blob: 752fd95323f3d777496f93c2144c7e158d936789 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Dynamic DMA mapping support.
3 *
Jan Beulich563aaf02007-02-05 18:51:25 -08004 * This implementation is a fallback for platforms that do not support
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 * I/O TLBs (aka DMA address translation hardware).
6 * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com>
7 * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com>
8 * Copyright (C) 2000, 2003 Hewlett-Packard Co
9 * David Mosberger-Tang <davidm@hpl.hp.com>
10 *
11 * 03/05/07 davidm Switch from PCI-DMA to generic device DMA API.
12 * 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid
13 * unnecessary i-cache flushing.
John W. Linville569c8bf2005-09-29 14:45:24 -070014 * 04/07/.. ak Better overflow handling. Assorted fixes.
15 * 05/09/10 linville Add support for syncing ranges, support syncing for
16 * DMA_BIDIRECTIONAL mappings, miscellaneous cleanup.
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 */
18
19#include <linux/cache.h>
Tony Luck17e5ad62005-09-29 15:52:13 -070020#include <linux/dma-mapping.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/mm.h>
22#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/spinlock.h>
24#include <linux/string.h>
25#include <linux/types.h>
26#include <linux/ctype.h>
27
28#include <asm/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <asm/dma.h>
Tony Luck17e5ad62005-09-29 15:52:13 -070030#include <asm/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
32#include <linux/init.h>
33#include <linux/bootmem.h>
34
35#define OFFSET(val,align) ((unsigned long) \
36 ( (val) & ( (align) - 1)))
37
38#define SG_ENT_VIRT_ADDRESS(sg) (page_address((sg)->page) + (sg)->offset)
Jan Beulich93fbff62007-02-05 18:49:45 -080039#define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg))
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41/*
42 * Maximum allowable number of contiguous slabs to map,
43 * must be a power of 2. What is the appropriate value ?
44 * The complexity of {map,unmap}_single is linearly dependent on this value.
45 */
46#define IO_TLB_SEGSIZE 128
47
48/*
49 * log of the size of each IO TLB slab. The number of slabs is command line
50 * controllable.
51 */
52#define IO_TLB_SHIFT 11
53
Alex Williamson0b9afed2005-09-06 11:20:49 -060054#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
55
56/*
57 * Minimum IO TLB size to bother booting with. Systems with mainly
58 * 64bit capable cards will only lightly use the swiotlb. If we can't
59 * allocate a contiguous 1MB, we're probably in trouble anyway.
60 */
61#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT)
62
John W. Linvillede69e0f2005-09-29 14:44:57 -070063/*
64 * Enumeration for sync targets
65 */
66enum dma_sync_target {
67 SYNC_FOR_CPU = 0,
68 SYNC_FOR_DEVICE = 1,
69};
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071int swiotlb_force;
72
73/*
74 * Used to do a quick range check in swiotlb_unmap_single and
75 * swiotlb_sync_single_*, to see if the memory was in fact allocated by this
76 * API.
77 */
78static char *io_tlb_start, *io_tlb_end;
79
80/*
81 * The number of IO TLB blocks (in groups of 64) betweeen io_tlb_start and
82 * io_tlb_end. This is command line adjustable via setup_io_tlb_npages.
83 */
84static unsigned long io_tlb_nslabs;
85
86/*
87 * When the IOMMU overflows we return a fallback buffer. This sets the size.
88 */
89static unsigned long io_tlb_overflow = 32*1024;
90
91void *io_tlb_overflow_buffer;
92
93/*
94 * This is a free list describing the number of free entries available from
95 * each index
96 */
97static unsigned int *io_tlb_list;
98static unsigned int io_tlb_index;
99
100/*
101 * We need to save away the original address corresponding to a mapped entry
102 * for the sync operations.
103 */
Tony Luck25667d62007-03-06 13:31:45 -0800104static unsigned char **io_tlb_orig_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105
106/*
107 * Protect the above data structures in the map and unmap calls
108 */
109static DEFINE_SPINLOCK(io_tlb_lock);
110
111static int __init
112setup_io_tlb_npages(char *str)
113{
114 if (isdigit(*str)) {
Alex Williamsone8579e72005-08-04 13:06:00 -0700115 io_tlb_nslabs = simple_strtoul(str, &str, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 /* avoid tail segment of size < IO_TLB_SEGSIZE */
117 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
118 }
119 if (*str == ',')
120 ++str;
121 if (!strcmp(str, "force"))
122 swiotlb_force = 1;
123 return 1;
124}
125__setup("swiotlb=", setup_io_tlb_npages);
126/* make io_tlb_overflow tunable too? */
127
128/*
129 * Statically reserve bounce buffer space and initialize bounce buffer data
Tony Luck17e5ad62005-09-29 15:52:13 -0700130 * structures for the software IO TLB used to implement the DMA API.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 */
Jan Beulich563aaf02007-02-05 18:51:25 -0800132void __init
133swiotlb_init_with_default_size(size_t default_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134{
Jan Beulich563aaf02007-02-05 18:51:25 -0800135 unsigned long i, bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137 if (!io_tlb_nslabs) {
Alex Williamsone8579e72005-08-04 13:06:00 -0700138 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
140 }
141
Jan Beulich563aaf02007-02-05 18:51:25 -0800142 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
143
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 /*
145 * Get IO TLB memory from the low pages
146 */
Jan Beulich563aaf02007-02-05 18:51:25 -0800147 io_tlb_start = alloc_bootmem_low_pages(bytes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 if (!io_tlb_start)
149 panic("Cannot allocate SWIOTLB buffer");
Jan Beulich563aaf02007-02-05 18:51:25 -0800150 io_tlb_end = io_tlb_start + bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152 /*
153 * Allocate and initialize the free list array. This array is used
154 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
155 * between io_tlb_start and io_tlb_end.
156 */
157 io_tlb_list = alloc_bootmem(io_tlb_nslabs * sizeof(int));
Tony Luck25667d62007-03-06 13:31:45 -0800158 for (i = 0; i < io_tlb_nslabs; i++)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
160 io_tlb_index = 0;
Tony Luck25667d62007-03-06 13:31:45 -0800161 io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
163 /*
164 * Get the overflow emergency buffer
165 */
166 io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
Jan Beulich563aaf02007-02-05 18:51:25 -0800167 if (!io_tlb_overflow_buffer)
168 panic("Cannot allocate SWIOTLB overflow buffer!\n");
169
Tony Luck25667d62007-03-06 13:31:45 -0800170 printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n",
171 virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172}
173
Jan Beulich563aaf02007-02-05 18:51:25 -0800174void __init
175swiotlb_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176{
Tony Luck25667d62007-03-06 13:31:45 -0800177 swiotlb_init_with_default_size(64 * (1<<20)); /* default to 64MB */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178}
179
Alex Williamson0b9afed2005-09-06 11:20:49 -0600180/*
181 * Systems with larger DMA zones (those that don't support ISA) can
182 * initialize the swiotlb later using the slab allocator if needed.
183 * This should be just like above, but with some error catching.
184 */
185int
Jan Beulich563aaf02007-02-05 18:51:25 -0800186swiotlb_late_init_with_default_size(size_t default_size)
Alex Williamson0b9afed2005-09-06 11:20:49 -0600187{
Jan Beulich563aaf02007-02-05 18:51:25 -0800188 unsigned long i, bytes, req_nslabs = io_tlb_nslabs;
Alex Williamson0b9afed2005-09-06 11:20:49 -0600189 unsigned int order;
190
191 if (!io_tlb_nslabs) {
192 io_tlb_nslabs = (default_size >> IO_TLB_SHIFT);
193 io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE);
194 }
195
196 /*
197 * Get IO TLB memory from the low pages
198 */
Jan Beulich563aaf02007-02-05 18:51:25 -0800199 order = get_order(io_tlb_nslabs << IO_TLB_SHIFT);
Alex Williamson0b9afed2005-09-06 11:20:49 -0600200 io_tlb_nslabs = SLABS_PER_PAGE << order;
Jan Beulich563aaf02007-02-05 18:51:25 -0800201 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
Alex Williamson0b9afed2005-09-06 11:20:49 -0600202
203 while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) {
204 io_tlb_start = (char *)__get_free_pages(GFP_DMA | __GFP_NOWARN,
205 order);
206 if (io_tlb_start)
207 break;
208 order--;
209 }
210
211 if (!io_tlb_start)
212 goto cleanup1;
213
Jan Beulich563aaf02007-02-05 18:51:25 -0800214 if (order != get_order(bytes)) {
Alex Williamson0b9afed2005-09-06 11:20:49 -0600215 printk(KERN_WARNING "Warning: only able to allocate %ld MB "
216 "for software IO TLB\n", (PAGE_SIZE << order) >> 20);
217 io_tlb_nslabs = SLABS_PER_PAGE << order;
Jan Beulich563aaf02007-02-05 18:51:25 -0800218 bytes = io_tlb_nslabs << IO_TLB_SHIFT;
Alex Williamson0b9afed2005-09-06 11:20:49 -0600219 }
Jan Beulich563aaf02007-02-05 18:51:25 -0800220 io_tlb_end = io_tlb_start + bytes;
221 memset(io_tlb_start, 0, bytes);
Alex Williamson0b9afed2005-09-06 11:20:49 -0600222
223 /*
224 * Allocate and initialize the free list array. This array is used
225 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
226 * between io_tlb_start and io_tlb_end.
227 */
228 io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL,
229 get_order(io_tlb_nslabs * sizeof(int)));
230 if (!io_tlb_list)
231 goto cleanup2;
232
233 for (i = 0; i < io_tlb_nslabs; i++)
234 io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
235 io_tlb_index = 0;
236
Tony Luck25667d62007-03-06 13:31:45 -0800237 io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
238 get_order(io_tlb_nslabs * sizeof(char *)));
Alex Williamson0b9afed2005-09-06 11:20:49 -0600239 if (!io_tlb_orig_addr)
240 goto cleanup3;
241
Tony Luck25667d62007-03-06 13:31:45 -0800242 memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));
Alex Williamson0b9afed2005-09-06 11:20:49 -0600243
244 /*
245 * Get the overflow emergency buffer
246 */
247 io_tlb_overflow_buffer = (void *)__get_free_pages(GFP_DMA,
248 get_order(io_tlb_overflow));
249 if (!io_tlb_overflow_buffer)
250 goto cleanup4;
251
Tony Luck25667d62007-03-06 13:31:45 -0800252 printk(KERN_INFO "Placing %luMB software IO TLB between 0x%lx - "
253 "0x%lx\n", bytes >> 20,
254 virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end));
Alex Williamson0b9afed2005-09-06 11:20:49 -0600255
256 return 0;
257
258cleanup4:
Tony Luck25667d62007-03-06 13:31:45 -0800259 free_pages((unsigned long)io_tlb_orig_addr, get_order(io_tlb_nslabs *
260 sizeof(char *)));
Alex Williamson0b9afed2005-09-06 11:20:49 -0600261 io_tlb_orig_addr = NULL;
262cleanup3:
Tony Luck25667d62007-03-06 13:31:45 -0800263 free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs *
264 sizeof(int)));
Alex Williamson0b9afed2005-09-06 11:20:49 -0600265 io_tlb_list = NULL;
Alex Williamson0b9afed2005-09-06 11:20:49 -0600266cleanup2:
Jan Beulich563aaf02007-02-05 18:51:25 -0800267 io_tlb_end = NULL;
Alex Williamson0b9afed2005-09-06 11:20:49 -0600268 free_pages((unsigned long)io_tlb_start, order);
269 io_tlb_start = NULL;
270cleanup1:
271 io_tlb_nslabs = req_nslabs;
272 return -ENOMEM;
273}
274
Andrew Mortonbe6b0262007-02-12 00:52:17 -0800275static int
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276address_needs_mapping(struct device *hwdev, dma_addr_t addr)
277{
278 dma_addr_t mask = 0xffffffff;
279 /* If the device has a mask, use it, otherwise default to 32 bits */
280 if (hwdev && hwdev->dma_mask)
281 mask = *hwdev->dma_mask;
282 return (addr & ~mask) != 0;
283}
284
285/*
286 * Allocates bounce buffer and returns its kernel virtual address.
287 */
288static void *
Tony Luck25667d62007-03-06 13:31:45 -0800289map_single(struct device *hwdev, char *buffer, size_t size, int dir)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290{
291 unsigned long flags;
292 char *dma_addr;
293 unsigned int nslots, stride, index, wrap;
294 int i;
295
296 /*
297 * For mappings greater than a page, we limit the stride (and
298 * hence alignment) to a page size.
299 */
300 nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
301 if (size > PAGE_SIZE)
302 stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
303 else
304 stride = 1;
305
Eric Sesterhenn34814542006-03-24 18:47:11 +0100306 BUG_ON(!nslots);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307
308 /*
309 * Find suitable number of IO TLB entries size that will fit this
310 * request and allocate a buffer from that IO TLB pool.
311 */
312 spin_lock_irqsave(&io_tlb_lock, flags);
313 {
314 wrap = index = ALIGN(io_tlb_index, stride);
315
316 if (index >= io_tlb_nslabs)
317 wrap = index = 0;
318
319 do {
320 /*
321 * If we find a slot that indicates we have 'nslots'
322 * number of contiguous buffers, we allocate the
323 * buffers from that slot and mark the entries as '0'
324 * indicating unavailable.
325 */
326 if (io_tlb_list[index] >= nslots) {
327 int count = 0;
328
329 for (i = index; i < (int) (index + nslots); i++)
330 io_tlb_list[i] = 0;
331 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
332 io_tlb_list[i] = ++count;
333 dma_addr = io_tlb_start + (index << IO_TLB_SHIFT);
334
335 /*
336 * Update the indices to avoid searching in
337 * the next round.
338 */
339 io_tlb_index = ((index + nslots) < io_tlb_nslabs
340 ? (index + nslots) : 0);
341
342 goto found;
343 }
344 index += stride;
345 if (index >= io_tlb_nslabs)
346 index = 0;
347 } while (index != wrap);
348
349 spin_unlock_irqrestore(&io_tlb_lock, flags);
350 return NULL;
351 }
352 found:
353 spin_unlock_irqrestore(&io_tlb_lock, flags);
354
355 /*
356 * Save away the mapping from the original address to the DMA address.
357 * This is needed when we sync the memory. Then we sync the buffer if
358 * needed.
359 */
Keir Fraserdf336d12007-07-21 04:37:24 -0700360 for (i = 0; i < nslots; i++)
361 io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
Tony Luck25667d62007-03-06 13:31:45 -0800363 memcpy(dma_addr, buffer, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364
365 return dma_addr;
366}
367
368/*
369 * dma_addr is the kernel virtual address of the bounce buffer to unmap.
370 */
371static void
372unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
373{
374 unsigned long flags;
375 int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
376 int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
Tony Luck25667d62007-03-06 13:31:45 -0800377 char *buffer = io_tlb_orig_addr[index];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378
379 /*
380 * First, sync the memory before unmapping the entry
381 */
Tony Luck25667d62007-03-06 13:31:45 -0800382 if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 /*
384 * bounce... copy the data back into the original buffer * and
385 * delete the bounce buffer.
386 */
Tony Luck25667d62007-03-06 13:31:45 -0800387 memcpy(buffer, dma_addr, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
389 /*
390 * Return the buffer to the free list by setting the corresponding
391 * entries to indicate the number of contigous entries available.
392 * While returning the entries to the free list, we merge the entries
393 * with slots below and above the pool being returned.
394 */
395 spin_lock_irqsave(&io_tlb_lock, flags);
396 {
397 count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ?
398 io_tlb_list[index + nslots] : 0);
399 /*
400 * Step 1: return the slots to the free list, merging the
401 * slots with superceeding slots
402 */
403 for (i = index + nslots - 1; i >= index; i--)
404 io_tlb_list[i] = ++count;
405 /*
406 * Step 2: merge the returned slots with the preceding slots,
407 * if available (non zero)
408 */
409 for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
410 io_tlb_list[i] = ++count;
411 }
412 spin_unlock_irqrestore(&io_tlb_lock, flags);
413}
414
415static void
John W. Linvillede69e0f2005-09-29 14:44:57 -0700416sync_single(struct device *hwdev, char *dma_addr, size_t size,
417 int dir, int target)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418{
419 int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
Tony Luck25667d62007-03-06 13:31:45 -0800420 char *buffer = io_tlb_orig_addr[index];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421
Keir Fraserdf336d12007-07-21 04:37:24 -0700422 buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
423
John W. Linvillede69e0f2005-09-29 14:44:57 -0700424 switch (target) {
425 case SYNC_FOR_CPU:
426 if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL))
Tony Luck25667d62007-03-06 13:31:45 -0800427 memcpy(buffer, dma_addr, size);
Eric Sesterhenn34814542006-03-24 18:47:11 +0100428 else
429 BUG_ON(dir != DMA_TO_DEVICE);
John W. Linvillede69e0f2005-09-29 14:44:57 -0700430 break;
431 case SYNC_FOR_DEVICE:
432 if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
Tony Luck25667d62007-03-06 13:31:45 -0800433 memcpy(dma_addr, buffer, size);
Eric Sesterhenn34814542006-03-24 18:47:11 +0100434 else
435 BUG_ON(dir != DMA_FROM_DEVICE);
John W. Linvillede69e0f2005-09-29 14:44:57 -0700436 break;
437 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 BUG();
John W. Linvillede69e0f2005-09-29 14:44:57 -0700439 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440}
441
442void *
443swiotlb_alloc_coherent(struct device *hwdev, size_t size,
Al Viro06a54492005-10-21 03:21:03 -0400444 dma_addr_t *dma_handle, gfp_t flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445{
Jan Beulich563aaf02007-02-05 18:51:25 -0800446 dma_addr_t dev_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 void *ret;
448 int order = get_order(size);
449
450 /*
451 * XXX fix me: the DMA API should pass us an explicit DMA mask
452 * instead, or use ZONE_DMA32 (ia64 overloads ZONE_DMA to be a ~32
453 * bit range instead of a 16MB one).
454 */
455 flags |= GFP_DMA;
456
Tony Luck25667d62007-03-06 13:31:45 -0800457 ret = (void *)__get_free_pages(flags, order);
Jan Beulich93fbff62007-02-05 18:49:45 -0800458 if (ret && address_needs_mapping(hwdev, virt_to_bus(ret))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 /*
460 * The allocated memory isn't reachable by the device.
461 * Fall back on swiotlb_map_single().
462 */
463 free_pages((unsigned long) ret, order);
464 ret = NULL;
465 }
466 if (!ret) {
467 /*
468 * We are either out of memory or the device can't DMA
469 * to GFP_DMA memory; fall back on
470 * swiotlb_map_single(), which will grab memory from
471 * the lowest available address range.
472 */
473 dma_addr_t handle;
474 handle = swiotlb_map_single(NULL, NULL, size, DMA_FROM_DEVICE);
Muli Ben-Yehuda17a941d2006-01-11 22:44:42 +0100475 if (swiotlb_dma_mapping_error(handle))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 return NULL;
477
Jan Beulich93fbff62007-02-05 18:49:45 -0800478 ret = bus_to_virt(handle);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 }
480
481 memset(ret, 0, size);
Jan Beulich93fbff62007-02-05 18:49:45 -0800482 dev_addr = virt_to_bus(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483
484 /* Confirm address can be DMA'd by device */
485 if (address_needs_mapping(hwdev, dev_addr)) {
Jan Beulich563aaf02007-02-05 18:51:25 -0800486 printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n",
487 (unsigned long long)*hwdev->dma_mask,
488 (unsigned long long)dev_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 panic("swiotlb_alloc_coherent: allocated memory is out of "
490 "range for device");
491 }
492 *dma_handle = dev_addr;
493 return ret;
494}
495
496void
497swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
498 dma_addr_t dma_handle)
499{
David Brownellaa248862007-08-10 13:10:27 -0700500 WARN_ON(irqs_disabled());
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 if (!(vaddr >= (void *)io_tlb_start
502 && vaddr < (void *)io_tlb_end))
503 free_pages((unsigned long) vaddr, get_order(size));
504 else
505 /* DMA_TO_DEVICE to avoid memcpy in unmap_single */
506 swiotlb_unmap_single (hwdev, dma_handle, size, DMA_TO_DEVICE);
507}
508
509static void
510swiotlb_full(struct device *dev, size_t size, int dir, int do_panic)
511{
512 /*
513 * Ran out of IOMMU space for this operation. This is very bad.
514 * Unfortunately the drivers cannot handle this operation properly.
Tony Luck17e5ad62005-09-29 15:52:13 -0700515 * unless they check for dma_mapping_error (most don't)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 * When the mapping is small enough return a static buffer to limit
517 * the damage, or panic when the transfer is too big.
518 */
Jan Beulich563aaf02007-02-05 18:51:25 -0800519 printk(KERN_ERR "DMA: Out of SW-IOMMU space for %zu bytes at "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 "device %s\n", size, dev ? dev->bus_id : "?");
521
522 if (size > io_tlb_overflow && do_panic) {
Tony Luck17e5ad62005-09-29 15:52:13 -0700523 if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
524 panic("DMA: Memory would be corrupted\n");
525 if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
526 panic("DMA: Random memory would be DMAed\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 }
528}
529
530/*
531 * Map a single buffer of the indicated size for DMA in streaming mode. The
Tony Luck17e5ad62005-09-29 15:52:13 -0700532 * physical address to use is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 *
534 * Once the device is given the dma address, the device owns this memory until
535 * either swiotlb_unmap_single or swiotlb_dma_sync_single is performed.
536 */
537dma_addr_t
538swiotlb_map_single(struct device *hwdev, void *ptr, size_t size, int dir)
539{
Jan Beulich563aaf02007-02-05 18:51:25 -0800540 dma_addr_t dev_addr = virt_to_bus(ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 void *map;
542
Eric Sesterhenn34814542006-03-24 18:47:11 +0100543 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 /*
545 * If the pointer passed in happens to be in the device's DMA window,
546 * we can safely return the device addr and not worry about bounce
547 * buffering it.
548 */
Tony Luck25667d62007-03-06 13:31:45 -0800549 if (!address_needs_mapping(hwdev, dev_addr) && !swiotlb_force)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 return dev_addr;
551
552 /*
553 * Oh well, have to allocate and map a bounce buffer.
554 */
Tony Luck25667d62007-03-06 13:31:45 -0800555 map = map_single(hwdev, ptr, size, dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 if (!map) {
557 swiotlb_full(hwdev, size, dir, 1);
558 map = io_tlb_overflow_buffer;
559 }
560
Jan Beulich93fbff62007-02-05 18:49:45 -0800561 dev_addr = virt_to_bus(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
563 /*
564 * Ensure that the address returned is DMA'ble
565 */
566 if (address_needs_mapping(hwdev, dev_addr))
567 panic("map_single: bounce buffer is not DMA'ble");
568
569 return dev_addr;
570}
571
572/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 * Unmap a single streaming mode DMA translation. The dma_addr and size must
574 * match what was provided for in a previous swiotlb_map_single call. All
575 * other usages are undefined.
576 *
577 * After this call, reads by the cpu to the buffer are guaranteed to see
578 * whatever the device wrote there.
579 */
580void
581swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size,
582 int dir)
583{
Jan Beulich93fbff62007-02-05 18:49:45 -0800584 char *dma_addr = bus_to_virt(dev_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585
Eric Sesterhenn34814542006-03-24 18:47:11 +0100586 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
588 unmap_single(hwdev, dma_addr, size, dir);
589 else if (dir == DMA_FROM_DEVICE)
Jan Beulichcde14bb2007-02-05 18:46:40 -0800590 dma_mark_clean(dma_addr, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591}
592
593/*
594 * Make physical memory consistent for a single streaming mode DMA translation
595 * after a transfer.
596 *
597 * If you perform a swiotlb_map_single() but wish to interrogate the buffer
Tony Luck17e5ad62005-09-29 15:52:13 -0700598 * using the cpu, yet do not wish to teardown the dma mapping, you must
599 * call this function before doing so. At the next point you give the dma
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 * address back to the card, you must first perform a
601 * swiotlb_dma_sync_for_device, and then the device again owns the buffer
602 */
Andrew Mortonbe6b0262007-02-12 00:52:17 -0800603static void
John W. Linville8270f3f2005-09-29 14:43:32 -0700604swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr,
John W. Linvillede69e0f2005-09-29 14:44:57 -0700605 size_t size, int dir, int target)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606{
Jan Beulich93fbff62007-02-05 18:49:45 -0800607 char *dma_addr = bus_to_virt(dev_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
Eric Sesterhenn34814542006-03-24 18:47:11 +0100609 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
John W. Linvillede69e0f2005-09-29 14:44:57 -0700611 sync_single(hwdev, dma_addr, size, dir, target);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 else if (dir == DMA_FROM_DEVICE)
Jan Beulichcde14bb2007-02-05 18:46:40 -0800613 dma_mark_clean(dma_addr, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614}
615
616void
John W. Linville8270f3f2005-09-29 14:43:32 -0700617swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
618 size_t size, int dir)
619{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700620 swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU);
John W. Linville8270f3f2005-09-29 14:43:32 -0700621}
622
623void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
625 size_t size, int dir)
626{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700627 swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628}
629
630/*
John W. Linville878a97c2005-09-29 14:44:23 -0700631 * Same as above, but for a sub-range of the mapping.
632 */
Andrew Mortonbe6b0262007-02-12 00:52:17 -0800633static void
John W. Linville878a97c2005-09-29 14:44:23 -0700634swiotlb_sync_single_range(struct device *hwdev, dma_addr_t dev_addr,
John W. Linvillede69e0f2005-09-29 14:44:57 -0700635 unsigned long offset, size_t size,
636 int dir, int target)
John W. Linville878a97c2005-09-29 14:44:23 -0700637{
Jan Beulich93fbff62007-02-05 18:49:45 -0800638 char *dma_addr = bus_to_virt(dev_addr) + offset;
John W. Linville878a97c2005-09-29 14:44:23 -0700639
Eric Sesterhenn34814542006-03-24 18:47:11 +0100640 BUG_ON(dir == DMA_NONE);
John W. Linville878a97c2005-09-29 14:44:23 -0700641 if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end)
John W. Linvillede69e0f2005-09-29 14:44:57 -0700642 sync_single(hwdev, dma_addr, size, dir, target);
John W. Linville878a97c2005-09-29 14:44:23 -0700643 else if (dir == DMA_FROM_DEVICE)
Jan Beulichcde14bb2007-02-05 18:46:40 -0800644 dma_mark_clean(dma_addr, size);
John W. Linville878a97c2005-09-29 14:44:23 -0700645}
646
647void
648swiotlb_sync_single_range_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
649 unsigned long offset, size_t size, int dir)
650{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700651 swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir,
652 SYNC_FOR_CPU);
John W. Linville878a97c2005-09-29 14:44:23 -0700653}
654
655void
656swiotlb_sync_single_range_for_device(struct device *hwdev, dma_addr_t dev_addr,
657 unsigned long offset, size_t size, int dir)
658{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700659 swiotlb_sync_single_range(hwdev, dev_addr, offset, size, dir,
660 SYNC_FOR_DEVICE);
John W. Linville878a97c2005-09-29 14:44:23 -0700661}
662
663/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 * Map a set of buffers described by scatterlist in streaming mode for DMA.
665 * This is the scatter-gather version of the above swiotlb_map_single
666 * interface. Here the scatter gather list elements are each tagged with the
667 * appropriate dma address and length. They are obtained via
668 * sg_dma_{address,length}(SG).
669 *
670 * NOTE: An implementation may be able to use a smaller number of
671 * DMA address/length pairs than there are SG table elements.
672 * (for example via virtual mapping capabilities)
673 * The routine returns the number of addr/length pairs actually
674 * used, at most nents.
675 *
676 * Device ownership issues as mentioned above for swiotlb_map_single are the
677 * same here.
678 */
679int
Jens Axboedbfd49f2007-05-11 14:56:18 +0200680swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 int dir)
682{
Jens Axboedbfd49f2007-05-11 14:56:18 +0200683 struct scatterlist *sg;
Tony Luck25667d62007-03-06 13:31:45 -0800684 void *addr;
Jan Beulich563aaf02007-02-05 18:51:25 -0800685 dma_addr_t dev_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 int i;
687
Eric Sesterhenn34814542006-03-24 18:47:11 +0100688 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689
Jens Axboedbfd49f2007-05-11 14:56:18 +0200690 for_each_sg(sgl, sg, nelems, i) {
Tony Luck25667d62007-03-06 13:31:45 -0800691 addr = SG_ENT_VIRT_ADDRESS(sg);
692 dev_addr = virt_to_bus(addr);
693 if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) {
694 void *map = map_single(hwdev, addr, sg->length, dir);
Andi Kleen7e870232005-12-20 14:45:19 +0100695 if (!map) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 /* Don't panic here, we expect map_sg users
697 to do proper error handling. */
698 swiotlb_full(hwdev, sg->length, dir, 0);
FUJITA Tomonori9e91fdb2007-10-17 10:06:18 +0200699 swiotlb_unmap_sg(hwdev, sgl, i, dir);
Jens Axboedbfd49f2007-05-11 14:56:18 +0200700 sgl[0].dma_length = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 return 0;
702 }
Jan Beulichcde14bb2007-02-05 18:46:40 -0800703 sg->dma_address = virt_to_bus(map);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 } else
705 sg->dma_address = dev_addr;
706 sg->dma_length = sg->length;
707 }
708 return nelems;
709}
710
711/*
712 * Unmap a set of streaming mode DMA translations. Again, cpu read rules
713 * concerning calls here are the same as for swiotlb_unmap_single() above.
714 */
715void
Jens Axboedbfd49f2007-05-11 14:56:18 +0200716swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 int dir)
718{
Jens Axboedbfd49f2007-05-11 14:56:18 +0200719 struct scatterlist *sg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 int i;
721
Eric Sesterhenn34814542006-03-24 18:47:11 +0100722 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723
Jens Axboedbfd49f2007-05-11 14:56:18 +0200724 for_each_sg(sgl, sg, nelems, i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
Jan Beulich93fbff62007-02-05 18:49:45 -0800726 unmap_single(hwdev, bus_to_virt(sg->dma_address),
727 sg->dma_length, dir);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 else if (dir == DMA_FROM_DEVICE)
Jan Beulichcde14bb2007-02-05 18:46:40 -0800729 dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
Jens Axboedbfd49f2007-05-11 14:56:18 +0200730 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731}
732
733/*
734 * Make physical memory consistent for a set of streaming mode DMA translations
735 * after a transfer.
736 *
737 * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules
738 * and usage.
739 */
Andrew Mortonbe6b0262007-02-12 00:52:17 -0800740static void
Jens Axboedbfd49f2007-05-11 14:56:18 +0200741swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
John W. Linvillede69e0f2005-09-29 14:44:57 -0700742 int nelems, int dir, int target)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743{
Jens Axboedbfd49f2007-05-11 14:56:18 +0200744 struct scatterlist *sg;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 int i;
746
Eric Sesterhenn34814542006-03-24 18:47:11 +0100747 BUG_ON(dir == DMA_NONE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748
Jens Axboedbfd49f2007-05-11 14:56:18 +0200749 for_each_sg(sgl, sg, nelems, i) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
Jan Beulich93fbff62007-02-05 18:49:45 -0800751 sync_single(hwdev, bus_to_virt(sg->dma_address),
John W. Linvillede69e0f2005-09-29 14:44:57 -0700752 sg->dma_length, dir, target);
Jan Beulichcde14bb2007-02-05 18:46:40 -0800753 else if (dir == DMA_FROM_DEVICE)
754 dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
Jens Axboedbfd49f2007-05-11 14:56:18 +0200755 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700756}
757
758void
John W. Linville8270f3f2005-09-29 14:43:32 -0700759swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
760 int nelems, int dir)
761{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700762 swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU);
John W. Linville8270f3f2005-09-29 14:43:32 -0700763}
764
765void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
767 int nelems, int dir)
768{
John W. Linvillede69e0f2005-09-29 14:44:57 -0700769 swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770}
771
772int
773swiotlb_dma_mapping_error(dma_addr_t dma_addr)
774{
Jan Beulich93fbff62007-02-05 18:49:45 -0800775 return (dma_addr == virt_to_bus(io_tlb_overflow_buffer));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776}
777
778/*
Tony Luck17e5ad62005-09-29 15:52:13 -0700779 * Return whether the given device DMA address mask can be supported
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 * properly. For example, if your device can only drive the low 24-bits
Tony Luck17e5ad62005-09-29 15:52:13 -0700781 * during bus mastering, then you would pass 0x00ffffff as the mask to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 * this function.
783 */
784int
Jan Beulich563aaf02007-02-05 18:51:25 -0800785swiotlb_dma_supported(struct device *hwdev, u64 mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786{
Tony Luck25667d62007-03-06 13:31:45 -0800787 return virt_to_bus(io_tlb_end - 1) <= mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788}
789
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790EXPORT_SYMBOL(swiotlb_map_single);
791EXPORT_SYMBOL(swiotlb_unmap_single);
792EXPORT_SYMBOL(swiotlb_map_sg);
793EXPORT_SYMBOL(swiotlb_unmap_sg);
794EXPORT_SYMBOL(swiotlb_sync_single_for_cpu);
795EXPORT_SYMBOL(swiotlb_sync_single_for_device);
John W. Linville878a97c2005-09-29 14:44:23 -0700796EXPORT_SYMBOL_GPL(swiotlb_sync_single_range_for_cpu);
797EXPORT_SYMBOL_GPL(swiotlb_sync_single_range_for_device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu);
799EXPORT_SYMBOL(swiotlb_sync_sg_for_device);
800EXPORT_SYMBOL(swiotlb_dma_mapping_error);
Tony Luck25667d62007-03-06 13:31:45 -0800801EXPORT_SYMBOL(swiotlb_alloc_coherent);
802EXPORT_SYMBOL(swiotlb_free_coherent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803EXPORT_SYMBOL(swiotlb_dma_supported);