sdio: clean up handling of byte mode transfer size

Make sure that the maximum size for a byte mode transfer is identical
in all places. Also tweak the transfer helper so that a single byte
mode transfer is preferred over (possibly multiple) block mode
request(s).

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 6ee7861fceae..cc42a41ff6ab 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -186,9 +186,20 @@ int sdio_set_block_size(struct sdio_func *func, unsigned blksz)
         func->cur_blksize = blksz;
         return 0;
 }
-
 EXPORT_SYMBOL_GPL(sdio_set_block_size);
 
+/*
+ * Calculate the maximum byte mode transfer size
+ */
+static inline unsigned int sdio_max_byte_size(struct sdio_func *func)
+{
+        return min(min(min(
+                func->card->host->max_seg_size,
+                func->card->host->max_blk_size),
+                func->max_blksize),
+                512u); /* maximum size for byte mode */
+}
+
 /**
  *      sdio_align_size - pads a transfer size to a more optimal value
  *      @func: SDIO function
@@ -222,7 +233,7 @@ unsigned int sdio_align_size(struct sdio_func *func, unsigned int sz)
          * If we can still do this with just a byte transfer, then
          * we're done.
          */
-        if ((sz <= func->cur_blksize) && (sz <= 512))
+        if (sz <= sdio_max_byte_size(func))
                 return sz;
 
         if (func->card->cccr.multi_block) {
@@ -253,7 +264,7 @@ unsigned int sdio_align_size(struct sdio_func *func, unsigned int sz)
                  */
                 byte_sz = mmc_align_data_size(func->card,
                                 sz % func->cur_blksize);
-                if ((byte_sz <= func->cur_blksize) && (byte_sz <= 512)) {
+                if (byte_sz <= sdio_max_byte_size(func)) {
                         blk_sz = sz / func->cur_blksize;
                         return blk_sz * func->cur_blksize + byte_sz;
                 }
@@ -263,8 +274,8 @@ unsigned int sdio_align_size(struct sdio_func *func, unsigned int sz)
                  * controller can handle the chunk size;
                  */
                 chunk_sz = mmc_align_data_size(func->card,
-                                min(func->cur_blksize, 512u));
-                if (chunk_sz == min(func->cur_blksize, 512u)) {
+                                sdio_max_byte_size(func));
+                if (chunk_sz == sdio_max_byte_size(func)) {
                         /*
                          * Fix up the size of the remainder (if any)
                          */
@@ -296,7 +307,7 @@ static int sdio_io_rw_ext_helper(struct sdio_func *func, int write,
         int ret;
 
         /* Do the bulk of the transfer using block mode (if supported). */
-        if (func->card->cccr.multi_block) {
+        if (func->card->cccr.multi_block && (size > sdio_max_byte_size(func))) {
                 /* 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. */
@@ -328,11 +339,7 @@ static int sdio_io_rw_ext_helper(struct sdio_func *func, int write,
 
         /* 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 */
+                size = min(remainder, sdio_max_byte_size(func));
 
                 ret = mmc_io_rw_extended(func->card, write, func->num, addr,
                          incr_addr, buf, 1, size);