On Jul 9, 2009, at 8:04 PM, FUJITA Tomonori wrote:
swiotlb_bus_to_virt is unncessary; we can use swiotlb_bus_to_phys and phys_to_virt instead.
phys_to_virt (also, virt_to_phys) is invalid for highmem addresses on ppc. In most of the uses in this file, it doesn't matter, as the iotlb buffers themselves are alloc'd out of lowmem, but the dma_mark_clean() calls could happen on a highmem addr. Currently, on powerpc, dma_mark_clean() doesn't do anything, so it isn't a functional problem. I'm fine with the bulk of this patch, because in reality, if I need to do something with a virtual address of a highmem page, I have to get a kmap for the page. So the existing swiotlb_bus_to_virt isn't really helping.
What is dma_mark_clean used for? Could it be made to take a paddr, and let the implementation deal with making sure there's a valid vaddr for the actual "clean" operation?
I'd also like to see a comment with swiotlb_virt_to_bus() that notes that it should only be called on addresses in lowmem.
Cheers, Becky
Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx> --- arch/powerpc/kernel/dma-swiotlb.c | 10 ----------lib/swiotlb.c | 34 +++++++++++++++ +------------------2 files changed, 16 insertions(+), 28 deletions(-)diff --git a/arch/powerpc/kernel/dma-swiotlb.c b/arch/powerpc/kernel/ dma-swiotlb.cindex 68ccf11..41534ae 100644 --- a/arch/powerpc/kernel/dma-swiotlb.c +++ b/arch/powerpc/kernel/dma-swiotlb.c @@ -24,16 +24,6 @@ int swiotlb __read_mostly; unsigned int ppc_swiotlb_enable; -void *swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t addr) -{ - unsigned long pfn = PFN_DOWN(swiotlb_bus_to_phys(hwdev, addr)); - void *pageaddr = page_address(pfn_to_page(pfn)); - - if (pageaddr != NULL) - return pageaddr + (addr % PAGE_SIZE); - return NULL; -} -dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr){ return paddr + get_dma_direct_offset(hwdev); diff --git a/lib/swiotlb.c b/lib/swiotlb.c index dc1cd1f..1a89c84 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c@@ -130,11 +130,6 @@ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,return swiotlb_phys_to_bus(hwdev, virt_to_phys(address)); }-void * __weak swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t address)-{ - return phys_to_virt(swiotlb_bus_to_phys(hwdev, address)); -} - int __weak swiotlb_arch_address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size) {@@ -307,9 +302,10 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)return swiotlb_arch_address_needs_mapping(hwdev, addr, size); } -static int is_swiotlb_buffer(char *addr) +static int is_swiotlb_buffer(phys_addr_t paddr) { - return addr >= io_tlb_start && addr < io_tlb_end; + return paddr >= virt_to_phys(io_tlb_start) && + paddr < virt_to_phys(io_tlb_end); } /* @@ -582,11 +578,13 @@ EXPORT_SYMBOL(swiotlb_alloc_coherent); void swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, - dma_addr_t dma_handle) + dma_addr_t dev_addr) { + phys_addr_t paddr = swiotlb_bus_to_phys(hwdev, dev_addr); + WARN_ON(irqs_disabled()); - if (!is_swiotlb_buffer(vaddr)) - free_pages((unsigned long) vaddr, get_order(size)); + if (!is_swiotlb_buffer(paddr)) + free_pages((unsigned long)vaddr, get_order(size)); else /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ do_unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE); @@ -671,19 +669,19 @@ EXPORT_SYMBOL_GPL(swiotlb_map_page); static void unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size, int dir) { - char *dma_addr = swiotlb_bus_to_virt(hwdev, dev_addr); + phys_addr_t paddr = swiotlb_bus_to_phys(hwdev, dev_addr); BUG_ON(dir == DMA_NONE); - if (is_swiotlb_buffer(dma_addr)) { - do_unmap_single(hwdev, dma_addr, size, dir); + if (is_swiotlb_buffer(paddr)) { + do_unmap_single(hwdev, phys_to_virt(paddr), size, dir); return; } if (dir != DMA_FROM_DEVICE) return; - dma_mark_clean(dma_addr, size); + dma_mark_clean(phys_to_virt(paddr), size); } void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, @@ -708,19 +706,19 @@ static void swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, size_t size, int dir, int target) { - char *dma_addr = swiotlb_bus_to_virt(hwdev, dev_addr); + phys_addr_t paddr = swiotlb_bus_to_phys(hwdev, dev_addr); BUG_ON(dir == DMA_NONE); - if (is_swiotlb_buffer(dma_addr)) { - sync_single(hwdev, dma_addr, size, dir, target); + if (is_swiotlb_buffer(paddr)) { + sync_single(hwdev, phys_to_virt(paddr), size, dir, target); return; } if (dir != DMA_FROM_DEVICE) return; - dma_mark_clean(dma_addr, size); + dma_mark_clean(phys_to_virt(paddr), size);
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