[PATCH] libata ata_data_xfer() fix
PATCH 1/2: ata_data_xfer() fix
Changes:
- Modify ata_mmio_data_xfer() and ata_pio_data_xfer() to handle odd-lengthed buffer.
- Add some function comments
This patch does not reuse ap->pad as alignment buffer since
using local variable seems good enough.
Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 73b1f72..8f6e536 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2519,6 +2519,20 @@
#endif /* __BIG_ENDIAN */
}
+/**
+ * ata_mmio_data_xfer - Transfer data by MMIO
+ * @ap: port to read/write
+ * @buf: data buffer
+ * @buflen: buffer length
+ * @do_write: read/write
+ *
+ * Transfer data from/to the device data register by MMIO.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ */
+
static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf,
unsigned int buflen, int write_data)
{
@@ -2527,6 +2541,7 @@
u16 *buf16 = (u16 *) buf;
void __iomem *mmio = (void __iomem *)ap->ioaddr.data_addr;
+ /* Transfer multiple of 2 bytes */
if (write_data) {
for (i = 0; i < words; i++)
writew(le16_to_cpu(buf16[i]), mmio);
@@ -2534,19 +2549,76 @@
for (i = 0; i < words; i++)
buf16[i] = cpu_to_le16(readw(mmio));
}
+
+ /* Transfer trailing 1 byte, if any. */
+ if (unlikely(buflen & 0x01)) {
+ u16 align_buf[1] = { 0 };
+ unsigned char *trailing_buf = buf + buflen - 1;
+
+ if (write_data) {
+ memcpy(align_buf, trailing_buf, 1);
+ writew(le16_to_cpu(align_buf[0]), mmio);
+ } else {
+ align_buf[0] = cpu_to_le16(readw(mmio));
+ memcpy(trailing_buf, align_buf, 1);
+ }
+ }
}
+/**
+ * ata_pio_data_xfer - Transfer data by PIO
+ * @ap: port to read/write
+ * @buf: data buffer
+ * @buflen: buffer length
+ * @do_write: read/write
+ *
+ * Transfer data from/to the device data register by PIO.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ */
+
static void ata_pio_data_xfer(struct ata_port *ap, unsigned char *buf,
unsigned int buflen, int write_data)
{
- unsigned int dwords = buflen >> 1;
+ unsigned int words = buflen >> 1;
+ /* Transfer multiple of 2 bytes */
if (write_data)
- outsw(ap->ioaddr.data_addr, buf, dwords);
+ outsw(ap->ioaddr.data_addr, buf, words);
else
- insw(ap->ioaddr.data_addr, buf, dwords);
+ insw(ap->ioaddr.data_addr, buf, words);
+
+ /* Transfer trailing 1 byte, if any. */
+ if (unlikely(buflen & 0x01)) {
+ u16 align_buf[1] = { 0 };
+ unsigned char *trailing_buf = buf + buflen - 1;
+
+ if (write_data) {
+ memcpy(align_buf, trailing_buf, 1);
+ outw(le16_to_cpu(align_buf[0]), ap->ioaddr.data_addr);
+ } else {
+ align_buf[0] = cpu_to_le16(inw(ap->ioaddr.data_addr));
+ memcpy(trailing_buf, align_buf, 1);
+ }
+ }
}
+/**
+ * ata_data_xfer - Transfer data from/to the data register.
+ * @ap: port to read/write
+ * @buf: data buffer
+ * @buflen: buffer length
+ * @do_write: read/write
+ *
+ * Transfer data from/to the device data register.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ */
+
static void ata_data_xfer(struct ata_port *ap, unsigned char *buf,
unsigned int buflen, int do_write)
{
@@ -2556,6 +2628,16 @@
ata_pio_data_xfer(ap, buf, buflen, do_write);
}
+/**
+ * ata_pio_sector - Transfer ATA_SECT_SIZE (512 bytes) of data.
+ * @qc: Command on going
+ *
+ * Transfer ATA_SECT_SIZE of data from/to the ATA device.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ */
+
static void ata_pio_sector(struct ata_queued_cmd *qc)
{
int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
@@ -2594,6 +2676,18 @@
kunmap(page);
}
+/**
+ * __atapi_pio_bytes - Transfer data from/to the ATAPI device.
+ * @qc: Command on going
+ * @bytes: number of bytes
+ *
+ * Transfer Transfer data from/to the ATAPI device.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ */
+
static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
{
int do_write = (qc->tf.flags & ATA_TFLAG_WRITE);
@@ -2645,6 +2739,17 @@
}
}
+/**
+ * atapi_pio_bytes - Transfer data from/to the ATAPI device.
+ * @qc: Command on going
+ *
+ * Transfer Transfer data from/to the ATAPI device.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ */
+
static void atapi_pio_bytes(struct ata_queued_cmd *qc)
{
struct ata_port *ap = qc->ap;