bgmac: implement unaligned addressing for DMA rings that support it
This is important patch for new devices that support unaligned
addressing. That devices suffer from the backward-compatibility bug in
DMA engine. In theory we should be able to use old mechanism, but in
practice DMA address seems to be randomly copied into status register
when hardware reaches end of a ring. This breaks reading slot number
from status register and we can't use DMA anymore.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c
index 59f3e0c..249468f 100644
--- a/drivers/net/ethernet/broadcom/bgmac.c
+++ b/drivers/net/ethernet/broadcom/bgmac.c
@@ -157,6 +157,7 @@
if (++ring->end >= BGMAC_TX_RING_SLOTS)
ring->end = 0;
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_TX_INDEX,
+ ring->index_base +
ring->end * sizeof(struct bgmac_dma_desc));
/* Always keep one slot free to allow detecting bugged calls. */
@@ -181,6 +182,8 @@
/* The last slot that hardware didn't consume yet */
empty_slot = bgmac_read(bgmac, ring->mmio_base + BGMAC_DMA_TX_STATUS);
empty_slot &= BGMAC_DMA_TX_STATDPTR;
+ empty_slot -= ring->index_base;
+ empty_slot &= BGMAC_DMA_TX_STATDPTR;
empty_slot /= sizeof(struct bgmac_dma_desc);
while (ring->start != empty_slot) {
@@ -274,6 +277,8 @@
end_slot = bgmac_read(bgmac, ring->mmio_base + BGMAC_DMA_RX_STATUS);
end_slot &= BGMAC_DMA_RX_STATDPTR;
+ end_slot -= ring->index_base;
+ end_slot &= BGMAC_DMA_RX_STATDPTR;
end_slot /= sizeof(struct bgmac_dma_desc);
ring->end = end_slot;
@@ -418,9 +423,6 @@
ring = &bgmac->tx_ring[i];
ring->num_slots = BGMAC_TX_RING_SLOTS;
ring->mmio_base = ring_base[i];
- if (bgmac_dma_unaligned(bgmac, ring, BGMAC_DMA_RING_TX))
- bgmac_warn(bgmac, "TX on ring 0x%X supports unaligned addressing but this feature is not implemented\n",
- ring->mmio_base);
/* Alloc ring of descriptors */
size = ring->num_slots * sizeof(struct bgmac_dma_desc);
@@ -435,6 +437,13 @@
if (ring->dma_base & 0xC0000000)
bgmac_warn(bgmac, "DMA address using 0xC0000000 bit(s), it may need translation trick\n");
+ ring->unaligned = bgmac_dma_unaligned(bgmac, ring,
+ BGMAC_DMA_RING_TX);
+ if (ring->unaligned)
+ ring->index_base = lower_32_bits(ring->dma_base);
+ else
+ ring->index_base = 0;
+
/* No need to alloc TX slots yet */
}
@@ -444,9 +453,6 @@
ring = &bgmac->rx_ring[i];
ring->num_slots = BGMAC_RX_RING_SLOTS;
ring->mmio_base = ring_base[i];
- if (bgmac_dma_unaligned(bgmac, ring, BGMAC_DMA_RING_RX))
- bgmac_warn(bgmac, "RX on ring 0x%X supports unaligned addressing but this feature is not implemented\n",
- ring->mmio_base);
/* Alloc ring of descriptors */
size = ring->num_slots * sizeof(struct bgmac_dma_desc);
@@ -462,6 +468,13 @@
if (ring->dma_base & 0xC0000000)
bgmac_warn(bgmac, "DMA address using 0xC0000000 bit(s), it may need translation trick\n");
+ ring->unaligned = bgmac_dma_unaligned(bgmac, ring,
+ BGMAC_DMA_RING_RX);
+ if (ring->unaligned)
+ ring->index_base = lower_32_bits(ring->dma_base);
+ else
+ ring->index_base = 0;
+
/* Alloc RX slots */
for (j = 0; j < ring->num_slots; j++) {
err = bgmac_dma_rx_skb_for_slot(bgmac, &ring->slots[j]);
@@ -489,12 +502,14 @@
for (i = 0; i < BGMAC_MAX_TX_RINGS; i++) {
ring = &bgmac->tx_ring[i];
- /* We don't implement unaligned addressing, so enable first */
- bgmac_dma_tx_enable(bgmac, ring);
+ if (!ring->unaligned)
+ bgmac_dma_tx_enable(bgmac, ring);
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_TX_RINGLO,
lower_32_bits(ring->dma_base));
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_TX_RINGHI,
upper_32_bits(ring->dma_base));
+ if (ring->unaligned)
+ bgmac_dma_tx_enable(bgmac, ring);
ring->start = 0;
ring->end = 0; /* Points the slot that should *not* be read */
@@ -505,12 +520,14 @@
ring = &bgmac->rx_ring[i];
- /* We don't implement unaligned addressing, so enable first */
- bgmac_dma_rx_enable(bgmac, ring);
+ if (!ring->unaligned)
+ bgmac_dma_rx_enable(bgmac, ring);
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_RX_RINGLO,
lower_32_bits(ring->dma_base));
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_RX_RINGHI,
upper_32_bits(ring->dma_base));
+ if (ring->unaligned)
+ bgmac_dma_rx_enable(bgmac, ring);
for (j = 0, dma_desc = ring->cpu_base; j < ring->num_slots;
j++, dma_desc++) {
@@ -531,6 +548,7 @@
}
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_RX_INDEX,
+ ring->index_base +
ring->num_slots * sizeof(struct bgmac_dma_desc));
ring->start = 0;