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1/*
2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
3 *
4 * Provide default implementations of the DMA mapping callbacks for
5 * directly mapped busses.
6 */
7
8#include <linux/device.h>
9#include <linux/dma-mapping.h>
10#include <linux/dma-debug.h>
11#include <linux/gfp.h>
12#include <linux/memblock.h>
13#include <linux/export.h>
14#include <linux/pci.h>
15#include <asm/vio.h>
16#include <asm/bug.h>
17#include <asm/machdep.h>
18#include <asm/swiotlb.h>
19#include <asm/iommu.h>
20
21/*
22 * Generic direct DMA implementation
23 *
24 * This implementation supports a per-device offset that can be applied if
25 * the address at which memory is visible to devices is not 0. Platform code
26 * can set archdata.dma_data to an unsigned long holding the offset. By
27 * default the offset is PCI_DRAM_OFFSET.
28 */
29
30static u64 __maybe_unused get_pfn_limit(struct device *dev)
31{
32 u64 pfn = (dev->coherent_dma_mask >> PAGE_SHIFT) + 1;
33 struct dev_archdata __maybe_unused *sd = &dev->archdata;
34
35#ifdef CONFIG_SWIOTLB
36 if (sd->max_direct_dma_addr && sd->dma_ops == &swiotlb_dma_ops)
37 pfn = min_t(u64, pfn, sd->max_direct_dma_addr >> PAGE_SHIFT);
38#endif
39
40 return pfn;
41}
42
43static int dma_direct_dma_supported(struct device *dev, u64 mask)
44{
45#ifdef CONFIG_PPC64
46 u64 limit = get_dma_offset(dev) + (memblock_end_of_DRAM() - 1);
47
48 /* Limit fits in the mask, we are good */
49 if (mask >= limit)
50 return 1;
51
52#ifdef CONFIG_FSL_SOC
53 /* Freescale gets another chance via ZONE_DMA/ZONE_DMA32, however
54 * that will have to be refined if/when they support iommus
55 */
56 return 1;
57#endif
58 /* Sorry ... */
59 return 0;
60#else
61 return 1;
62#endif
63}
64
65void *__dma_direct_alloc_coherent(struct device *dev, size_t size,
66 dma_addr_t *dma_handle, gfp_t flag,
67 unsigned long attrs)
68{
69 void *ret;
70#ifdef CONFIG_NOT_COHERENT_CACHE
71 ret = __dma_alloc_coherent(dev, size, dma_handle, flag);
72 if (ret == NULL)
73 return NULL;
74 *dma_handle += get_dma_offset(dev);
75 return ret;
76#else
77 struct page *page;
78 int node = dev_to_node(dev);
79#ifdef CONFIG_FSL_SOC
80 u64 pfn = get_pfn_limit(dev);
81 int zone;
82
83 /*
84 * This code should be OK on other platforms, but we have drivers that
85 * don't set coherent_dma_mask. As a workaround we just ifdef it. This
86 * whole routine needs some serious cleanup.
87 */
88
89 zone = dma_pfn_limit_to_zone(pfn);
90 if (zone < 0) {
91 dev_err(dev, "%s: No suitable zone for pfn %#llx\n",
92 __func__, pfn);
93 return NULL;
94 }
95
96 switch (zone) {
97 case ZONE_DMA:
98 flag |= GFP_DMA;
99 break;
100#ifdef CONFIG_ZONE_DMA32
101 case ZONE_DMA32:
102 flag |= GFP_DMA32;
103 break;
104#endif
105 };
106#endif /* CONFIG_FSL_SOC */
107
108 /* ignore region specifiers */
109 flag &= ~(__GFP_HIGHMEM);
110
111 page = alloc_pages_node(node, flag, get_order(size));
112 if (page == NULL)
113 return NULL;
114 ret = page_address(page);
115 memset(ret, 0, size);
116 *dma_handle = __pa(ret) + get_dma_offset(dev);
117
118 return ret;
119#endif
120}
121
122void __dma_direct_free_coherent(struct device *dev, size_t size,
123 void *vaddr, dma_addr_t dma_handle,
124 unsigned long attrs)
125{
126#ifdef CONFIG_NOT_COHERENT_CACHE
127 __dma_free_coherent(size, vaddr);
128#else
129 free_pages((unsigned long)vaddr, get_order(size));
130#endif
131}
132
133static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
134 dma_addr_t *dma_handle, gfp_t flag,
135 unsigned long attrs)
136{
137 struct iommu_table *iommu;
138
139 /* The coherent mask may be smaller than the real mask, check if
140 * we can really use the direct ops
141 */
142 if (dma_direct_dma_supported(dev, dev->coherent_dma_mask))
143 return __dma_direct_alloc_coherent(dev, size, dma_handle,
144 flag, attrs);
145
146 /* Ok we can't ... do we have an iommu ? If not, fail */
147 iommu = get_iommu_table_base(dev);
148 if (!iommu)
149 return NULL;
150
151 /* Try to use the iommu */
152 return iommu_alloc_coherent(dev, iommu, size, dma_handle,
153 dev->coherent_dma_mask, flag,
154 dev_to_node(dev));
155}
156
157static void dma_direct_free_coherent(struct device *dev, size_t size,
158 void *vaddr, dma_addr_t dma_handle,
159 unsigned long attrs)
160{
161 struct iommu_table *iommu;
162
163 /* See comments in dma_direct_alloc_coherent() */
164 if (dma_direct_dma_supported(dev, dev->coherent_dma_mask))
165 return __dma_direct_free_coherent(dev, size, vaddr, dma_handle,
166 attrs);
167 /* Maybe we used an iommu ... */
168 iommu = get_iommu_table_base(dev);
169
170 /* If we hit that we should have never allocated in the first
171 * place so how come we are freeing ?
172 */
173 if (WARN_ON(!iommu))
174 return;
175 iommu_free_coherent(iommu, size, vaddr, dma_handle);
176}
177
178int dma_direct_mmap_coherent(struct device *dev, struct vm_area_struct *vma,
179 void *cpu_addr, dma_addr_t handle, size_t size,
180 unsigned long attrs)
181{
182 unsigned long pfn;
183
184#ifdef CONFIG_NOT_COHERENT_CACHE
185 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
186 pfn = __dma_get_coherent_pfn((unsigned long)cpu_addr);
187#else
188 pfn = page_to_pfn(virt_to_page(cpu_addr));
189#endif
190 return remap_pfn_range(vma, vma->vm_start,
191 pfn + vma->vm_pgoff,
192 vma->vm_end - vma->vm_start,
193 vma->vm_page_prot);
194}
195
196static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
197 int nents, enum dma_data_direction direction,
198 unsigned long attrs)
199{
200 struct scatterlist *sg;
201 int i;
202
203 for_each_sg(sgl, sg, nents, i) {
204 sg->dma_address = sg_phys(sg) + get_dma_offset(dev);
205 sg->dma_length = sg->length;
206
207 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
208 continue;
209
210 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
211 }
212
213 return nents;
214}
215
216static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
217 int nents, enum dma_data_direction direction,
218 unsigned long attrs)
219{
220}
221
222static u64 dma_direct_get_required_mask(struct device *dev)
223{
224 u64 end, mask;
225
226 end = memblock_end_of_DRAM() + get_dma_offset(dev);
227
228 mask = 1ULL << (fls64(end) - 1);
229 mask += mask - 1;
230
231 return mask;
232}
233
234static inline dma_addr_t dma_direct_map_page(struct device *dev,
235 struct page *page,
236 unsigned long offset,
237 size_t size,
238 enum dma_data_direction dir,
239 unsigned long attrs)
240{
241 BUG_ON(dir == DMA_NONE);
242
243 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
244 __dma_sync_page(page, offset, size, dir);
245
246 return page_to_phys(page) + offset + get_dma_offset(dev);
247}
248
249static inline void dma_direct_unmap_page(struct device *dev,
250 dma_addr_t dma_address,
251 size_t size,
252 enum dma_data_direction direction,
253 unsigned long attrs)
254{
255}
256
257#ifdef CONFIG_NOT_COHERENT_CACHE
258static inline void dma_direct_sync_sg(struct device *dev,
259 struct scatterlist *sgl, int nents,
260 enum dma_data_direction direction)
261{
262 struct scatterlist *sg;
263 int i;
264
265 for_each_sg(sgl, sg, nents, i)
266 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
267}
268
269static inline void dma_direct_sync_single(struct device *dev,
270 dma_addr_t dma_handle, size_t size,
271 enum dma_data_direction direction)
272{
273 __dma_sync(bus_to_virt(dma_handle), size, direction);
274}
275#endif
276
277struct dma_map_ops dma_direct_ops = {
278 .alloc = dma_direct_alloc_coherent,
279 .free = dma_direct_free_coherent,
280 .mmap = dma_direct_mmap_coherent,
281 .map_sg = dma_direct_map_sg,
282 .unmap_sg = dma_direct_unmap_sg,
283 .dma_supported = dma_direct_dma_supported,
284 .map_page = dma_direct_map_page,
285 .unmap_page = dma_direct_unmap_page,
286 .get_required_mask = dma_direct_get_required_mask,
287#ifdef CONFIG_NOT_COHERENT_CACHE
288 .sync_single_for_cpu = dma_direct_sync_single,
289 .sync_single_for_device = dma_direct_sync_single,
290 .sync_sg_for_cpu = dma_direct_sync_sg,
291 .sync_sg_for_device = dma_direct_sync_sg,
292#endif
293};
294EXPORT_SYMBOL(dma_direct_ops);
295
296int dma_set_coherent_mask(struct device *dev, u64 mask)
297{
298 if (!dma_supported(dev, mask)) {
299 /*
300 * We need to special case the direct DMA ops which can
301 * support a fallback for coherent allocations. There
302 * is no dma_op->set_coherent_mask() so we have to do
303 * things the hard way:
304 */
305 if (get_dma_ops(dev) != &dma_direct_ops ||
306 get_iommu_table_base(dev) == NULL ||
307 !dma_iommu_dma_supported(dev, mask))
308 return -EIO;
309 }
310 dev->coherent_dma_mask = mask;
311 return 0;
312}
313EXPORT_SYMBOL(dma_set_coherent_mask);
314
315#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
316
317int __dma_set_mask(struct device *dev, u64 dma_mask)
318{
319 struct dma_map_ops *dma_ops = get_dma_ops(dev);
320
321 if ((dma_ops != NULL) && (dma_ops->set_dma_mask != NULL))
322 return dma_ops->set_dma_mask(dev, dma_mask);
323 if (!dev->dma_mask || !dma_supported(dev, dma_mask))
324 return -EIO;
325 *dev->dma_mask = dma_mask;
326 return 0;
327}
328
329int dma_set_mask(struct device *dev, u64 dma_mask)
330{
331 if (ppc_md.dma_set_mask)
332 return ppc_md.dma_set_mask(dev, dma_mask);
333
334 if (dev_is_pci(dev)) {
335 struct pci_dev *pdev = to_pci_dev(dev);
336 struct pci_controller *phb = pci_bus_to_host(pdev->bus);
337 if (phb->controller_ops.dma_set_mask)
338 return phb->controller_ops.dma_set_mask(pdev, dma_mask);
339 }
340
341 return __dma_set_mask(dev, dma_mask);
342}
343EXPORT_SYMBOL(dma_set_mask);
344
345u64 __dma_get_required_mask(struct device *dev)
346{
347 struct dma_map_ops *dma_ops = get_dma_ops(dev);
348
349 if (unlikely(dma_ops == NULL))
350 return 0;
351
352 if (dma_ops->get_required_mask)
353 return dma_ops->get_required_mask(dev);
354
355 return DMA_BIT_MASK(8 * sizeof(dma_addr_t));
356}
357
358u64 dma_get_required_mask(struct device *dev)
359{
360 if (ppc_md.dma_get_required_mask)
361 return ppc_md.dma_get_required_mask(dev);
362
363 if (dev_is_pci(dev)) {
364 struct pci_dev *pdev = to_pci_dev(dev);
365 struct pci_controller *phb = pci_bus_to_host(pdev->bus);
366 if (phb->controller_ops.dma_get_required_mask)
367 return phb->controller_ops.dma_get_required_mask(pdev);
368 }
369
370 return __dma_get_required_mask(dev);
371}
372EXPORT_SYMBOL_GPL(dma_get_required_mask);
373
374static int __init dma_init(void)
375{
376 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
377#ifdef CONFIG_PCI
378 dma_debug_add_bus(&pci_bus_type);
379#endif
380#ifdef CONFIG_IBMVIO
381 dma_debug_add_bus(&vio_bus_type);
382#endif
383
384 return 0;
385}
386fs_initcall(dma_init);
387