[libata] sata_mv: clean up DMA boundary issues, turn on 64-bit DMA

The chips covered by sata_mv have a 32-bit DMA boundary they must not
cross, not a 64K boundary.  We are merely limited to a 64K maximum
segment size.  Therefore, the DMA scatter/gather table fill code can be
greatly simplified, and we need not cut in half the S/G table size as
reported to the SCSI layer.

Also, the driver forget to turn on 64-bit DMA at the PCI layer.  All
other data structures (both hardware and software) have been prepped for
64-bit PCI DMA.  It was simply never turned on.  <fingers crossed> let's
see if it still works...

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 55 insertions, 29 deletions

diff --git a/drivers/ata/sata_mv.c b/drivers/ata/sata_mv.c
index 5f3d524c3387..7b73c73b3f34 100644
--- a/drivers/ata/sata_mv.c
+++ b/drivers/ata/sata_mv.c
@@ -253,10 +253,7 @@ enum {
 #define IS_GEN_IIE(hpriv) ((hpriv)->hp_flags & MV_HP_GEN_IIE)
 
 enum {
-        /* Our DMA boundary is determined by an ePRD being unable to handle
-         * anything larger than 64KB
-         */
-        MV_DMA_BOUNDARY         = 0xffffU,
+        MV_DMA_BOUNDARY         = 0xffffffffU,
 
         EDMA_REQ_Q_BASE_LO_MASK = 0xfffffc00U,
 
@@ -384,10 +381,10 @@ static struct scsi_host_template mv_sht = {
         .queuecommand           = ata_scsi_queuecmd,
         .can_queue              = MV_USE_Q_DEPTH,
         .this_id                = ATA_SHT_THIS_ID,
-        .sg_tablesize           = MV_MAX_SG_CT / 2,
+        .sg_tablesize           = MV_MAX_SG_CT,
         .cmd_per_lun            = ATA_SHT_CMD_PER_LUN,
         .emulated               = ATA_SHT_EMULATED,
-        .use_clustering         = ATA_SHT_USE_CLUSTERING,
+        .use_clustering         = 1,
         .proc_name              = DRV_NAME,
         .dma_boundary           = MV_DMA_BOUNDARY,
         .slave_configure        = ata_scsi_slave_config,
@@ -585,6 +582,39 @@ static const struct mv_hw_ops mv6xxx_ops = {
 static int msi;       /* Use PCI msi; either zero (off, default) or non-zero */
 
 
+/* move to PCI layer or libata core? */
+static int pci_go_64(struct pci_dev *pdev)
+{
+        int rc;
+
+        if (!pci_set_dma_mask(pdev, DMA_64BIT_MASK)) {
+                rc = pci_set_consistent_dma_mask(pdev, DMA_64BIT_MASK);
+                if (rc) {
+                        rc = pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK);
+                        if (rc) {
+                                dev_printk(KERN_ERR, &pdev->dev,
+                                           "64-bit DMA enable failed\n");
+                                return rc;
+                        }
+                }
+        } else {
+                rc = pci_set_dma_mask(pdev, DMA_32BIT_MASK);
+                if (rc) {
+                        dev_printk(KERN_ERR, &pdev->dev,
+                                   "32-bit DMA enable failed\n");
+                        return rc;
+                }
+                rc = pci_set_consistent_dma_mask(pdev, DMA_32BIT_MASK);
+                if (rc) {
+                        dev_printk(KERN_ERR, &pdev->dev,
+                                   "32-bit consistent DMA enable failed\n");
+                        return rc;
+                }
+        }
+
+        return rc;
+}
+
 /*
  * Functions
  */
@@ -957,38 +987,30 @@ static void mv_port_stop(struct ata_port *ap)
  *      LOCKING:
  *      Inherited from caller.
  */
-static void mv_fill_sg(struct ata_queued_cmd *qc)
+static unsigned int mv_fill_sg(struct ata_queued_cmd *qc)
 {
         struct mv_port_priv *pp = qc->ap->private_data;
-        unsigned int i = 0;
+        unsigned int n_sg = 0;
         struct scatterlist *sg;
+        struct mv_sg *mv_sg;
 
+        mv_sg = pp->sg_tbl;
         ata_for_each_sg(sg, qc) {
-                dma_addr_t addr;
-                u32 sg_len, len, offset;
-
-                addr = sg_dma_address(sg);
-                sg_len = sg_dma_len(sg);
-
-                while (sg_len) {
-                        offset = addr & MV_DMA_BOUNDARY;
-                        len = sg_len;
-                        if ((offset + sg_len) > 0x10000)
-                                len = 0x10000 - offset;
-
-                        pp->sg_tbl[i].addr = cpu_to_le32(addr & 0xffffffff);
-                        pp->sg_tbl[i].addr_hi = cpu_to_le32((addr >> 16) >> 16);
-                        pp->sg_tbl[i].flags_size = cpu_to_le32(len & 0xffff);
+                dma_addr_t addr = sg_dma_address(sg);
+                u32 sg_len = sg_dma_len(sg);
 
-                        sg_len -= len;
-                        addr += len;
+                mv_sg->addr = cpu_to_le32(addr & 0xffffffff);
+                mv_sg->addr_hi = cpu_to_le32((addr >> 16) >> 16);
+                mv_sg->flags_size = cpu_to_le32(sg_len & 0xffff);
 
-                        if (!sg_len && ata_sg_is_last(sg, qc))
-                                pp->sg_tbl[i].flags_size |= cpu_to_le32(EPRD_FLAG_END_OF_TBL);
+                if (ata_sg_is_last(sg, qc))
+                        mv_sg->flags_size |= cpu_to_le32(EPRD_FLAG_END_OF_TBL);
 
-                        i++;
-                }
+                mv_sg++;
+                n_sg++;
         }
+
+        return n_sg;
 }
 
 static inline unsigned mv_inc_q_index(unsigned index)
@@ -2327,6 +2349,10 @@ static int mv_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
         if (rc)
                 return rc;
 
+        rc = pci_go_64(pdev);
+        if (rc)
+                return rc;
+
         probe_ent = devm_kzalloc(dev, sizeof(*probe_ent), GFP_KERNEL);
         if (probe_ent == NULL)
                 return -ENOMEM;