From e05ed4d1fad9e730995abb08cb9bc3bffac5018b Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Mon, 15 Oct 2012 10:19:39 -0700 Subject: swiotlb: Return physical addresses when calling swiotlb_tbl_map_single This change makes it so that swiotlb_tbl_map_single will return a physical address instead of a virtual address when called. The advantage to this once again is that we are avoiding a number of virt_to_phys and phys_to_virt translations by working with everything as a physical address. One change I had to make in order to support using physical addresses is that I could no longer trust 0 to be a invalid physical address on all platforms. So instead I made it so that ~0 is returned on error. This should never be a valid return value as it implies that only one byte would be available for use. In order to clarify things since we now have 2 physical addresses in use inside of swiotlb_tbl_map_single I am renaming phys to orig_addr, and dma_addr to tlb_addr. This way is should be clear that orig_addr is contained within io_orig_addr and tlb_addr is an address within the io_tlb_addr buffer. Signed-off-by: Alexander Duyck Signed-off-by: Konrad Rzeszutek Wilk --- include/linux/swiotlb.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'include/linux/swiotlb.h') diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 8d08b3e..1995f3e 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -34,9 +34,14 @@ enum dma_sync_target { SYNC_FOR_CPU = 0, SYNC_FOR_DEVICE = 1, }; -extern void *swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, - phys_addr_t phys, size_t size, - enum dma_data_direction dir); + +/* define the last possible byte of physical address space as a mapping error */ +#define SWIOTLB_MAP_ERROR (~(phys_addr_t)0x0) + +extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, + dma_addr_t tbl_dma_addr, + phys_addr_t phys, size_t size, + enum dma_data_direction dir); extern void swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr, size_t size, enum dma_data_direction dir); -- cgit v1.1