xtensa: support DMA buffers in high memory

If a DMA buffer is allocated in high memory and kernel mapping is
required use dma_common_contiguous_remap to map buffer to the vmalloc
region and dma_common_free_remap to unmap it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

diff --git a/arch/xtensa/kernel/pci-dma.c b/arch/xtensa/kernel/pci-dma.c
index 623720a..732631c 100644 (file)
--- a/arch/xtensa/kernel/pci-dma.c
+++ b/arch/xtensa/kernel/pci-dma.c
@@ -16,6 +16,7 @@
  */
 
 #include <linux/dma-contiguous.h>
+#include <linux/dma-direct.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/mm.h>
@@ -123,7 +124,7 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
                              unsigned long attrs)
 {
        unsigned long ret;
-       unsigned long uncached = 0;
+       unsigned long uncached;
        unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
        struct page *page = NULL;
 
@@ -144,15 +145,27 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
        if (!page)
                return NULL;
 
-       ret = (unsigned long)page_address(page);
+       *handle = phys_to_dma(dev, page_to_phys(page));
 
-       /* We currently don't support coherent memory outside KSEG */
+#ifdef CONFIG_MMU
+       if (PageHighMem(page)) {
+               void *p;
 
+               p = dma_common_contiguous_remap(page, size, VM_MAP,
+                                               pgprot_noncached(PAGE_KERNEL),
+                                               __builtin_return_address(0));
+               if (!p) {
+                       if (!dma_release_from_contiguous(dev, page, count))
+                               __free_pages(page, get_order(size));
+               }
+               return p;
+       }
+#endif
+       ret = (unsigned long)page_address(page);
        BUG_ON(ret < XCHAL_KSEG_CACHED_VADDR ||
               ret > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
 
        uncached = ret + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
-       *handle = virt_to_bus((void *)ret);
        __invalidate_dcache_range(ret, size);
 
        return (void *)uncached;
@@ -161,13 +174,20 @@ static void *xtensa_dma_alloc(struct device *dev, size_t size,
 static void xtensa_dma_free(struct device *dev, size_t size, void *vaddr,
                            dma_addr_t dma_handle, unsigned long attrs)
 {
-       unsigned long addr = (unsigned long)vaddr +
-               XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
-       struct page *page = virt_to_page(addr);
        unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
-
-       BUG_ON(addr < XCHAL_KSEG_CACHED_VADDR ||
-              addr > XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE - 1);
+       unsigned long addr = (unsigned long)vaddr;
+       struct page *page;
+
+       if (addr >= XCHAL_KSEG_BYPASS_VADDR &&
+           addr - XCHAL_KSEG_BYPASS_VADDR < XCHAL_KSEG_SIZE) {
+               addr += XCHAL_KSEG_CACHED_VADDR - XCHAL_KSEG_BYPASS_VADDR;
+               page = virt_to_page(addr);
+       } else {
+#ifdef CONFIG_MMU
+               dma_common_free_remap(vaddr, size, VM_MAP);
+#endif
+               page = pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_handle)));
+       }
 
        if (!dma_release_from_contiguous(dev, page, count))
                __free_pages(page, get_order(size));