--- /dev/null
+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>
+
+--- a/drivers/net/ethernet/broadcom/bgmac.c
++++ b/drivers/net/ethernet/broadcom/bgmac.c
+@@ -162,6 +162,7 @@ static netdev_tx_t bgmac_dma_tx_add(stru
+ 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. */
+@@ -186,6 +187,8 @@ static void bgmac_dma_tx_free(struct bgm
+ /* 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) {
+@@ -279,6 +282,8 @@ static int bgmac_dma_rx_read(struct bgma
+
+ 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;
+@@ -423,9 +428,6 @@ static int bgmac_dma_alloc(struct bgmac
+ 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);
+@@ -440,6 +442,13 @@ static int bgmac_dma_alloc(struct bgmac
+ 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 */
+ }
+
+@@ -449,9 +458,6 @@ static int bgmac_dma_alloc(struct bgmac
+ 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);
+@@ -467,6 +473,13 @@ static int bgmac_dma_alloc(struct bgmac
+ 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]);
+@@ -494,12 +507,14 @@ static void bgmac_dma_init(struct bgmac
+ 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 */
+@@ -510,12 +525,14 @@ static void bgmac_dma_init(struct bgmac
+
+ 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++) {
+@@ -536,6 +553,7 @@ static void bgmac_dma_init(struct bgmac
+ }
+
+ bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_RX_INDEX,
++ ring->index_base +
+ ring->num_slots * sizeof(struct bgmac_dma_desc));
+
+ ring->start = 0;
+--- a/drivers/net/ethernet/broadcom/bgmac.h
++++ b/drivers/net/ethernet/broadcom/bgmac.h
+@@ -386,6 +386,8 @@ struct bgmac_dma_ring {
+ u16 mmio_base;
+ struct bgmac_dma_desc *cpu_base;
+ dma_addr_t dma_base;
++ u32 index_base; /* Used for unaligned rings only, otherwise 0 */
++ bool unaligned;
+
+ struct bgmac_slot_info slots[BGMAC_RX_RING_SLOTS];
+ };
projects / openwrt.git / blobdiff