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fa8dda1e WH |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Driver for FPGA Accelerated Function Unit (AFU) DMA Region Management | |
4 | * | |
5 | * Copyright (C) 2017-2018 Intel Corporation, Inc. | |
6 | * | |
7 | * Authors: | |
8 | * Wu Hao <hao.wu@intel.com> | |
9 | * Xiao Guangrong <guangrong.xiao@linux.intel.com> | |
10 | */ | |
11 | ||
12 | #include <linux/dma-mapping.h> | |
13 | #include <linux/sched/signal.h> | |
14 | #include <linux/uaccess.h> | |
79eb597c | 15 | #include <linux/mm.h> |
fa8dda1e WH |
16 | |
17 | #include "dfl-afu.h" | |
18 | ||
fa8dda1e WH |
19 | void afu_dma_region_init(struct dfl_feature_platform_data *pdata) |
20 | { | |
21 | struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata); | |
22 | ||
23 | afu->dma_regions = RB_ROOT; | |
24 | } | |
25 | ||
fa8dda1e WH |
26 | /** |
27 | * afu_dma_pin_pages - pin pages of given dma memory region | |
28 | * @pdata: feature device platform data | |
29 | * @region: dma memory region to be pinned | |
30 | * | |
31 | * Pin all the pages of given dfl_afu_dma_region. | |
32 | * Return 0 for success or negative error code. | |
33 | */ | |
34 | static int afu_dma_pin_pages(struct dfl_feature_platform_data *pdata, | |
35 | struct dfl_afu_dma_region *region) | |
36 | { | |
37 | int npages = region->length >> PAGE_SHIFT; | |
38 | struct device *dev = &pdata->dev->dev; | |
39 | int ret, pinned; | |
40 | ||
79eb597c | 41 | ret = account_locked_vm(current->mm, npages, true); |
fa8dda1e WH |
42 | if (ret) |
43 | return ret; | |
44 | ||
45 | region->pages = kcalloc(npages, sizeof(struct page *), GFP_KERNEL); | |
46 | if (!region->pages) { | |
47 | ret = -ENOMEM; | |
48 | goto unlock_vm; | |
49 | } | |
50 | ||
55dc9b87 | 51 | pinned = pin_user_pages_fast(region->user_addr, npages, FOLL_WRITE, |
fa8dda1e WH |
52 | region->pages); |
53 | if (pinned < 0) { | |
54 | ret = pinned; | |
c9d7e3da | 55 | goto free_pages; |
fa8dda1e WH |
56 | } else if (pinned != npages) { |
57 | ret = -EFAULT; | |
55dc9b87 | 58 | goto unpin_pages; |
fa8dda1e WH |
59 | } |
60 | ||
61 | dev_dbg(dev, "%d pages pinned\n", pinned); | |
62 | ||
63 | return 0; | |
64 | ||
55dc9b87 JH |
65 | unpin_pages: |
66 | unpin_user_pages(region->pages, pinned); | |
fa8dda1e WH |
67 | free_pages: |
68 | kfree(region->pages); | |
69 | unlock_vm: | |
79eb597c | 70 | account_locked_vm(current->mm, npages, false); |
fa8dda1e WH |
71 | return ret; |
72 | } | |
73 | ||
74 | /** | |
75 | * afu_dma_unpin_pages - unpin pages of given dma memory region | |
76 | * @pdata: feature device platform data | |
77 | * @region: dma memory region to be unpinned | |
78 | * | |
79 | * Unpin all the pages of given dfl_afu_dma_region. | |
80 | * Return 0 for success or negative error code. | |
81 | */ | |
82 | static void afu_dma_unpin_pages(struct dfl_feature_platform_data *pdata, | |
83 | struct dfl_afu_dma_region *region) | |
84 | { | |
85 | long npages = region->length >> PAGE_SHIFT; | |
86 | struct device *dev = &pdata->dev->dev; | |
87 | ||
55dc9b87 | 88 | unpin_user_pages(region->pages, npages); |
fa8dda1e | 89 | kfree(region->pages); |
79eb597c | 90 | account_locked_vm(current->mm, npages, false); |
fa8dda1e WH |
91 | |
92 | dev_dbg(dev, "%ld pages unpinned\n", npages); | |
93 | } | |
94 | ||
95 | /** | |
96 | * afu_dma_check_continuous_pages - check if pages are continuous | |
97 | * @region: dma memory region | |
98 | * | |
99 | * Return true if pages of given dma memory region have continuous physical | |
100 | * address, otherwise return false. | |
101 | */ | |
102 | static bool afu_dma_check_continuous_pages(struct dfl_afu_dma_region *region) | |
103 | { | |
104 | int npages = region->length >> PAGE_SHIFT; | |
105 | int i; | |
106 | ||
107 | for (i = 0; i < npages - 1; i++) | |
108 | if (page_to_pfn(region->pages[i]) + 1 != | |
109 | page_to_pfn(region->pages[i + 1])) | |
110 | return false; | |
111 | ||
112 | return true; | |
113 | } | |
114 | ||
115 | /** | |
116 | * dma_region_check_iova - check if memory area is fully contained in the region | |
117 | * @region: dma memory region | |
118 | * @iova: address of the dma memory area | |
119 | * @size: size of the dma memory area | |
120 | * | |
121 | * Compare the dma memory area defined by @iova and @size with given dma region. | |
122 | * Return true if memory area is fully contained in the region, otherwise false. | |
123 | */ | |
124 | static bool dma_region_check_iova(struct dfl_afu_dma_region *region, | |
125 | u64 iova, u64 size) | |
126 | { | |
127 | if (!size && region->iova != iova) | |
128 | return false; | |
129 | ||
130 | return (region->iova <= iova) && | |
131 | (region->length + region->iova >= iova + size); | |
132 | } | |
133 | ||
134 | /** | |
135 | * afu_dma_region_add - add given dma region to rbtree | |
136 | * @pdata: feature device platform data | |
137 | * @region: dma region to be added | |
138 | * | |
139 | * Return 0 for success, -EEXIST if dma region has already been added. | |
140 | * | |
141 | * Needs to be called with pdata->lock heold. | |
142 | */ | |
143 | static int afu_dma_region_add(struct dfl_feature_platform_data *pdata, | |
144 | struct dfl_afu_dma_region *region) | |
145 | { | |
146 | struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata); | |
147 | struct rb_node **new, *parent = NULL; | |
148 | ||
149 | dev_dbg(&pdata->dev->dev, "add region (iova = %llx)\n", | |
150 | (unsigned long long)region->iova); | |
151 | ||
152 | new = &afu->dma_regions.rb_node; | |
153 | ||
154 | while (*new) { | |
155 | struct dfl_afu_dma_region *this; | |
156 | ||
157 | this = container_of(*new, struct dfl_afu_dma_region, node); | |
158 | ||
159 | parent = *new; | |
160 | ||
161 | if (dma_region_check_iova(this, region->iova, region->length)) | |
162 | return -EEXIST; | |
163 | ||
164 | if (region->iova < this->iova) | |
165 | new = &((*new)->rb_left); | |
166 | else if (region->iova > this->iova) | |
167 | new = &((*new)->rb_right); | |
168 | else | |
169 | return -EEXIST; | |
170 | } | |
171 | ||
172 | rb_link_node(®ion->node, parent, new); | |
173 | rb_insert_color(®ion->node, &afu->dma_regions); | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | /** | |
179 | * afu_dma_region_remove - remove given dma region from rbtree | |
180 | * @pdata: feature device platform data | |
181 | * @region: dma region to be removed | |
182 | * | |
183 | * Needs to be called with pdata->lock heold. | |
184 | */ | |
185 | static void afu_dma_region_remove(struct dfl_feature_platform_data *pdata, | |
186 | struct dfl_afu_dma_region *region) | |
187 | { | |
188 | struct dfl_afu *afu; | |
189 | ||
190 | dev_dbg(&pdata->dev->dev, "del region (iova = %llx)\n", | |
191 | (unsigned long long)region->iova); | |
192 | ||
193 | afu = dfl_fpga_pdata_get_private(pdata); | |
194 | rb_erase(®ion->node, &afu->dma_regions); | |
195 | } | |
196 | ||
197 | /** | |
198 | * afu_dma_region_destroy - destroy all regions in rbtree | |
199 | * @pdata: feature device platform data | |
200 | * | |
201 | * Needs to be called with pdata->lock heold. | |
202 | */ | |
203 | void afu_dma_region_destroy(struct dfl_feature_platform_data *pdata) | |
204 | { | |
205 | struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata); | |
206 | struct rb_node *node = rb_first(&afu->dma_regions); | |
207 | struct dfl_afu_dma_region *region; | |
208 | ||
209 | while (node) { | |
210 | region = container_of(node, struct dfl_afu_dma_region, node); | |
211 | ||
212 | dev_dbg(&pdata->dev->dev, "del region (iova = %llx)\n", | |
213 | (unsigned long long)region->iova); | |
214 | ||
215 | rb_erase(node, &afu->dma_regions); | |
216 | ||
217 | if (region->iova) | |
218 | dma_unmap_page(dfl_fpga_pdata_to_parent(pdata), | |
219 | region->iova, region->length, | |
220 | DMA_BIDIRECTIONAL); | |
221 | ||
222 | if (region->pages) | |
223 | afu_dma_unpin_pages(pdata, region); | |
224 | ||
225 | node = rb_next(node); | |
226 | kfree(region); | |
227 | } | |
228 | } | |
229 | ||
230 | /** | |
231 | * afu_dma_region_find - find the dma region from rbtree based on iova and size | |
232 | * @pdata: feature device platform data | |
233 | * @iova: address of the dma memory area | |
234 | * @size: size of the dma memory area | |
235 | * | |
236 | * It finds the dma region from the rbtree based on @iova and @size: | |
237 | * - if @size == 0, it finds the dma region which starts from @iova | |
238 | * - otherwise, it finds the dma region which fully contains | |
239 | * [@iova, @iova+size) | |
240 | * If nothing is matched returns NULL. | |
241 | * | |
242 | * Needs to be called with pdata->lock held. | |
243 | */ | |
244 | struct dfl_afu_dma_region * | |
245 | afu_dma_region_find(struct dfl_feature_platform_data *pdata, u64 iova, u64 size) | |
246 | { | |
247 | struct dfl_afu *afu = dfl_fpga_pdata_get_private(pdata); | |
248 | struct rb_node *node = afu->dma_regions.rb_node; | |
249 | struct device *dev = &pdata->dev->dev; | |
250 | ||
251 | while (node) { | |
252 | struct dfl_afu_dma_region *region; | |
253 | ||
254 | region = container_of(node, struct dfl_afu_dma_region, node); | |
255 | ||
256 | if (dma_region_check_iova(region, iova, size)) { | |
257 | dev_dbg(dev, "find region (iova = %llx)\n", | |
258 | (unsigned long long)region->iova); | |
259 | return region; | |
260 | } | |
261 | ||
262 | if (iova < region->iova) | |
263 | node = node->rb_left; | |
264 | else if (iova > region->iova) | |
265 | node = node->rb_right; | |
266 | else | |
267 | /* the iova region is not fully covered. */ | |
268 | break; | |
269 | } | |
270 | ||
271 | dev_dbg(dev, "region with iova %llx and size %llx is not found\n", | |
272 | (unsigned long long)iova, (unsigned long long)size); | |
273 | ||
274 | return NULL; | |
275 | } | |
276 | ||
277 | /** | |
278 | * afu_dma_region_find_iova - find the dma region from rbtree by iova | |
279 | * @pdata: feature device platform data | |
280 | * @iova: address of the dma region | |
281 | * | |
282 | * Needs to be called with pdata->lock held. | |
283 | */ | |
284 | static struct dfl_afu_dma_region * | |
285 | afu_dma_region_find_iova(struct dfl_feature_platform_data *pdata, u64 iova) | |
286 | { | |
287 | return afu_dma_region_find(pdata, iova, 0); | |
288 | } | |
289 | ||
290 | /** | |
291 | * afu_dma_map_region - map memory region for dma | |
292 | * @pdata: feature device platform data | |
293 | * @user_addr: address of the memory region | |
294 | * @length: size of the memory region | |
295 | * @iova: pointer of iova address | |
296 | * | |
297 | * Map memory region defined by @user_addr and @length, and return dma address | |
298 | * of the memory region via @iova. | |
299 | * Return 0 for success, otherwise error code. | |
300 | */ | |
301 | int afu_dma_map_region(struct dfl_feature_platform_data *pdata, | |
302 | u64 user_addr, u64 length, u64 *iova) | |
303 | { | |
304 | struct dfl_afu_dma_region *region; | |
305 | int ret; | |
306 | ||
307 | /* | |
308 | * Check Inputs, only accept page-aligned user memory region with | |
309 | * valid length. | |
310 | */ | |
311 | if (!PAGE_ALIGNED(user_addr) || !PAGE_ALIGNED(length) || !length) | |
312 | return -EINVAL; | |
313 | ||
314 | /* Check overflow */ | |
315 | if (user_addr + length < user_addr) | |
316 | return -EINVAL; | |
317 | ||
fa8dda1e WH |
318 | region = kzalloc(sizeof(*region), GFP_KERNEL); |
319 | if (!region) | |
320 | return -ENOMEM; | |
321 | ||
322 | region->user_addr = user_addr; | |
323 | region->length = length; | |
324 | ||
325 | /* Pin the user memory region */ | |
326 | ret = afu_dma_pin_pages(pdata, region); | |
327 | if (ret) { | |
328 | dev_err(&pdata->dev->dev, "failed to pin memory region\n"); | |
329 | goto free_region; | |
330 | } | |
331 | ||
332 | /* Only accept continuous pages, return error else */ | |
333 | if (!afu_dma_check_continuous_pages(region)) { | |
334 | dev_err(&pdata->dev->dev, "pages are not continuous\n"); | |
335 | ret = -EINVAL; | |
336 | goto unpin_pages; | |
337 | } | |
338 | ||
339 | /* As pages are continuous then start to do DMA mapping */ | |
340 | region->iova = dma_map_page(dfl_fpga_pdata_to_parent(pdata), | |
341 | region->pages[0], 0, | |
342 | region->length, | |
343 | DMA_BIDIRECTIONAL); | |
13069847 | 344 | if (dma_mapping_error(dfl_fpga_pdata_to_parent(pdata), region->iova)) { |
fa8dda1e WH |
345 | dev_err(&pdata->dev->dev, "failed to map for dma\n"); |
346 | ret = -EFAULT; | |
347 | goto unpin_pages; | |
348 | } | |
349 | ||
350 | *iova = region->iova; | |
351 | ||
352 | mutex_lock(&pdata->lock); | |
353 | ret = afu_dma_region_add(pdata, region); | |
354 | mutex_unlock(&pdata->lock); | |
355 | if (ret) { | |
356 | dev_err(&pdata->dev->dev, "failed to add dma region\n"); | |
357 | goto unmap_dma; | |
358 | } | |
359 | ||
360 | return 0; | |
361 | ||
362 | unmap_dma: | |
363 | dma_unmap_page(dfl_fpga_pdata_to_parent(pdata), | |
364 | region->iova, region->length, DMA_BIDIRECTIONAL); | |
365 | unpin_pages: | |
366 | afu_dma_unpin_pages(pdata, region); | |
367 | free_region: | |
368 | kfree(region); | |
369 | return ret; | |
370 | } | |
371 | ||
372 | /** | |
373 | * afu_dma_unmap_region - unmap dma memory region | |
374 | * @pdata: feature device platform data | |
375 | * @iova: dma address of the region | |
376 | * | |
377 | * Unmap dma memory region based on @iova. | |
378 | * Return 0 for success, otherwise error code. | |
379 | */ | |
380 | int afu_dma_unmap_region(struct dfl_feature_platform_data *pdata, u64 iova) | |
381 | { | |
382 | struct dfl_afu_dma_region *region; | |
383 | ||
384 | mutex_lock(&pdata->lock); | |
385 | region = afu_dma_region_find_iova(pdata, iova); | |
386 | if (!region) { | |
387 | mutex_unlock(&pdata->lock); | |
388 | return -EINVAL; | |
389 | } | |
390 | ||
391 | if (region->in_use) { | |
392 | mutex_unlock(&pdata->lock); | |
393 | return -EBUSY; | |
394 | } | |
395 | ||
396 | afu_dma_region_remove(pdata, region); | |
397 | mutex_unlock(&pdata->lock); | |
398 | ||
399 | dma_unmap_page(dfl_fpga_pdata_to_parent(pdata), | |
400 | region->iova, region->length, DMA_BIDIRECTIONAL); | |
401 | afu_dma_unpin_pages(pdata, region); | |
402 | kfree(region); | |
403 | ||
404 | return 0; | |
405 | } |