/spare/repo/libata-dev branch 'upstream-fixes'

1 files changed, 133 insertions, 6 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 6e56af23957b..3544f5d020c6 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -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);
@@ -2534,19 +2549,76 @@ 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);
@@ -2603,10 +2697,33 @@ static void __atapi_pio_bytes(struct ata_queued_cmd *qc, unsigned int bytes)
         unsigned char *buf;
         unsigned int offset, count;
 
-        if (qc->curbytes == qc->nbytes - bytes)
+        if (qc->curbytes + bytes >= qc->nbytes)
                 ap->pio_task_state = PIO_ST_LAST;
 
 next_sg:
+        if (unlikely(qc->cursg >= qc->n_elem)) {
+                /* 
+                 * The end of qc->sg is reached and the device expects
+                 * more data to transfer. In order not to overrun qc->sg
+                 * and fulfill length specified in the byte count register,
+                 *    - for read case, discard trailing data from the device
+                 *    - for write case, padding zero data to the device
+                 */
+                u16 pad_buf[1] = { 0 };
+                unsigned int words = bytes >> 1;
+                unsigned int i;
+
+                if (words) /* warning if bytes > 1 */
+                        printk(KERN_WARNING "ata%u: %u bytes trailing data\n", 
+                               ap->id, bytes);
+
+                for (i = 0; i < words; i++)
+                        ata_data_xfer(ap, (unsigned char*)pad_buf, 2, do_write);
+
+                ap->pio_task_state = PIO_ST_LAST;
+                return;
+        }
+
         sg = &qc->sg[qc->cursg];
 
         page = sg->page;
@@ -2640,11 +2757,21 @@ next_sg:
 
         kunmap(page);
 
-        if (bytes) {
+        if (bytes)
                 goto 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;