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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: 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>
This commit is contained in:
James Harper 2014-06-12 06:53:38 -03:00 committed by Mauro Carvalho Chehab
parent b601fe5688
commit 7b4eeed174
2 changed files with 61 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/media/v4l2-core/videobuf-dma-sg.c
View File

@ -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:

3
include/media/videobuf-dma-sg.h
View File

@ -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;