amd-xgbe: Add support for per DMA channel interrupts

This patch provides support for interrupts that are generated by the
Tx/Rx DMA channel pairs of the device.  This allows for Tx and Rx
processing to run across multiple processsors.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/amd-xgbe.txt

@@ -7,7 +7,10 @@ Required properties:
    - PCS registers
 - interrupt-parent: Should be the phandle for the interrupt controller
   that services interrupts for this device
-- interrupts: Should contain the amd-xgbe interrupt
+- interrupts: Should contain the amd-xgbe interrupt(s). The first interrupt
+  listed is required and is the general device interrupt. If the optional
+  amd,per-channel-interrupt property is specified, then one additional
+  interrupt for each DMA channel supported by the device should be specified
 - clocks:
    - DMA clock for the amd-xgbe device (used for calculating the
      correct Rx interrupt watchdog timer value on a DMA channel
@@ -23,6 +26,9 @@ Optional properties:
 - mac-address: mac address to be assigned to the device. Can be overridden
   by UEFI.
 - dma-coherent: Present if dma operations are coherent
+- amd,per-channel-interrupt: Indicates that Rx and Tx complete will generate
+  a unique interrupt for each DMA channel - this requires an additional
+  interrupt be configured for each DMA channel
 
 Example:
 	xgbe@e0700000 {
@@ -30,7 +36,9 @@ Example:
 		reg = <0 0xe0700000 0 0x80000>,
 		      <0 0xe0780000 0 0x80000>;
 		interrupt-parent = <&gic>;
-		interrupts = <0 325 4>;
+		interrupts = <0 325 4>,
+			     <0 326 1>, <0 327 1>, <0 328 1>, <0 329 1>;
+		amd,per-channel-interrupt;
 		clocks = <&xgbe_dma_clk>, <&xgbe_ptp_clk>;
 		clock-names = "dma_clk", "ptp_clk";
 		phy-handle = <&phy>;

drivers/net/ethernet/amd/xgbe/xgbe-dev.c

@@ -481,17 +481,21 @@ static void xgbe_enable_dma_interrupts(struct xgbe_prv_data *pdata)
 
 		if (channel->tx_ring) {
 			/* Enable the following Tx interrupts
-			 *   TIE  - Transmit Interrupt Enable (unless polling)
+			 *   TIE  - Transmit Interrupt Enable (unless using
+			 *          per channel interrupts)
 			 */
-			XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 1);
+			if (!pdata->per_channel_irq)
+				XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, TIE, 1);
 		}
 		if (channel->rx_ring) {
 			/* Enable following Rx interrupts
 			 *   RBUE - Receive Buffer Unavailable Enable
-			 *   RIE  - Receive Interrupt Enable
+			 *   RIE  - Receive Interrupt Enable (unless using
+			 *          per channel interrupts)
 			 */
 			XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RBUE, 1);
-			XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 1);
+			if (!pdata->per_channel_irq)
+				XGMAC_SET_BITS(dma_ch_ier, DMA_CH_IER, RIE, 1);
 		}
 
 		XGMAC_DMA_IOWRITE(channel, DMA_CH_IER, dma_ch_ier);

drivers/net/ethernet/amd/xgbe/xgbe-main.c

@@ -264,12 +264,18 @@ static int xgbe_probe(struct platform_device *pdev)
 		pdata->awcache = XGBE_DMA_SYS_AWCACHE;
 	}
 
+	/* Check for per channel interrupt support */
+	if (of_property_read_bool(dev->of_node, XGBE_DMA_IRQS))
+		pdata->per_channel_irq = 1;
+
 	ret = platform_get_irq(pdev, 0);
 	if (ret < 0) {
-		dev_err(dev, "platform_get_irq failed\n");
+		dev_err(dev, "platform_get_irq 0 failed\n");
 		goto err_io;
 	}
-	netdev->irq = ret;
+	pdata->dev_irq = ret;
+
+	netdev->irq = pdata->dev_irq;
 	netdev->base_addr = (unsigned long)pdata->xgmac_regs;
 
 	/* Set all the function pointers */

drivers/net/ethernet/amd/xgbe/xgbe.h

@@ -173,6 +173,7 @@
 /* Device-tree clock names */
 #define XGBE_DMA_CLOCK		"dma_clk"
 #define XGBE_PTP_CLOCK		"ptp_clk"
+#define XGBE_DMA_IRQS		"amd,per-channel-interrupt"
 
 /* Timestamp support - values based on 50MHz PTP clock
  *   50MHz => 20 nsec
@@ -359,6 +360,12 @@ struct xgbe_channel {
 	unsigned int queue_index;
 	void __iomem *dma_regs;
 
+	/* Per channel interrupt irq number */
+	int dma_irq;
+
+	/* Netdev related settings */
+	struct napi_struct napi;
+
 	unsigned int saved_ier;
 
 	unsigned int tx_timer_active;
@@ -609,7 +616,8 @@ struct xgbe_prv_data {
 	/* XPCS indirect addressing mutex */
 	struct mutex xpcs_mutex;
 
-	int irq_number;
+	int dev_irq;
+	unsigned int per_channel_irq;
 
 	struct xgbe_hw_if hw_if;
 	struct xgbe_desc_if desc_if;