solos-pci: ensure all TX packets are aligned to 4 bytes

The FPGA can't handled unaligned DMA (yet). So copy into an aligned buffer,
if skb->data isn't suitably aligned.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 4 deletions

diff --git a/drivers/atm/solos-pci.c b/drivers/atm/solos-pci.c
index aa4f35d52a92..d70abe77f737 100644
--- a/drivers/atm/solos-pci.c
+++ b/drivers/atm/solos-pci.c
@@ -128,9 +128,11 @@ struct solos_card {
         struct sk_buff_head cli_queue[4];
         struct sk_buff *tx_skb[4];
         struct sk_buff *rx_skb[4];
+        unsigned char *dma_bounce;
         wait_queue_head_t param_wq;
         wait_queue_head_t fw_wq;
         int using_dma;
+        int dma_alignment;
         int fpga_version;
         int buffer_size;
         int atmel_flash;
@@ -1083,7 +1085,12 @@ static uint32_t fpga_tx(struct solos_card *card)
                                 tx_started |= 1 << port;
                                 oldskb = skb; /* We're done with this skb already */
                         } else if (skb && card->using_dma) {
-                                SKB_CB(skb)->dma_addr = pci_map_single(card->dev, skb->data,
+                                unsigned char *data = skb->data;
+                                if ((unsigned long)data & card->dma_alignment) {
+                                        data = card->dma_bounce + (BUF_SIZE * port);
+                                        memcpy(data, skb->data, skb->len);
+                                }
+                                SKB_CB(skb)->dma_addr = pci_map_single(card->dev, data,
                                                                        skb->len, PCI_DMA_TODEVICE);
                                 card->tx_skb[port] = skb;
                                 iowrite32(SKB_CB(skb)->dma_addr,
@@ -1261,18 +1268,27 @@ static int fpga_probe(struct pci_dev *dev, const struct pci_device_id *id)
         else
                 card->atmel_flash = 0;
 
+        data32 = ioread32(card->config_regs + PORTS);
+        card->nr_ports = (data32 & 0x000000FF);
+
         if (card->fpga_version >= DMA_SUPPORTED) {
                 pci_set_master(dev);
                 card->using_dma = 1;
+                if (1) { /* All known FPGA versions so far */
+                        card->dma_alignment = 3;
+                        card->dma_bounce = kmalloc(card->nr_ports * BUF_SIZE, GFP_KERNEL);
+                        if (!card->dma_bounce) {
+                                dev_warn(&card->dev->dev, "Failed to allocate DMA bounce buffers\n");
+                                /* Fallback to MMIO doesn't work */
+                                goto out_unmap_both;
+                        }
+                }
         } else {
                 card->using_dma = 0;
                 /* Set RX empty flag for all ports */
                 iowrite32(0xF0, card->config_regs + FLAGS_ADDR);
         }
 
-        data32 = ioread32(card->config_regs + PORTS);
-        card->nr_ports = (data32 & 0x000000FF);
-
         pci_set_drvdata(dev, card);
 
         tasklet_init(&card->tlet, solos_bh, (unsigned long)card);
@@ -1319,6 +1335,7 @@ static int fpga_probe(struct pci_dev *dev, const struct pci_device_id *id)
         tasklet_kill(&card->tlet);
         
  out_unmap_both:
+        kfree(card->dma_bounce);
         pci_set_drvdata(dev, NULL);
         pci_iounmap(dev, card->buffers);
  out_unmap_config:
@@ -1429,6 +1446,8 @@ static void fpga_remove(struct pci_dev *dev)
         free_irq(dev->irq, card);
         tasklet_kill(&card->tlet);
 
+        kfree(card->dma_bounce);
+
         /* Release device from reset */
         iowrite32(0, card->config_regs + FPGA_MODE);
         (void)ioread32(card->config_regs + FPGA_MODE);