Messages in this thread Patch in this message | | | From | Ilya Lipnitskiy <> | Subject | [PATCH net-next 10/14] net: ethernet: mtk_eth_soc: cache HW pointer of last freed TX descriptor | Date | Wed, 21 Apr 2021 21:09:10 -0700 |
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From: Felix Fietkau <nbd@nbd.name>
The value is only updated by the CPU, so it is cheaper to access from the ring data structure than from a hardware register.
Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com> --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 ++++---- drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 ++ 2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index 043ab5446524..01ad10c76d53 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -1362,7 +1362,7 @@ static int mtk_poll_tx_qdma(struct mtk_eth *eth, int budget, struct mtk_tx_buf *tx_buf; u32 cpu, dma; - cpu = mtk_r32(eth, MTK_QTX_CRX_PTR); + cpu = ring->last_free_ptr; dma = mtk_r32(eth, MTK_QTX_DRX_PTR); desc = mtk_qdma_phys_to_virt(ring, cpu); @@ -1396,6 +1396,7 @@ static int mtk_poll_tx_qdma(struct mtk_eth *eth, int budget, cpu = next_cpu; } + ring->last_free_ptr = cpu; mtk_w32(eth, cpu, MTK_QTX_CRX_PTR); return budget; @@ -1596,6 +1597,7 @@ static int mtk_tx_alloc(struct mtk_eth *eth) atomic_set(&ring->free_count, MTK_DMA_SIZE - 2); ring->next_free = &ring->dma[0]; ring->last_free = &ring->dma[MTK_DMA_SIZE - 1]; + ring->last_free_ptr = (u32)(ring->phys + ((MTK_DMA_SIZE - 1) * sz)); ring->thresh = MAX_SKB_FRAGS; /* make sure that all changes to the dma ring are flushed before we @@ -1609,9 +1611,7 @@ static int mtk_tx_alloc(struct mtk_eth *eth) mtk_w32(eth, ring->phys + ((MTK_DMA_SIZE - 1) * sz), MTK_QTX_CRX_PTR); - mtk_w32(eth, - ring->phys + ((MTK_DMA_SIZE - 1) * sz), - MTK_QTX_DRX_PTR); + mtk_w32(eth, ring->last_free_ptr, MTK_QTX_DRX_PTR); mtk_w32(eth, (QDMA_RES_THRES << 8) | QDMA_RES_THRES, MTK_QTX_CFG(0)); } else { diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h index a8d388b02558..214da569e869 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h @@ -642,6 +642,7 @@ struct mtk_tx_buf { * @phys: The physical addr of tx_buf * @next_free: Pointer to the next free descriptor * @last_free: Pointer to the last free descriptor + * @last_free_ptr: Hardware pointer value of the last free descriptor * @thresh: The threshold of minimum amount of free descriptors * @free_count: QDMA uses a linked list. Track how many free descriptors * are present @@ -652,6 +653,7 @@ struct mtk_tx_ring { dma_addr_t phys; struct mtk_tx_dma *next_free; struct mtk_tx_dma *last_free; + u32 last_free_ptr; u16 thresh; atomic_t free_count; int dma_size; -- 2.31.1
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