Commit 4e6bf609 authored by Felix Fietkau's avatar Felix Fietkau Committed by David S. Miller
Browse files

net: ethernet: mtk_eth_soc: cache HW pointer of last freed TX descriptor 



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: default avatarFelix Fietkau <nbd@nbd.name>
Signed-off-by: default avatarIlya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e9229ffd

drivers/net/ethernet/mediatek/mtk_eth_soc.c

+4 −4
Original line number Diff line number Diff line
@@ -1364,7 +1364,7 @@ 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);
@@ -1398,6 +1398,7 @@ 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;
@@ -1598,6 +1599,7 @@ 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
@@ -1611,9 +1613,7 @@ 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 {

drivers/net/ethernet/mediatek/mtk_eth_soc.h

+2 −0
Original line number Diff line number Diff line
@@ -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;