| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | From: Felix Fietkau <nbd@nbd.name> |
| 2 | Date: Thu, 27 Aug 2020 06:32:03 +0200 |
| 3 | Subject: [PATCH] net: ethernet: mtk_eth_soc: cache hardware pointer of last |
| 4 | freed tx descriptor |
| 5 | |
| 6 | The value is only updated by the CPU, so it is cheaper to access from the ring |
| 7 | data structure than from a hardware register |
| 8 | |
| 9 | Signed-off-by: Felix Fietkau <nbd@nbd.name> |
| 10 | --- |
| 11 | |
| 12 | --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| 13 | +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c |
| 14 | @@ -1393,7 +1393,7 @@ static int mtk_poll_tx_qdma(struct mtk_e |
| 15 | struct mtk_tx_buf *tx_buf; |
| 16 | u32 cpu, dma; |
| 17 | |
| 18 | - cpu = mtk_r32(eth, MTK_QTX_CRX_PTR); |
| 19 | + cpu = ring->last_free_ptr; |
| 20 | dma = mtk_r32(eth, MTK_QTX_DRX_PTR); |
| 21 | |
| 22 | desc = mtk_qdma_phys_to_virt(ring, cpu); |
| 23 | @@ -1427,6 +1427,7 @@ static int mtk_poll_tx_qdma(struct mtk_e |
| 24 | cpu = next_cpu; |
| 25 | } |
| 26 | |
| 27 | + ring->last_free_ptr = cpu; |
| 28 | mtk_w32(eth, cpu, MTK_QTX_CRX_PTR); |
| 29 | |
| 30 | return budget; |
| 31 | @@ -1627,6 +1628,7 @@ static int mtk_tx_alloc(struct mtk_eth * |
| 32 | atomic_set(&ring->free_count, MTK_DMA_SIZE - 2); |
| 33 | ring->next_free = &ring->dma[0]; |
| 34 | ring->last_free = &ring->dma[MTK_DMA_SIZE - 1]; |
| 35 | + ring->last_free_ptr = (u32)(ring->phys + ((MTK_DMA_SIZE - 1) * sz)); |
| 36 | ring->thresh = MAX_SKB_FRAGS; |
| 37 | |
| 38 | /* make sure that all changes to the dma ring are flushed before we |
| 39 | @@ -1640,9 +1642,7 @@ static int mtk_tx_alloc(struct mtk_eth * |
| 40 | mtk_w32(eth, |
| 41 | ring->phys + ((MTK_DMA_SIZE - 1) * sz), |
| 42 | MTK_QTX_CRX_PTR); |
| 43 | - mtk_w32(eth, |
| 44 | - ring->phys + ((MTK_DMA_SIZE - 1) * sz), |
| 45 | - MTK_QTX_DRX_PTR); |
| 46 | + mtk_w32(eth, ring->last_free_ptr, MTK_QTX_DRX_PTR); |
| 47 | mtk_w32(eth, (QDMA_RES_THRES << 8) | QDMA_RES_THRES, |
| 48 | MTK_QTX_CFG(0)); |
| 49 | } else { |
| 50 | --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h |
| 51 | +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h |
| 52 | @@ -644,6 +644,7 @@ struct mtk_tx_buf { |
| 53 | * @phys: The physical addr of tx_buf |
| 54 | * @next_free: Pointer to the next free descriptor |
| 55 | * @last_free: Pointer to the last free descriptor |
| 56 | + * @last_free_ptr: Hardware pointer value of the last free descriptor |
| 57 | * @thresh: The threshold of minimum amount of free descriptors |
| 58 | * @free_count: QDMA uses a linked list. Track how many free descriptors |
| 59 | * are present |
| 60 | @@ -654,6 +655,7 @@ struct mtk_tx_ring { |
| 61 | dma_addr_t phys; |
| 62 | struct mtk_tx_dma *next_free; |
| 63 | struct mtk_tx_dma *last_free; |
| 64 | + u32 last_free_ptr; |
| 65 | u16 thresh; |
| 66 | atomic_t free_count; |
| 67 | int dma_size; |