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: <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         if (buffer->vmap_cnt)
 128                 invalidate_kernel_vmap_range(buffer->vaddr, buffer->len);
 129
 130         mutex_lock(&buffer->lock);
 131         list_for_each_entry(a, &buffer->attachments, list) {
 132                 if (!a->mapped)
 133                         continue;
 134                 dma_sync_sgtable_for_cpu(a->dev, &a->table, direction);
 135         }
 136         mutex_unlock(&buffer->lock);
 137
 138         return 0;
 139 }
 140
 141 static int cma_heap_dma_buf_end_cpu_access(struct dma_buf *dmabuf,
 142                                            enum dma_data_direction direction)
 143 {
 144         struct cma_heap_buffer *buffer = dmabuf->priv;
 145         struct dma_heap_attachment *a;
 146
 147         if (buffer->vmap_cnt)
 148                 flush_kernel_vmap_range(buffer->vaddr, buffer->len);
 149
 150         mutex_lock(&buffer->lock);
 151         list_for_each_entry(a, &buffer->attachments, list) {
 152                 if (!a->mapped)
 153                         continue;
 154                 dma_sync_sgtable_for_device(a->dev, &a->table, direction);
 155         }
 156         mutex_unlock(&buffer->lock);
 157
 158         return 0;
 159 }
 160
 161 static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf)
 162 {
 163         struct vm_area_struct *vma = vmf->vma;
 164         struct cma_heap_buffer *buffer = vma->vm_private_data;
 165
 166         if (vmf->pgoff > buffer->pagecount)
 167                 return VM_FAULT_SIGBUS;
 168
 169         vmf->page = buffer->pages[vmf->pgoff];
 170         get_page(vmf->page);
 171
 172         return 0;
 173 }
 174
 175 static const struct vm_operations_struct dma_heap_vm_ops = {
 176         .fault = cma_heap_vm_fault,
 177 };
 178
 179 static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
 180 {
 181         struct cma_heap_buffer *buffer = dmabuf->priv;
 182
 183         if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
 184                 return -EINVAL;
 185
 186         vma->vm_ops = &dma_heap_vm_ops;
 187         vma->vm_private_data = buffer;
 188
 189         return 0;
 190 }
 191
 192 static void *cma_heap_do_vmap(struct cma_heap_buffer *buffer)
 193 {
 194         void *vaddr;
 195
 196         vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
 197         if (!vaddr)
 198                 return ERR_PTR(-ENOMEM);
 199
 200         return vaddr;
 201 }
 202
 203 static int cma_heap_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
 204 {
 205         struct cma_heap_buffer *buffer = dmabuf->priv;
 206         void *vaddr;
 207         int ret = 0;
 208
 209         mutex_lock(&buffer->lock);
 210         if (buffer->vmap_cnt) {
 211                 buffer->vmap_cnt++;
 212                 dma_buf_map_set_vaddr(map, buffer->vaddr);
 213                 goto out;
 214         }
 215
 216         vaddr = cma_heap_do_vmap(buffer);
 217         if (IS_ERR(vaddr)) {
 218                 ret = PTR_ERR(vaddr);
 219                 goto out;
 220         }
 221         buffer->vaddr = vaddr;
 222         buffer->vmap_cnt++;
 223         dma_buf_map_set_vaddr(map, buffer->vaddr);
 224 out:
 225         mutex_unlock(&buffer->lock);
 226
 227         return ret;
 228 }
 229
 230 static void cma_heap_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map)
 231 {
 232         struct cma_heap_buffer *buffer = dmabuf->priv;
 233
 234         mutex_lock(&buffer->lock);
 235         if (!--buffer->vmap_cnt) {
 236                 vunmap(buffer->vaddr);
 237                 buffer->vaddr = NULL;
 238         }
 239         mutex_unlock(&buffer->lock);
 240         dma_buf_map_clear(map);
 241 }
 242
 243 static void cma_heap_dma_buf_release(struct dma_buf *dmabuf)
 244 {
 245         struct cma_heap_buffer *buffer = dmabuf->priv;
 246         struct cma_heap *cma_heap = buffer->heap;
 247
 248         if (buffer->vmap_cnt > 0) {
 249                 WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
 250                 vunmap(buffer->vaddr);
 251                 buffer->vaddr = NULL;
 252         }
 253
 254         cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
 255         kfree(buffer);
 256 }
 257
 258 static const struct dma_buf_ops cma_heap_buf_ops = {
 259         .attach = cma_heap_attach,
 260         .detach = cma_heap_detach,
 261         .map_dma_buf = cma_heap_map_dma_buf,
 262         .unmap_dma_buf = cma_heap_unmap_dma_buf,
 263         .begin_cpu_access = cma_heap_dma_buf_begin_cpu_access,
 264         .end_cpu_access = cma_heap_dma_buf_end_cpu_access,
 265         .mmap = cma_heap_mmap,
 266         .vmap = cma_heap_vmap,
 267         .vunmap = cma_heap_vunmap,
 268         .release = cma_heap_dma_buf_release,
 269 };
 270
 271 static int cma_heap_allocate(struct dma_heap *heap,
 272                                   unsigned long len,
 273                                   unsigned long fd_flags,
 274                                   unsigned long heap_flags)
 275 {
 276         struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
 277         struct cma_heap_buffer *buffer;
 278         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 279         size_t size = PAGE_ALIGN(len);
 280         pgoff_t pagecount = size >> PAGE_SHIFT;
 281         unsigned long align = get_order(size);
 282         struct page *cma_pages;
 283         struct dma_buf *dmabuf;
 284         int ret = -ENOMEM;
 285         pgoff_t pg;
 286
 287         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 288         if (!buffer)
 289                 return -ENOMEM;
 290
 291         INIT_LIST_HEAD(&buffer->attachments);
 292         mutex_init(&buffer->lock);
 293         buffer->len = size;
 294
 295         if (align > CONFIG_CMA_ALIGNMENT)
 296                 align = CONFIG_CMA_ALIGNMENT;
 297
 298         cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
 299         if (!cma_pages)
 300                 goto free_buffer;
 301
 302         /* Clear the cma pages */
 303         if (PageHighMem(cma_pages)) {
 304                 unsigned long nr_clear_pages = pagecount;
 305                 struct page *page = cma_pages;
 306
 307                 while (nr_clear_pages > 0) {
 308                         void *vaddr = kmap_atomic(page);
 309
 310                         memset(vaddr, 0, PAGE_SIZE);
 311                         kunmap_atomic(vaddr);
 312                         /*
 313                          * Avoid wasting time zeroing memory if the process
 314                          * has been killed by by SIGKILL
 315                          */
 316                         if (fatal_signal_pending(current))
 317                                 goto free_cma;
 318                         page++;
 319                         nr_clear_pages--;
 320                 }
 321         } else {
 322                 memset(page_address(cma_pages), 0, size);
 323         }
 324
 325         buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), GFP_KERNEL);
 326         if (!buffer->pages) {
 327                 ret = -ENOMEM;
 328                 goto free_cma;
 329         }
 330
 331         for (pg = 0; pg < pagecount; pg++)
 332                 buffer->pages[pg] = &cma_pages[pg];
 333
 334         buffer->cma_pages = cma_pages;
 335         buffer->heap = cma_heap;
 336         buffer->pagecount = pagecount;
 337
 338         /* create the dmabuf */
 339         exp_info.ops = &cma_heap_buf_ops;
 340         exp_info.size = buffer->len;
 341         exp_info.flags = fd_flags;
 342         exp_info.priv = buffer;
 343         dmabuf = dma_buf_export(&exp_info);
 344         if (IS_ERR(dmabuf)) {
 345                 ret = PTR_ERR(dmabuf);
 346                 goto free_pages;
 347         }
 348
 349         ret = dma_buf_fd(dmabuf, fd_flags);
 350         if (ret < 0) {
 351                 dma_buf_put(dmabuf);
 352                 /* just return, as put will call release and that will free */
 353                 return ret;
 354         }
 355
 356         return ret;
 357
 358 free_pages:
 359         kfree(buffer->pages);
 360 free_cma:
 361         cma_release(cma_heap->cma, cma_pages, pagecount);
 362 free_buffer:
 363         kfree(buffer);
 364
 365         return ret;
 366 }
 367
 368 static const struct dma_heap_ops cma_heap_ops = {
 369         .allocate = cma_heap_allocate,
 370 };
 371
 372 static int __add_cma_heap(struct cma *cma, void *data)
 373 {
 374         struct cma_heap *cma_heap;
 375         struct dma_heap_export_info exp_info;
 376
 377         cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
 378         if (!cma_heap)
 379                 return -ENOMEM;
 380         cma_heap->cma = cma;
 381
 382         exp_info.name = cma_get_name(cma);
 383         exp_info.ops = &cma_heap_ops;
 384         exp_info.priv = cma_heap;
 385
 386         cma_heap->heap = dma_heap_add(&exp_info);
 387         if (IS_ERR(cma_heap->heap)) {
 388                 int ret = PTR_ERR(cma_heap->heap);
 389
 390                 kfree(cma_heap);
 391                 return ret;
 392         }
 393
 394         return 0;
 395 }
 396
 397 static int add_default_cma_heap(void)
 398 {
 399         struct cma *default_cma = dev_get_cma_area(NULL);
 400         int ret = 0;
 401
 402         if (default_cma)
 403                 ret = __add_cma_heap(default_cma, NULL);
 404
 405         return ret;
 406 }
 407 module_init(add_default_cma_heap);
 408 MODULE_DESCRIPTION("DMA-BUF CMA Heap");
 409 MODULE_LICENSE("GPL v2");