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Commit ff7204a7 authored by Alexander Duyck's avatar Alexander Duyck Committed by Konrad Rzeszutek Wilk
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swiotlb: Make io_tlb_start a physical address instead of a virtual one 



This change replaces all references to the virtual address for io_tlb_start
with references to the physical address io_tlb_end.  The main advantage of
replacing the virtual address with a physical address is that we can avoid
having to do multiple translations from the virtual address to the physical
one needed for testing an existing DMA address.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent c40dba06

lib/swiotlb.c

+29 −29
Original line number Diff line number Diff line
@@ -57,8 +57,7 @@ int swiotlb_force; 
 * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this

 * API.

 */

static char *io_tlb_start;

static phys_addr_t io_tlb_end;

static phys_addr_t io_tlb_start, io_tlb_end;



/*

 * The number of IO TLB blocks (in groups of 64) between io_tlb_start and
@@ -126,16 +125,15 @@ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev, 
void swiotlb_print_info(void)

{

	unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT;

	phys_addr_t pstart;

	unsigned char *vend;

	unsigned char *vstart, *vend;



	pstart = virt_to_phys(io_tlb_start);

	vstart = phys_to_virt(io_tlb_start);

	vend = phys_to_virt(io_tlb_end);



	printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n",

	       (unsigned long long)pstart,

	       (unsigned long long)io_tlb_start,

	       (unsigned long long)io_tlb_end,

	       bytes >> 20, io_tlb_start, vend - 1);

	       bytes >> 20, vstart, vend - 1);

}



void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
@@ -145,8 +143,8 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) 
	bytes = nslabs << IO_TLB_SHIFT;



	io_tlb_nslabs = nslabs;

	io_tlb_start = tlb;

	io_tlb_end = __pa(io_tlb_start) + bytes;

	io_tlb_start = __pa(tlb);

	io_tlb_end = io_tlb_start + bytes;



	/*

	 * Allocate and initialize the free list array.  This array is used
@@ -176,6 +174,7 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) 
static void __init

swiotlb_init_with_default_size(size_t default_size, int verbose)

{

	unsigned char *vstart;

	unsigned long bytes;



	if (!io_tlb_nslabs) {
@@ -188,11 +187,11 @@ swiotlb_init_with_default_size(size_t default_size, int verbose) 
	/*

	 * Get IO TLB memory from the low pages

	 */

	io_tlb_start = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));

	if (!io_tlb_start)

	vstart = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));

	if (!vstart)

		panic("Cannot allocate SWIOTLB buffer");



	swiotlb_init_with_tbl(io_tlb_start, io_tlb_nslabs, verbose);

	swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose);

}



void __init
@@ -210,6 +209,7 @@ int 
swiotlb_late_init_with_default_size(size_t default_size)

{

	unsigned long bytes, req_nslabs = io_tlb_nslabs;

	unsigned char *vstart = NULL;

	unsigned int order;

	int rc = 0;
@@ -226,14 +226,14 @@ 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 = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,

		vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN,

						  order);

		if (io_tlb_start)

		if (vstart)

			break;

		order--;

	}



	if (!io_tlb_start) {

	if (!vstart) {

		io_tlb_nslabs = req_nslabs;

		return -ENOMEM;

	}
@@ -242,9 +242,9 @@ swiotlb_late_init_with_default_size(size_t default_size) 
		       "for software IO TLB\n", (PAGE_SIZE << order) >> 20);

		io_tlb_nslabs = SLABS_PER_PAGE << order;

	}

	rc = swiotlb_late_init_with_tbl(io_tlb_start, io_tlb_nslabs);

	rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs);

	if (rc)

		free_pages((unsigned long)io_tlb_start, order);

		free_pages((unsigned long)vstart, order);

	return rc;

}
@@ -256,10 +256,10 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) 
	bytes = nslabs << IO_TLB_SHIFT;



	io_tlb_nslabs = nslabs;

	io_tlb_start = tlb;

	io_tlb_end = virt_to_phys(io_tlb_start) + bytes;

	io_tlb_start = virt_to_phys(tlb);

	io_tlb_end = io_tlb_start + bytes;



	memset(io_tlb_start, 0, bytes);

	memset(tlb, 0, bytes);



	/*

	 * Allocate and initialize the free list array.  This array is used
@@ -308,7 +308,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) 
	io_tlb_list = NULL;

cleanup2:

	io_tlb_end = 0;

	io_tlb_start = NULL;

	io_tlb_start = 0;

	io_tlb_nslabs = 0;

	return -ENOMEM;

}
@@ -325,7 +325,7 @@ void __init swiotlb_free(void) 
			   get_order(io_tlb_nslabs * sizeof(phys_addr_t)));

		free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *

								 sizeof(int)));

		free_pages((unsigned long)io_tlb_start,

		free_pages((unsigned long)phys_to_virt(io_tlb_start),

			   get_order(io_tlb_nslabs << IO_TLB_SHIFT));

	} else {

		free_bootmem_late(__pa(io_tlb_overflow_buffer),
@@ -334,7 +334,7 @@ void __init swiotlb_free(void) 
				  PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));

		free_bootmem_late(__pa(io_tlb_list),

				  PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));

		free_bootmem_late(__pa(io_tlb_start),

		free_bootmem_late(io_tlb_start,

				  PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));

	}

	io_tlb_nslabs = 0;
@@ -342,7 +342,7 @@ void __init swiotlb_free(void) 


static int is_swiotlb_buffer(phys_addr_t paddr)

{

	return paddr >= virt_to_phys(io_tlb_start) && paddr < io_tlb_end;

	return paddr >= io_tlb_start && paddr < io_tlb_end;

}



/*
@@ -455,7 +455,7 @@ void *swiotlb_tbl_map_single(struct device *hwdev, dma_addr_t tbl_dma_addr, 
				io_tlb_list[i] = 0;

			for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--)

				io_tlb_list[i] = ++count;

			dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);

			dma_addr = (char *)phys_to_virt(io_tlb_start) + (index << IO_TLB_SHIFT);



			/*

			 * Update the indices to avoid searching in the next
@@ -499,7 +499,7 @@ static void * 
map_single(struct device *hwdev, phys_addr_t phys, size_t size,

	   enum dma_data_direction dir)

{

	dma_addr_t start_dma_addr = swiotlb_virt_to_bus(hwdev, io_tlb_start);

	dma_addr_t start_dma_addr = phys_to_dma(hwdev, io_tlb_start);



	return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir);

}
@@ -513,7 +513,7 @@ swiotlb_tbl_unmap_single(struct device *hwdev, char *dma_addr, size_t size, 
{

	unsigned long flags;

	int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;

	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;

	int index = (dma_addr - (char *)phys_to_virt(io_tlb_start)) >> IO_TLB_SHIFT;

	phys_addr_t phys = io_tlb_orig_addr[index];



	/*
@@ -554,7 +554,7 @@ swiotlb_tbl_sync_single(struct device *hwdev, char *dma_addr, size_t size, 
			enum dma_data_direction dir,

			enum dma_sync_target target)

{

	int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;

	int index = (dma_addr - (char *)phys_to_virt(io_tlb_start)) >> IO_TLB_SHIFT;

	phys_addr_t phys = io_tlb_orig_addr[index];



	phys += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));