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swiotlb: add arch hook to force mapping 

Impact: generalize the sw-IOTLB range checks

Some architectures require special rules to determine whether a range
needs mapping or not.  This adds a weak function for architectures to
override.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ian Campbell 2008-12-16 12:17:31 -08:00 committed by Ingo Molnar
parent e08e1f7adb
commit b81ea27b23
2 changed files with 15 additions and 2 deletions
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2
include/linux/swiotlb.h
View File

@ -30,6 +30,8 @@ extern void *swiotlb_alloc(unsigned order, unsigned long nslabs);
extern dma_addr_t swiotlb_phys_to_bus(phys_addr_t address);
extern phys_addr_t swiotlb_bus_to_phys(dma_addr_t address);
extern int swiotlb_arch_range_needs_mapping(void *ptr, size_t size);
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags);

15
lib/swiotlb.c
View File

@ -145,6 +145,11 @@ static void *swiotlb_bus_to_virt(dma_addr_t address)
return phys_to_virt(swiotlb_bus_to_phys(address));
}
int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
{
return 0;
}
/*
* Statically reserve bounce buffer space and initialize bounce buffer data
* structures for the software IO TLB used to implement the DMA API.
@ -297,6 +302,11 @@ address_needs_mapping(struct device *hwdev, dma_addr_t addr, size_t size)
return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
}
static inline int range_needs_mapping(void *ptr, size_t size)
{
return swiotlb_force || swiotlb_arch_range_needs_mapping(ptr, size);
}
static int is_swiotlb_buffer(char *addr)
{
return addr >= io_tlb_start && addr < io_tlb_end;
@ -585,7 +595,8 @@ swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
* we can safely return the device addr and not worry about bounce
* buffering it.
*/
if (!address_needs_mapping(hwdev, dev_addr, size) && !swiotlb_force)
if (!address_needs_mapping(hwdev, dev_addr, size) &&
!range_needs_mapping(ptr, size))
return dev_addr;
/*
@ -745,7 +756,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
for_each_sg(sgl, sg, nelems, i) {
addr = SG_ENT_VIRT_ADDRESS(sg);
dev_addr = swiotlb_virt_to_bus(addr);
if (swiotlb_force ||
if (range_needs_mapping(sg_virt(sg), sg->length) ||
address_needs_mapping(hwdev, dev_addr, sg->length)) {
void *map = map_single(hwdev, addr, sg->length, dir);
if (!map) {