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path: root/drivers/xen/grant-dma-ops.c
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Diffstat (limited to 'drivers/xen/grant-dma-ops.c')
-rw-r--r--drivers/xen/grant-dma-ops.c48
1 files changed, 41 insertions, 7 deletions
diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c
index aaff35cda517..fc0142484001 100644
--- a/drivers/xen/grant-dma-ops.c
+++ b/drivers/xen/grant-dma-ops.c
@@ -56,11 +56,6 @@ static struct xen_grant_dma_data *find_xen_grant_dma_data(struct device *dev)
* Such a DMA address is formed by using the grant reference as a frame
* number and setting the highest address bit (this bit is for the backend
* to be able to distinguish it from e.g. a mmio address).
- *
- * Note that for now we hard wire dom0 to be the backend domain. In order
- * to support any domain as backend we'd need to add a way to communicate
- * the domid of this backend, e.g. via Xenstore, via the PCI-device's
- * config space or DT/ACPI.
*/
static void *xen_grant_dma_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
@@ -276,9 +271,26 @@ 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)
+{
+ 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");
+ of_node_put(iommu_np);
+
+ return has_iommu;
+}
+
void xen_grant_setup_dma_ops(struct device *dev)
{
struct xen_grant_dma_data *data;
+ struct of_phandle_args iommu_spec;
data = find_xen_grant_dma_data(dev);
if (data) {
@@ -286,12 +298,34 @@ void xen_grant_setup_dma_ops(struct device *dev)
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;
+ }
+
+ 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;
+ }
+
+ of_node_put(iommu_spec.np);
+
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
goto err;
- /* XXX The dom0 is hardcoded as the backend domain for now */
- data->backend_domid = 0;
+ /*
+ * The endpoint ID here means the ID of the domain where the corresponding
+ * backend is running
+ */
+ data->backend_domid = iommu_spec.args[0];
if (xa_err(xa_store(&xen_grant_dma_devices, (unsigned long)dev, data,
GFP_KERNEL))) {