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[PATCH] libata ata_data_xfer() fix

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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>
This commit is contained in:
Albert Lee 2005-08-12 14:15:34 +08:00 committed by Jeff Garzik
parent bc68552faa
commit 6ae4cfb571
1 changed files with 108 additions and 3 deletions
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111
drivers/scsi/libata-core.c
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@ -2519,6 +2519,20 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
#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 @@ static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf,
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);
@ -2534,18 +2549,75 @@ static void ata_mmio_data_xfer(struct ata_port *ap, unsigned char *buf,
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 @@ static void ata_data_xfer(struct ata_port *ap, unsigned char *buf,
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 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
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 @@ next_sg:
}
}
/**
* 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;