sdio: set the functions' block size

[linux-2.6-omap-h63xx.git] / drivers / mmc / core / sdio_io.c

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index ecdb77242e98f9033156435d90e57bc2258d2b03..c2bad1195e3bffa8a1045f11d5a3d65a543e2cce 100644 (file)
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -140,6 +140,55 @@ err:
 }
 EXPORT_SYMBOL_GPL(sdio_disable_func);
 
+/**
+ *     sdio_set_block_size - set the block size of an SDIO function
+ *     @func: SDIO function to change
+ *     @blksz: new block size or 0 to use the default.
+ *
+ *     The default block size is the largest supported by both the function
+ *     and the host, with a maximum of 512 to ensure that arbitrarily sized
+ *     data transfer use the optimal (least) number of commands.
+ *
+ *     A driver may call this to override the default block size set by the
+ *     core. This can be used to set a block size greater than the maximum
+ *     that reported by the card; it is the driver's responsibility to ensure
+ *     it uses a value that the card supports.
+ *
+ *     Returns 0 on success, -EINVAL if the host does not support the
+ *     requested block size, or -EIO (etc.) if one of the resultant FBR block
+ *     size register writes failed.
+ *
+ */
+int sdio_set_block_size(struct sdio_func *func, unsigned blksz)
+{
+       int ret;
+
+       if (blksz > func->card->host->max_blk_size)
+               return -EINVAL;
+
+       if (blksz == 0) {
+               blksz = min(min(
+                       func->max_blksize,
+                       func->card->host->max_blk_size),
+                       512u);
+       }
+
+       ret = mmc_io_rw_direct(func->card, 1, 0,
+               SDIO_FBR_BASE(func->num) + SDIO_FBR_BLKSIZE,
+               blksz & 0xff, NULL);
+       if (ret)
+               return ret;
+       ret = mmc_io_rw_direct(func->card, 1, 0,
+               SDIO_FBR_BASE(func->num) + SDIO_FBR_BLKSIZE + 1,
+               (blksz >> 8) & 0xff, NULL);
+       if (ret)
+               return ret;
+       func->cur_blksize = blksz;
+       return 0;
+}
+
+EXPORT_SYMBOL_GPL(sdio_set_block_size);
+
 /**
  *     sdio_readb - read a single byte from a SDIO function
  *     @func: SDIO function to access