libata: Add 32bit PIO support

This matters for some controllers and in one or two cases almost doubles
PIO performance. Add a bmdma32 operations set we can inherit and activate
it for some controllers

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 9033d164c4ec..b58549fac460 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -78,6 +78,13 @@ const struct ata_port_operations ata_bmdma_port_ops = {
         .bmdma_status           = ata_bmdma_status,
 };
 
+const struct ata_port_operations ata_bmdma32_port_ops = {
+        .inherits               = &ata_bmdma_port_ops,
+
+        .sff_data_xfer          = ata_sff_data_xfer32,
+};
+EXPORT_SYMBOL_GPL(ata_bmdma32_port_ops);
+
 /**
  *      ata_fill_sg - Fill PCI IDE PRD table
  *      @qc: Metadata associated with taskfile to be transferred
@@ -719,6 +726,52 @@ unsigned int ata_sff_data_xfer(struct ata_device *dev, unsigned char *buf,
 }
 
 /**
+ *      ata_sff_data_xfer32 - Transfer data by PIO
+ *      @dev: device to target
+ *      @buf: data buffer
+ *      @buflen: buffer length
+ *      @rw: read/write
+ *
+ *      Transfer data from/to the device data register by PIO using 32bit
+ *      I/O operations.
+ *
+ *      LOCKING:
+ *      Inherited from caller.
+ *
+ *      RETURNS:
+ *      Bytes consumed.
+ */
+
+unsigned int ata_sff_data_xfer32(struct ata_device *dev, unsigned char *buf,
+                               unsigned int buflen, int rw)
+{
+        struct ata_port *ap = dev->link->ap;
+        void __iomem *data_addr = ap->ioaddr.data_addr;
+        unsigned int words = buflen >> 2;
+        int slop = buflen & 3;
+
+        /* Transfer multiple of 4 bytes */
+        if (rw == READ)
+                ioread32_rep(data_addr, buf, words);
+        else
+                iowrite32_rep(data_addr, buf, words);
+
+        if (unlikely(slop)) {
+                __le32 pad;
+                if (rw == READ) {
+                        pad = cpu_to_le32(ioread32(ap->ioaddr.data_addr));
+                        memcpy(buf + buflen - slop, &pad, slop);
+                } else {
+                        memcpy(&pad, buf + buflen - slop, slop);
+                        iowrite32(le32_to_cpu(pad), ap->ioaddr.data_addr);
+                }
+                words++;
+        }
+        return words << 2;
+}
+EXPORT_SYMBOL_GPL(ata_sff_data_xfer32);
+
+/**
  *      ata_sff_data_xfer_noirq - Transfer data by PIO
  *      @dev: device to target
  *      @buf: data buffer