virtio: Implement get_shm_region for MMIO transport

[linux-2.6-microblaze.git] / drivers / virtio / virtio_mmio.c

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 627ac04..238383f 100644 (file)
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -498,6 +498,36 @@ static const char *vm_bus_name(struct virtio_device *vdev)
        return vm_dev->pdev->name;
 }
 
+static bool vm_get_shm_region(struct virtio_device *vdev,
+                             struct virtio_shm_region *region, u8 id)
+{
+       struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+       u64 len, addr;
+
+       /* Select the region we're interested in */
+       writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
+
+       /* Read the region size */
+       len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
+       len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
+
+       region->len = len;
+
+       /* Check if region length is -1. If that's the case, the shared memory
+        * region does not exist and there is no need to proceed further.
+        */
+       if (len == ~(u64)0)
+               return false;
+
+       /* Read the region base address */
+       addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
+       addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
+
+       region->addr = addr;
+
+       return true;
+}
+
 static const struct virtio_config_ops virtio_mmio_config_ops = {
        .get            = vm_get,
        .set            = vm_set,
@@ -510,6 +540,7 @@ static const struct virtio_config_ops virtio_mmio_config_ops = {
        .get_features   = vm_get_features,
        .finalize_features = vm_finalize_features,
        .bus_name       = vm_bus_name,
+       .get_shm_region = vm_get_shm_region,
 };