1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * DMABUF CMA heap exporter 4 * 5 * Copyright (C) 2012, 2019, 2020 Linaro Ltd. 6 * Author: <benjamin.gaignard@linaro.org> for ST-Ericsson. 7 * 8 * Also utilizing parts of Andrew Davis' SRAM heap: 9 * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/ 10 * Andrew F. Davis <afd@ti.com> 11 */ 12 #include <linux/cma.h> 13 #include <linux/dma-buf.h> 14 #include <linux/dma-heap.h> 15 #include <linux/dma-map-ops.h> 16 #include <linux/err.h> 17 #include <linux/highmem.h> 18 #include <linux/io.h> 19 #include <linux/mm.h> 20 #include <linux/module.h> 21 #include <linux/scatterlist.h> 22 #include <linux/slab.h> 23 #include <linux/vmalloc.h> 24 25 26 struct cma_heap { 27 struct dma_heap *heap; 28 struct cma *cma; 29 }; 30 31 struct cma_heap_buffer { 32 struct cma_heap *heap; 33 struct list_head attachments; 34 struct mutex lock; 35 unsigned long len; 36 struct page *cma_pages; 37 struct page **pages; 38 pgoff_t pagecount; 39 int vmap_cnt; 40 void *vaddr; 41 }; 42 43 struct dma_heap_attachment { 44 struct device *dev; 45 struct sg_table table; 46 struct list_head list; 47 bool mapped; 48 }; 49 50 static int cma_heap_attach(struct dma_buf *dmabuf, 51 struct dma_buf_attachment *attachment) 52 { 53 struct cma_heap_buffer *buffer = dmabuf->priv; 54 struct dma_heap_attachment *a; 55 int ret; 56 57 a = kzalloc(sizeof(*a), GFP_KERNEL); 58 if (!a) 59 return -ENOMEM; 60 61 ret = sg_alloc_table_from_pages(&a->table, buffer->pages, 62 buffer->pagecount, 0, 63 buffer->pagecount << PAGE_SHIFT, 64 GFP_KERNEL); 65 if (ret) { 66 kfree(a); 67 return ret; 68 } 69 70 a->dev = attachment->dev; 71 INIT_LIST_HEAD(&a->list); 72 a->mapped = false; 73 74 attachment->priv = a; 75 76 mutex_lock(&buffer->lock); 77 list_add(&a->list, &buffer->attachments); 78 mutex_unlock(&buffer->lock); 79 80 return 0; 81 } 82 83 static void cma_heap_detach(struct dma_buf *dmabuf, 84 struct dma_buf_attachment *attachment) 85 { 86 struct cma_heap_buffer *buffer = dmabuf->priv; 87 struct dma_heap_attachment *a = attachment->priv; 88 89 mutex_lock(&buffer->lock); 90 list_del(&a->list); 91 mutex_unlock(&buffer->lock); 92 93 sg_free_table(&a->table); 94 kfree(a); 95 } 96 97 static struct sg_table *cma_heap_map_dma_buf(struct dma_buf_attachment *attachment, 98 enum dma_data_direction direction) 99 { 100 struct dma_heap_attachment *a = attachment->priv; 101 struct sg_table *table = &a->table; 102 int ret; 103 104 ret = dma_map_sgtable(attachment->dev, table, direction, 0); 105 if (ret) 106 return ERR_PTR(-ENOMEM); 107 a->mapped = true; 108 return table; 109 } 110 111 static void cma_heap_unmap_dma_buf(struct dma_buf_attachment *attachment, 112 struct sg_table *table, 113 enum dma_data_direction direction) 114 { 115 struct dma_heap_attachment *a = attachment->priv; 116 117 a->mapped = false; 118 dma_unmap_sgtable(attachment->dev, table, direction, 0); 119 } 120 121 static int cma_heap_dma_buf_begin_cpu_access(struct dma_buf *dmabuf, 122 enum dma_data_direction direction) 123 { 124 struct cma_heap_buffer *buffer = dmabuf->priv; 125 struct dma_heap_attachment *a; 126 127 mutex_lock(&buffer->lock); 128 129 if (buffer->vmap_cnt) 130 invalidate_kernel_vmap_range(buffer->vaddr, buffer->len); 131 132 list_for_each_entry(a, &buffer->attachments, list) { 133 if (!a->mapped) 134 continue; 135 dma_sync_sgtable_for_cpu(a->dev, &a->table, direction); 136 } 137 mutex_unlock(&buffer->lock); 138 139 return 0; 140 } 141 142 static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf, 143 enum dma_data_direction direction) 144 { 145 struct cma_heap_buffer *buffer = dmabuf->priv; 146 struct dma_heap_attachment *a; 147 148 mutex_lock(&buffer->lock); 149 150 if (buffer->vmap_cnt) 151 flush_kernel_vmap_range(buffer->vaddr, buffer->len); 152 153 list_for_each_entry(a, &buffer->attachments, list) { 154 if (!a->mapped) 155 continue; 156 dma_sync_sgtable_for_device(a->dev, &a->table, direction); 157 } 158 mutex_unlock(&buffer->lock); 159 160 return 0; 161 } 162 163 static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf) 164 { 165 struct vm_area_struct *vma = vmf->vma; 166 struct cma_heap_buffer *buffer = vma->vm_private_data; 167 168 if (vmf->pgoff > buffer->pagecount) 169 return VM_FAULT_SIGBUS; 170 171 vmf->page = buffer->pages[vmf->pgoff]; 172 get_page(vmf->page); 173 174 return 0; 175 } 176 177 static const struct vm_operations_struct dma_heap_vm_ops = { 178 .fault = cma_heap_vm_fault, 179 }; 180 181 static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) 182 { 183 struct cma_heap_buffer *buffer = dmabuf->priv; 184 185 if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0) 186 return -EINVAL; 187 188 vma->vm_ops = &dma_heap_vm_ops; 189 vma->vm_private_data = buffer; 190 191 return 0; 192 } 193 194 static void *cma_heap_do_vmap(struct cma_heap_buffer *buffer) 195 { 196 void *vaddr; 197 198 vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL); 199 if (!vaddr) 200 return ERR_PTR(-ENOMEM); 201 202 return vaddr; 203 } 204 205 static int cma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map) 206 { 207 struct cma_heap_buffer *buffer = dmabuf->priv; 208 void *vaddr; 209 int ret = 0; 210 211 mutex_lock(&buffer->lock); 212 if (buffer->vmap_cnt) { 213 buffer->vmap_cnt++; 214 iosys_map_set_vaddr(map, buffer->vaddr); 215 goto out; 216 } 217 218 vaddr = cma_heap_do_vmap(buffer); 219 if (IS_ERR(vaddr)) { 220 ret = PTR_ERR(vaddr); 221 goto out; 222 } 223 buffer->vaddr = vaddr; 224 buffer->vmap_cnt++; 225 iosys_map_set_vaddr(map, buffer->vaddr); 226 out: 227 mutex_unlock(&buffer->lock); 228 229 return ret; 230 } 231 232 static void cma_heap_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) 233 { 234 struct cma_heap_buffer *buffer = dmabuf->priv; 235 236 mutex_lock(&buffer->lock); 237 if (!--buffer->vmap_cnt) { 238 vunmap(buffer->vaddr); 239 buffer->vaddr = NULL; 240 } 241 mutex_unlock(&buffer->lock); 242 iosys_map_clear(map); 243 } 244 245 static void cma_heap_dma_buf_release(struct dma_buf *dmabuf) 246 { 247 struct cma_heap_buffer *buffer = dmabuf->priv; 248 struct cma_heap *cma_heap = buffer->heap; 249 250 if (buffer->vmap_cnt > 0) { 251 WARN(1, "%s: buffer still mapped in the kernel\n", __func__); 252 vunmap(buffer->vaddr); 253 buffer->vaddr = NULL; 254 } 255 256 /* free page list */ 257 kfree(buffer->pages); 258 /* release memory */ 259 cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount); 260 kfree(buffer); 261 } 262 263 static const struct dma_buf_ops cma_heap_buf_ops = { 264 .attach = cma_heap_attach, 265 .detach = cma_heap_detach, 266 .map_dma_buf = cma_heap_map_dma_buf, 267 .unmap_dma_buf = cma_heap_unmap_dma_buf, 268 .begin_cpu_access = cma_heap_dma_buf_begin_cpu_access, 269 .end_cpu_access = cma_heap_dma_buf_end_cpu_access, 270 .mmap = cma_heap_mmap, 271 .vmap = cma_heap_vmap, 272 .vunmap = cma_heap_vunmap, 273 .release = cma_heap_dma_buf_release, 274 }; 275 276 static struct dma_buf *cma_heap_allocate(struct dma_heap *heap, 277 unsigned long len, 278 unsigned long fd_flags, 279 unsigned long heap_flags) 280 { 281 struct cma_heap *cma_heap = dma_heap_get_drvdata(heap); 282 struct cma_heap_buffer *buffer; 283 DEFINE_DMA_BUF_EXPORT_INFO(exp_info); 284 size_t size = PAGE_ALIGN(len); 285 pgoff_t pagecount = size >> PAGE_SHIFT; 286 unsigned long align = get_order(size); 287 struct page *cma_pages; 288 struct dma_buf *dmabuf; 289 int ret = -ENOMEM; 290 pgoff_t pg; 291 292 buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); 293 if (!buffer) 294 return ERR_PTR(-ENOMEM); 295 296 INIT_LIST_HEAD(&buffer->attachments); 297 mutex_init(&buffer->lock); 298 buffer->len = size; 299 300 if (align > CONFIG_CMA_ALIGNMENT) 301 align = CONFIG_CMA_ALIGNMENT; 302 303 cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false); 304 if (!cma_pages) 305 goto free_buffer; 306 307 /* Clear the cma pages */ 308 if (PageHighMem(cma_pages)) { 309 unsigned long nr_clear_pages = pagecount; 310 struct page *page = cma_pages; 311 312 while (nr_clear_pages > 0) { 313 void *vaddr = kmap_atomic(page); 314 315 memset(vaddr, 0, PAGE_SIZE); 316 kunmap_atomic(vaddr); 317 /* 318 * Avoid wasting time zeroing memory if the process 319 * has been killed by by SIGKILL 320 */ 321 if (fatal_signal_pending(current)) 322 goto free_cma; 323 page++; 324 nr_clear_pages--; 325 } 326 } else { 327 memset(page_address(cma_pages), 0, size); 328 } 329 330 buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), GFP_KERNEL); 331 if (!buffer->pages) { 332 ret = -ENOMEM; 333 goto free_cma; 334 } 335 336 for (pg = 0; pg < pagecount; pg++) 337 buffer->pages[pg] = &cma_pages[pg]; 338 339 buffer->cma_pages = cma_pages; 340 buffer->heap = cma_heap; 341 buffer->pagecount = pagecount; 342 343 /* create the dmabuf */ 344 exp_info.exp_name = dma_heap_get_name(heap); 345 exp_info.ops = &cma_heap_buf_ops; 346 exp_info.size = buffer->len; 347 exp_info.flags = fd_flags; 348 exp_info.priv = buffer; 349 dmabuf = dma_buf_export(&exp_info); 350 if (IS_ERR(dmabuf)) { 351 ret = PTR_ERR(dmabuf); 352 goto free_pages; 353 } 354 return dmabuf; 355 356 free_pages: 357 kfree(buffer->pages); 358 free_cma: 359 cma_release(cma_heap->cma, cma_pages, pagecount); 360 free_buffer: 361 kfree(buffer); 362 363 return ERR_PTR(ret); 364 } 365 366 static const struct dma_heap_ops cma_heap_ops = { 367 .allocate = cma_heap_allocate, 368 }; 369 370 static int __add_cma_heap(struct cma *cma, void *data) 371 { 372 struct cma_heap *cma_heap; 373 struct dma_heap_export_info exp_info; 374 375 cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL); 376 if (!cma_heap) 377 return -ENOMEM; 378 cma_heap->cma = cma; 379 380 exp_info.name = cma_get_name(cma); 381 exp_info.ops = &cma_heap_ops; 382 exp_info.priv = cma_heap; 383 384 cma_heap->heap = dma_heap_add(&exp_info); 385 if (IS_ERR(cma_heap->heap)) { 386 int ret = PTR_ERR(cma_heap->heap); 387 388 kfree(cma_heap); 389 return ret; 390 } 391 392 return 0; 393 } 394 395 static int add_default_cma_heap(void) 396 { 397 struct cma *default_cma = dev_get_cma_area(NULL); 398 int ret = 0; 399 400 if (default_cma) 401 ret = __add_cma_heap(default_cma, NULL); 402 403 return ret; 404 } 405 module_init(add_default_cma_heap); 406 MODULE_DESCRIPTION("DMA-BUF CMA Heap"); 407 MODULE_LICENSE("GPL v2"); 408