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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * PowerPC version derived from arch/arm/mm/consistent.c
4 * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
5 *
6 * Copyright (C) 2000 Russell King
7 */
8
9#include <linux/kernel.h>
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/highmem.h>
13#include <linux/dma-direct.h>
14#include <linux/dma-map-ops.h>
15
16#include <asm/tlbflush.h>
17#include <asm/dma.h>
18
19/*
20 * make an area consistent.
21 */
22static void __dma_sync(void *vaddr, size_t size, int direction)
23{
24 unsigned long start = (unsigned long)vaddr;
25 unsigned long end = start + size;
26
27 switch (direction) {
28 case DMA_NONE:
29 BUG();
30 case DMA_FROM_DEVICE:
31 /*
32 * invalidate only when cache-line aligned otherwise there is
33 * the potential for discarding uncommitted data from the cache
34 */
35 if ((start | end) & (L1_CACHE_BYTES - 1))
36 flush_dcache_range(start, end);
37 else
38 invalidate_dcache_range(start, end);
39 break;
40 case DMA_TO_DEVICE: /* writeback only */
41 clean_dcache_range(start, end);
42 break;
43 case DMA_BIDIRECTIONAL: /* writeback and invalidate */
44 flush_dcache_range(start, end);
45 break;
46 }
47}
48
49#ifdef CONFIG_HIGHMEM
50/*
51 * __dma_sync_page() implementation for systems using highmem.
52 * In this case, each page of a buffer must be kmapped/kunmapped
53 * in order to have a virtual address for __dma_sync(). This must
54 * not sleep so kmap_atomic()/kunmap_atomic() are used.
55 *
56 * Note: yes, it is possible and correct to have a buffer extend
57 * beyond the first page.
58 */
59static inline void __dma_sync_page_highmem(struct page *page,
60 unsigned long offset, size_t size, int direction)
61{
62 size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
63 size_t cur_size = seg_size;
64 unsigned long flags, start, seg_offset = offset;
65 int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
66 int seg_nr = 0;
67
68 local_irq_save(flags);
69
70 do {
71 start = (unsigned long)kmap_atomic(page + seg_nr) + seg_offset;
72
73 /* Sync this buffer segment */
74 __dma_sync((void *)start, seg_size, direction);
75 kunmap_atomic((void *)start);
76 seg_nr++;
77
78 /* Calculate next buffer segment size */
79 seg_size = min((size_t)PAGE_SIZE, size - cur_size);
80
81 /* Add the segment size to our running total */
82 cur_size += seg_size;
83 seg_offset = 0;
84 } while (seg_nr < nr_segs);
85
86 local_irq_restore(flags);
87}
88#endif /* CONFIG_HIGHMEM */
89
90/*
91 * __dma_sync_page makes memory consistent. identical to __dma_sync, but
92 * takes a struct page instead of a virtual address
93 */
94static void __dma_sync_page(phys_addr_t paddr, size_t size, int dir)
95{
96 struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
97 unsigned offset = paddr & ~PAGE_MASK;
98
99#ifdef CONFIG_HIGHMEM
100 __dma_sync_page_highmem(page, offset, size, dir);
101#else
102 unsigned long start = (unsigned long)page_address(page) + offset;
103 __dma_sync((void *)start, size, dir);
104#endif
105}
106
107void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
108 enum dma_data_direction dir)
109{
110 __dma_sync_page(paddr, size, dir);
111}
112
113void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
114 enum dma_data_direction dir)
115{
116 __dma_sync_page(paddr, size, dir);
117}
118
119void arch_dma_prep_coherent(struct page *page, size_t size)
120{
121 unsigned long kaddr = (unsigned long)page_address(page);
122
123 flush_dcache_range(kaddr, kaddr + size);
124}
1/*
2 * PowerPC version derived from arch/arm/mm/consistent.c
3 * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
4 *
5 * Copyright (C) 2000 Russell King
6 *
7 * Consistent memory allocators. Used for DMA devices that want to
8 * share uncached memory with the processor core. The function return
9 * is the virtual address and 'dma_handle' is the physical address.
10 * Mostly stolen from the ARM port, with some changes for PowerPC.
11 * -- Dan
12 *
13 * Reorganized to get rid of the arch-specific consistent_* functions
14 * and provide non-coherent implementations for the DMA API. -Matt
15 *
16 * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
17 * implementation. This is pulled straight from ARM and barely
18 * modified. -Matt
19 *
20 * This program is free software; you can redistribute it and/or modify
21 * it under the terms of the GNU General Public License version 2 as
22 * published by the Free Software Foundation.
23 */
24
25#include <linux/sched.h>
26#include <linux/slab.h>
27#include <linux/kernel.h>
28#include <linux/errno.h>
29#include <linux/string.h>
30#include <linux/types.h>
31#include <linux/highmem.h>
32#include <linux/dma-mapping.h>
33
34#include <asm/tlbflush.h>
35
36#include "mmu_decl.h"
37
38/*
39 * This address range defaults to a value that is safe for all
40 * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
41 * can be further configured for specific applications under
42 * the "Advanced Setup" menu. -Matt
43 */
44#define CONSISTENT_BASE (IOREMAP_TOP)
45#define CONSISTENT_END (CONSISTENT_BASE + CONFIG_CONSISTENT_SIZE)
46#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
47
48/*
49 * This is the page table (2MB) covering uncached, DMA consistent allocations
50 */
51static DEFINE_SPINLOCK(consistent_lock);
52
53/*
54 * VM region handling support.
55 *
56 * This should become something generic, handling VM region allocations for
57 * vmalloc and similar (ioremap, module space, etc).
58 *
59 * I envisage vmalloc()'s supporting vm_struct becoming:
60 *
61 * struct vm_struct {
62 * struct vm_region region;
63 * unsigned long flags;
64 * struct page **pages;
65 * unsigned int nr_pages;
66 * unsigned long phys_addr;
67 * };
68 *
69 * get_vm_area() would then call vm_region_alloc with an appropriate
70 * struct vm_region head (eg):
71 *
72 * struct vm_region vmalloc_head = {
73 * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
74 * .vm_start = VMALLOC_START,
75 * .vm_end = VMALLOC_END,
76 * };
77 *
78 * However, vmalloc_head.vm_start is variable (typically, it is dependent on
79 * the amount of RAM found at boot time.) I would imagine that get_vm_area()
80 * would have to initialise this each time prior to calling vm_region_alloc().
81 */
82struct ppc_vm_region {
83 struct list_head vm_list;
84 unsigned long vm_start;
85 unsigned long vm_end;
86};
87
88static struct ppc_vm_region consistent_head = {
89 .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
90 .vm_start = CONSISTENT_BASE,
91 .vm_end = CONSISTENT_END,
92};
93
94static struct ppc_vm_region *
95ppc_vm_region_alloc(struct ppc_vm_region *head, size_t size, gfp_t gfp)
96{
97 unsigned long addr = head->vm_start, end = head->vm_end - size;
98 unsigned long flags;
99 struct ppc_vm_region *c, *new;
100
101 new = kmalloc(sizeof(struct ppc_vm_region), gfp);
102 if (!new)
103 goto out;
104
105 spin_lock_irqsave(&consistent_lock, flags);
106
107 list_for_each_entry(c, &head->vm_list, vm_list) {
108 if ((addr + size) < addr)
109 goto nospc;
110 if ((addr + size) <= c->vm_start)
111 goto found;
112 addr = c->vm_end;
113 if (addr > end)
114 goto nospc;
115 }
116
117 found:
118 /*
119 * Insert this entry _before_ the one we found.
120 */
121 list_add_tail(&new->vm_list, &c->vm_list);
122 new->vm_start = addr;
123 new->vm_end = addr + size;
124
125 spin_unlock_irqrestore(&consistent_lock, flags);
126 return new;
127
128 nospc:
129 spin_unlock_irqrestore(&consistent_lock, flags);
130 kfree(new);
131 out:
132 return NULL;
133}
134
135static struct ppc_vm_region *ppc_vm_region_find(struct ppc_vm_region *head, unsigned long addr)
136{
137 struct ppc_vm_region *c;
138
139 list_for_each_entry(c, &head->vm_list, vm_list) {
140 if (c->vm_start == addr)
141 goto out;
142 }
143 c = NULL;
144 out:
145 return c;
146}
147
148/*
149 * Allocate DMA-coherent memory space and return both the kernel remapped
150 * virtual and bus address for that space.
151 */
152void *
153__dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
154{
155 struct page *page;
156 struct ppc_vm_region *c;
157 unsigned long order;
158 u64 mask = ISA_DMA_THRESHOLD, limit;
159
160 if (dev) {
161 mask = dev->coherent_dma_mask;
162
163 /*
164 * Sanity check the DMA mask - it must be non-zero, and
165 * must be able to be satisfied by a DMA allocation.
166 */
167 if (mask == 0) {
168 dev_warn(dev, "coherent DMA mask is unset\n");
169 goto no_page;
170 }
171
172 if ((~mask) & ISA_DMA_THRESHOLD) {
173 dev_warn(dev, "coherent DMA mask %#llx is smaller "
174 "than system GFP_DMA mask %#llx\n",
175 mask, (unsigned long long)ISA_DMA_THRESHOLD);
176 goto no_page;
177 }
178 }
179
180
181 size = PAGE_ALIGN(size);
182 limit = (mask + 1) & ~mask;
183 if ((limit && size >= limit) ||
184 size >= (CONSISTENT_END - CONSISTENT_BASE)) {
185 printk(KERN_WARNING "coherent allocation too big (requested %#x mask %#Lx)\n",
186 size, mask);
187 return NULL;
188 }
189
190 order = get_order(size);
191
192 /* Might be useful if we ever have a real legacy DMA zone... */
193 if (mask != 0xffffffff)
194 gfp |= GFP_DMA;
195
196 page = alloc_pages(gfp, order);
197 if (!page)
198 goto no_page;
199
200 /*
201 * Invalidate any data that might be lurking in the
202 * kernel direct-mapped region for device DMA.
203 */
204 {
205 unsigned long kaddr = (unsigned long)page_address(page);
206 memset(page_address(page), 0, size);
207 flush_dcache_range(kaddr, kaddr + size);
208 }
209
210 /*
211 * Allocate a virtual address in the consistent mapping region.
212 */
213 c = ppc_vm_region_alloc(&consistent_head, size,
214 gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
215 if (c) {
216 unsigned long vaddr = c->vm_start;
217 struct page *end = page + (1 << order);
218
219 split_page(page, order);
220
221 /*
222 * Set the "dma handle"
223 */
224 *handle = page_to_phys(page);
225
226 do {
227 SetPageReserved(page);
228 map_page(vaddr, page_to_phys(page),
229 pgprot_noncached(PAGE_KERNEL));
230 page++;
231 vaddr += PAGE_SIZE;
232 } while (size -= PAGE_SIZE);
233
234 /*
235 * Free the otherwise unused pages.
236 */
237 while (page < end) {
238 __free_page(page);
239 page++;
240 }
241
242 return (void *)c->vm_start;
243 }
244
245 if (page)
246 __free_pages(page, order);
247 no_page:
248 return NULL;
249}
250EXPORT_SYMBOL(__dma_alloc_coherent);
251
252/*
253 * free a page as defined by the above mapping.
254 */
255void __dma_free_coherent(size_t size, void *vaddr)
256{
257 struct ppc_vm_region *c;
258 unsigned long flags, addr;
259
260 size = PAGE_ALIGN(size);
261
262 spin_lock_irqsave(&consistent_lock, flags);
263
264 c = ppc_vm_region_find(&consistent_head, (unsigned long)vaddr);
265 if (!c)
266 goto no_area;
267
268 if ((c->vm_end - c->vm_start) != size) {
269 printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
270 __func__, c->vm_end - c->vm_start, size);
271 dump_stack();
272 size = c->vm_end - c->vm_start;
273 }
274
275 addr = c->vm_start;
276 do {
277 pte_t *ptep;
278 unsigned long pfn;
279
280 ptep = pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(addr),
281 addr),
282 addr),
283 addr);
284 if (!pte_none(*ptep) && pte_present(*ptep)) {
285 pfn = pte_pfn(*ptep);
286 pte_clear(&init_mm, addr, ptep);
287 if (pfn_valid(pfn)) {
288 struct page *page = pfn_to_page(pfn);
289
290 ClearPageReserved(page);
291 __free_page(page);
292 }
293 }
294 addr += PAGE_SIZE;
295 } while (size -= PAGE_SIZE);
296
297 flush_tlb_kernel_range(c->vm_start, c->vm_end);
298
299 list_del(&c->vm_list);
300
301 spin_unlock_irqrestore(&consistent_lock, flags);
302
303 kfree(c);
304 return;
305
306 no_area:
307 spin_unlock_irqrestore(&consistent_lock, flags);
308 printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
309 __func__, vaddr);
310 dump_stack();
311}
312EXPORT_SYMBOL(__dma_free_coherent);
313
314/*
315 * make an area consistent.
316 */
317void __dma_sync(void *vaddr, size_t size, int direction)
318{
319 unsigned long start = (unsigned long)vaddr;
320 unsigned long end = start + size;
321
322 switch (direction) {
323 case DMA_NONE:
324 BUG();
325 case DMA_FROM_DEVICE:
326 /*
327 * invalidate only when cache-line aligned otherwise there is
328 * the potential for discarding uncommitted data from the cache
329 */
330 if ((start & (L1_CACHE_BYTES - 1)) || (size & (L1_CACHE_BYTES - 1)))
331 flush_dcache_range(start, end);
332 else
333 invalidate_dcache_range(start, end);
334 break;
335 case DMA_TO_DEVICE: /* writeback only */
336 clean_dcache_range(start, end);
337 break;
338 case DMA_BIDIRECTIONAL: /* writeback and invalidate */
339 flush_dcache_range(start, end);
340 break;
341 }
342}
343EXPORT_SYMBOL(__dma_sync);
344
345#ifdef CONFIG_HIGHMEM
346/*
347 * __dma_sync_page() implementation for systems using highmem.
348 * In this case, each page of a buffer must be kmapped/kunmapped
349 * in order to have a virtual address for __dma_sync(). This must
350 * not sleep so kmap_atomic()/kunmap_atomic() are used.
351 *
352 * Note: yes, it is possible and correct to have a buffer extend
353 * beyond the first page.
354 */
355static inline void __dma_sync_page_highmem(struct page *page,
356 unsigned long offset, size_t size, int direction)
357{
358 size_t seg_size = min((size_t)(PAGE_SIZE - offset), size);
359 size_t cur_size = seg_size;
360 unsigned long flags, start, seg_offset = offset;
361 int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/PAGE_SIZE;
362 int seg_nr = 0;
363
364 local_irq_save(flags);
365
366 do {
367 start = (unsigned long)kmap_atomic(page + seg_nr,
368 KM_PPC_SYNC_PAGE) + seg_offset;
369
370 /* Sync this buffer segment */
371 __dma_sync((void *)start, seg_size, direction);
372 kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
373 seg_nr++;
374
375 /* Calculate next buffer segment size */
376 seg_size = min((size_t)PAGE_SIZE, size - cur_size);
377
378 /* Add the segment size to our running total */
379 cur_size += seg_size;
380 seg_offset = 0;
381 } while (seg_nr < nr_segs);
382
383 local_irq_restore(flags);
384}
385#endif /* CONFIG_HIGHMEM */
386
387/*
388 * __dma_sync_page makes memory consistent. identical to __dma_sync, but
389 * takes a struct page instead of a virtual address
390 */
391void __dma_sync_page(struct page *page, unsigned long offset,
392 size_t size, int direction)
393{
394#ifdef CONFIG_HIGHMEM
395 __dma_sync_page_highmem(page, offset, size, direction);
396#else
397 unsigned long start = (unsigned long)page_address(page) + offset;
398 __dma_sync((void *)start, size, direction);
399#endif
400}
401EXPORT_SYMBOL(__dma_sync_page);
402
403/*
404 * Return the PFN for a given cpu virtual address returned by
405 * __dma_alloc_coherent. This is used by dma_mmap_coherent()
406 */
407unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr)
408{
409 /* This should always be populated, so we don't test every
410 * level. If that fails, we'll have a nice crash which
411 * will be as good as a BUG_ON()
412 */
413 pgd_t *pgd = pgd_offset_k(cpu_addr);
414 pud_t *pud = pud_offset(pgd, cpu_addr);
415 pmd_t *pmd = pmd_offset(pud, cpu_addr);
416 pte_t *ptep = pte_offset_kernel(pmd, cpu_addr);
417
418 if (pte_none(*ptep) || !pte_present(*ptep))
419 return 0;
420 return pte_pfn(*ptep);
421}