1 files changed, 37 insertions, 92 deletions

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index 018093fef80a..38fa917c8585 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <linux/cpu.h>
-#include <linux/dma-mapping.h>
+#include <linux/dma-noncoherent.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/export.h>
@@ -38,105 +38,56 @@ unsigned long xen_get_swiotlb_free_pages(unsigned int order)
 	return __get_free_pages(flags, order);
 }
 
-enum dma_cache_op {
-       DMA_UNMAP,
-       DMA_MAP,
-};
 static bool hypercall_cflush = false;
 
-/* functions called by SWIOTLB */
-
-static void dma_cache_maint(dma_addr_t handle, unsigned long offset,
-	size_t size, enum dma_data_direction dir, enum dma_cache_op op)
+/* buffers in highmem or foreign pages cannot cross page boundaries */
+static void dma_cache_maint(dma_addr_t handle, size_t size, u32 op)
 {
 	struct gnttab_cache_flush cflush;
-	unsigned long xen_pfn;
-	size_t left = size;
 
-	xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE;
-	offset %= XEN_PAGE_SIZE;
+	cflush.a.dev_bus_addr = handle & XEN_PAGE_MASK;
+	cflush.offset = xen_offset_in_page(handle);
+	cflush.op = op;
 
 	do {
-		size_t len = left;
-	
-		/* buffers in highmem or foreign pages cannot cross page
-		 * boundaries */
-		if (len + offset > XEN_PAGE_SIZE)
-			len = XEN_PAGE_SIZE - offset;
-
-		cflush.op = 0;
-		cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT;
-		cflush.offset = offset;
-		cflush.length = len;
-
-		if (op == DMA_UNMAP && dir != DMA_TO_DEVICE)
-			cflush.op = GNTTAB_CACHE_INVAL;
-		if (op == DMA_MAP) {
-			if (dir == DMA_FROM_DEVICE)
-				cflush.op = GNTTAB_CACHE_INVAL;
-			else
-				cflush.op = GNTTAB_CACHE_CLEAN;
-		}
-		if (cflush.op)
-			HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);
-
-		offset = 0;
-		xen_pfn++;
-		left -= len;
-	} while (left);
-}
-
-static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP);
-}
-
-static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir)
-{
-	dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP);
-}
+		if (size + cflush.offset > XEN_PAGE_SIZE)
+			cflush.length = XEN_PAGE_SIZE - cflush.offset;
+		else
+			cflush.length = size;
 
-void __xen_dma_map_page(struct device *hwdev, struct page *page,
-	     dma_addr_t dev_addr, unsigned long offset, size_t size,
-	     enum dma_data_direction dir, unsigned long attrs)
-{
-	if (is_device_dma_coherent(hwdev))
-		return;
-	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
-		return;
+		HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1);
 
-	__xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir);
+		cflush.offset = 0;
+		cflush.a.dev_bus_addr += cflush.length;
+		size -= cflush.length;
+	} while (size);
 }
 
-void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
-		size_t size, enum dma_data_direction dir,
-		unsigned long attrs)
-
+/*
+ * Dom0 is mapped 1:1, and while the Linux page can span across multiple Xen
+ * pages, it is not possible for it to contain a mix of local and foreign Xen
+ * pages.  Calling pfn_valid on a foreign mfn will always return false, so if
+ * pfn_valid returns true the pages is local and we can use the native
+ * dma-direct functions, otherwise we call the Xen specific version.
+ */
+void xen_dma_sync_for_cpu(struct device *dev, dma_addr_t handle,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
 {
-	if (is_device_dma_coherent(hwdev))
-		return;
-	if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
-		return;
-
-	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
+	if (pfn_valid(PFN_DOWN(handle)))
+		arch_sync_dma_for_cpu(dev, paddr, size, dir);
+	else if (dir != DMA_TO_DEVICE)
+		dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL);
 }
 
-void __xen_dma_sync_single_for_cpu(struct device *hwdev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
+void xen_dma_sync_for_device(struct device *dev, dma_addr_t handle,
+		phys_addr_t paddr, size_t size, enum dma_data_direction dir)
 {
-	if (is_device_dma_coherent(hwdev))
-		return;
-	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
-}
-
-void __xen_dma_sync_single_for_device(struct device *hwdev,
-		dma_addr_t handle, size_t size, enum dma_data_direction dir)
-{
-	if (is_device_dma_coherent(hwdev))
-		return;
-	__xen_dma_page_cpu_to_dev(hwdev, handle, size, dir);
+	if (pfn_valid(PFN_DOWN(handle)))
+		arch_sync_dma_for_device(dev, paddr, size, dir);
+	else if (dir == DMA_FROM_DEVICE)
+		dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL);
+	else
+		dma_cache_maint(handle, size, GNTTAB_CACHE_CLEAN);
 }
 
 bool xen_arch_need_swiotlb(struct device *dev,
@@ -162,7 +113,7 @@ bool xen_arch_need_swiotlb(struct device *dev,
 	 * memory and we are not able to flush the cache.
 	 */
 	return (!hypercall_cflush && (xen_pfn != bfn) &&
-		!is_device_dma_coherent(dev));
+		!dev_is_dma_coherent(dev));
 }
 
 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
@@ -176,16 +127,11 @@ int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
 	*dma_handle = pstart;
 	return 0;
 }
-EXPORT_SYMBOL_GPL(xen_create_contiguous_region);
 
 void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
 {
 	return;
 }
-EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
-
-const struct dma_map_ops *xen_dma_ops;
-EXPORT_SYMBOL(xen_dma_ops);
 
 int __init xen_mm_init(void)
 {
@@ -193,7 +139,6 @@ int __init xen_mm_init(void)
 	if (!xen_initial_domain())
 		return 0;
 	xen_swiotlb_init(1, false);
-	xen_dma_ops = &xen_swiotlb_dma_ops;
 
 	cflush.op = 0;
 	cflush.a.dev_bus_addr = 0;