[PATCH] b44: alternate allocation option for DMA descriptors
This is a (final?) hack to support the odd DMA allocation requirements
of the b44 hardware. The b44 hardware has a 30-bit DMA mask. On x86,
anything less than a 32-bit DMA mask forces allocations into the 16MB
GFP_DMA range. The memory there is somewhat limited, often resulting
in an inability to initialize the b44 driver.
This hack uses streaming DMA allocation APIs in order to provide an
alternative in case the GFP_DMA allocation fails. It is somewhat ugly,
but not much worse than the similar existing hacks to support SKB
allocations in the same driver. FWIW, I have received positive
feedback on this from several Fedora users.
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index d27e870..282ebd1 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -106,6 +106,29 @@
static void b44_poll_controller(struct net_device *dev);
#endif
+static int dma_desc_align_mask;
+static int dma_desc_sync_size;
+
+static inline void b44_sync_dma_desc_for_device(struct pci_dev *pdev,
+ dma_addr_t dma_base,
+ unsigned long offset,
+ enum dma_data_direction dir)
+{
+ dma_sync_single_range_for_device(&pdev->dev, dma_base,
+ offset & dma_desc_align_mask,
+ dma_desc_sync_size, dir);
+}
+
+static inline void b44_sync_dma_desc_for_cpu(struct pci_dev *pdev,
+ dma_addr_t dma_base,
+ unsigned long offset,
+ enum dma_data_direction dir)
+{
+ dma_sync_single_range_for_cpu(&pdev->dev, dma_base,
+ offset & dma_desc_align_mask,
+ dma_desc_sync_size, dir);
+}
+
static inline unsigned long br32(const struct b44 *bp, unsigned long reg)
{
return readl(bp->regs + reg);
@@ -668,6 +691,11 @@
dp->ctrl = cpu_to_le32(ctrl);
dp->addr = cpu_to_le32((u32) mapping + bp->rx_offset + bp->dma_offset);
+ if (bp->flags & B44_FLAG_RX_RING_HACK)
+ b44_sync_dma_desc_for_device(bp->pdev, bp->rx_ring_dma,
+ dest_idx * sizeof(dp),
+ DMA_BIDIRECTIONAL);
+
return RX_PKT_BUF_SZ;
}
@@ -692,6 +720,11 @@
pci_unmap_addr_set(dest_map, mapping,
pci_unmap_addr(src_map, mapping));
+ if (bp->flags & B44_FLAG_RX_RING_HACK)
+ b44_sync_dma_desc_for_cpu(bp->pdev, bp->rx_ring_dma,
+ src_idx * sizeof(src_desc),
+ DMA_BIDIRECTIONAL);
+
ctrl = src_desc->ctrl;
if (dest_idx == (B44_RX_RING_SIZE - 1))
ctrl |= cpu_to_le32(DESC_CTRL_EOT);
@@ -700,8 +733,14 @@
dest_desc->ctrl = ctrl;
dest_desc->addr = src_desc->addr;
+
src_map->skb = NULL;
+ if (bp->flags & B44_FLAG_RX_RING_HACK)
+ b44_sync_dma_desc_for_device(bp->pdev, bp->rx_ring_dma,
+ dest_idx * sizeof(dest_desc),
+ DMA_BIDIRECTIONAL);
+
pci_dma_sync_single_for_device(bp->pdev, src_desc->addr,
RX_PKT_BUF_SZ,
PCI_DMA_FROMDEVICE);
@@ -959,6 +998,11 @@
bp->tx_ring[entry].ctrl = cpu_to_le32(ctrl);
bp->tx_ring[entry].addr = cpu_to_le32((u32) mapping+bp->dma_offset);
+ if (bp->flags & B44_FLAG_TX_RING_HACK)
+ b44_sync_dma_desc_for_device(bp->pdev, bp->tx_ring_dma,
+ entry * sizeof(bp->tx_ring[0]),
+ DMA_TO_DEVICE);
+
entry = NEXT_TX(entry);
bp->tx_prod = entry;
@@ -1064,6 +1108,16 @@
memset(bp->rx_ring, 0, B44_RX_RING_BYTES);
memset(bp->tx_ring, 0, B44_TX_RING_BYTES);
+ if (bp->flags & B44_FLAG_RX_RING_HACK)
+ dma_sync_single_for_device(&bp->pdev->dev, bp->rx_ring_dma,
+ DMA_TABLE_BYTES,
+ PCI_DMA_BIDIRECTIONAL);
+
+ if (bp->flags & B44_FLAG_TX_RING_HACK)
+ dma_sync_single_for_device(&bp->pdev->dev, bp->tx_ring_dma,
+ DMA_TABLE_BYTES,
+ PCI_DMA_TODEVICE);
+
for (i = 0; i < bp->rx_pending; i++) {
if (b44_alloc_rx_skb(bp, -1, i) < 0)
break;
@@ -1085,14 +1139,28 @@
bp->tx_buffers = NULL;
}
if (bp->rx_ring) {
- pci_free_consistent(bp->pdev, DMA_TABLE_BYTES,
- bp->rx_ring, bp->rx_ring_dma);
+ if (bp->flags & B44_FLAG_RX_RING_HACK) {
+ dma_unmap_single(&bp->pdev->dev, bp->rx_ring_dma,
+ DMA_TABLE_BYTES,
+ DMA_BIDIRECTIONAL);
+ kfree(bp->rx_ring);
+ } else
+ pci_free_consistent(bp->pdev, DMA_TABLE_BYTES,
+ bp->rx_ring, bp->rx_ring_dma);
bp->rx_ring = NULL;
+ bp->flags &= ~B44_FLAG_RX_RING_HACK;
}
if (bp->tx_ring) {
- pci_free_consistent(bp->pdev, DMA_TABLE_BYTES,
- bp->tx_ring, bp->tx_ring_dma);
+ if (bp->flags & B44_FLAG_TX_RING_HACK) {
+ dma_unmap_single(&bp->pdev->dev, bp->tx_ring_dma,
+ DMA_TABLE_BYTES,
+ DMA_TO_DEVICE);
+ kfree(bp->tx_ring);
+ } else
+ pci_free_consistent(bp->pdev, DMA_TABLE_BYTES,
+ bp->tx_ring, bp->tx_ring_dma);
bp->tx_ring = NULL;
+ bp->flags &= ~B44_FLAG_TX_RING_HACK;
}
}
@@ -1118,12 +1186,56 @@
size = DMA_TABLE_BYTES;
bp->rx_ring = pci_alloc_consistent(bp->pdev, size, &bp->rx_ring_dma);
- if (!bp->rx_ring)
- goto out_err;
+ if (!bp->rx_ring) {
+ /* Allocation may have failed due to pci_alloc_consistent
+ insisting on use of GFP_DMA, which is more restrictive
+ than necessary... */
+ struct dma_desc *rx_ring;
+ dma_addr_t rx_ring_dma;
+
+ if (!(rx_ring = (struct dma_desc *)kmalloc(size, GFP_KERNEL)))
+ goto out_err;
+
+ memset(rx_ring, 0, size);
+ rx_ring_dma = dma_map_single(&bp->pdev->dev, rx_ring,
+ DMA_TABLE_BYTES,
+ DMA_BIDIRECTIONAL);
+
+ if (rx_ring_dma + size > B44_DMA_MASK) {
+ kfree(rx_ring);
+ goto out_err;
+ }
+
+ bp->rx_ring = rx_ring;
+ bp->rx_ring_dma = rx_ring_dma;
+ bp->flags |= B44_FLAG_RX_RING_HACK;
+ }
bp->tx_ring = pci_alloc_consistent(bp->pdev, size, &bp->tx_ring_dma);
- if (!bp->tx_ring)
- goto out_err;
+ if (!bp->tx_ring) {
+ /* Allocation may have failed due to pci_alloc_consistent
+ insisting on use of GFP_DMA, which is more restrictive
+ than necessary... */
+ struct dma_desc *tx_ring;
+ dma_addr_t tx_ring_dma;
+
+ if (!(tx_ring = (struct dma_desc *)kmalloc(size, GFP_KERNEL)))
+ goto out_err;
+
+ memset(tx_ring, 0, size);
+ tx_ring_dma = dma_map_single(&bp->pdev->dev, tx_ring,
+ DMA_TABLE_BYTES,
+ DMA_TO_DEVICE);
+
+ if (tx_ring_dma + size > B44_DMA_MASK) {
+ kfree(tx_ring);
+ goto out_err;
+ }
+
+ bp->tx_ring = tx_ring;
+ bp->tx_ring_dma = tx_ring_dma;
+ bp->flags |= B44_FLAG_TX_RING_HACK;
+ }
return 0;
@@ -1973,6 +2085,12 @@
static int __init b44_init(void)
{
+ unsigned int dma_desc_align_size = dma_get_cache_alignment();
+
+ /* Setup paramaters for syncing RX/TX DMA descriptors */
+ dma_desc_align_mask = ~(dma_desc_align_size - 1);
+ dma_desc_sync_size = max(dma_desc_align_size, sizeof(struct dma_desc));
+
return pci_module_init(&b44_driver);
}
diff --git a/drivers/net/b44.h b/drivers/net/b44.h
index 11c40a2..593cb0a 100644
--- a/drivers/net/b44.h
+++ b/drivers/net/b44.h
@@ -400,6 +400,8 @@
#define B44_FLAG_ADV_100HALF 0x04000000
#define B44_FLAG_ADV_100FULL 0x08000000
#define B44_FLAG_INTERNAL_PHY 0x10000000
+#define B44_FLAG_RX_RING_HACK 0x20000000
+#define B44_FLAG_TX_RING_HACK 0x40000000
u32 rx_offset;