Merge master.kernel.org:/home/rmk/linux-2.6-serial
[linux-2.6] / arch / arm / mm / consistent.c
1 /*
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  */
32 static pte_t *consistent_pte;
33 static 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  */
64 struct vm_region {
65         struct list_head        vm_list;
66         unsigned long           vm_start;
67         unsigned long           vm_end;
68         struct page             *vm_pages;
69 };
70
71 static struct vm_region consistent_head = {
72         .vm_list        = LIST_HEAD_INIT(consistent_head.vm_list),
73         .vm_start       = CONSISTENT_BASE,
74         .vm_end         = CONSISTENT_END,
75 };
76
77 static struct vm_region *
78 vm_region_alloc(struct vm_region *head, size_t size, int gfp)
79 {
80         unsigned long addr = head->vm_start, end = head->vm_end - size;
81         unsigned long flags;
82         struct vm_region *c, *new;
83
84         new = kmalloc(sizeof(struct vm_region), gfp);
85         if (!new)
86                 goto out;
87
88         spin_lock_irqsave(&consistent_lock, flags);
89
90         list_for_each_entry(c, &head->vm_list, vm_list) {
91                 if ((addr + size) < addr)
92                         goto nospc;
93                 if ((addr + size) <= c->vm_start)
94                         goto found;
95                 addr = c->vm_end;
96                 if (addr > end)
97                         goto nospc;
98         }
99
100  found:
101         /*
102          * Insert this entry _before_ the one we found.
103          */
104         list_add_tail(&new->vm_list, &c->vm_list);
105         new->vm_start = addr;
106         new->vm_end = addr + size;
107
108         spin_unlock_irqrestore(&consistent_lock, flags);
109         return new;
110
111  nospc:
112         spin_unlock_irqrestore(&consistent_lock, flags);
113         kfree(new);
114  out:
115         return NULL;
116 }
117
118 static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
119 {
120         struct vm_region *c;
121         
122         list_for_each_entry(c, &head->vm_list, vm_list) {
123                 if (c->vm_start == addr)
124                         goto out;
125         }
126         c = NULL;
127  out:
128         return c;
129 }
130
131 #ifdef CONFIG_HUGETLB_PAGE
132 #error ARM Coherent DMA allocator does not (yet) support huge TLB
133 #endif
134
135 static void *
136 __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, int gfp,
137             pgprot_t prot)
138 {
139         struct page *page;
140         struct vm_region *c;
141         unsigned long order;
142         u64 mask = ISA_DMA_THRESHOLD, limit;
143
144         if (!consistent_pte) {
145                 printk(KERN_ERR "%s: not initialised\n", __func__);
146                 dump_stack();
147                 return NULL;
148         }
149
150         if (dev) {
151                 mask = dev->coherent_dma_mask;
152
153                 /*
154                  * Sanity check the DMA mask - it must be non-zero, and
155                  * must be able to be satisfied by a DMA allocation.
156                  */
157                 if (mask == 0) {
158                         dev_warn(dev, "coherent DMA mask is unset\n");
159                         goto no_page;
160                 }
161
162                 if ((~mask) & ISA_DMA_THRESHOLD) {
163                         dev_warn(dev, "coherent DMA mask %#llx is smaller "
164                                  "than system GFP_DMA mask %#llx\n",
165                                  mask, (unsigned long long)ISA_DMA_THRESHOLD);
166                         goto no_page;
167                 }
168         }
169
170         /*
171          * Sanity check the allocation size.
172          */
173         size = PAGE_ALIGN(size);
174         limit = (mask + 1) & ~mask;
175         if ((limit && size >= limit) ||
176             size >= (CONSISTENT_END - CONSISTENT_BASE)) {
177                 printk(KERN_WARNING "coherent allocation too big "
178                        "(requested %#x mask %#llx)\n", size, mask);
179                 goto no_page;
180         }
181
182         order = get_order(size);
183
184         if (mask != 0xffffffff)
185                 gfp |= GFP_DMA;
186
187         page = alloc_pages(gfp, order);
188         if (!page)
189                 goto no_page;
190
191         /*
192          * Invalidate any data that might be lurking in the
193          * kernel direct-mapped region for device DMA.
194          */
195         {
196                 unsigned long kaddr = (unsigned long)page_address(page);
197                 memset(page_address(page), 0, size);
198                 dmac_flush_range(kaddr, kaddr + size);
199         }
200
201         /*
202          * Allocate a virtual address in the consistent mapping region.
203          */
204         c = vm_region_alloc(&consistent_head, size,
205                             gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
206         if (c) {
207                 pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
208                 struct page *end = page + (1 << order);
209
210                 c->vm_pages = page;
211
212                 /*
213                  * Set the "dma handle"
214                  */
215                 *handle = page_to_dma(dev, page);
216
217                 do {
218                         BUG_ON(!pte_none(*pte));
219
220                         set_page_count(page, 1);
221                         /*
222                          * x86 does not mark the pages reserved...
223                          */
224                         SetPageReserved(page);
225                         set_pte(pte, mk_pte(page, prot));
226                         page++;
227                         pte++;
228                 } while (size -= PAGE_SIZE);
229
230                 /*
231                  * Free the otherwise unused pages.
232                  */
233                 while (page < end) {
234                         set_page_count(page, 1);
235                         __free_page(page);
236                         page++;
237                 }
238
239                 return (void *)c->vm_start;
240         }
241
242         if (page)
243                 __free_pages(page, order);
244  no_page:
245         *handle = ~0;
246         return NULL;
247 }
248
249 /*
250  * Allocate DMA-coherent memory space and return both the kernel remapped
251  * virtual and bus address for that space.
252  */
253 void *
254 dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
255 {
256         return __dma_alloc(dev, size, handle, gfp,
257                            pgprot_noncached(pgprot_kernel));
258 }
259 EXPORT_SYMBOL(dma_alloc_coherent);
260
261 /*
262  * Allocate a writecombining region, in much the same way as
263  * dma_alloc_coherent above.
264  */
265 void *
266 dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, int gfp)
267 {
268         return __dma_alloc(dev, size, handle, gfp,
269                            pgprot_writecombine(pgprot_kernel));
270 }
271 EXPORT_SYMBOL(dma_alloc_writecombine);
272
273 static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
274                     void *cpu_addr, dma_addr_t dma_addr, size_t size)
275 {
276         unsigned long flags, user_size, kern_size;
277         struct vm_region *c;
278         int ret = -ENXIO;
279
280         user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
281
282         spin_lock_irqsave(&consistent_lock, flags);
283         c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
284         spin_unlock_irqrestore(&consistent_lock, flags);
285
286         if (c) {
287                 unsigned long off = vma->vm_pgoff;
288
289                 kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
290
291                 if (off < kern_size &&
292                     user_size <= (kern_size - off)) {
293                         vma->vm_flags |= VM_RESERVED;
294                         ret = remap_pfn_range(vma, vma->vm_start,
295                                               page_to_pfn(c->vm_pages) + off,
296                                               user_size << PAGE_SHIFT,
297                                               vma->vm_page_prot);
298                 }
299         }
300
301         return ret;
302 }
303
304 int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
305                       void *cpu_addr, dma_addr_t dma_addr, size_t size)
306 {
307         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
308         return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
309 }
310 EXPORT_SYMBOL(dma_mmap_coherent);
311
312 int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
313                           void *cpu_addr, dma_addr_t dma_addr, size_t size)
314 {
315         vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
316         return dma_mmap(dev, vma, cpu_addr, dma_addr, size);
317 }
318 EXPORT_SYMBOL(dma_mmap_writecombine);
319
320 /*
321  * free a page as defined by the above mapping.
322  */
323 void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
324 {
325         struct vm_region *c;
326         unsigned long flags, addr;
327         pte_t *ptep;
328
329         size = PAGE_ALIGN(size);
330
331         spin_lock_irqsave(&consistent_lock, flags);
332
333         c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
334         if (!c)
335                 goto no_area;
336
337         if ((c->vm_end - c->vm_start) != size) {
338                 printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
339                        __func__, c->vm_end - c->vm_start, size);
340                 dump_stack();
341                 size = c->vm_end - c->vm_start;
342         }
343
344         ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
345         addr = c->vm_start;
346         do {
347                 pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
348                 unsigned long pfn;
349
350                 ptep++;
351                 addr += PAGE_SIZE;
352
353                 if (!pte_none(pte) && pte_present(pte)) {
354                         pfn = pte_pfn(pte);
355
356                         if (pfn_valid(pfn)) {
357                                 struct page *page = pfn_to_page(pfn);
358
359                                 /*
360                                  * x86 does not mark the pages reserved...
361                                  */
362                                 ClearPageReserved(page);
363
364                                 __free_page(page);
365                                 continue;
366                         }
367                 }
368
369                 printk(KERN_CRIT "%s: bad page in kernel page table\n",
370                        __func__);
371         } while (size -= PAGE_SIZE);
372
373         flush_tlb_kernel_range(c->vm_start, c->vm_end);
374
375         list_del(&c->vm_list);
376
377         spin_unlock_irqrestore(&consistent_lock, flags);
378
379         kfree(c);
380         return;
381
382  no_area:
383         spin_unlock_irqrestore(&consistent_lock, flags);
384         printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
385                __func__, cpu_addr);
386         dump_stack();
387 }
388 EXPORT_SYMBOL(dma_free_coherent);
389
390 /*
391  * Initialise the consistent memory allocation.
392  */
393 static int __init consistent_init(void)
394 {
395         pgd_t *pgd;
396         pmd_t *pmd;
397         pte_t *pte;
398         int ret = 0;
399
400         spin_lock(&init_mm.page_table_lock);
401
402         do {
403                 pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
404                 pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
405                 if (!pmd) {
406                         printk(KERN_ERR "%s: no pmd tables\n", __func__);
407                         ret = -ENOMEM;
408                         break;
409                 }
410                 WARN_ON(!pmd_none(*pmd));
411
412                 pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
413                 if (!pte) {
414                         printk(KERN_ERR "%s: no pte tables\n", __func__);
415                         ret = -ENOMEM;
416                         break;
417                 }
418
419                 consistent_pte = pte;
420         } while (0);
421
422         spin_unlock(&init_mm.page_table_lock);
423
424         return ret;
425 }
426
427 core_initcall(consistent_init);
428
429 /*
430  * Make an area consistent for devices.
431  */
432 void consistent_sync(void *vaddr, size_t size, int direction)
433 {
434         unsigned long start = (unsigned long)vaddr;
435         unsigned long end   = start + size;
436
437         switch (direction) {
438         case DMA_FROM_DEVICE:           /* invalidate only */
439                 dmac_inv_range(start, end);
440                 break;
441         case DMA_TO_DEVICE:             /* writeback only */
442                 dmac_clean_range(start, end);
443                 break;
444         case DMA_BIDIRECTIONAL:         /* writeback and invalidate */
445                 dmac_flush_range(start, end);
446                 break;
447         default:
448                 BUG();
449         }
450 }
451 EXPORT_SYMBOL(consistent_sync);