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         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         return vmf_insert_pfn(vma, vmf->address, page_to_pfn(buffer->pages[vmf->pgoff]));
 172 }
 173
 174 static const struct vm_operations_struct dma_heap_vm_ops = {
 175         .fault = cma_heap_vm_fault,
 176 };
 177
 178 static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
 179 {
 180         struct cma_heap_buffer *buffer = dmabuf->priv;
 181
 182         if ((vma->vm_flags & (VM_SHARED | VM_MAYSHARE)) == 0)
 183                 return -EINVAL;
 184
 185         vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
 186
 187         vma->vm_ops = &dma_heap_vm_ops;
 188         vma->vm_private_data = buffer;
 189
 190         return 0;
 191 }
 192
 193 static void *cma_heap_do_vmap(struct cma_heap_buffer *buffer)
 194 {
 195         void *vaddr;
 196
 197         vaddr = vmap(buffer->pages, buffer->pagecount, VM_MAP, PAGE_KERNEL);
 198         if (!vaddr)
 199                 return ERR_PTR(-ENOMEM);
 200
 201         return vaddr;
 202 }
 203
 204 static int cma_heap_vmap(struct dma_buf *dmabuf, struct iosys_map *map)
 205 {
 206         struct cma_heap_buffer *buffer = dmabuf->priv;
 207         void *vaddr;
 208         int ret = 0;
 209
 210         mutex_lock(&buffer->lock);
 211         if (buffer->vmap_cnt) {
 212                 buffer->vmap_cnt++;
 213                 iosys_map_set_vaddr(map, buffer->vaddr);
 214                 goto out;
 215         }
 216
 217         vaddr = cma_heap_do_vmap(buffer);
 218         if (IS_ERR(vaddr)) {
 219                 ret = PTR_ERR(vaddr);
 220                 goto out;
 221         }
 222         buffer->vaddr = vaddr;
 223         buffer->vmap_cnt++;
 224         iosys_map_set_vaddr(map, buffer->vaddr);
 225 out:
 226         mutex_unlock(&buffer->lock);
 227
 228         return ret;
 229 }
 230
 231 static void cma_heap_vunmap(struct dma_buf *dmabuf, struct iosys_map *map)
 232 {
 233         struct cma_heap_buffer *buffer = dmabuf->priv;
 234
 235         mutex_lock(&buffer->lock);
 236         if (!--buffer->vmap_cnt) {
 237                 vunmap(buffer->vaddr);
 238                 buffer->vaddr = NULL;
 239         }
 240         mutex_unlock(&buffer->lock);
 241         iosys_map_clear(map);
 242 }
 243
 244 static void cma_heap_dma_buf_release(struct dma_buf *dmabuf)
 245 {
 246         struct cma_heap_buffer *buffer = dmabuf->priv;
 247         struct cma_heap *cma_heap = buffer->heap;
 248
 249         if (buffer->vmap_cnt > 0) {
 250                 WARN(1, "%s: buffer still mapped in the kernel\n", __func__);
 251                 vunmap(buffer->vaddr);
 252                 buffer->vaddr = NULL;
 253         }
 254
 255         /* free page list */
 256         kfree(buffer->pages);
 257         /* release memory */
 258         cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
 259         kfree(buffer);
 260 }
 261
 262 static const struct dma_buf_ops cma_heap_buf_ops = {
 263         .attach = cma_heap_attach,
 264         .detach = cma_heap_detach,
 265         .map_dma_buf = cma_heap_map_dma_buf,
 266         .unmap_dma_buf = cma_heap_unmap_dma_buf,
 267         .begin_cpu_access = cma_heap_dma_buf_begin_cpu_access,
 268         .end_cpu_access = cma_heap_dma_buf_end_cpu_access,
 269         .mmap = cma_heap_mmap,
 270         .vmap = cma_heap_vmap,
 271         .vunmap = cma_heap_vunmap,
 272         .release = cma_heap_dma_buf_release,
 273 };
 274
 275 static struct dma_buf *cma_heap_allocate(struct dma_heap *heap,
 276                                          unsigned long len,
 277                                          u32 fd_flags,
 278                                          u64 heap_flags)
 279 {
 280         struct cma_heap *cma_heap = dma_heap_get_drvdata(heap);
 281         struct cma_heap_buffer *buffer;
 282         DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 283         size_t size = PAGE_ALIGN(len);
 284         pgoff_t pagecount = size >> PAGE_SHIFT;
 285         unsigned long align = get_order(size);
 286         struct page *cma_pages;
 287         struct dma_buf *dmabuf;
 288         int ret = -ENOMEM;
 289         pgoff_t pg;
 290
 291         buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
 292         if (!buffer)
 293                 return ERR_PTR(-ENOMEM);
 294
 295         INIT_LIST_HEAD(&buffer->attachments);
 296         mutex_init(&buffer->lock);
 297         buffer->len = size;
 298
 299         if (align > CONFIG_CMA_ALIGNMENT)
 300                 align = CONFIG_CMA_ALIGNMENT;
 301
 302         cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
 303         if (!cma_pages)
 304                 goto free_buffer;
 305
 306         /* Clear the cma pages */
 307         if (PageHighMem(cma_pages)) {
 308                 unsigned long nr_clear_pages = pagecount;
 309                 struct page *page = cma_pages;
 310
 311                 while (nr_clear_pages > 0) {
 312                         void *vaddr = kmap_local_page(page);
 313
 314                         memset(vaddr, 0, PAGE_SIZE);
 315                         kunmap_local(vaddr);
 316                         /*
 317                          * Avoid wasting time zeroing memory if the process
 318                          * has been killed by SIGKILL.
 319                          */
 320                         if (fatal_signal_pending(current))
 321                                 goto free_cma;
 322                         page++;
 323                         nr_clear_pages--;
 324                 }
 325         } else {
 326                 memset(page_address(cma_pages), 0, size);
 327         }
 328
 329         buffer->pages = kmalloc_array(pagecount, sizeof(*buffer->pages), GFP_KERNEL);
 330         if (!buffer->pages) {
 331                 ret = -ENOMEM;
 332                 goto free_cma;
 333         }
 334
 335         for (pg = 0; pg < pagecount; pg++)
 336                 buffer->pages[pg] = &cma_pages[pg];
 337
 338         buffer->cma_pages = cma_pages;
 339         buffer->heap = cma_heap;
 340         buffer->pagecount = pagecount;
 341
 342         /* create the dmabuf */
 343         exp_info.exp_name = dma_heap_get_name(heap);
 344         exp_info.ops = &cma_heap_buf_ops;
 345         exp_info.size = buffer->len;
 346         exp_info.flags = fd_flags;
 347         exp_info.priv = buffer;
 348         dmabuf = dma_buf_export(&exp_info);
 349         if (IS_ERR(dmabuf)) {
 350                 ret = PTR_ERR(dmabuf);
 351                 goto free_pages;
 352         }
 353         return dmabuf;
 354
 355 free_pages:
 356         kfree(buffer->pages);
 357 free_cma:
 358         cma_release(cma_heap->cma, cma_pages, pagecount);
 359 free_buffer:
 360         kfree(buffer);
 361
 362         return ERR_PTR(ret);
 363 }
 364
 365 static const struct dma_heap_ops cma_heap_ops = {
 366         .allocate = cma_heap_allocate,
 367 };
 368
 369 static int __init __add_cma_heap(struct cma *cma, void *data)
 370 {
 371         struct cma_heap *cma_heap;
 372         struct dma_heap_export_info exp_info;
 373
 374         cma_heap = kzalloc(sizeof(*cma_heap), GFP_KERNEL);
 375         if (!cma_heap)
 376                 return -ENOMEM;
 377         cma_heap->cma = cma;
 378
 379         exp_info.name = cma_get_name(cma);
 380         exp_info.ops = &cma_heap_ops;
 381         exp_info.priv = cma_heap;
 382
 383         cma_heap->heap = dma_heap_add(&exp_info);
 384         if (IS_ERR(cma_heap->heap)) {
 385                 int ret = PTR_ERR(cma_heap->heap);
 386
 387                 kfree(cma_heap);
 388                 return ret;
 389         }
 390
 391         return 0;
 392 }
 393
 394 static int __init add_default_cma_heap(void)
 395 {
 396         struct cma *default_cma = dev_get_cma_area(NULL);
 397         int ret = 0;
 398
 399         if (default_cma)
 400                 ret = __add_cma_heap(default_cma, NULL);
 401
 402         return ret;
 403 }
 404 module_init(add_default_cma_heap);
 405 MODULE_DESCRIPTION("DMA-BUF CMA Heap");