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From:   Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
To:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <robh+dt@kernel.org>,
        <krzysztof.kozlowski+dt@linaro.org>, <conor+dt@kernel.org>,
        <michal.simek@amd.com>, <linux@armlinux.org.uk>,
        <f.fainelli@gmail.com>
CC:     <netdev@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <git@amd.com>,
        Sarath Babu Naidu Gaddam <sarath.babu.naidu.gaddam@amd.com>,
        Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Subject: [PATCH net-next v8 2/3] net: axienet: Preparatory changes for dmaengine support
Date:   Wed, 18 Oct 2023 00:47:53 +0530
Message-ID: <1697570274-798170-3-git-send-email-radhey.shyam.pandey@amd.com>
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From: Sarath Babu Naidu Gaddam <sarath.babu.naidu.gaddam@amd.com>

The axiethernet driver has inbuilt dma programming. In order to add
dmaengine support and make it's integration seamless the current axidma
inbuilt programming code is put under use_dmaengine check.

It also performs minor code reordering to minimize conditional
use_dmaengine checks and there is no functional change. It uses
"dmas" property to identify whether it should use a dmaengine
framework or inbuilt axidma programming.

Signed-off-by: Sarath Babu Naidu Gaddam <sarath.babu.naidu.gaddam@amd.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
---
Changes for v8:
- Remove spurious new line and inline attribute from axienet_init_legacy_dma().
- Drop indirection for xmit() func. For dmaengine flow have separate
  netdev_ops.

Changes for v7:
- None

Changes for v6:
- None

Changes for v5:
- Fix git apply failure due to commit
  f1bc9fc4a06de0108e0dca2a9a7e99ba1fc632f9

Changes for v4:
- Renamed has_dmas to use_dmaegine.
- Removed the AXIENET_USE_DMA.
- Changed the start_xmit_** functions description.

Changes for v3:
- New patch
---
 drivers/net/ethernet/xilinx/xilinx_axienet.h  |   2 +
 .../net/ethernet/xilinx/xilinx_axienet_main.c | 284 ++++++++++--------
 2 files changed, 162 insertions(+), 124 deletions(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet.h b/drivers/net/ethernet/xilinx/xilinx_axienet.h
index 575ff9de8985..3ead0bac597b 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet.h
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet.h
@@ -435,6 +435,7 @@ struct axidma_bd {
  * @coalesce_usec_rx:	IRQ coalesce delay for RX
  * @coalesce_count_tx:	Store the irq coalesce on TX side.
  * @coalesce_usec_tx:	IRQ coalesce delay for TX
+ * @use_dmaengine: flag to check dmaengine framework usage.
  */
 struct axienet_local {
 	struct net_device *ndev;
@@ -499,6 +500,7 @@ struct axienet_local {
 	u32 coalesce_usec_rx;
 	u32 coalesce_count_tx;
 	u32 coalesce_usec_tx;
+	u8  use_dmaengine;
 };
 
 /**
diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 82d0d44b2b02..188b03e86263 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -589,10 +589,6 @@ static int axienet_device_reset(struct net_device *ndev)
 	struct axienet_local *lp = netdev_priv(ndev);
 	int ret;
 
-	ret = __axienet_device_reset(lp);
-	if (ret)
-		return ret;
-
 	lp->max_frm_size = XAE_MAX_VLAN_FRAME_SIZE;
 	lp->options |= XAE_OPTION_VLAN;
 	lp->options &= (~XAE_OPTION_JUMBO);
@@ -606,11 +602,17 @@ static int axienet_device_reset(struct net_device *ndev)
 			lp->options |= XAE_OPTION_JUMBO;
 	}
 
-	ret = axienet_dma_bd_init(ndev);
-	if (ret) {
-		netdev_err(ndev, "%s: descriptor allocation failed\n",
-			   __func__);
-		return ret;
+	if (!lp->use_dmaengine) {
+		ret = __axienet_device_reset(lp);
+		if (ret)
+			return ret;
+
+		ret = axienet_dma_bd_init(ndev);
+		if (ret) {
+			netdev_err(ndev, "%s: descriptor allocation failed\n",
+				   __func__);
+			return ret;
+		}
 	}
 
 	axienet_status = axienet_ior(lp, XAE_RCW1_OFFSET);
@@ -1125,41 +1127,21 @@ static irqreturn_t axienet_eth_irq(int irq, void *_ndev)
 static void axienet_dma_err_handler(struct work_struct *work);
 
 /**
- * axienet_open - Driver open routine.
- * @ndev:	Pointer to net_device structure
+ * axienet_init_legacy_dma - init the dma legacy code.
+ * @ndev:       Pointer to net_device structure
  *
  * Return: 0, on success.
- *	    non-zero error value on failure
+ *          non-zero error value on failure
+ *
+ * This is the dma  initialization code. It also allocates interrupt
+ * service routines, enables the interrupt lines and ISR handling.
  *
- * This is the driver open routine. It calls phylink_start to start the
- * PHY device.
- * It also allocates interrupt service routines, enables the interrupt lines
- * and ISR handling. Axi Ethernet core is reset through Axi DMA core. Buffer
- * descriptors are initialized.
  */
-static int axienet_open(struct net_device *ndev)
+static int axienet_init_legacy_dma(struct net_device *ndev)
 {
 	int ret;
 	struct axienet_local *lp = netdev_priv(ndev);
 
-	dev_dbg(&ndev->dev, "axienet_open()\n");
-
-	/* When we do an Axi Ethernet reset, it resets the complete core
-	 * including the MDIO. MDIO must be disabled before resetting.
-	 * Hold MDIO bus lock to avoid MDIO accesses during the reset.
-	 */
-	axienet_lock_mii(lp);
-	ret = axienet_device_reset(ndev);
-	axienet_unlock_mii(lp);
-
-	ret = phylink_of_phy_connect(lp->phylink, lp->dev->of_node, 0);
-	if (ret) {
-		dev_err(lp->dev, "phylink_of_phy_connect() failed: %d\n", ret);
-		return ret;
-	}
-
-	phylink_start(lp->phylink);
-
 	/* Enable worker thread for Axi DMA error handling */
 	INIT_WORK(&lp->dma_err_task, axienet_dma_err_handler);
 
@@ -1193,13 +1175,61 @@ static int axienet_open(struct net_device *ndev)
 err_tx_irq:
 	napi_disable(&lp->napi_tx);
 	napi_disable(&lp->napi_rx);
-	phylink_stop(lp->phylink);
-	phylink_disconnect_phy(lp->phylink);
 	cancel_work_sync(&lp->dma_err_task);
 	dev_err(lp->dev, "request_irq() failed\n");
 	return ret;
 }
 
+/**
+ * axienet_open - Driver open routine.
+ * @ndev:	Pointer to net_device structure
+ *
+ * Return: 0, on success.
+ *	    non-zero error value on failure
+ *
+ * This is the driver open routine. It calls phylink_start to start the
+ * PHY device.
+ * It also allocates interrupt service routines, enables the interrupt lines
+ * and ISR handling. Axi Ethernet core is reset through Axi DMA core. Buffer
+ * descriptors are initialized.
+ */
+static int axienet_open(struct net_device *ndev)
+{
+	int ret;
+	struct axienet_local *lp = netdev_priv(ndev);
+
+	dev_dbg(&ndev->dev, "%s\n", __func__);
+
+	/* When we do an Axi Ethernet reset, it resets the complete core
+	 * including the MDIO. MDIO must be disabled before resetting.
+	 * Hold MDIO bus lock to avoid MDIO accesses during the reset.
+	 */
+	axienet_lock_mii(lp);
+	ret = axienet_device_reset(ndev);
+	axienet_unlock_mii(lp);
+
+	ret = phylink_of_phy_connect(lp->phylink, lp->dev->of_node, 0);
+	if (ret) {
+		dev_err(lp->dev, "phylink_of_phy_connect() failed: %d\n", ret);
+		return ret;
+	}
+
+	phylink_start(lp->phylink);
+
+	if (!lp->use_dmaengine) {
+		ret = axienet_init_legacy_dma(ndev);
+		if (ret)
+			goto err_phy;
+	}
+
+	return 0;
+
+err_phy:
+	phylink_stop(lp->phylink);
+	phylink_disconnect_phy(lp->phylink);
+	return ret;
+}
+
 /**
  * axienet_stop - Driver stop routine.
  * @ndev:	Pointer to net_device structure
@@ -1216,8 +1246,10 @@ static int axienet_stop(struct net_device *ndev)
 
 	dev_dbg(&ndev->dev, "axienet_close()\n");
 
-	napi_disable(&lp->napi_tx);
-	napi_disable(&lp->napi_rx);
+	if (!lp->use_dmaengine) {
+		napi_disable(&lp->napi_tx);
+		napi_disable(&lp->napi_rx);
+	}
 
 	phylink_stop(lp->phylink);
 	phylink_disconnect_phy(lp->phylink);
@@ -1225,18 +1257,18 @@ static int axienet_stop(struct net_device *ndev)
 	axienet_setoptions(ndev, lp->options &
 			   ~(XAE_OPTION_TXEN | XAE_OPTION_RXEN));
 
-	axienet_dma_stop(lp);
+	if (!lp->use_dmaengine) {
+		axienet_dma_stop(lp);
+		cancel_work_sync(&lp->dma_err_task);
+		free_irq(lp->tx_irq, ndev);
+		free_irq(lp->rx_irq, ndev);
+		axienet_dma_bd_release(ndev);
+	}
 
 	axienet_iow(lp, XAE_IE_OFFSET, 0);
 
-	cancel_work_sync(&lp->dma_err_task);
-
 	if (lp->eth_irq > 0)
 		free_irq(lp->eth_irq, ndev);
-	free_irq(lp->tx_irq, ndev);
-	free_irq(lp->rx_irq, ndev);
-
-	axienet_dma_bd_release(ndev);
 	return 0;
 }
 
@@ -1412,14 +1444,16 @@ static void axienet_ethtools_get_regs(struct net_device *ndev,
 	data[29] = axienet_ior(lp, XAE_FMI_OFFSET);
 	data[30] = axienet_ior(lp, XAE_AF0_OFFSET);
 	data[31] = axienet_ior(lp, XAE_AF1_OFFSET);
-	data[32] = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
-	data[33] = axienet_dma_in32(lp, XAXIDMA_TX_SR_OFFSET);
-	data[34] = axienet_dma_in32(lp, XAXIDMA_TX_CDESC_OFFSET);
-	data[35] = axienet_dma_in32(lp, XAXIDMA_TX_TDESC_OFFSET);
-	data[36] = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
-	data[37] = axienet_dma_in32(lp, XAXIDMA_RX_SR_OFFSET);
-	data[38] = axienet_dma_in32(lp, XAXIDMA_RX_CDESC_OFFSET);
-	data[39] = axienet_dma_in32(lp, XAXIDMA_RX_TDESC_OFFSET);
+	if (!lp->use_dmaengine) {
+		data[32] = axienet_dma_in32(lp, XAXIDMA_TX_CR_OFFSET);
+		data[33] = axienet_dma_in32(lp, XAXIDMA_TX_SR_OFFSET);
+		data[34] = axienet_dma_in32(lp, XAXIDMA_TX_CDESC_OFFSET);
+		data[35] = axienet_dma_in32(lp, XAXIDMA_TX_TDESC_OFFSET);
+		data[36] = axienet_dma_in32(lp, XAXIDMA_RX_CR_OFFSET);
+		data[37] = axienet_dma_in32(lp, XAXIDMA_RX_SR_OFFSET);
+		data[38] = axienet_dma_in32(lp, XAXIDMA_RX_CDESC_OFFSET);
+		data[39] = axienet_dma_in32(lp, XAXIDMA_RX_TDESC_OFFSET);
+	}
 }
 
 static void
@@ -1880,9 +1914,6 @@ static int axienet_probe(struct platform_device *pdev)
 	u64_stats_init(&lp->rx_stat_sync);
 	u64_stats_init(&lp->tx_stat_sync);
 
-	netif_napi_add(ndev, &lp->napi_rx, axienet_rx_poll);
-	netif_napi_add(ndev, &lp->napi_tx, axienet_tx_poll);
-
 	lp->axi_clk = devm_clk_get_optional(&pdev->dev, "s_axi_lite_clk");
 	if (!lp->axi_clk) {
 		/* For backward compatibility, if named AXI clock is not present,
@@ -2008,80 +2039,85 @@ static int axienet_probe(struct platform_device *pdev)
 		goto cleanup_clk;
 	}
 
-	/* Find the DMA node, map the DMA registers, and decode the DMA IRQs */
-	np = of_parse_phandle(pdev->dev.of_node, "axistream-connected", 0);
-	if (np) {
-		struct resource dmares;
+	if (!of_find_property(pdev->dev.of_node, "dmas", NULL)) {
+		/* Find the DMA node, map the DMA registers, and decode the DMA IRQs */
+		np = of_parse_phandle(pdev->dev.of_node, "axistream-connected", 0);
 
-		ret = of_address_to_resource(np, 0, &dmares);
-		if (ret) {
-			dev_err(&pdev->dev,
-				"unable to get DMA resource\n");
+		if (np) {
+			struct resource dmares;
+
+			ret = of_address_to_resource(np, 0, &dmares);
+			if (ret) {
+				dev_err(&pdev->dev,
+					"unable to get DMA resource\n");
+				of_node_put(np);
+				goto cleanup_clk;
+			}
+			lp->dma_regs = devm_ioremap_resource(&pdev->dev,
+							     &dmares);
+			lp->rx_irq = irq_of_parse_and_map(np, 1);
+			lp->tx_irq = irq_of_parse_and_map(np, 0);
 			of_node_put(np);
+			lp->eth_irq = platform_get_irq_optional(pdev, 0);
+		} else {
+			/* Check for these resources directly on the Ethernet node. */
+			lp->dma_regs = devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
+			lp->rx_irq = platform_get_irq(pdev, 1);
+			lp->tx_irq = platform_get_irq(pdev, 0);
+			lp->eth_irq = platform_get_irq_optional(pdev, 2);
+		}
+		if (IS_ERR(lp->dma_regs)) {
+			dev_err(&pdev->dev, "could not map DMA regs\n");
+			ret = PTR_ERR(lp->dma_regs);
+			goto cleanup_clk;
+		}
+		if (lp->rx_irq <= 0 || lp->tx_irq <= 0) {
+			dev_err(&pdev->dev, "could not determine irqs\n");
+			ret = -ENOMEM;
 			goto cleanup_clk;
 		}
-		lp->dma_regs = devm_ioremap_resource(&pdev->dev,
-						     &dmares);
-		lp->rx_irq = irq_of_parse_and_map(np, 1);
-		lp->tx_irq = irq_of_parse_and_map(np, 0);
-		of_node_put(np);
-		lp->eth_irq = platform_get_irq_optional(pdev, 0);
-	} else {
-		/* Check for these resources directly on the Ethernet node. */
-		lp->dma_regs = devm_platform_get_and_ioremap_resource(pdev, 1, NULL);
-		lp->rx_irq = platform_get_irq(pdev, 1);
-		lp->tx_irq = platform_get_irq(pdev, 0);
-		lp->eth_irq = platform_get_irq_optional(pdev, 2);
-	}
-	if (IS_ERR(lp->dma_regs)) {
-		dev_err(&pdev->dev, "could not map DMA regs\n");
-		ret = PTR_ERR(lp->dma_regs);
-		goto cleanup_clk;
-	}
-	if ((lp->rx_irq <= 0) || (lp->tx_irq <= 0)) {
-		dev_err(&pdev->dev, "could not determine irqs\n");
-		ret = -ENOMEM;
-		goto cleanup_clk;
-	}
 
-	/* Reset core now that clocks are enabled, prior to accessing MDIO */
-	ret = __axienet_device_reset(lp);
-	if (ret)
-		goto cleanup_clk;
+		/* Reset core now that clocks are enabled, prior to accessing MDIO */
+		ret = __axienet_device_reset(lp);
+		if (ret)
+			goto cleanup_clk;
+
+		/* Autodetect the need for 64-bit DMA pointers.
+		 * When the IP is configured for a bus width bigger than 32 bits,
+		 * writing the MSB registers is mandatory, even if they are all 0.
+		 * We can detect this case by writing all 1's to one such register
+		 * and see if that sticks: when the IP is configured for 32 bits
+		 * only, those registers are RES0.
+		 * Those MSB registers were introduced in IP v7.1, which we check first.
+		 */
+		if ((axienet_ior(lp, XAE_ID_OFFSET) >> 24) >= 0x9) {
+			void __iomem *desc = lp->dma_regs + XAXIDMA_TX_CDESC_OFFSET + 4;
 
-	/* Autodetect the need for 64-bit DMA pointers.
-	 * When the IP is configured for a bus width bigger than 32 bits,
-	 * writing the MSB registers is mandatory, even if they are all 0.
-	 * We can detect this case by writing all 1's to one such register
-	 * and see if that sticks: when the IP is configured for 32 bits
-	 * only, those registers are RES0.
-	 * Those MSB registers were introduced in IP v7.1, which we check first.
-	 */
-	if ((axienet_ior(lp, XAE_ID_OFFSET) >> 24) >= 0x9) {
-		void __iomem *desc = lp->dma_regs + XAXIDMA_TX_CDESC_OFFSET + 4;
-
-		iowrite32(0x0, desc);
-		if (ioread32(desc) == 0) {	/* sanity check */
-			iowrite32(0xffffffff, desc);
-			if (ioread32(desc) > 0) {
-				lp->features |= XAE_FEATURE_DMA_64BIT;
-				addr_width = 64;
-				dev_info(&pdev->dev,
-					 "autodetected 64-bit DMA range\n");
-			}
 			iowrite32(0x0, desc);
+			if (ioread32(desc) == 0) {	/* sanity check */
+				iowrite32(0xffffffff, desc);
+				if (ioread32(desc) > 0) {
+					lp->features |= XAE_FEATURE_DMA_64BIT;
+					addr_width = 64;
+					dev_info(&pdev->dev,
+						 "autodetected 64-bit DMA range\n");
+				}
+				iowrite32(0x0, desc);
+			}
+		}
+		if (!IS_ENABLED(CONFIG_64BIT) && lp->features & XAE_FEATURE_DMA_64BIT) {
+			dev_err(&pdev->dev, "64-bit addressable DMA is not compatible with 32-bit archecture\n");
+			ret = -EINVAL;
+			goto cleanup_clk;
 		}
-	}
-	if (!IS_ENABLED(CONFIG_64BIT) && lp->features & XAE_FEATURE_DMA_64BIT) {
-		dev_err(&pdev->dev, "64-bit addressable DMA is not compatible with 32-bit archecture\n");
-		ret = -EINVAL;
-		goto cleanup_clk;
-	}
 
-	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(addr_width));
-	if (ret) {
-		dev_err(&pdev->dev, "No suitable DMA available\n");
-		goto cleanup_clk;
+		ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(addr_width));
+		if (ret) {
+			dev_err(&pdev->dev, "No suitable DMA available\n");
+			goto cleanup_clk;
+		}
+		netif_napi_add(ndev, &lp->napi_rx, axienet_rx_poll);
+		netif_napi_add(ndev, &lp->napi_tx, axienet_tx_poll);
 	}
 
 	/* Check for Ethernet core IRQ (optional) */
@@ -2099,8 +2135,8 @@ static int axienet_probe(struct platform_device *pdev)
 	}
 
 	lp->coalesce_count_rx = XAXIDMA_DFT_RX_THRESHOLD;
-	lp->coalesce_usec_rx = XAXIDMA_DFT_RX_USEC;
 	lp->coalesce_count_tx = XAXIDMA_DFT_TX_THRESHOLD;
+	lp->coalesce_usec_rx = XAXIDMA_DFT_RX_USEC;
 	lp->coalesce_usec_tx = XAXIDMA_DFT_TX_USEC;
 
 	ret = axienet_mdio_setup(lp);
-- 
2.34.1