1 files changed, 121 insertions, 0 deletions

diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c
index b0e77de99148..351b24a979d4 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)
@@ -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);