Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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); |