From b38c83dd08665a93e439c4ffd9eef31bc098a6ea Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 14 Apr 2015 12:07:54 +0200 Subject: bgmac: simplify tx ring index handling MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Rafał Miłecki Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bgmac.c | 46 +++++++++++++++-------------------- drivers/net/ethernet/broadcom/bgmac.h | 6 ++--- 2 files changed, 23 insertions(+), 29 deletions(-) (limited to 'drivers/net/ethernet/broadcom') diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c index fa8f9e147c34..b9e02e484d72 100644 --- a/drivers/net/ethernet/broadcom/bgmac.c +++ b/drivers/net/ethernet/broadcom/bgmac.c @@ -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; } diff --git a/drivers/net/ethernet/broadcom/bgmac.h b/drivers/net/ethernet/broadcom/bgmac.h index 3ad965fe7fcc..5a198d56f3e7 100644 --- a/drivers/net/ethernet/broadcom/bgmac.h +++ b/drivers/net/ethernet/broadcom/bgmac.h @@ -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; -- cgit v1.2.3-59-g8ed1b