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bgmac: simplify tx ring index handling 

Keep incrementing ring->start and ring->end instead of pointing it to
the actual ring slot entry. This simplifies the calculation of the
number of free slots.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Acked-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Felix Fietkau 2015-04-14 12:07:54 +02:00 committed by David S. Miller
parent e07678341b
commit b38c83dd08
2 changed files with 23 additions and 29 deletions
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46
drivers/net/ethernet/broadcom/bgmac.c
View File

@ -142,11 +142,10 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
{
struct device *dma_dev = bgmac->core->dma_dev;
struct net_device *net_dev = bgmac->net_dev;
struct bgmac_slot_info *slot = &ring->slots[ring->end];
int free_slots;
int index = ring->end % BGMAC_TX_RING_SLOTS;
struct bgmac_slot_info *slot = &ring->slots[index];
int nr_frags;
u32 flags;
int index = ring->end;
int i;
if (skb->len > BGMAC_DESC_CTL1_LEN) {
@ -159,12 +158,10 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
nr_frags = skb_shinfo(skb)->nr_frags;
if (ring->start <= ring->end)
free_slots = ring->start - ring->end + BGMAC_TX_RING_SLOTS;
else
free_slots = ring->start - ring->end;
if (free_slots <= nr_frags + 1) {
/* ring->end - ring->start will return the number of valid slots,
* even when ring->end overflows
*/
if (ring->end - ring->start + nr_frags + 1 >= BGMAC_TX_RING_SLOTS) {
bgmac_err(bgmac, "TX ring is full, queue should be stopped!\n");
netif_stop_queue(net_dev);
return NETDEV_TX_BUSY;
@ -200,7 +197,7 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
}
slot->skb = skb;
ring->end += nr_frags + 1;
netdev_sent_queue(net_dev, skb->len);
wmb();
@ -208,13 +205,12 @@ static netdev_tx_t bgmac_dma_tx_add(struct bgmac *bgmac,
/* Increase ring->end to point empty slot. We tell hardware the first
* slot it should *not* read.
*/
ring->end = (index + 1) % BGMAC_TX_RING_SLOTS;
bgmac_write(bgmac, ring->mmio_base + BGMAC_DMA_TX_INDEX,
ring->index_base +
ring->end * sizeof(struct bgmac_dma_desc));
(ring->end % BGMAC_TX_RING_SLOTS) *
sizeof(struct bgmac_dma_desc));
free_slots -= nr_frags + 1;
if (free_slots < 8)
if (ring->end - ring->start >= BGMAC_TX_RING_SLOTS - 8)
netif_stop_queue(net_dev);
return NETDEV_TX_OK;
@ -256,17 +252,17 @@ static void bgmac_dma_tx_free(struct bgmac *bgmac, struct bgmac_dma_ring *ring)
empty_slot &= BGMAC_DMA_TX_STATDPTR;
empty_slot /= sizeof(struct bgmac_dma_desc);
while (ring->start != empty_slot) {
struct bgmac_slot_info *slot = &ring->slots[ring->start];
u32 ctl1 = le32_to_cpu(ring->cpu_base[ring->start].ctl1);
int len = ctl1 & BGMAC_DESC_CTL1_LEN;
while (ring->start != ring->end) {
int slot_idx = ring->start % BGMAC_TX_RING_SLOTS;
struct bgmac_slot_info *slot = &ring->slots[slot_idx];
u32 ctl1;
int len;
if (!slot->dma_addr) {
bgmac_err(bgmac, "Hardware reported transmission for empty TX ring slot %d! End of ring: %d\n",
ring->start, ring->end);
goto next;
}
if (slot_idx == empty_slot)
break;
ctl1 = le32_to_cpu(ring->cpu_base[slot_idx].ctl1);
len = ctl1 & BGMAC_DESC_CTL1_LEN;
if (ctl1 & BGMAC_DESC_CTL0_SOF)
/* Unmap no longer used buffer */
dma_unmap_single(dma_dev, slot->dma_addr, len,
@ -284,10 +280,8 @@ static void bgmac_dma_tx_free(struct bgmac *bgmac, struct bgmac_dma_ring *ring)
slot->skb = NULL;
}
next:
slot->dma_addr = 0;
if (++ring->start >= BGMAC_TX_RING_SLOTS)
ring->start = 0;
ring->start++;
freed = true;
}

6
drivers/net/ethernet/broadcom/bgmac.h
View File

@ -414,10 +414,10 @@ enum bgmac_dma_ring_type {
* empty.
*/
struct bgmac_dma_ring {
u16 num_slots;
u16 start;
u16 end;
u32 start;
u32 end;
u16 num_slots;
u16 mmio_base;
struct bgmac_dma_desc *cpu_base;
dma_addr_t dma_base;