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Commit 74838b75 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

swiotlb: add the late swiotlb initialization function with iotlb memory 



This enables the caller to initialize swiotlb with its own iotlb
memory late in the bootup.

See git commit eb605a57
"swiotlb: add swiotlb_tbl_map_single library function" which will
explain the full details of what it can be used for.

CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[v1: Fold in smatch warning]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent fc2341df

include/linux/swiotlb.h

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ extern int swiotlb_force; 
extern void swiotlb_init(int verbose);

extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);

extern unsigned long swiotlb_nr_tbl(void);

extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);



/*

 * Enumeration for sync targets

lib/swiotlb.c

+24 −9
Original line number Diff line number Diff line
@@ -170,7 +170,7 @@ void __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) 
 * Statically reserve bounce buffer space and initialize bounce buffer data

 * structures for the software IO TLB used to implement the DMA API.

 */

void __init

static void __init

swiotlb_init_with_default_size(size_t default_size, int verbose)

{

	unsigned long bytes;
@@ -206,8 +206,9 @@ swiotlb_init(int verbose) 
int

swiotlb_late_init_with_default_size(size_t default_size)

{

	unsigned long i, bytes, req_nslabs = io_tlb_nslabs;

	unsigned long bytes, req_nslabs = io_tlb_nslabs;

	unsigned int order;

	int rc = 0;



	if (!io_tlb_nslabs) {

		io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
@@ -229,16 +230,32 @@ swiotlb_late_init_with_default_size(size_t default_size) 
		order--;

	}



	if (!io_tlb_start)

		goto cleanup1;



	if (!io_tlb_start) {

		io_tlb_nslabs = req_nslabs;

		return -ENOMEM;

	}

	if (order != get_order(bytes)) {

		printk(KERN_WARNING "Warning: only able to allocate %ld MB "

		       "for software IO TLB\n", (PAGE_SIZE << order) >> 20);

		io_tlb_nslabs = SLABS_PER_PAGE << order;

		bytes = io_tlb_nslabs << IO_TLB_SHIFT;

	}

	rc = swiotlb_late_init_with_tbl(io_tlb_start, io_tlb_nslabs);

	if (rc)

		free_pages((unsigned long)io_tlb_start, order);

	return rc;

}



int

swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)

{

	unsigned long i, bytes;



	bytes = nslabs << IO_TLB_SHIFT;



	io_tlb_nslabs = nslabs;

	io_tlb_start = tlb;

	io_tlb_end = io_tlb_start + bytes;



	memset(io_tlb_start, 0, bytes);



	/*
@@ -288,10 +305,8 @@ swiotlb_late_init_with_default_size(size_t default_size) 
	io_tlb_list = NULL;

cleanup2:

	io_tlb_end = NULL;

	free_pages((unsigned long)io_tlb_start, order);

	io_tlb_start = NULL;

cleanup1:

	io_tlb_nslabs = req_nslabs;

	io_tlb_nslabs = 0;

	return -ENOMEM;

}