1 // SPDX-License-Identifier: GPL-2.0-only
3  * Xen grant DMA-mapping layer - contains special DMA-mapping routines
4  * for providing grant references as DMA addresses to be used by frontends
11 #include <linux/dma-map-ops.h>
19 #include <xen/xen-ops.h>
33 static inline dma_addr_t grant_to_dma(grant_ref_t grant)  in grant_to_dma()  argument
35 	return XEN_GRANT_DMA_ADDR_OFF | ((dma_addr_t)grant << XEN_PAGE_SHIFT);  in grant_to_dma()
38 static inline grant_ref_t dma_to_grant(dma_addr_t dma)  in dma_to_grant()  argument
40 	return (grant_ref_t)((dma & ~XEN_GRANT_DMA_ADDR_OFF) >> XEN_PAGE_SHIFT);  in dma_to_grant()
70  * DMA ops for Xen frontends (e.g. virtio).
73  * DMA addresses.
74  * Such a DMA address is formed by using the grant reference as a frame
85 	grant_ref_t grant;  in xen_grant_dma_alloc()  local
92 	if (unlikely(data->broken))  in xen_grant_dma_alloc()
101 	if (gnttab_alloc_grant_reference_seq(n_pages, &grant)) {  in xen_grant_dma_alloc()
107 		gnttab_grant_foreign_access_ref(grant + i, data->backend_domid,  in xen_grant_dma_alloc()
111 	*dma_handle = grant_to_dma(grant);  in xen_grant_dma_alloc()
121 	grant_ref_t grant;  in xen_grant_dma_free()  local
127 	if (unlikely(data->broken))  in xen_grant_dma_free()
130 	grant = dma_to_grant(dma_handle);  in xen_grant_dma_free()
133 		if (unlikely(!gnttab_end_foreign_access_ref(grant + i))) {  in xen_grant_dma_free()
134 			dev_alert(dev, "Grant still in use by backend domain, disabled for further use\n");  in xen_grant_dma_free()
135 			data->broken = true;  in xen_grant_dma_free()
140 	gnttab_free_grant_reference_seq(grant, n_pages);  in xen_grant_dma_free()
175 	grant_ref_t grant;  in xen_grant_dma_map_page()  local
185 	if (unlikely(data->broken))  in xen_grant_dma_map_page()
188 	if (gnttab_alloc_grant_reference_seq(n_pages, &grant))  in xen_grant_dma_map_page()
192 		gnttab_grant_foreign_access_ref(grant + i, data->backend_domid,  in xen_grant_dma_map_page()
197 	dma_handle = grant_to_dma(grant) + dma_offset;  in xen_grant_dma_map_page()
209 	grant_ref_t grant;  in xen_grant_dma_unmap_page()  local
218 	if (unlikely(data->broken))  in xen_grant_dma_unmap_page()
221 	grant = dma_to_grant(dma_handle);  in xen_grant_dma_unmap_page()
224 		if (unlikely(!gnttab_end_foreign_access_ref(grant + i))) {  in xen_grant_dma_unmap_page()
225 			dev_alert(dev, "Grant still in use by backend domain, disabled for further use\n");  in xen_grant_dma_unmap_page()
226 			data->broken = true;  in xen_grant_dma_unmap_page()
231 	gnttab_free_grant_reference_seq(grant, n_pages);  in xen_grant_dma_unmap_page()
245 		xen_grant_dma_unmap_page(dev, s->dma_address, sg_dma_len(s), dir,  in xen_grant_dma_unmap_sg()
257 		return -EINVAL;  in xen_grant_dma_map_sg()
260 		s->dma_address = xen_grant_dma_map_page(dev, sg_page(s), s->offset,  in xen_grant_dma_map_sg()
261 				s->length, dir, attrs);  in xen_grant_dma_map_sg()
262 		if (s->dma_address == DMA_MAPPING_ERROR)  in xen_grant_dma_map_sg()
265 		sg_dma_len(s) = s->length;  in xen_grant_dma_map_sg()
274 	return -EIO;  in xen_grant_dma_map_sg()
300 		struct pci_bus *bus = pdev->bus;  in xen_dt_get_node()
304 			bus = bus->parent;  in xen_dt_get_node()
306 		if (!bus->bridge->parent)  in xen_dt_get_node()
308 		return of_node_get(bus->bridge->parent->of_node);  in xen_dt_get_node()
311 	return of_node_get(dev->of_node);  in xen_dt_get_node()
322 		u32 rid = PCI_DEVID(pdev->bus->number, pdev->devfn);  in xen_dt_grant_init_backend_domid()
324 		if (of_map_id(np, rid, "iommu-map", "iommu-map-mask", &iommu_spec.np,  in xen_dt_grant_init_backend_domid()
327 			return -ESRCH;  in xen_dt_grant_init_backend_domid()
330 		if (of_parse_phandle_with_args(np, "iommus", "#iommu-cells",  in xen_dt_grant_init_backend_domid()
333 			return -ESRCH;  in xen_dt_grant_init_backend_domid()
337 	if (!of_device_is_compatible(iommu_spec.np, "xen,grant-dma") ||  in xen_dt_grant_init_backend_domid()
341 		return -ESRCH;  in xen_dt_grant_init_backend_domid()
359 	int ret = -ENODEV;  in xen_grant_init_backend_domid()
380 		dev_err(dev, "Xen grant DMA data is already created\n");  in xen_grant_setup_dma_ops()
388 	data->backend_domid = backend_domid;  in xen_grant_setup_dma_ops()
391 		dev_err(dev, "Cannot store Xen grant DMA data\n");  in xen_grant_setup_dma_ops()
395 	dev->dma_ops = &xen_grant_dma_ops;  in xen_grant_setup_dma_ops()
401 	dev_err(dev, "Cannot set up Xen grant DMA ops, retain platform DMA ops\n");  in xen_grant_setup_dma_ops()
408 	if (!xen_grant_init_backend_domid(dev->dev.parent, &backend_domid)) {  in xen_virtio_restricted_mem_acc()
409 		xen_grant_setup_dma_ops(dev->dev.parent, backend_domid);  in xen_virtio_restricted_mem_acc()
416 MODULE_DESCRIPTION("Xen grant DMA-mapping layer");