[media] vmalloc_sg: make sure all pages in vmalloc area are really DMA-ready

Patch originally written by Konrad. Rebased on current linux media tree.

Under Xen, vmalloc_32() isn't guaranteed to return pages which are really
under 4G in machine physical addresses (only in virtual pseudo-physical
addresses).  To work around this, implement a vmalloc variant which
allocates each page with dma_alloc_coherent() to guarantee that each
page is suitable for the device in question.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: James Harper <james.harper@ejbdigital.com.au>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf-dma-sg.c b/drivers/media/v4l2-core/videobuf-dma-sg.c
index 828e7c1..3c8cc02 100644 (file)
--- a/drivers/media/v4l2-core/videobuf-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf-dma-sg.c
@@ -211,13 +211,36 @@ EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
                             int nr_pages)
 {
+       int i;
+
        dprintk(1, "init kernel [%d pages]\n", nr_pages);
 
        dma->direction = direction;
-       dma->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
+       dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages),
+                                  GFP_KERNEL);
+       if (!dma->vaddr_pages)
+               return -ENOMEM;
+
+       dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL);
+       if (!dma->dma_addr) {
+               kfree(dma->vaddr_pages);
+               return -ENOMEM;
+       }
+       for (i = 0; i < nr_pages; i++) {
+               void *addr;
+
+               addr = dma_alloc_coherent(dma->dev, PAGE_SIZE,
+                                         &(dma->dma_addr[i]), GFP_KERNEL);
+               if (addr == NULL)
+                       goto out_free_pages;
+
+               dma->vaddr_pages[i] = virt_to_page(addr);
+       }
+       dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP,
+                         PAGE_KERNEL);
        if (NULL == dma->vaddr) {
                dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
-               return -ENOMEM;
+               goto out_free_pages;
        }
 
        dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
@@ -228,6 +251,19 @@ int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
        dma->nr_pages = nr_pages;
 
        return 0;
+out_free_pages:
+       while (i > 0) {
+               void *addr = page_address(dma->vaddr_pages[i]);
+               dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
+               i--;
+       }
+       kfree(dma->dma_addr);
+       dma->dma_addr = NULL;
+       kfree(dma->vaddr_pages);
+       dma->vaddr_pages = NULL;
+
+       return -ENOMEM;
+
 }
 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
 
@@ -322,8 +358,21 @@ int videobuf_dma_free(struct videobuf_dmabuf *dma)
                dma->pages = NULL;
        }
 
-       vfree(dma->vaddr);
-       dma->vaddr = NULL;
+       if (dma->dma_addr) {
+               for (i = 0; i < dma->nr_pages; i++) {
+                       void *addr;
+
+                       addr = page_address(dma->vaddr_pages[i]);
+                       dma_free_coherent(dma->dev, PAGE_SIZE, addr,
+                                         dma->dma_addr[i]);
+               }
+               kfree(dma->dma_addr);
+               dma->dma_addr = NULL;
+               kfree(dma->vaddr_pages);
+               dma->vaddr_pages = NULL;
+               vunmap(dma->vaddr);
+               dma->vaddr = NULL;
+       }
 
        if (dma->bus_addr)
                dma->bus_addr = 0;
@@ -461,6 +510,11 @@ static int __videobuf_iolock(struct videobuf_queue *q,
 
        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
 
+       if (!mem->dma.dev)
+               mem->dma.dev = q->dev;
+       else
+               WARN_ON(mem->dma.dev != q->dev);
+
        switch (vb->memory) {
        case V4L2_MEMORY_MMAP:
        case V4L2_MEMORY_USERPTR:

diff --git a/include/media/videobuf-dma-sg.h b/include/media/videobuf-dma-sg.h
index d8fb601..fb6fd4d 100644 (file)
--- a/include/media/videobuf-dma-sg.h
+++ b/include/media/videobuf-dma-sg.h
@@ -53,6 +53,9 @@ struct videobuf_dmabuf {
 
        /* for kernel buffers */
        void                *vaddr;
+       struct page         **vaddr_pages;
+       dma_addr_t          *dma_addr;
+       struct device       *dev;
 
        /* for overlay buffers (pci-pci dma) */
        dma_addr_t          bus_addr;