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swiotlb: allow architectures to override swiotlb pool allocation 

Impact: generalize swiotlb allocation code

Architectures may need to allocate memory specially for use with
the swiotlb.  Create the weak function swiotlb_alloc_boot() and
swiotlb_alloc() defaulting to the current behaviour.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge 2008-12-16 12:17:26 -08:00 committed by Ingo Molnar
parent a79b7a2a75
commit 8c5df16bec
2 changed files with 16 additions and 3 deletions
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3
include/linux/swiotlb.h
View File

@ -10,6 +10,9 @@ struct scatterlist;
extern void
swiotlb_init(void);
extern void *swiotlb_alloc_boot(size_t bytes, unsigned long nslabs);
extern void *swiotlb_alloc(unsigned order, unsigned long nslabs);
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags);

16
lib/swiotlb.c
View File

@ -21,6 +21,7 @@
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/swiotlb.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ctype.h>
@ -126,6 +127,16 @@ setup_io_tlb_npages(char *str)
__setup("swiotlb=", setup_io_tlb_npages);
/* make io_tlb_overflow tunable too? */
void * __weak swiotlb_alloc_boot(size_t size, unsigned long nslabs)
{
return alloc_bootmem_low_pages(size);
}
void * __weak swiotlb_alloc(unsigned order, unsigned long nslabs)
{
return (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order);
}
/*
* Statically reserve bounce buffer space and initialize bounce buffer data
* structures for the software IO TLB used to implement the DMA API.
@ -145,7 +156,7 @@ swiotlb_init_with_default_size(size_t default_size)
/*
* Get IO TLB memory from the low pages
*/
io_tlb_start = alloc_bootmem_low_pages(bytes);
io_tlb_start = swiotlb_alloc_boot(bytes, io_tlb_nslabs);
if (!io_tlb_start)
panic("Cannot allocate SWIOTLB buffer");
io_tlb_end = io_tlb_start + bytes;
@ -202,8 +213,7 @@ swiotlb_late_init_with_default_size(size_t default_size)
bytes = io_tlb_nslabs << IO_TLB_SHIFT;
while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
io_tlb_start = (char *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
order);
io_tlb_start = swiotlb_alloc(order, io_tlb_nslabs);
if (io_tlb_start)
break;
order--;