libata: update ->data_xfer hook for ATAPI

Depending on how many bytes are transferred as a unit, PIO data
transfer may consume more bytes than requested.  Knowing how much
data is consumed is necessary to determine how much is left for
draining.  This patch update ->data_xfer such that it returns the
number of consumed bytes.

While at it, it also makes the following changes.

* s/adev/dev/
* use READ/WRITE constants for rw indication
* misc clean ups

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 15 insertions, 13 deletions

diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
index 7842cc487359..41cd921082ba 100644
--- a/drivers/ata/pata_bf54x.c
+++ b/drivers/ata/pata_bf54x.c
@@ -1167,34 +1167,36 @@ static unsigned char bfin_bmdma_status(struct ata_port *ap)
  *      Note: Original code is ata_data_xfer().
  */
 
-static void bfin_data_xfer(struct ata_device *adev, unsigned char *buf,
-                           unsigned int buflen, int write_data)
+static unsigned int bfin_data_xfer(struct ata_device *dev, unsigned char *buf,
+                                   unsigned int buflen, int rw)
 {
-        struct ata_port *ap = adev->link->ap;
-        unsigned int words = buflen >> 1;
-        unsigned short *buf16 = (u16 *) buf;
+        struct ata_port *ap = dev->link->ap;
         void __iomem *base = (void __iomem *)ap->ioaddr.ctl_addr;
+        unsigned int words = buflen >> 1;
+        unsigned short *buf16 = (u16 *)buf;
 
         /* Transfer multiple of 2 bytes */
-        if (write_data) {
-                write_atapi_data(base, words, buf16);
-        } else {
+        if (rw == READ)
                 read_atapi_data(base, words, buf16);
-        }
+        else
+                write_atapi_data(base, words, buf16);
 
         /* Transfer trailing 1 byte, if any. */
         if (unlikely(buflen & 0x01)) {
                 unsigned short align_buf[1] = { 0 };
                 unsigned char *trailing_buf = buf + buflen - 1;
 
-                if (write_data) {
-                        memcpy(align_buf, trailing_buf, 1);
-                        write_atapi_data(base, 1, align_buf);
-                } else {
+                if (rw == READ) {
                         read_atapi_data(base, 1, align_buf);
                         memcpy(trailing_buf, align_buf, 1);
+                } else {
+                        memcpy(align_buf, trailing_buf, 1);
+                        write_atapi_data(base, 1, align_buf);
                 }
+                words++;
         }
+
+        return words << 1;
 }
 
 /**