[PATCH 07 of 14] swiotlb: add arch hook to force mapping

Jeremy Fitzhardinge
2008-12-16T20:21:32Z

From: Ian Campbell <ian.campbell@citrix.com>

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>
---
include/linux/swiotlb.h | 2 ++
lib/swiotlb.c | 15 +++++++++++++--
2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -30,6 +30,8 @@
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);
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -145,6 +145,11 @@
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 @@
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;
@@ -581,7 +591,8 @@
* 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;

/*
@@ -741,7 +752,7 @@
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) {