Some mainboards/CPUs don't allow DMA masks bigger than a certain limit.
Some VIA crap^h^h^h^hdevices have an upper limit of 0xFFFFFFFF. So in this
case a 64-bit b43 device would always fail to acquire the mask.
Implement a workaround to fallback to lower DMA mask, as we can always
also support a lower mask.
This patch is in wireless-testing.git, commit
91725545159f81f1c9dc738dfc329199583f649a
Signed-off-by: Michael Buesch <mb@xxxxxxxxx>
Index: linux-2.6.25/drivers/net/wireless/b43/dma.c
===================================================================
--- linux-2.6.25.orig/drivers/net/wireless/b43/dma.c 2008-04-19 18:29:16.000000000 +0200
+++ linux-2.6.25/drivers/net/wireless/b43/dma.c 2008-04-23 18:35:33.000000000 +0200
@@ -819,12 +819,24 @@ static u64 supported_dma_mask(struct b43
if (tmp & B43_DMA32_TXADDREXT_MASK)
return DMA_32BIT_MASK;
return DMA_30BIT_MASK;
}
+static enum b43_dmatype dma_mask_to_engine_type(u64 dmamask)
+{
+ if (dmamask == DMA_30BIT_MASK)
+ return B43_DMA_30BIT;
+ if (dmamask == DMA_32BIT_MASK)
+ return B43_DMA_32BIT;
+ if (dmamask == DMA_64BIT_MASK)
+ return B43_DMA_64BIT;
+ B43_WARN_ON(1);
+ return B43_DMA_30BIT;
+}
+
/* Main initialization function. */
static
struct b43_dmaring *b43_setup_dmaring(struct b43_wldev *dev,
int controller_index,
int for_tx,
enum b43_dmatype type)
@@ -979,42 +991,61 @@ void b43_dma_free(struct b43_wldev *dev)
b43_destroy_dmaring(dma->tx_ring1);
dma->tx_ring1 = NULL;
b43_destroy_dmaring(dma->tx_ring0);
dma->tx_ring0 = NULL;
}
+static int b43_dma_set_mask(struct b43_wldev *dev, u64 mask)
+{
+ u64 orig_mask = mask;
+ bool fallback = 0;
+ int err;
+
+ /* Try to set the DMA mask. If it fails, try falling back to a
+ * lower mask, as we can always also support a lower one. */
+ while (1) {
+ err = ssb_dma_set_mask(dev->dev, mask);
+ if (!err)
+ break;
+ if (mask == DMA_64BIT_MASK) {
+ mask = DMA_32BIT_MASK;
+ fallback = 1;
+ continue;
+ }
+ if (mask == DMA_32BIT_MASK) {
+ mask = DMA_30BIT_MASK;
+ fallback = 1;
+ continue;
+ }
+ b43err(dev->wl, "The machine/kernel does not support "
+ "the required %u-bit DMA mask\n",
+ (unsigned int)dma_mask_to_engine_type(orig_mask));
+ return -EOPNOTSUPP;
+ }
+ if (fallback) {
+ b43info(dev->wl, "DMA mask fallback from %u-bit to %u-bit\n",
+ (unsigned int)dma_mask_to_engine_type(orig_mask),
+ (unsigned int)dma_mask_to_engine_type(mask));
+ }
+
+ return 0;
+}
+
int b43_dma_init(struct b43_wldev *dev)
{
struct b43_dma *dma = &dev->dma;
struct b43_dmaring *ring;
int err;
u64 dmamask;
enum b43_dmatype type;
dmamask = supported_dma_mask(dev);
- switch (dmamask) {
- default:
- B43_WARN_ON(1);
- case DMA_30BIT_MASK:
- type = B43_DMA_30BIT;
- break;
- case DMA_32BIT_MASK:
- type = B43_DMA_32BIT;
- break;
- case DMA_64BIT_MASK:
- type = B43_DMA_64BIT;
- break;
- }
- err = ssb_dma_set_mask(dev->dev, dmamask);
- if (err) {
- b43err(dev->wl, "The machine/kernel does not support "
- "the required DMA mask (0x%08X%08X)\n",
- (unsigned int)((dmamask & 0xFFFFFFFF00000000ULL) >> 32),
- (unsigned int)(dmamask & 0x00000000FFFFFFFFULL));
- return -EOPNOTSUPP;
- }
+ type = dma_mask_to_engine_type(dmamask);
+ err = b43_dma_set_mask(dev, dmamask);
+ if (err)
+ return err;
err = -ENOMEM;
/* setup TX DMA channels. */
ring = b43_setup_dmaring(dev, 0, 1, type);
if (!ring)
goto out;
--
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