Andrzej Pietrasiewicz | 5ba3f75 | 2010-11-29 11:53:34 -0300 | [diff] [blame] | 1 | /* |
| 2 | * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2 |
| 3 | * |
| 4 | * Copyright (C) 2010 Samsung Electronics |
| 5 | * |
| 6 | * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/mm.h> |
| 15 | #include <linux/scatterlist.h> |
| 16 | #include <linux/sched.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/vmalloc.h> |
| 19 | |
| 20 | #include <media/videobuf2-core.h> |
| 21 | #include <media/videobuf2-memops.h> |
| 22 | #include <media/videobuf2-dma-sg.h> |
| 23 | |
| 24 | struct vb2_dma_sg_buf { |
| 25 | void *vaddr; |
| 26 | struct page **pages; |
| 27 | int write; |
| 28 | int offset; |
| 29 | struct vb2_dma_sg_desc sg_desc; |
| 30 | atomic_t refcount; |
| 31 | struct vb2_vmarea_handler handler; |
| 32 | }; |
| 33 | |
| 34 | static void vb2_dma_sg_put(void *buf_priv); |
| 35 | |
| 36 | static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size) |
| 37 | { |
| 38 | struct vb2_dma_sg_buf *buf; |
| 39 | int i; |
| 40 | |
| 41 | buf = kzalloc(sizeof *buf, GFP_KERNEL); |
| 42 | if (!buf) |
| 43 | return NULL; |
| 44 | |
| 45 | buf->vaddr = NULL; |
| 46 | buf->write = 0; |
| 47 | buf->offset = 0; |
| 48 | buf->sg_desc.size = size; |
| 49 | buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 50 | |
| 51 | buf->sg_desc.sglist = vmalloc(buf->sg_desc.num_pages * |
| 52 | sizeof(*buf->sg_desc.sglist)); |
| 53 | if (!buf->sg_desc.sglist) |
| 54 | goto fail_sglist_alloc; |
| 55 | memset(buf->sg_desc.sglist, 0, buf->sg_desc.num_pages * |
| 56 | sizeof(*buf->sg_desc.sglist)); |
| 57 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
| 58 | |
| 59 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), |
| 60 | GFP_KERNEL); |
| 61 | if (!buf->pages) |
| 62 | goto fail_pages_array_alloc; |
| 63 | |
| 64 | for (i = 0; i < buf->sg_desc.num_pages; ++i) { |
Andrzej Pietrasiewicz | 941f896 | 2011-03-02 09:12:13 -0300 | [diff] [blame] | 65 | buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO); |
Andrzej Pietrasiewicz | 5ba3f75 | 2010-11-29 11:53:34 -0300 | [diff] [blame] | 66 | if (NULL == buf->pages[i]) |
| 67 | goto fail_pages_alloc; |
| 68 | sg_set_page(&buf->sg_desc.sglist[i], |
| 69 | buf->pages[i], PAGE_SIZE, 0); |
| 70 | } |
| 71 | |
| 72 | buf->handler.refcount = &buf->refcount; |
| 73 | buf->handler.put = vb2_dma_sg_put; |
| 74 | buf->handler.arg = buf; |
| 75 | |
| 76 | atomic_inc(&buf->refcount); |
| 77 | |
| 78 | printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n", |
| 79 | __func__, buf->sg_desc.num_pages); |
| 80 | |
| 81 | if (!buf->vaddr) |
| 82 | buf->vaddr = vm_map_ram(buf->pages, |
| 83 | buf->sg_desc.num_pages, |
| 84 | -1, |
| 85 | PAGE_KERNEL); |
| 86 | return buf; |
| 87 | |
| 88 | fail_pages_alloc: |
| 89 | while (--i >= 0) |
| 90 | __free_page(buf->pages[i]); |
Andrzej Pietrasiewicz | a9bb36a | 2011-01-28 09:42:51 -0300 | [diff] [blame] | 91 | kfree(buf->pages); |
Andrzej Pietrasiewicz | 5ba3f75 | 2010-11-29 11:53:34 -0300 | [diff] [blame] | 92 | |
| 93 | fail_pages_array_alloc: |
| 94 | vfree(buf->sg_desc.sglist); |
| 95 | |
| 96 | fail_sglist_alloc: |
| 97 | kfree(buf); |
| 98 | return NULL; |
| 99 | } |
| 100 | |
| 101 | static void vb2_dma_sg_put(void *buf_priv) |
| 102 | { |
| 103 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 104 | int i = buf->sg_desc.num_pages; |
| 105 | |
| 106 | if (atomic_dec_and_test(&buf->refcount)) { |
| 107 | printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__, |
| 108 | buf->sg_desc.num_pages); |
| 109 | if (buf->vaddr) |
| 110 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); |
| 111 | vfree(buf->sg_desc.sglist); |
| 112 | while (--i >= 0) |
| 113 | __free_page(buf->pages[i]); |
| 114 | kfree(buf->pages); |
| 115 | kfree(buf); |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr, |
| 120 | unsigned long size, int write) |
| 121 | { |
| 122 | struct vb2_dma_sg_buf *buf; |
| 123 | unsigned long first, last; |
| 124 | int num_pages_from_user, i; |
| 125 | |
| 126 | buf = kzalloc(sizeof *buf, GFP_KERNEL); |
| 127 | if (!buf) |
| 128 | return NULL; |
| 129 | |
| 130 | buf->vaddr = NULL; |
| 131 | buf->write = write; |
| 132 | buf->offset = vaddr & ~PAGE_MASK; |
| 133 | buf->sg_desc.size = size; |
| 134 | |
| 135 | first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; |
| 136 | last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; |
| 137 | buf->sg_desc.num_pages = last - first + 1; |
| 138 | |
| 139 | buf->sg_desc.sglist = vmalloc( |
| 140 | buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); |
| 141 | if (!buf->sg_desc.sglist) |
| 142 | goto userptr_fail_sglist_alloc; |
| 143 | |
| 144 | memset(buf->sg_desc.sglist, 0, |
| 145 | buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist)); |
| 146 | sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages); |
| 147 | |
| 148 | buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *), |
| 149 | GFP_KERNEL); |
| 150 | if (!buf->pages) |
| 151 | goto userptr_fail_pages_array_alloc; |
| 152 | |
| 153 | down_read(¤t->mm->mmap_sem); |
| 154 | num_pages_from_user = get_user_pages(current, current->mm, |
| 155 | vaddr & PAGE_MASK, |
| 156 | buf->sg_desc.num_pages, |
| 157 | write, |
| 158 | 1, /* force */ |
| 159 | buf->pages, |
| 160 | NULL); |
| 161 | up_read(¤t->mm->mmap_sem); |
| 162 | if (num_pages_from_user != buf->sg_desc.num_pages) |
| 163 | goto userptr_fail_get_user_pages; |
| 164 | |
| 165 | sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0], |
| 166 | PAGE_SIZE - buf->offset, buf->offset); |
| 167 | size -= PAGE_SIZE - buf->offset; |
| 168 | for (i = 1; i < buf->sg_desc.num_pages; ++i) { |
| 169 | sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i], |
| 170 | min_t(size_t, PAGE_SIZE, size), 0); |
| 171 | size -= min_t(size_t, PAGE_SIZE, size); |
| 172 | } |
| 173 | return buf; |
| 174 | |
| 175 | userptr_fail_get_user_pages: |
| 176 | printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n", |
| 177 | num_pages_from_user, buf->sg_desc.num_pages); |
| 178 | while (--num_pages_from_user >= 0) |
| 179 | put_page(buf->pages[num_pages_from_user]); |
Andrzej Pietrasiewicz | a9bb36a | 2011-01-28 09:42:51 -0300 | [diff] [blame] | 180 | kfree(buf->pages); |
Andrzej Pietrasiewicz | 5ba3f75 | 2010-11-29 11:53:34 -0300 | [diff] [blame] | 181 | |
| 182 | userptr_fail_pages_array_alloc: |
| 183 | vfree(buf->sg_desc.sglist); |
| 184 | |
| 185 | userptr_fail_sglist_alloc: |
| 186 | kfree(buf); |
| 187 | return NULL; |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * @put_userptr: inform the allocator that a USERPTR buffer will no longer |
| 192 | * be used |
| 193 | */ |
| 194 | static void vb2_dma_sg_put_userptr(void *buf_priv) |
| 195 | { |
| 196 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 197 | int i = buf->sg_desc.num_pages; |
| 198 | |
| 199 | printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n", |
| 200 | __func__, buf->sg_desc.num_pages); |
| 201 | if (buf->vaddr) |
| 202 | vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages); |
| 203 | while (--i >= 0) { |
| 204 | if (buf->write) |
| 205 | set_page_dirty_lock(buf->pages[i]); |
| 206 | put_page(buf->pages[i]); |
| 207 | } |
| 208 | vfree(buf->sg_desc.sglist); |
| 209 | kfree(buf->pages); |
| 210 | kfree(buf); |
| 211 | } |
| 212 | |
| 213 | static void *vb2_dma_sg_vaddr(void *buf_priv) |
| 214 | { |
| 215 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 216 | |
| 217 | BUG_ON(!buf); |
| 218 | |
| 219 | if (!buf->vaddr) |
| 220 | buf->vaddr = vm_map_ram(buf->pages, |
| 221 | buf->sg_desc.num_pages, |
| 222 | -1, |
| 223 | PAGE_KERNEL); |
| 224 | |
| 225 | /* add offset in case userptr is not page-aligned */ |
| 226 | return buf->vaddr + buf->offset; |
| 227 | } |
| 228 | |
| 229 | static unsigned int vb2_dma_sg_num_users(void *buf_priv) |
| 230 | { |
| 231 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 232 | |
| 233 | return atomic_read(&buf->refcount); |
| 234 | } |
| 235 | |
| 236 | static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) |
| 237 | { |
| 238 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 239 | unsigned long uaddr = vma->vm_start; |
| 240 | unsigned long usize = vma->vm_end - vma->vm_start; |
| 241 | int i = 0; |
| 242 | |
| 243 | if (!buf) { |
| 244 | printk(KERN_ERR "No memory to map\n"); |
| 245 | return -EINVAL; |
| 246 | } |
| 247 | |
| 248 | do { |
| 249 | int ret; |
| 250 | |
| 251 | ret = vm_insert_page(vma, uaddr, buf->pages[i++]); |
| 252 | if (ret) { |
| 253 | printk(KERN_ERR "Remapping memory, error: %d\n", ret); |
| 254 | return ret; |
| 255 | } |
| 256 | |
| 257 | uaddr += PAGE_SIZE; |
| 258 | usize -= PAGE_SIZE; |
| 259 | } while (usize > 0); |
| 260 | |
| 261 | |
| 262 | /* |
| 263 | * Use common vm_area operations to track buffer refcount. |
| 264 | */ |
| 265 | vma->vm_private_data = &buf->handler; |
| 266 | vma->vm_ops = &vb2_common_vm_ops; |
| 267 | |
| 268 | vma->vm_ops->open(vma); |
| 269 | |
| 270 | return 0; |
| 271 | } |
| 272 | |
| 273 | static void *vb2_dma_sg_cookie(void *buf_priv) |
| 274 | { |
| 275 | struct vb2_dma_sg_buf *buf = buf_priv; |
| 276 | |
| 277 | return &buf->sg_desc; |
| 278 | } |
| 279 | |
| 280 | const struct vb2_mem_ops vb2_dma_sg_memops = { |
| 281 | .alloc = vb2_dma_sg_alloc, |
| 282 | .put = vb2_dma_sg_put, |
| 283 | .get_userptr = vb2_dma_sg_get_userptr, |
| 284 | .put_userptr = vb2_dma_sg_put_userptr, |
| 285 | .vaddr = vb2_dma_sg_vaddr, |
| 286 | .mmap = vb2_dma_sg_mmap, |
| 287 | .num_users = vb2_dma_sg_num_users, |
| 288 | .cookie = vb2_dma_sg_cookie, |
| 289 | }; |
| 290 | EXPORT_SYMBOL_GPL(vb2_dma_sg_memops); |
| 291 | |
| 292 | MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2"); |
| 293 | MODULE_AUTHOR("Andrzej Pietrasiewicz"); |
| 294 | MODULE_LICENSE("GPL"); |