From 7e6e185c74dd8a8dc539300c079adc6bc27045d6 Mon Sep 17 00:00:00 2001 From: Florian Fainelli Date: Mon, 22 Apr 2019 09:46:44 -0700 Subject: [PATCH] net: systemport: Remove need for DMA descriptor All we do is write the length/status and address bits to a DMA descriptor only to write its contents into on-chip registers right after, eliminate this unnecessary step. Signed-off-by: Florian Fainelli Reviewed-by: Jakub Kicinski Signed-off-by: David S. Miller --- drivers/net/ethernet/broadcom/bcmsysport.c | 56 +++------------------- drivers/net/ethernet/broadcom/bcmsysport.h | 10 +--- 2 files changed, 8 insertions(+), 58 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c index dfe46dacf5cf..4e87a303f83e 100644 --- a/drivers/net/ethernet/broadcom/bcmsysport.c +++ b/drivers/net/ethernet/broadcom/bcmsysport.c @@ -116,15 +116,6 @@ static inline void dma_desc_set_addr(struct bcm_sysport_priv *priv, writel_relaxed(lower_32_bits(addr), d + DESC_ADDR_LO); } -static inline void tdma_port_write_desc_addr(struct bcm_sysport_priv *priv, - struct dma_desc *desc, - unsigned int port) -{ - /* Ports are latched, so write upper address first */ - tdma_writel(priv, desc->addr_status_len, TDMA_WRITE_PORT_HI(port)); - tdma_writel(priv, desc->addr_lo, TDMA_WRITE_PORT_LO(port)); -} - /* Ethtool operations */ static void bcm_sysport_set_rx_csum(struct net_device *dev, netdev_features_t wanted) @@ -1291,11 +1282,10 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, struct bcm_sysport_tx_ring *ring; struct bcm_sysport_cb *cb; struct netdev_queue *txq; - struct dma_desc *desc; + u32 len_status, addr_lo; unsigned int skb_len; unsigned long flags; dma_addr_t mapping; - u32 len_status; u16 queue; int ret; @@ -1338,10 +1328,7 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, dma_unmap_addr_set(cb, dma_addr, mapping); dma_unmap_len_set(cb, dma_len, skb_len); - /* Fetch a descriptor entry from our pool */ - desc = ring->desc_cpu; - - desc->addr_lo = lower_32_bits(mapping); + addr_lo = lower_32_bits(mapping); len_status = upper_32_bits(mapping) & DESC_ADDR_HI_MASK; len_status |= (skb_len << DESC_LEN_SHIFT); len_status |= (DESC_SOP | DESC_EOP | TX_STATUS_APP_CRC) << @@ -1354,16 +1341,9 @@ static netdev_tx_t bcm_sysport_xmit(struct sk_buff *skb, ring->curr_desc = 0; ring->desc_count--; - /* Ensure write completion of the descriptor status/length - * in DRAM before the System Port WRITE_PORT register latches - * the value - */ - wmb(); - desc->addr_status_len = len_status; - wmb(); - - /* Write this descriptor address to the RING write port */ - tdma_port_write_desc_addr(priv, desc, ring->index); + /* Ports are latched, so write upper address first */ + tdma_writel(priv, len_status, TDMA_WRITE_PORT_HI(ring->index)); + tdma_writel(priv, addr_lo, TDMA_WRITE_PORT_LO(ring->index)); /* Check ring space and update SW control flow */ if (ring->desc_count == 0) @@ -1489,28 +1469,14 @@ static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv, unsigned int index) { struct bcm_sysport_tx_ring *ring = &priv->tx_rings[index]; - struct device *kdev = &priv->pdev->dev; size_t size; - void *p; u32 reg; /* Simple descriptors partitioning for now */ size = 256; - /* We just need one DMA descriptor which is DMA-able, since writing to - * the port will allocate a new descriptor in its internal linked-list - */ - p = dma_alloc_coherent(kdev, sizeof(struct dma_desc), &ring->desc_dma, - GFP_KERNEL); - if (!p) { - netif_err(priv, hw, priv->netdev, "DMA alloc failed\n"); - return -ENOMEM; - } - ring->cbs = kcalloc(size, sizeof(struct bcm_sysport_cb), GFP_KERNEL); if (!ring->cbs) { - dma_free_coherent(kdev, sizeof(struct dma_desc), - ring->desc_cpu, ring->desc_dma); netif_err(priv, hw, priv->netdev, "CB allocation failed\n"); return -ENOMEM; } @@ -1523,7 +1489,6 @@ static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv, ring->size = size; ring->clean_index = 0; ring->alloc_size = ring->size; - ring->desc_cpu = p; ring->desc_count = ring->size; ring->curr_desc = 0; @@ -1578,8 +1543,8 @@ static int bcm_sysport_init_tx_ring(struct bcm_sysport_priv *priv, napi_enable(&ring->napi); netif_dbg(priv, hw, priv->netdev, - "TDMA cfg, size=%d, desc_cpu=%p switch q=%d,port=%d\n", - ring->size, ring->desc_cpu, ring->switch_queue, + "TDMA cfg, size=%d, switch q=%d,port=%d\n", + ring->size, ring->switch_queue, ring->switch_port); return 0; @@ -1589,7 +1554,6 @@ static void bcm_sysport_fini_tx_ring(struct bcm_sysport_priv *priv, unsigned int index) { struct bcm_sysport_tx_ring *ring = &priv->tx_rings[index]; - struct device *kdev = &priv->pdev->dev; u32 reg; /* Caller should stop the TDMA engine */ @@ -1611,12 +1575,6 @@ static void bcm_sysport_fini_tx_ring(struct bcm_sysport_priv *priv, kfree(ring->cbs); ring->cbs = NULL; - - if (ring->desc_dma) { - dma_free_coherent(kdev, sizeof(struct dma_desc), - ring->desc_cpu, ring->desc_dma); - ring->desc_dma = 0; - } ring->size = 0; ring->alloc_size = 0; diff --git a/drivers/net/ethernet/broadcom/bcmsysport.h b/drivers/net/ethernet/broadcom/bcmsysport.h index 0b192fea9c5d..6f3141c86436 100644 --- a/drivers/net/ethernet/broadcom/bcmsysport.h +++ b/drivers/net/ethernet/broadcom/bcmsysport.h @@ -516,12 +516,6 @@ struct bcm_rsb { #define TDMA_DEBUG 0x64c -/* Transmit/Receive descriptor */ -struct dma_desc { - u32 addr_status_len; - u32 addr_lo; -}; - /* Number of Receive hardware descriptor words */ #define SP_NUM_HW_RX_DESC_WORDS 1024 #define SP_LT_NUM_HW_RX_DESC_WORDS 256 @@ -530,7 +524,7 @@ struct dma_desc { #define SP_NUM_TX_DESC 1536 #define SP_LT_NUM_TX_DESC 256 -#define WORDS_PER_DESC (sizeof(struct dma_desc) / sizeof(u32)) +#define WORDS_PER_DESC 2 /* Rx/Tx common counter group.*/ struct bcm_sysport_pkt_counters { @@ -718,7 +712,6 @@ struct bcm_sysport_net_dim { struct bcm_sysport_tx_ring { spinlock_t lock; /* Ring lock for tx reclaim/xmit */ struct napi_struct napi; /* NAPI per tx queue */ - dma_addr_t desc_dma; /* DMA cookie */ unsigned int index; /* Ring index */ unsigned int size; /* Ring current size */ unsigned int alloc_size; /* Ring one-time allocated size */ @@ -727,7 +720,6 @@ struct bcm_sysport_tx_ring { unsigned int c_index; /* Last consumer index */ unsigned int clean_index; /* Current clean index */ struct bcm_sysport_cb *cbs; /* Transmit control blocks */ - struct dma_desc *desc_cpu; /* CPU view of the descriptor */ struct bcm_sysport_priv *priv; /* private context backpointer */ unsigned long packets; /* packets statistics */ unsigned long bytes; /* bytes statistics */