1 files changed, 122 insertions, 1 deletions

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index b0e77de99148..793551d15f1d 100644
--- a/arch/arm/xen/mm.c
+++ b/arch/arm/xen/mm.c
@@ -1,6 +1,10 @@
+#include <linux/cpu.h>
+#include <linux/dma-mapping.h>
 #include <linux/bootmem.h>
 #include <linux/gfp.h>
+#include <linux/highmem.h>
 #include <linux/export.h>
+#include <linux/of_address.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/dma-mapping.h>
@@ -8,6 +12,7 @@
 #include <linux/swiotlb.h>
 
 #include <xen/xen.h>
+#include <xen/interface/grant_table.h>
 #include <xen/interface/memory.h>
 #include <xen/swiotlb-xen.h>
 
@@ -16,6 +21,114 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/interface.h>
 
+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)
+{
+	struct gnttab_cache_flush cflush;
+	unsigned long pfn;
+	size_t left = size;
+
+	pfn = (handle >> PAGE_SHIFT) + offset / PAGE_SIZE;
+	offset %= PAGE_SIZE;
+
+	do {
+		size_t len = left;
+	
+		/* buffers in highmem or foreign pages cannot cross page
+		 * boundaries */
+		if (len + offset > PAGE_SIZE)
+			len = PAGE_SIZE - offset;
+
+		cflush.op = 0;
+		cflush.a.dev_bus_addr = pfn << 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;
+		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);
+}
+
+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, struct dma_attrs *attrs)
+{
+	if (is_device_dma_coherent(hwdev))
+		return;
+	if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		return;
+
+	__xen_dma_page_cpu_to_dev(hwdev, dev_addr, size, dir);
+}
+
+void __xen_dma_unmap_page(struct device *hwdev, dma_addr_t handle,
+		size_t size, enum dma_data_direction dir,
+		struct dma_attrs *attrs)
+
+{
+	if (is_device_dma_coherent(hwdev))
+		return;
+	if (dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs))
+		return;
+
+	__xen_dma_page_dev_to_cpu(hwdev, handle, size, dir);
+}
+
+void __xen_dma_sync_single_for_cpu(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_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);
+}
+
+bool xen_arch_need_swiotlb(struct device *dev,
+			   unsigned long pfn,
+			   unsigned long mfn)
+{
+	return (!hypercall_cflush && (pfn != mfn) && !is_device_dma_coherent(dev));
+}
+
 int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order,
 				 unsigned int address_bits,
 				 dma_addr_t *dma_handle)
@@ -36,7 +149,7 @@ void xen_destroy_contiguous_region(phys_addr_t pstart, unsigned int order)
 EXPORT_SYMBOL_GPL(xen_destroy_contiguous_region);
 
 struct dma_map_ops *xen_dma_ops;
-EXPORT_SYMBOL_GPL(xen_dma_ops);
+EXPORT_SYMBOL(xen_dma_ops);
 
 static struct dma_map_ops xen_swiotlb_dma_ops = {
 	.mapping_error = xen_swiotlb_dma_mapping_error,
@@ -56,10 +169,18 @@ static struct dma_map_ops xen_swiotlb_dma_ops = {
 
 int __init xen_mm_init(void)
 {
+	struct gnttab_cache_flush cflush;
 	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;
+	cflush.offset = 0;
+	cflush.length = 0;
+	if (HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1) != -ENOSYS)
+		hypercall_cflush = true;
 	return 0;
 }
 arch_initcall(xen_mm_init);