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Commit 8c5df16b authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
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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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIan Campbell <ian.campbell@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a79b7a2a

include/linux/swiotlb.h

+3 −0
Original line number Diff line number Diff line
@@ -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);

lib/swiotlb.c

+13 −3
Original line number Diff line number Diff line
@@ -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--;