blob: dbfe9e891f015a87f3efb5b31349d8c1baca20c8 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/mm/consistent.c
3 *
4 * Copyright (C) 2000-2004 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * DMA uncached mapping support.
11 */
12#include <linux/module.h>
13#include <linux/mm.h>
14#include <linux/slab.h>
15#include <linux/errno.h>
16#include <linux/list.h>
17#include <linux/init.h>
18#include <linux/device.h>
19#include <linux/dma-mapping.h>
20
21#include <asm/cacheflush.h>
22#include <asm/io.h>
23#include <asm/tlbflush.h>
24
25#define CONSISTENT_BASE (0xffc00000)
26#define CONSISTENT_END (0xffe00000)
27#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
28
29/*
30 * This is the page table (2MB) covering uncached, DMA consistent allocations
31 */
32static pte_t *consistent_pte;
33static DEFINE_SPINLOCK(consistent_lock);
34
35/*
36 * VM region handling support.
37 *
38 * This should become something generic, handling VM region allocations for
39 * vmalloc and similar (ioremap, module space, etc).
40 *
41 * I envisage vmalloc()'s supporting vm_struct becoming:
42 *
43 * struct vm_struct {
44 * struct vm_region region;
45 * unsigned long flags;
46 * struct page **pages;
47 * unsigned int nr_pages;
48 * unsigned long phys_addr;
49 * };
50 *
51 * get_vm_area() would then call vm_region_alloc with an appropriate
52 * struct vm_region head (eg):
53 *
54 * struct vm_region vmalloc_head = {
55 * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
56 * .vm_start = VMALLOC_START,
57 * .vm_end = VMALLOC_END,
58 * };
59 *
60 * However, vmalloc_head.vm_start is variable (typically, it is dependent on
61 * the amount of RAM found at boot time.) I would imagine that get_vm_area()
62 * would have to initialise this each time prior to calling vm_region_alloc().
63 */
64struct vm_region {
65 struct list_head vm_list;
66 unsigned long vm_start;
67 unsigned long vm_end;
68 struct page *vm_pages;
Russell King5edf71a2005-11-25 15:52:51 +000069 int vm_active;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070};
71
72static struct vm_region consistent_head = {
73 .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
74 .vm_start = CONSISTENT_BASE,
75 .vm_end = CONSISTENT_END,
76};
77
78static struct vm_region *
Al Virof9e32142005-10-21 03:20:58 -040079vm_region_alloc(struct vm_region *head, size_t size, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
81 unsigned long addr = head->vm_start, end = head->vm_end - size;
82 unsigned long flags;
83 struct vm_region *c, *new;
84
85 new = kmalloc(sizeof(struct vm_region), gfp);
86 if (!new)
87 goto out;
88
89 spin_lock_irqsave(&consistent_lock, flags);
90
91 list_for_each_entry(c, &head->vm_list, vm_list) {
92 if ((addr + size) < addr)
93 goto nospc;
94 if ((addr + size) <= c->vm_start)
95 goto found;
96 addr = c->vm_end;
97 if (addr > end)
98 goto nospc;
99 }
100
101 found:
102 /*
103 * Insert this entry _before_ the one we found.
104 */
105 list_add_tail(&new->vm_list, &c->vm_list);
106 new->vm_start = addr;
107 new->vm_end = addr + size;
Russell King5edf71a2005-11-25 15:52:51 +0000108 new->vm_active = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
110 spin_unlock_irqrestore(&consistent_lock, flags);
111 return new;
112
113 nospc:
114 spin_unlock_irqrestore(&consistent_lock, flags);
115 kfree(new);
116 out:
117 return NULL;
118}
119
120static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
121{
122 struct vm_region *c;
123
124 list_for_each_entry(c, &head->vm_list, vm_list) {
Russell King5edf71a2005-11-25 15:52:51 +0000125 if (c->vm_active && c->vm_start == addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 goto out;
127 }
128 c = NULL;
129 out:
130 return c;
131}
132
133#ifdef CONFIG_HUGETLB_PAGE
134#error ARM Coherent DMA allocator does not (yet) support huge TLB
135#endif
136
137static void *
Al Virof9e32142005-10-21 03:20:58 -0400138__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 pgprot_t prot)
140{
141 struct page *page;
142 struct vm_region *c;
143 unsigned long order;
144 u64 mask = ISA_DMA_THRESHOLD, limit;
145
146 if (!consistent_pte) {
147 printk(KERN_ERR "%s: not initialised\n", __func__);
148 dump_stack();
149 return NULL;
150 }
151
152 if (dev) {
153 mask = dev->coherent_dma_mask;
154
155 /*
156 * Sanity check the DMA mask - it must be non-zero, and
157 * must be able to be satisfied by a DMA allocation.
158 */
159 if (mask == 0) {
160 dev_warn(dev, "coherent DMA mask is unset\n");
161 goto no_page;
162 }
163
164 if ((~mask) & ISA_DMA_THRESHOLD) {
165 dev_warn(dev, "coherent DMA mask %#llx is smaller "
166 "than system GFP_DMA mask %#llx\n",
167 mask, (unsigned long long)ISA_DMA_THRESHOLD);
168 goto no_page;
169 }
170 }
171
172 /*
173 * Sanity check the allocation size.
174 */
175 size = PAGE_ALIGN(size);
176 limit = (mask + 1) & ~mask;
177 if ((limit && size >= limit) ||
178 size >= (CONSISTENT_END - CONSISTENT_BASE)) {
179 printk(KERN_WARNING "coherent allocation too big "
180 "(requested %#x mask %#llx)\n", size, mask);
181 goto no_page;
182 }
183
184 order = get_order(size);
185
186 if (mask != 0xffffffff)
187 gfp |= GFP_DMA;
188
189 page = alloc_pages(gfp, order);
190 if (!page)
191 goto no_page;
192
193 /*
194 * Invalidate any data that might be lurking in the
195 * kernel direct-mapped region for device DMA.
196 */
197 {
198 unsigned long kaddr = (unsigned long)page_address(page);
199 memset(page_address(page), 0, size);
200 dmac_flush_range(kaddr, kaddr + size);
201 }
202
203 /*
204 * Allocate a virtual address in the consistent mapping region.
205 */
206 c = vm_region_alloc(&consistent_head, size,
207 gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
208 if (c) {
209 pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
210 struct page *end = page + (1 << order);
211
212 c->vm_pages = page;
213
214 /*
215 * Set the "dma handle"
216 */
217 *handle = page_to_dma(dev, page);
218
219 do {
220 BUG_ON(!pte_none(*pte));
221
222 set_page_count(page, 1);
223 /*
224 * x86 does not mark the pages reserved...
225 */
226 SetPageReserved(page);
227 set_pte(pte, mk_pte(page, prot));
228 page++;
229 pte++;
230 } while (size -= PAGE_SIZE);
231
232 /*
233 * Free the otherwise unused pages.
234 */
235 while (page < end) {
236 set_page_count(page, 1);
237 __free_page(page);
238 page++;
239 }
240
241 return (void *)c->vm_start;
242 }
243
244 if (page)
245 __free_pages(page, order);
246 no_page:
247 *handle = ~0;
248 return NULL;
249}
250
251/*
252 * Allocate DMA-coherent memory space and return both the kernel remapped
253 * virtual and bus address for that space.
254 */
255void *
Al Virof9e32142005-10-21 03:20:58 -0400256dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257{
258 return __dma_alloc(dev, size, handle, gfp,
259 pgprot_noncached(pgprot_kernel));
260}
261EXPORT_SYMBOL(dma_alloc_coherent);
262
263/*
264 * Allocate a writecombining region, in much the same way as
265 * dma_alloc_coherent above.
266 */
267void *
Al Virof9e32142005-10-21 03:20:58 -0400268dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269{
270 return __dma_alloc(dev, size, handle, gfp,
271 pgprot_writecombine(pgprot_kernel));
272}
273EXPORT_SYMBOL(dma_alloc_writecombine);
274
275static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
276 void *cpu_addr, dma_addr_t dma_addr, size_t size)
277{
278 unsigned long flags, user_size, kern_size;
279 struct vm_region *c;
280 int ret = -ENXIO;
281
282 user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
283
284 spin_lock_irqsave(&consistent_lock, flags);
285 c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
286 spin_unlock_irqrestore(&consistent_lock, flags);
287
288 if (c) {
289 unsigned long off = vma->vm_pgoff;
290
291 kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
292
293 if (off < kern_size &&
294 user_size <= (kern_size - off)) {
295 vma->vm_flags |= VM_RESERVED;
296 ret = remap_pfn_range(vma, vma->vm_start,
297 page_to_pfn(c->vm_pages) + off,
298 user_size << PAGE_SHIFT,
299 vma->vm_page_prot);
300 }
301 }
302
303 return ret;
304}
305
306int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
307 void *cpu_addr, dma_addr_t dma_addr, size_t size)
308{
309 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
310 return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
311}
312EXPORT_SYMBOL(dma_mmap_coherent);
313
314int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
315 void *cpu_addr, dma_addr_t dma_addr, size_t size)
316{
317 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
318 return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
319}
320EXPORT_SYMBOL(dma_mmap_writecombine);
321
322/*
323 * free a page as defined by the above mapping.
Russell King5edf71a2005-11-25 15:52:51 +0000324 * Must not be called with IRQs disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 */
326void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
327{
328 struct vm_region *c;
329 unsigned long flags, addr;
330 pte_t *ptep;
331
Russell King5edf71a2005-11-25 15:52:51 +0000332 WARN_ON(irqs_disabled());
333
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 size = PAGE_ALIGN(size);
335
336 spin_lock_irqsave(&consistent_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
338 if (!c)
339 goto no_area;
340
Russell King5edf71a2005-11-25 15:52:51 +0000341 c->vm_active = 0;
342 spin_unlock_irqrestore(&consistent_lock, flags);
343
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 if ((c->vm_end - c->vm_start) != size) {
345 printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
346 __func__, c->vm_end - c->vm_start, size);
347 dump_stack();
348 size = c->vm_end - c->vm_start;
349 }
350
351 ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
352 addr = c->vm_start;
353 do {
354 pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
355 unsigned long pfn;
356
357 ptep++;
358 addr += PAGE_SIZE;
359
360 if (!pte_none(pte) && pte_present(pte)) {
361 pfn = pte_pfn(pte);
362
363 if (pfn_valid(pfn)) {
364 struct page *page = pfn_to_page(pfn);
365
366 /*
367 * x86 does not mark the pages reserved...
368 */
369 ClearPageReserved(page);
370
371 __free_page(page);
372 continue;
373 }
374 }
375
376 printk(KERN_CRIT "%s: bad page in kernel page table\n",
377 __func__);
378 } while (size -= PAGE_SIZE);
379
380 flush_tlb_kernel_range(c->vm_start, c->vm_end);
381
Russell King5edf71a2005-11-25 15:52:51 +0000382 spin_lock_irqsave(&consistent_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 list_del(&c->vm_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 spin_unlock_irqrestore(&consistent_lock, flags);
385
386 kfree(c);
387 return;
388
389 no_area:
390 spin_unlock_irqrestore(&consistent_lock, flags);
391 printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
392 __func__, cpu_addr);
393 dump_stack();
394}
395EXPORT_SYMBOL(dma_free_coherent);
396
397/*
398 * Initialise the consistent memory allocation.
399 */
400static int __init consistent_init(void)
401{
402 pgd_t *pgd;
403 pmd_t *pmd;
404 pte_t *pte;
405 int ret = 0;
406
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407 do {
408 pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
409 pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
410 if (!pmd) {
411 printk(KERN_ERR "%s: no pmd tables\n", __func__);
412 ret = -ENOMEM;
413 break;
414 }
415 WARN_ON(!pmd_none(*pmd));
416
Hugh Dickins872fec12005-10-29 18:16:21 -0700417 pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (!pte) {
419 printk(KERN_ERR "%s: no pte tables\n", __func__);
420 ret = -ENOMEM;
421 break;
422 }
423
424 consistent_pte = pte;
425 } while (0);
426
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 return ret;
428}
429
430core_initcall(consistent_init);
431
432/*
433 * Make an area consistent for devices.
434 */
435void consistent_sync(void *vaddr, size_t size, int direction)
436{
437 unsigned long start = (unsigned long)vaddr;
438 unsigned long end = start + size;
439
440 switch (direction) {
441 case DMA_FROM_DEVICE: /* invalidate only */
442 dmac_inv_range(start, end);
443 break;
444 case DMA_TO_DEVICE: /* writeback only */
445 dmac_clean_range(start, end);
446 break;
447 case DMA_BIDIRECTIONAL: /* writeback and invalidate */
448 dmac_flush_range(start, end);
449 break;
450 default:
451 BUG();
452 }
453}
454EXPORT_SYMBOL(consistent_sync);