
    - * Reads up to 512 bytes from the address space of a given SDIO
    - * function. Return value indicates if the transfer succeeded or
    - * not.
    + * Reads from the address space of a given SDIO function. Return
    + * value indicates if the transfer succeeded or not.
    */
    int sdio_memcpy_fromio(struct sdio_func *func, void *dst,
    unsigned int addr, int count)
    {
    - return mmc_io_rw_extended(func->card, 0, func->num, addr, 0, dst,
    + return sdio_io_rw_ext_helper(func, 0, func->num, addr, 1, dst,
    count);
    }

    @@ -255,14 +294,13 @@ EXPORT_SYMBOL_GPL(sdio_memcpy_fromio);
    * @src: buffer that contains the data to write
    * @count: number of bytes to write
    *
    - * Writes up to 512 bytes to the address space of a given SDIO
    - * function. Return value indicates if the transfer succeeded or
    - * not.
    + * Writes to the address space of a given SDIO function. Return
    + * value indicates if the transfer succeeded or not.
    */
    int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
    void *src, int count)
    {
    - return mmc_io_rw_extended(func->card, 1, func->num, addr, 0, src,
    + return sdio_io_rw_ext_helper(func, 1, func->num, addr, 1, src,
    count);
    }

    @@ -273,14 +311,13 @@ int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
    * @addr: address of (single byte) FIFO
    * @count: number of bytes to read
    *
    - * Reads up to 512 bytes from the specified FIFO of a given SDIO
    - * function. Return value indicates if the transfer succeeded or
    - * not.
    + * Reads from the specified FIFO of a given SDIO function. Return
    + * value indicates if the transfer succeeded or not.
    */
    int sdio_readsb(struct sdio_func *func, void *dst, unsigned int addr,
    int count)
    {
    - return mmc_io_rw_extended(func->card, 0, func->num, addr, 1, dst,
    + return sdio_io_rw_ext_helper(func, 0, func->num, addr, 0, dst,
    count);
    }

    @@ -300,7 +337,7 @@ EXPORT_SYMBOL_GPL(sdio_readsb);
    int sdio_writesb(struct sdio_func *func, unsigned int addr, void *src,
    int count)
    {
    - return mmc_io_rw_extended(func->card, 1, func->num, addr, 1, src,
    + return sdio_io_rw_ext_helper(func, 1, func->num, addr, 0, src,
    count);
    }

    diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c
    index a91fe41..72590c4 100644
    --- a/drivers/mmc/core/sdio_ops.c
    +++ b/drivers/mmc/core/sdio_ops.c
    @@ -92,7 +92,7 @@ int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn,
    }

    int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
    - unsigned addr, int bang, u8 *buf, unsigned size)
    + unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz)
    {
    struct mmc_request mrq;
    struct mmc_command cmd;
    @@ -101,7 +101,6 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,

    BUG_ON(!card);
    BUG_ON(fn > 7);
    - BUG_ON(size > 512);

    memset(&mrq, 0, sizeof(struct mmc_request));
    memset(&cmd, 0, sizeof(struct mmc_command));
    @@ -113,18 +112,22 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
    cmd.opcode = SD_IO_RW_EXTENDED;
    cmd.arg = write ? 0x80000000 : 0x00000000;
    cmd.arg |= fn << 28;
    - cmd.arg |= bang ? 0x00000000 : 0x04000000;
    + cmd.arg |= incr_addr ? 0x04000000 : 0x00000000;
    cmd.arg |= addr << 9;
    - cmd.arg |= (size == 512) ? 0 : size;
    + if (blocks > 1) {
    + cmd.arg |= 0x08000000;
    + cmd.arg |= blocks;
    + } else
    + cmd.arg |= (blksz == 512) ? 0 : blksz;
    cmd.flags = MMC_RSP_R5 | MMC_CMD_ADTC;

    - data.blksz = size;
    - data.blocks = 1;
    + data.blksz = blksz;
    + data.blocks = blocks;
    data.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ;
    data.sg = &sg;
    data.sg_len = 1;

    - sg_init_one(&sg, buf, size);
    + sg_init_one(&sg, buf, blksz * blocks);

    mmc_set_data_timeout(&data, card, 0);

    diff --git a/drivers/mmc/core/sdio_ops.h b/drivers/mmc/core/sdio_ops.h
    index 1d42e4f..e2e74b0 100644
    --- a/drivers/mmc/core/sdio_ops.h
    +++ b/drivers/mmc/core/sdio_ops.h
    @@ -16,7 +16,7 @@ int mmc_send_io_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr);
    int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn,
    unsigned addr, u8 in, u8* out);
    int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
    - unsigned addr, int bang, u8 *data, unsigned size);
    + unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz);

    #endif

    -
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