dmaengine: xilinx: xdma: Add user logic interrupt support

The Xilinx DMA/Bridge Subsystem for PCIe (XDMA) provides up to 16 user
interrupt wires to user logic that generate interrupts to the host.
This patch adds APIs to register/unregister interrupt handler for a given
interrupt wire index.

Signed-off-by: Lizhi Hou <lizhi.hou@amd.com>
Signed-off-by: Sonal Santan <sonal.santan@amd.com>
Signed-off-by: Max Zhen <max.zhen@amd.com>
Signed-off-by: Brian Xu <brian.xu@amd.com>

drivers/dma/xilinx/xdma.c

@@ -742,6 +742,7 @@ static int xdma_set_vector_reg(struct xdma_device *xdev, u32 vec_tbl_start,
 static int xdma_irq_init(struct xdma_device *xdev)
 {
 	u32 irq = xdev->irq_start;
+	u32 user_irq_start;
 	int i, j, ret;
 
 	/* return failure if there are not enough IRQs */
@@ -795,6 +796,18 @@ static int xdma_irq_init(struct xdma_device *xdev)
 		goto failed;
 	}
 
+	/* config user IRQ registers if needed */
+	user_irq_start = xdev->h2c_chan_num + xdev->c2h_chan_num;
+	if (xdev->irq_num > user_irq_start) {
+		ret = xdma_set_vector_reg(xdev, XDMA_IRQ_USER_VEC_NUM,
+					  user_irq_start,
+					  xdev->irq_num - user_irq_start);
+		if (ret) {
+			xdma_err(xdev, "failed to set user vectors: %d", ret);
+			goto failed;
+		}
+	}
+
 	/* enable interrupt */
 	ret = xdma_enable_intr(xdev);
 	if (ret) {
@@ -826,6 +839,77 @@ static bool xdma_filter_fn(struct dma_chan *chan, void *param)
 	return true;
 }
 
+/**
+ * xdma_free_user_irq - Free user interrupt
+ * @pdev: Pointer to the platform_device structure
+ * @user_irq_index: User IRQ index
+ * @arg: User interrupt cookie
+ */
+void xdma_free_user_irq(struct platform_device *pdev, u32 user_irq_index,
+			void *arg)
+{
+	struct xdma_device *xdev = platform_get_drvdata(pdev);
+	u32 user_irq;
+	int ret;
+
+	user_irq = xdev->h2c_chan_num + xdev->c2h_chan_num + user_irq_index;
+	if (user_irq >= xdev->irq_num) {
+		xdma_err(xdev, "invalid user irq index");
+		return;
+	}
+	user_irq += xdev->irq_start;
+
+	ret = xdma_write_reg(xdev, XDMA_IRQ_BASE, XDMA_IRQ_USER_INT_EN_W1C,
+			     (1 << user_irq_index));
+	if (ret) {
+		xdma_err(xdev, "clear user irq mask failed, %d", ret);
+		return;
+	}
+
+	free_irq(user_irq, arg);
+}
+EXPORT_SYMBOL(xdma_free_user_irq);
+
+/**
+ * xdma_request_user_irq - Register user interrupt
+ * @pdev: Pointer to the platform_device structure
+ * @user_irq_index: User IRQ index
+ * @flags: Handling flags
+ * @handler: User interrupt handler
+ * @arg: User interrupt cookie
+ */
+int xdma_request_user_irq(struct platform_device *pdev, u32 user_irq_index,
+			  irq_handler_t handler, void *arg, ulong flags)
+{
+	struct xdma_device *xdev = platform_get_drvdata(pdev);
+	u32 user_irq;
+	int ret;
+
+	user_irq = xdev->h2c_chan_num + xdev->c2h_chan_num + user_irq_index;
+	if (user_irq >= xdev->irq_num) {
+		xdma_err(xdev, "invalid user irq index");
+		return -EINVAL;
+	}
+	user_irq += xdev->irq_start;
+
+	ret = request_irq(user_irq, handler, flags, "xdma-user", arg);
+	if (ret) {
+		xdma_err(xdev, "request irq failed, %d", ret);
+		return ret;
+	}
+
+	ret = xdma_write_reg(xdev, XDMA_IRQ_BASE, XDMA_IRQ_USER_INT_EN_W1S,
+			     (1 << user_irq_index));
+	if (ret) {
+		xdma_err(xdev, "set user irq mask failed, %d", ret);
+		free_irq(user_irq, arg);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(xdma_request_user_irq);
+
 /**
  * xdma_remove - Driver remove function
  * @pdev: Pointer to the platform_device structure

include/linux/dma/amd_xdma.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2022 Advanced Micro Devices, Inc. All rights reserved.
+ */
+
+#ifndef _DMAENGINE_AMD_XDMA_H
+#define _DMAENGINE_AMD_XDMA_H
+
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+
+int xdma_request_user_irq(struct platform_device *pdev, u32 user_irq_index,
+			  irq_handler_t handler, void *arg, ulong flags);
+void xdma_free_user_irq(struct platform_device *pdev, u32 user_irq_index,
+			void *arg);
+
+#endif /* _DMAENGINE_AMD_XDMA_H */