[PATCH V2 net-next 5/6] net: hns3: use writel() to optimize the barrier operation
From: Huazhong Tan <hidden>
Date: 2020-09-16 09:37:47
Also in:
lkml
Subsystem:
hisilicon network subsystem 3 driver (hns3), hisilicon network subsystem driver, networking drivers, the rest · Maintainers:
Jian Shen, Jijie Shao, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Yunsheng Lin <redacted> writel() can be used to order I/O vs memory by default when writing portable drivers. Use writel() to replace wmb() + writel_relaxed(), and writel() is dma_wmb() + writel_relaxed() for ARM64, so there is an optimization here because dma_wmb() is a lighter barrier than wmb(). Signed-off-by: Yunsheng Lin <redacted> Signed-off-by: Huazhong Tan <redacted> --- drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 8 +++----- drivers/net/ethernet/hisilicon/hns3/hns3_enet.h | 3 --- 2 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 8490754..4a49a76 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c@@ -1398,9 +1398,8 @@ static void hns3_tx_doorbell(struct hns3_enet_ring *ring, int num, if (!ring->pending_buf) return; - wmb(); /* Commit all data before submit */ - - hnae3_queue_xmit(ring->tqp, ring->pending_buf); + writel(ring->pending_buf, + ring->tqp->io_base + HNS3_RING_TX_RING_TAIL_REG); ring->pending_buf = 0; WRITE_ONCE(ring->last_to_use, ring->next_to_use); }
@@ -2618,8 +2617,7 @@ static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring, ring_ptr_move_fw(ring, next_to_use); } - wmb(); /* Make all data has been write before submit */ - writel_relaxed(i, ring->tqp->io_base + HNS3_RING_RX_RING_HEAD_REG); + writel(i, ring->tqp->io_base + HNS3_RING_RX_RING_HEAD_REG); } static bool hns3_page_is_reusable(struct page *page)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
index 876dc09..20e62ce 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.h@@ -539,9 +539,6 @@ static inline bool hns3_nic_resetting(struct net_device *netdev) #define hns3_write_dev(a, reg, value) \ hns3_write_reg((a)->io_base, (reg), (value)) -#define hnae3_queue_xmit(tqp, buf_num) writel_relaxed(buf_num, \ - (tqp)->io_base + HNS3_RING_TX_RING_TAIL_REG) - #define ring_to_dev(ring) ((ring)->dev) #define ring_to_netdev(ring) ((ring)->tqp_vector->napi.dev)
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2.7.4