net: bcmasp: Keep buffers through power management

There is no advantage of freeing and re-allocating buffers through
suspend and resume. This waste cycles and makes suspend/resume time
longer. We also open ourselves to failed allocations in systems with
heavy memory fragmentation.
Signed-off-by: Justin Chen <justin.chen@broadcom.com>
Acked-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/asp2/bcmasp.h

@@ -315,6 +315,7 @@ struct bcmasp_intf {
 	struct bcmasp_desc		*rx_edpkt_cpu;
 	dma_addr_t			rx_edpkt_dma_addr;
 	dma_addr_t			rx_edpkt_dma_read;
+	dma_addr_t			rx_edpkt_dma_valid;
 
 	/* RX buffer prefetcher ring*/
 	void				*rx_ring_cpu;

drivers/net/ethernet/broadcom/asp2/bcmasp_intf.c

@@ -674,40 +674,78 @@ static void bcmasp_adj_link(struct net_device *dev)
 		phy_print_status(phydev);
 }
 
-static int bcmasp_init_rx(struct bcmasp_intf *intf)
+static int bcmasp_alloc_buffers(struct bcmasp_intf *intf)
 {
 	struct device *kdev = &intf->parent->pdev->dev;
 	struct page *buffer_pg;
-	dma_addr_t dma;
-	void *p;
-	u32 reg;
-	int ret;
 
+	/* Alloc RX */
 	intf->rx_buf_order = get_order(RING_BUFFER_SIZE);
 	buffer_pg = alloc_pages(GFP_KERNEL, intf->rx_buf_order);
 	if (!buffer_pg)
 		return -ENOMEM;
 
-	dma = dma_map_page(kdev, buffer_pg, 0, RING_BUFFER_SIZE,
-			   DMA_FROM_DEVICE);
-	if (dma_mapping_error(kdev, dma)) {
-		__free_pages(buffer_pg, intf->rx_buf_order);
-		return -ENOMEM;
-	}
 	intf->rx_ring_cpu = page_to_virt(buffer_pg);
-	intf->rx_ring_dma = dma;
-	intf->rx_ring_dma_valid = intf->rx_ring_dma + RING_BUFFER_SIZE - 1;
+	intf->rx_ring_dma = dma_map_page(kdev, buffer_pg, 0, RING_BUFFER_SIZE,
+					 DMA_FROM_DEVICE);
+	if (dma_mapping_error(kdev, intf->rx_ring_dma))
+		goto free_rx_buffer;
+
+	intf->rx_edpkt_cpu = dma_alloc_coherent(kdev, DESC_RING_SIZE,
+						&intf->rx_edpkt_dma_addr, GFP_KERNEL);
+	if (!intf->rx_edpkt_cpu)
+		goto free_rx_buffer_dma;
+
+	/* Alloc TX */
+	intf->tx_spb_cpu = dma_alloc_coherent(kdev, DESC_RING_SIZE,
+					      &intf->tx_spb_dma_addr, GFP_KERNEL);
+	if (!intf->tx_spb_cpu)
+		goto free_rx_edpkt_dma;
 
-	p = dma_alloc_coherent(kdev, DESC_RING_SIZE, &intf->rx_edpkt_dma_addr,
+	intf->tx_cbs = kcalloc(DESC_RING_COUNT, sizeof(struct bcmasp_tx_cb),
 			       GFP_KERNEL);
-	if (!p) {
-		ret = -ENOMEM;
-		goto free_rx_ring;
-	}
-	intf->rx_edpkt_cpu = p;
+	if (!intf->tx_cbs)
+		goto free_tx_spb_dma;
 
-	netif_napi_add(intf->ndev, &intf->rx_napi, bcmasp_rx_poll);
+	return 0;
+
+free_tx_spb_dma:
+	dma_free_coherent(kdev, DESC_RING_SIZE, intf->tx_spb_cpu,
+			  intf->tx_spb_dma_addr);
+free_rx_edpkt_dma:
+	dma_free_coherent(kdev, DESC_RING_SIZE, intf->rx_edpkt_cpu,
+			  intf->rx_edpkt_dma_addr);
+free_rx_buffer_dma:
+	dma_unmap_page(kdev, intf->rx_ring_dma, RING_BUFFER_SIZE,
+		       DMA_FROM_DEVICE);
+free_rx_buffer:
+	__free_pages(buffer_pg, intf->rx_buf_order);
+
+	return -ENOMEM;
+}
+
+static void bcmasp_reclaim_free_buffers(struct bcmasp_intf *intf)
+{
+	struct device *kdev = &intf->parent->pdev->dev;
+
+	/* RX buffers */
+	dma_free_coherent(kdev, DESC_RING_SIZE, intf->rx_edpkt_cpu,
+			  intf->rx_edpkt_dma_addr);
+	dma_unmap_page(kdev, intf->rx_ring_dma, RING_BUFFER_SIZE,
+		       DMA_FROM_DEVICE);
+	__free_pages(virt_to_page(intf->rx_ring_cpu), intf->rx_buf_order);
+
+	/* TX buffers */
+	dma_free_coherent(kdev, DESC_RING_SIZE, intf->tx_spb_cpu,
+			  intf->tx_spb_dma_addr);
+	kfree(intf->tx_cbs);
+}
 
+static void bcmasp_init_rx(struct bcmasp_intf *intf)
+{
+	/* Restart from index 0 */
+	intf->rx_ring_dma_valid = intf->rx_ring_dma + RING_BUFFER_SIZE - 1;
+	intf->rx_edpkt_dma_valid = intf->rx_edpkt_dma_addr + (DESC_RING_SIZE - 1);
 	intf->rx_edpkt_dma_read = intf->rx_edpkt_dma_addr;
 	intf->rx_edpkt_index = 0;
 
@@ -733,64 +771,23 @@ static int bcmasp_init_rx(struct bcmasp_intf *intf)
 	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_addr, RX_EDPKT_DMA_WRITE);
 	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_addr, RX_EDPKT_DMA_READ);
 	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_addr, RX_EDPKT_DMA_BASE);
-	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_addr + (DESC_RING_SIZE - 1),
-			RX_EDPKT_DMA_END);
-	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_addr + (DESC_RING_SIZE - 1),
-			RX_EDPKT_DMA_VALID);
-
-	reg = UMAC2FB_CFG_DEFAULT_EN |
-	      ((intf->channel + 11) << UMAC2FB_CFG_CHID_SHIFT);
-	reg |= (0xd << UMAC2FB_CFG_OK_SEND_SHIFT);
-	umac2fb_wl(intf, reg, UMAC2FB_CFG);
+	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_valid, RX_EDPKT_DMA_END);
+	rx_edpkt_dma_wq(intf, intf->rx_edpkt_dma_valid, RX_EDPKT_DMA_VALID);
 
-	return 0;
-
-free_rx_ring:
-	dma_unmap_page(kdev, intf->rx_ring_dma, RING_BUFFER_SIZE,
-		       DMA_FROM_DEVICE);
-	__free_pages(virt_to_page(intf->rx_ring_cpu), intf->rx_buf_order);
-
-	return ret;
+	umac2fb_wl(intf, UMAC2FB_CFG_DEFAULT_EN | ((intf->channel + 11) <<
+		   UMAC2FB_CFG_CHID_SHIFT) | (0xd << UMAC2FB_CFG_OK_SEND_SHIFT),
+		   UMAC2FB_CFG);
 }
 
-static void bcmasp_reclaim_free_all_rx(struct bcmasp_intf *intf)
-{
-	struct device *kdev = &intf->parent->pdev->dev;
 
-	dma_free_coherent(kdev, DESC_RING_SIZE, intf->rx_edpkt_cpu,
-			  intf->rx_edpkt_dma_addr);
-	dma_unmap_page(kdev, intf->rx_ring_dma, RING_BUFFER_SIZE,
-		       DMA_FROM_DEVICE);
-	__free_pages(virt_to_page(intf->rx_ring_cpu), intf->rx_buf_order);
-}
-
-static int bcmasp_init_tx(struct bcmasp_intf *intf)
+static void bcmasp_init_tx(struct bcmasp_intf *intf)
 {
-	struct device *kdev = &intf->parent->pdev->dev;
-	void *p;
-	int ret;
-
-	p = dma_alloc_coherent(kdev, DESC_RING_SIZE, &intf->tx_spb_dma_addr,
-			       GFP_KERNEL);
-	if (!p)
-		return -ENOMEM;
-
-	intf->tx_spb_cpu = p;
+	/* Restart from index 0 */
 	intf->tx_spb_dma_valid = intf->tx_spb_dma_addr + DESC_RING_SIZE - 1;
 	intf->tx_spb_dma_read = intf->tx_spb_dma_addr;
-
-	intf->tx_cbs = kcalloc(DESC_RING_COUNT, sizeof(struct bcmasp_tx_cb),
-			       GFP_KERNEL);
-	if (!intf->tx_cbs) {
-		ret = -ENOMEM;
-		goto free_tx_spb;
-	}
-
 	intf->tx_spb_index = 0;
 	intf->tx_spb_clean_index = 0;
 
-	netif_napi_add_tx(intf->ndev, &intf->tx_napi, bcmasp_tx_poll);
-
 	/* Make sure channels are disabled */
 	tx_spb_ctrl_wl(intf, 0x0, TX_SPB_CTRL_ENABLE);
 	tx_epkt_core_wl(intf, 0x0, TX_EPKT_C_CFG_MISC);
@@ -806,26 +803,6 @@ static int bcmasp_init_tx(struct bcmasp_intf *intf)
 	tx_spb_dma_wq(intf, intf->tx_spb_dma_addr, TX_SPB_DMA_BASE);
 	tx_spb_dma_wq(intf, intf->tx_spb_dma_valid, TX_SPB_DMA_END);
 	tx_spb_dma_wq(intf, intf->tx_spb_dma_valid, TX_SPB_DMA_VALID);
-
-	return 0;
-
-free_tx_spb:
-	dma_free_coherent(kdev, DESC_RING_SIZE, intf->tx_spb_cpu,
-			  intf->tx_spb_dma_addr);
-
-	return ret;
-}
-
-static void bcmasp_reclaim_free_all_tx(struct bcmasp_intf *intf)
-{
-	struct device *kdev = &intf->parent->pdev->dev;
-
-	/* Free descriptors */
-	dma_free_coherent(kdev, DESC_RING_SIZE, intf->tx_spb_cpu,
-			  intf->tx_spb_dma_addr);
-
-	/* Free cbs */
-	kfree(intf->tx_cbs);
 }
 
 static void bcmasp_ephy_enable_set(struct bcmasp_intf *intf, bool enable)
@@ -915,10 +892,7 @@ static void bcmasp_netif_deinit(struct net_device *dev)
 	bcmasp_enable_rx_irq(intf, 0);
 
 	netif_napi_del(&intf->tx_napi);
-	bcmasp_reclaim_free_all_tx(intf);
-
 	netif_napi_del(&intf->rx_napi);
-	bcmasp_reclaim_free_all_rx(intf);
 }
 
 static int bcmasp_stop(struct net_device *dev)
@@ -932,6 +906,8 @@ static int bcmasp_stop(struct net_device *dev)
 
 	bcmasp_netif_deinit(dev);
 
+	bcmasp_reclaim_free_buffers(intf);
+
 	phy_disconnect(dev->phydev);
 
 	/* Disable internal EPHY or external PHY */
@@ -1073,17 +1049,12 @@ static int bcmasp_netif_init(struct net_device *dev, bool phy_connect)
 	intf->old_link = -1;
 	intf->old_pause = -1;
 
-	ret = bcmasp_init_tx(intf);
-	if (ret)
-		goto err_phy_disconnect;
-
-	/* Turn on asp */
+	bcmasp_init_tx(intf);
+	netif_napi_add_tx(intf->ndev, &intf->tx_napi, bcmasp_tx_poll);
 	bcmasp_enable_tx(intf, 1);
 
-	ret = bcmasp_init_rx(intf);
-	if (ret)
-		goto err_reclaim_tx;
-
+	bcmasp_init_rx(intf);
+	netif_napi_add(intf->ndev, &intf->rx_napi, bcmasp_rx_poll);
 	bcmasp_enable_rx(intf, 1);
 
 	/* Turn on UniMAC TX/RX */
@@ -1097,12 +1068,6 @@ static int bcmasp_netif_init(struct net_device *dev, bool phy_connect)
 
 	return 0;
 
-err_reclaim_tx:
-	netif_napi_del(&intf->tx_napi);
-	bcmasp_reclaim_free_all_tx(intf);
-err_phy_disconnect:
-	if (phydev)
-		phy_disconnect(phydev);
 err_phy_disable:
 	if (intf->internal_phy)
 		bcmasp_ephy_enable_set(intf, false);
@@ -1118,13 +1083,24 @@ static int bcmasp_open(struct net_device *dev)
 
 	netif_dbg(intf, ifup, dev, "bcmasp open\n");
 
-	ret = clk_prepare_enable(intf->parent->clk);
+	ret = bcmasp_alloc_buffers(intf);
 	if (ret)
 		return ret;
 
-	ret = bcmasp_netif_init(dev, true);
+	ret = clk_prepare_enable(intf->parent->clk);
 	if (ret)
+		goto err_free_mem;
+
+	ret = bcmasp_netif_init(dev, true);
+	if (ret) {
 		clk_disable_unprepare(intf->parent->clk);
+		goto err_free_mem;
+	}
+
+	return ret;
+
+err_free_mem:
+	bcmasp_reclaim_free_buffers(intf);
 
 	return ret;
 }