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Commit 7b4eeed1 authored by James Harper's avatar James Harper Committed by Mauro Carvalho Chehab
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[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: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarJames Harper <james.harper@ejbdigital.com.au>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent b601fe56

drivers/media/v4l2-core/videobuf-dma-sg.c

+58 −4
Original line number Diff line number Diff line
@@ -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);

	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:

include/media/videobuf-dma-sg.h

+3 −0
Original line number Diff line number Diff line
@@ -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;