sdio: extend sdio_readsb() and friends to handle any length of buffer
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 but we also handle lack of block mode support and the block size
being greater than 512 (the maximum byte mode transfer size).
host->max_seg_size <= host->max_req_size so there's no need to check both
when determining the maximum data size for a single command.
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index c2bad11..34b085d 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -189,6 +189,67 @@
EXPORT_SYMBOL_GPL(sdio_set_block_size);
+/* 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 addr, int incr_addr, u8 *buf, unsigned size)
+{
+ unsigned remainder = size;
+ unsigned max_blocks;
+ int ret;
+
+ /* Do the bulk of the transfer using block mode (if supported). */
+ if (func->card->cccr.multi_block) {
+ /* Blocks per command is limited by host count, host transfer
+ * size (we only use a single sg entry) and the maximum for
+ * IO_RW_EXTENDED of 511 blocks. */
+ max_blocks = min(min(
+ func->card->host->max_blk_count,
+ func->card->host->max_seg_size / func->cur_blksize),
+ 511u);
+
+ while (remainder > func->cur_blksize) {
+ unsigned blocks;
+
+ blocks = remainder / func->cur_blksize;
+ if (blocks > max_blocks)
+ blocks = max_blocks;
+ size = blocks * func->cur_blksize;
+
+ ret = mmc_io_rw_extended(func->card, write,
+ func->num, addr, incr_addr, buf,
+ blocks, func->cur_blksize);
+ if (ret)
+ return ret;
+
+ remainder -= size;
+ buf += size;
+ if (incr_addr)
+ addr += size;
+ }
+ }
+
+ /* Write the remainder using byte mode. */
+ while (remainder > 0) {
+ size = remainder;
+ if (size > func->cur_blksize)
+ size = func->cur_blksize;
+ if (size > 512)
+ size = 512; /* maximum size for byte mode */
+
+ ret = mmc_io_rw_extended(func->card, write, func->num, addr,
+ incr_addr, buf, 1, size);
+ if (ret)
+ return ret;
+
+ remainder -= size;
+ buf += size;
+ if (incr_addr)
+ addr += size;
+ }
+ return 0;
+}
+
/**
* sdio_readb - read a single byte from a SDIO function
* @func: SDIO function to access
@@ -252,15 +313,13 @@
* @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,
- count);
+ return sdio_io_rw_ext_helper(func, 0, addr, 1, dst, count);
}
EXPORT_SYMBOL_GPL(sdio_memcpy_fromio);
@@ -271,15 +330,13 @@
* @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,
- count);
+ return sdio_io_rw_ext_helper(func, 1, addr, 1, src, count);
}
EXPORT_SYMBOL_GPL(sdio_memcpy_toio);
@@ -290,15 +347,13 @@
* @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,
- count);
+ return sdio_io_rw_ext_helper(func, 0, addr, 0, dst, count);
}
EXPORT_SYMBOL_GPL(sdio_readsb);
@@ -310,15 +365,13 @@
* @src: buffer that contains the data to write
* @count: number of bytes to write
*
- * Writes up to 512 bytes to the specified FIFO of a given SDIO
- * function. Return value indicates if the transfer succeeded or
- * not.
+ * Writes to the specified FIFO of a given SDIO function. Return
+ * value indicates if the transfer succeeded or not.
*/
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,
- count);
+ return sdio_io_rw_ext_helper(func, 1, addr, 0, src, count);
}
EXPORT_SYMBOL_GPL(sdio_writesb);