[PATCH v3 4/7] fpga: dfl: afu: add interrupt support for error reporting

[Xu Yilun <yilun.xu@intel.com>]

Error reporting interrupt is very useful to notify users that some
errors are detected by the hardware. Once users are notified, they
could query hardware logged error states, no need to continuously
poll on these states.

This patch follows the common DFL interrupt notification and handling
mechanism, implements two ioctl commands below for user to query
number of irqs supported, and set/unset interrupt triggers.

 Ioctls:
 * DFL_FPGA_PORT_ERR_GET_IRQ_NUM
   get the number of irqs, which is used to determine whether/how many
   interrupts error reporting feature supports.

 * DFL_FPGA_PORT_ERR_SET_IRQ
   set/unset given eventfds as error interrupt triggers.

Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
----
v2: use DFL_FPGA_PORT_ERR_GET_IRQ_NUM instead of
    DFL_FPGA_PORT_ERR_GET_INFO
    Delete flag field for DFL_FPGA_PORT_ERR_SET_IRQ param
v3: put_user() instead of copy_to_user()
    improves comments
---
 drivers/fpga/dfl-afu-error.c  | 60 +++++++++++++++++++++++++++++++++++++++++++
 drivers/fpga/dfl-afu-main.c   |  4 +++
 include/uapi/linux/fpga-dfl.h | 29 +++++++++++++++++++++
 3 files changed, 93 insertions(+)

diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c
index c1467ae..757f9f5 100644
--- a/drivers/fpga/dfl-afu-error.c
+++ b/drivers/fpga/dfl-afu-error.c
@@ -15,6 +15,7 @@
  */
 
 #include <linux/uaccess.h>
+#include <linux/fpga-dfl.h>
 
 #include "dfl-afu.h"
 
@@ -219,6 +220,64 @@ static void port_err_uinit(struct platform_device *pdev,
 	afu_port_err_mask(&pdev->dev, true);
 }
 
+static long
+port_err_get_num_irqs(struct platform_device *pdev,
+		      struct dfl_feature *feature, unsigned long arg)
+{
+	return put_user(feature->nr_irqs, (__u32 __user *)arg);
+}
+
+static long port_err_set_irq(struct platform_device *pdev,
+			     struct dfl_feature *feature, unsigned long arg)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
+	struct dfl_fpga_irq_set hdr;
+	s32 *fds;
+	long ret;
+
+	if (!feature->nr_irqs)
+		return -ENOENT;
+
+	if (copy_from_user(&hdr, (void __user *)arg, sizeof(hdr)))
+		return -EFAULT;
+
+	if (!hdr.count || (hdr.start + hdr.count > feature->nr_irqs) ||
+	    (hdr.start + hdr.count < hdr.start))
+		return -EINVAL;
+
+	fds = memdup_user((void __user *)(arg + sizeof(hdr)),
+			  hdr.count * sizeof(s32));
+	if (IS_ERR(fds))
+		return PTR_ERR(fds);
+
+	mutex_lock(&pdata->lock);
+	ret = dfl_fpga_set_irq_triggers(feature, hdr.start, hdr.count, fds);
+	mutex_unlock(&pdata->lock);
+
+	kfree(fds);
+	return ret;
+}
+
+static long
+port_err_ioctl(struct platform_device *pdev, struct dfl_feature *feature,
+	       unsigned int cmd, unsigned long arg)
+{
+	long ret = -ENODEV;
+
+	switch (cmd) {
+	case DFL_FPGA_PORT_ERR_GET_IRQ_NUM:
+		ret = port_err_get_num_irqs(pdev, feature, arg);
+		break;
+	case DFL_FPGA_PORT_ERR_SET_IRQ:
+		ret = port_err_set_irq(pdev, feature, arg);
+		break;
+	default:
+		dev_dbg(&pdev->dev, "%x cmd not handled", cmd);
+	}
+
+	return ret;
+}
+
 const struct dfl_feature_id port_err_id_table[] = {
 	{.id = PORT_FEATURE_ID_ERROR,},
 	{0,}
@@ -227,4 +286,5 @@ const struct dfl_feature_id port_err_id_table[] = {
 const struct dfl_feature_ops port_err_ops = {
 	.init = port_err_init,
 	.uinit = port_err_uinit,
+	.ioctl = port_err_ioctl,
 };
diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index b0c3178..357cd5d 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c
@@ -577,6 +577,7 @@ static int afu_release(struct inode *inode, struct file *filp)
 {
 	struct platform_device *pdev = filp->private_data;
 	struct dfl_feature_platform_data *pdata;
+	struct dfl_feature *feature;
 
 	dev_dbg(&pdev->dev, "Device File Release\n");
 
@@ -586,6 +587,9 @@ static int afu_release(struct inode *inode, struct file *filp)
 	dfl_feature_dev_use_end(pdata);
 
 	if (!dfl_feature_dev_use_count(pdata)) {
+		dfl_fpga_dev_for_each_feature(pdata, feature)
+			dfl_fpga_set_irq_triggers(feature, 0,
+						  feature->nr_irqs, NULL);
 		__port_reset(pdev);
 		afu_dma_region_destroy(pdata);
 	}
diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h
index ec70a0746..9ade943 100644
--- a/include/uapi/linux/fpga-dfl.h
+++ b/include/uapi/linux/fpga-dfl.h
@@ -151,6 +151,35 @@ struct dfl_fpga_port_dma_unmap {
 
 #define DFL_FPGA_PORT_DMA_UNMAP		_IO(DFL_FPGA_MAGIC, DFL_PORT_BASE + 4)
 
+/**
+ * DFL_FPGA_PORT_ERR_GET_IRQ_NUM - _IOR(DFL_FPGA_MAGIC, DFL_PORT_BASE + 5,
+ *								__u32 num_irqs)
+ *
+ * Get the number of irqs supported by the fpga port error reporting private
+ * feature. Currently hardware supports up to 1 irq.
+ * Return: 0 on success, -errno on failure.
+ */
+#define DFL_FPGA_PORT_ERR_GET_IRQ_NUM	_IOR(DFL_FPGA_MAGIC,	\
+					     DFL_PORT_BASE + 5, __u32)
+
+/**
+ * DFL_FPGA_PORT_ERR_SET_IRQ - _IOW(DFL_FPGA_MAGIC, DFL_PORT_BASE + 6,
+ *						struct dfl_fpga_irq_set)
+ *
+ * Set fpga port error reporting interrupt trigger if evtfds[n] is valid.
+ * Unset related interrupt trigger if evtfds[n] is a negative value.
+ * Return: 0 on success, -errno on failure.
+ */
+struct dfl_fpga_irq_set {
+	__u32 start;		/* Index of the first irq */
+	__u32 count;		/* The number of eventfd handler */
+	__s32 evtfds[];		/* Eventfd handler */
+};
+
+#define DFL_FPGA_PORT_ERR_SET_IRQ	_IOW(DFL_FPGA_MAGIC,	\
+					     DFL_PORT_BASE + 6,	\
+					     struct dfl_fpga_irq_set)
+
 /* IOCTLs for FME file descriptor */
 
 /**
-- 
2.7.4