[PATCH 1/3] xen/virtio: restructure xen grant dma setup

[Juergen Gross <jgross@xxxxxxxx>]

In order to prepare supporting other means than device tree for
setting up virtio devices under Xen, restructure the functions
xen_is_grant_dma_device() and xen_grant_setup_dma_ops() a little bit.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 drivers/xen/grant-dma-ops.c | 68 +++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 25 deletions(-)

diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index 8973fc1e9ccc..f29759d5301f 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -273,22 +273,28 @@ static const struct dma_map_ops xen_grant_dma_ops = {
        .dma_supported = xen_grant_dma_supported,
 };
 
-bool xen_is_grant_dma_device(struct device *dev)
+static bool xen_is_dt_grant_dma_device(struct device *dev)
 {
        struct device_node *iommu_np;
        bool has_iommu;
 
-       /* XXX Handle only DT devices for now */
-       if (!dev->of_node)
-               return false;
-
        iommu_np = of_parse_phandle(dev->of_node, "iommus", 0);
-       has_iommu = iommu_np && of_device_is_compatible(iommu_np, 
"xen,grant-dma");
+       has_iommu = iommu_np &&
+                   of_device_is_compatible(iommu_np, "xen,grant-dma");
        of_node_put(iommu_np);
 
        return has_iommu;
 }
 
+bool xen_is_grant_dma_device(struct device *dev)
+{
+       /* XXX Handle only DT devices for now */
+       if (dev->of_node)
+               return xen_is_dt_grant_dma_device(dev);
+
+       return false;
+}
+
 bool xen_virtio_mem_acc(struct virtio_device *dev)
 {
        if (IS_ENABLED(CONFIG_XEN_VIRTIO_FORCE_GRANT))
@@ -297,45 +303,56 @@ bool xen_virtio_mem_acc(struct virtio_device *dev)
        return xen_is_grant_dma_device(dev->dev.parent);
 }
 
-void xen_grant_setup_dma_ops(struct device *dev)
+static int xen_dt_grant_setup_dma_ops(struct device *dev,
+                                      struct xen_grant_dma_data *data)
 {
-       struct xen_grant_dma_data *data;
        struct of_phandle_args iommu_spec;
 
-       data = find_xen_grant_dma_data(dev);
-       if (data) {
-               dev_err(dev, "Xen grant DMA data is already created\n");
-               return;
-       }
-
-       /* XXX ACPI device unsupported for now */
-       if (!dev->of_node)
-               goto err;
-
        if (of_parse_phandle_with_args(dev->of_node, "iommus", "#iommu-cells",
                        0, &iommu_spec)) {
                dev_err(dev, "Cannot parse iommus property\n");
-               goto err;
+               return -ESRCH;
        }
 
        if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") ||
                        iommu_spec.args_count != 1) {
                dev_err(dev, "Incompatible IOMMU node\n");
                of_node_put(iommu_spec.np);
-               goto err;
+               return -ESRCH;
        }
 
        of_node_put(iommu_spec.np);
 
+       /*
+        * The endpoint ID here means the ID of the domain where the
+        * corresponding backend is running
+        */
+       data->backend_domid = iommu_spec.args[0];
+
+       return 0;
+}
+
+void xen_grant_setup_dma_ops(struct device *dev)
+{
+       struct xen_grant_dma_data *data;
+
+       data = find_xen_grant_dma_data(dev);
+       if (data) {
+               dev_err(dev, "Xen grant DMA data is already created\n");
+               return;
+       }
+
        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                goto err;
 
-       /*
-        * The endpoint ID here means the ID of the domain where the 
corresponding
-        * backend is running
-        */
-       data->backend_domid = iommu_spec.args[0];
+       if (dev->of_node) {
+               if (xen_dt_grant_setup_dma_ops(dev, data))
+                       goto err;
+       } else {
+               /* XXX ACPI device unsupported for now */
+               goto err;
+       }
 
        if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data,
                        GFP_KERNEL))) {
@@ -348,6 +365,7 @@ void xen_grant_setup_dma_ops(struct device *dev)
        return;
 
 err:
+       devm_kfree(dev, data);
        dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA 
ops\n");
 }
 
-- 
2.35.3