vfio: amba: VFIO support for AMBA devices

Add support for discovering AMBA devices with VFIO and handle them
similarly to Linux platform devices.

Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com>
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
Reviewed-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

2 files changed, 116 insertions, 0 deletions

diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
new file mode 100644
index 000000000000..ff0331f72526
--- /dev/null
+++ b/drivers/vfio/platform/vfio_amba.c
@@ -0,0 +1,115 @@
+/*
+ * Copyright (C) 2013 - Virtual Open Systems
+ * Author: Antonios Motakis <a.motakis@virtualopensystems.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/vfio.h>
+#include <linux/amba/bus.h>
+
+#include "vfio_platform_private.h"
+
+#define DRIVER_VERSION  "0.10"
+#define DRIVER_AUTHOR   "Antonios Motakis <a.motakis@virtualopensystems.com>"
+#define DRIVER_DESC     "VFIO for AMBA devices - User Level meta-driver"
+
+/* probing devices from the AMBA bus */
+
+static struct resource *get_amba_resource(struct vfio_platform_device *vdev,
+                                          int i)
+{
+        struct amba_device *adev = (struct amba_device *) vdev->opaque;
+
+        if (i == 0)
+                return &adev->res;
+
+        return NULL;
+}
+
+static int get_amba_irq(struct vfio_platform_device *vdev, int i)
+{
+        struct amba_device *adev = (struct amba_device *) vdev->opaque;
+        int ret = 0;
+
+        if (i < AMBA_NR_IRQS)
+                ret = adev->irq[i];
+
+        /* zero is an unset IRQ for AMBA devices */
+        return ret ? ret : -ENXIO;
+}
+
+static int vfio_amba_probe(struct amba_device *adev, const struct amba_id *id)
+{
+        struct vfio_platform_device *vdev;
+        int ret;
+
+        vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+        if (!vdev)
+                return -ENOMEM;
+
+        vdev->name = kasprintf(GFP_KERNEL, "vfio-amba-%08x", adev->periphid);
+        if (!vdev->name) {
+                kfree(vdev);
+                return -ENOMEM;
+        }
+
+        vdev->opaque = (void *) adev;
+        vdev->flags = VFIO_DEVICE_FLAGS_AMBA;
+        vdev->get_resource = get_amba_resource;
+        vdev->get_irq = get_amba_irq;
+
+        ret = vfio_platform_probe_common(vdev, &adev->dev);
+        if (ret) {
+                kfree(vdev->name);
+                kfree(vdev);
+        }
+
+        return ret;
+}
+
+static int vfio_amba_remove(struct amba_device *adev)
+{
+        struct vfio_platform_device *vdev;
+
+        vdev = vfio_platform_remove_common(&adev->dev);
+        if (vdev) {
+                kfree(vdev->name);
+                kfree(vdev);
+                return 0;
+        }
+
+        return -EINVAL;
+}
+
+static struct amba_id pl330_ids[] = {
+        { 0, 0 },
+};
+
+MODULE_DEVICE_TABLE(amba, pl330_ids);
+
+static struct amba_driver vfio_amba_driver = {
+        .probe = vfio_amba_probe,
+        .remove = vfio_amba_remove,
+        .id_table = pl330_ids,
+        .drv = {
+                .name = "vfio-amba",
+                .owner = THIS_MODULE,
+        },
+};
+
+module_amba_driver(vfio_amba_driver);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index ea9514b6bb5c..b57b750c222f 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -161,6 +161,7 @@ struct vfio_device_info {
 #define VFIO_DEVICE_FLAGS_RESET (1 << 0)        /* Device supports reset */
 #define VFIO_DEVICE_FLAGS_PCI   (1 << 1)        /* vfio-pci device */
 #define VFIO_DEVICE_FLAGS_PLATFORM (1 << 2)     /* vfio-platform device */
+#define VFIO_DEVICE_FLAGS_AMBA  (1 << 3)        /* vfio-amba device */
         __u32   num_regions;    /* Max region index + 1 */
         __u32   num_irqs;       /* Max IRQ index + 1 */
 };