1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_ARM_XEN_PAGE_COHERENT_H
  3#define _ASM_ARM_XEN_PAGE_COHERENT_H
  4
  5#include <asm/page.h>
  6#include <asm/dma-mapping.h>
  7#include <linux/dma-mapping.h>
  8
  9static inline const struct dma_map_ops *xen_get_dma_ops(struct device *dev)
 10{
 11	if (dev && dev->archdata.dev_dma_ops)
 12		return dev->archdata.dev_dma_ops;
 13	return get_arch_dma_ops(NULL);
 14}
 15
 16void __xen_dma_map_page(struct device *hwdev, struct page *page,
 17	     dma_addr_t dev_addr, unsigned long offset, size_t size,
 18	     enum dma_data_direction dir, unsigned long attrs);
 19void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
 20		size_t size, enum dma_data_direction dir,
 21		unsigned long attrs);
 22void __xen_dma_sync_single_for_cpu(struct device *hwdev,
 23		dma_addr_t handle, size_t size, enum dma_data_direction dir);
 24
 25void __xen_dma_sync_single_for_device(struct device *hwdev,
 26		dma_addr_t handle, size_t size, enum dma_data_direction dir);
 27
 28static inline void *xen_alloc_coherent_pages(struct device *hwdev, size_t size,
 29		dma_addr_t *dma_handle, gfp_t flags, unsigned long attrs)
 30{
 31	return xen_get_dma_ops(hwdev)->alloc(hwdev, size, dma_handle, flags, attrs);
 32}
 33
 34static inline void xen_free_coherent_pages(struct device *hwdev, size_t size,
 35		void *cpu_addr, dma_addr_t dma_handle, unsigned long attrs)
 36{
 37	xen_get_dma_ops(hwdev)->free(hwdev, size, cpu_addr, dma_handle, attrs);
 38}
 39
 40static inline void xen_dma_map_page(struct device *hwdev, struct page *page,
 41	     dma_addr_t dev_addr, unsigned long offset, size_t size,
 42	     enum dma_data_direction dir, unsigned long attrs)
 43{
 44	unsigned long page_pfn = page_to_xen_pfn(page);
 45	unsigned long dev_pfn = XEN_PFN_DOWN(dev_addr);
 46	unsigned long compound_pages =
 47		(1<<compound_order(page)) * XEN_PFN_PER_PAGE;
 48	bool local = (page_pfn <= dev_pfn) &&
 49		(dev_pfn - page_pfn < compound_pages);
 50
 51	/*
 52	 * Dom0 is mapped 1:1, while the Linux page can span across
 53	 * multiple Xen pages, it's not possible for it to contain a
 54	 * mix of local and foreign Xen pages. So if the first xen_pfn
 55	 * == mfn the page is local otherwise it's a foreign page
 56	 * grant-mapped in dom0. If the page is local we can safely
 57	 * call the native dma_ops function, otherwise we call the xen
 58	 * specific function.
 59	 */
 60	if (local)
 61		xen_get_dma_ops(hwdev)->map_page(hwdev, page, offset, size, dir, attrs);
 62	else
 63		__xen_dma_map_page(hwdev, page, dev_addr, offset, size, dir, attrs);
 64}
 65
 66static inline void xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
 67		size_t size, enum dma_data_direction dir, unsigned long attrs)
 68{
 69	unsigned long pfn = PFN_DOWN(handle);
 70	/*
 71	 * Dom0 is mapped 1:1, while the Linux page can be spanned accross
 72	 * multiple Xen page, it's not possible to have a mix of local and
 73	 * foreign Xen page. Dom0 is mapped 1:1, so calling pfn_valid on a
 74	 * foreign mfn will always return false. If the page is local we can
 75	 * safely call the native dma_ops function, otherwise we call the xen
 76	 * specific function.
 77	 */
 78	if (pfn_valid(pfn)) {
 79		if (xen_get_dma_ops(hwdev)->unmap_page)
 80			xen_get_dma_ops(hwdev)->unmap_page(hwdev, handle, size, dir, attrs);
 81	} else
 82		__xen_dma_unmap_page(hwdev, handle, size, dir, attrs);
 83}
 84
 85static inline void xen_dma_sync_single_for_cpu(struct device *hwdev,
 86		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 87{
 88	unsigned long pfn = PFN_DOWN(handle);
 89	if (pfn_valid(pfn)) {
 90		if (xen_get_dma_ops(hwdev)->sync_single_for_cpu)
 91			xen_get_dma_ops(hwdev)->sync_single_for_cpu(hwdev, handle, size, dir);
 92	} else
 93		__xen_dma_sync_single_for_cpu(hwdev, handle, size, dir);
 94}
 95
 96static inline void xen_dma_sync_single_for_device(struct device *hwdev,
 97		dma_addr_t handle, size_t size, enum dma_data_direction dir)
 98{
 99	unsigned long pfn = PFN_DOWN(handle);
100	if (pfn_valid(pfn)) {
101		if (xen_get_dma_ops(hwdev)->sync_single_for_device)
102			xen_get_dma_ops(hwdev)->sync_single_for_device(hwdev, handle, size, dir);
103	} else
104		__xen_dma_sync_single_for_device(hwdev, handle, size, dir);
105}
106
107#endif /* _ASM_ARM_XEN_PAGE_COHERENT_H */