vfio/fsl-mc: Add irq infrastructure for fsl-mc devices

This patch adds the skeleton for interrupt support
for fsl-mc devices. The interrupts are not yet functional,
the functionality will be added by subsequent patches.

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/fsl-mc/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
 
-vfio-fsl-mc-y := vfio_fsl_mc.o
+vfio-fsl-mc-y := vfio_fsl_mc.o vfio_fsl_mc_intr.o
 obj-$(CONFIG_VFIO_FSL_MC) += vfio-fsl-mc.o

drivers/vfio/fsl-mc/vfio_fsl_mc.c

@@ -217,11 +217,55 @@ static long vfio_fsl_mc_ioctl(void *device_data, unsigned int cmd,
 	}
 	case VFIO_DEVICE_GET_IRQ_INFO:
 	{
-		return -ENOTTY;
+		struct vfio_irq_info info;
+
+		minsz = offsetofend(struct vfio_irq_info, count);
+		if (copy_from_user(&info, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (info.argsz < minsz)
+			return -EINVAL;
+
+		if (info.index >= mc_dev->obj_desc.irq_count)
+			return -EINVAL;
+
+		info.flags = VFIO_IRQ_INFO_EVENTFD;
+		info.count = 1;
+
+		return copy_to_user((void __user *)arg, &info, minsz);
 	}
 	case VFIO_DEVICE_SET_IRQS:
 	{
-		return -ENOTTY;
+		struct vfio_irq_set hdr;
+		u8 *data = NULL;
+		int ret = 0;
+		size_t data_size = 0;
+
+		minsz = offsetofend(struct vfio_irq_set, count);
+
+		if (copy_from_user(&hdr, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		ret = vfio_set_irqs_validate_and_prepare(&hdr, mc_dev->obj_desc.irq_count,
+					mc_dev->obj_desc.irq_count, &data_size);
+		if (ret)
+			return ret;
+
+		if (data_size) {
+			data = memdup_user((void __user *)(arg + minsz),
+				   data_size);
+			if (IS_ERR(data))
+				return PTR_ERR(data);
+		}
+
+		mutex_lock(&vdev->igate);
+		ret = vfio_fsl_mc_set_irqs_ioctl(vdev, hdr.flags,
+						 hdr.index, hdr.start,
+						 hdr.count, data);
+		mutex_unlock(&vdev->igate);
+		kfree(data);
+
+		return ret;
 	}
 	case VFIO_DEVICE_RESET:
 	{
@@ -423,6 +467,8 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 	if (ret)
 		goto out_reflck;
 
+	mutex_init(&vdev->igate);
+
 	return 0;
 
 out_reflck:
@@ -443,6 +489,8 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
 	if (!vdev)
 		return -EINVAL;
 
+	mutex_destroy(&vdev->igate);
+
 	vfio_fsl_mc_reflck_put(vdev->reflck);
 
 	if (is_fsl_mc_bus_dprc(mc_dev)) {

drivers/vfio/fsl-mc/vfio_fsl_mc_intr.c

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
+/*
+ * Copyright 2013-2016 Freescale Semiconductor Inc.
+ * Copyright 2019 NXP
+ */
+
+#include <linux/vfio.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/eventfd.h>
+#include <linux/msi.h>
+
+#include "linux/fsl/mc.h"
+#include "vfio_fsl_mc_private.h"
+
+static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev,
+				       unsigned int index, unsigned int start,
+				       unsigned int count, u32 flags,
+				       void *data)
+{
+	return -EINVAL;
+}
+
+int vfio_fsl_mc_set_irqs_ioctl(struct vfio_fsl_mc_device *vdev,
+			       u32 flags, unsigned int index,
+			       unsigned int start, unsigned int count,
+			       void *data)
+{
+	if (flags & VFIO_IRQ_SET_ACTION_TRIGGER)
+		return  vfio_fsl_mc_set_irq_trigger(vdev, index, start,
+			  count, flags, data);
+	else
+		return -EINVAL;
+}

drivers/vfio/fsl-mc/vfio_fsl_mc_private.h

@@ -33,6 +33,12 @@ struct vfio_fsl_mc_device {
 	int				refcnt;
 	struct vfio_fsl_mc_region	*regions;
 	struct vfio_fsl_mc_reflck   *reflck;
+	struct mutex         igate;
 };
 
+extern int vfio_fsl_mc_set_irqs_ioctl(struct vfio_fsl_mc_device *vdev,
+			       u32 flags, unsigned int index,
+			       unsigned int start, unsigned int count,
+			       void *data);
+
 #endif /* VFIO_FSL_MC_PRIVATE_H */