drivers/dma-buf/heaps/cma_heap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * DMABUF CMA heap exporter
   4  *
   5  * Copyright (C) 2012, 2019, 2020 Linaro Ltd.
   6  * Author: <[email protected]> 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 <[email protected]>
  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");