1 /* 2 * drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c 3 * 4 * Copyright (C) 2011 Texas Instruments 5 * Author: Rob Clark <rob.clark@linaro.org> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 as published by 9 * the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14 * more details. 15 * 16 * You should have received a copy of the GNU General Public License along with 17 * this program. If not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include "omap_drv.h" 21 22 #include <linux/dma-buf.h> 23 24 static struct sg_table *omap_gem_map_dma_buf( 25 struct dma_buf_attachment *attachment, 26 enum dma_data_direction dir) 27 { 28 struct drm_gem_object *obj = attachment->dmabuf->priv; 29 struct sg_table *sg; 30 dma_addr_t paddr; 31 int ret; 32 33 sg = kzalloc(sizeof(*sg), GFP_KERNEL); 34 if (!sg) 35 return ERR_PTR(-ENOMEM); 36 37 /* camera, etc, need physically contiguous.. but we need a 38 * better way to know this.. 39 */ 40 ret = omap_gem_get_paddr(obj, &paddr, true); 41 if (ret) 42 goto out; 43 44 ret = sg_alloc_table(sg, 1, GFP_KERNEL); 45 if (ret) 46 goto out; 47 48 sg_init_table(sg->sgl, 1); 49 sg_dma_len(sg->sgl) = obj->size; 50 sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(paddr)), obj->size, 0); 51 sg_dma_address(sg->sgl) = paddr; 52 53 /* this should be after _get_paddr() to ensure we have pages attached */ 54 omap_gem_dma_sync(obj, dir); 55 56 return sg; 57 out: 58 kfree(sg); 59 return ERR_PTR(ret); 60 } 61 62 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment, 63 struct sg_table *sg, enum dma_data_direction dir) 64 { 65 struct drm_gem_object *obj = attachment->dmabuf->priv; 66 omap_gem_put_paddr(obj); 67 sg_free_table(sg); 68 kfree(sg); 69 } 70 71 static void omap_gem_dmabuf_release(struct dma_buf *buffer) 72 { 73 struct drm_gem_object *obj = buffer->priv; 74 /* release reference that was taken when dmabuf was exported 75 * in omap_gem_prime_set().. 76 */ 77 drm_gem_object_unreference_unlocked(obj); 78 } 79 80 81 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer, 82 size_t start, size_t len, enum dma_data_direction dir) 83 { 84 struct drm_gem_object *obj = buffer->priv; 85 struct page **pages; 86 if (omap_gem_flags(obj) & OMAP_BO_TILED) { 87 /* TODO we would need to pin at least part of the buffer to 88 * get de-tiled view. For now just reject it. 89 */ 90 return -ENOMEM; 91 } 92 /* make sure we have the pages: */ 93 return omap_gem_get_pages(obj, &pages, true); 94 } 95 96 static void omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer, 97 size_t start, size_t len, enum dma_data_direction dir) 98 { 99 struct drm_gem_object *obj = buffer->priv; 100 omap_gem_put_pages(obj); 101 } 102 103 104 static void *omap_gem_dmabuf_kmap_atomic(struct dma_buf *buffer, 105 unsigned long page_num) 106 { 107 struct drm_gem_object *obj = buffer->priv; 108 struct page **pages; 109 omap_gem_get_pages(obj, &pages, false); 110 omap_gem_cpu_sync(obj, page_num); 111 return kmap_atomic(pages[page_num]); 112 } 113 114 static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer, 115 unsigned long page_num, void *addr) 116 { 117 kunmap_atomic(addr); 118 } 119 120 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer, 121 unsigned long page_num) 122 { 123 struct drm_gem_object *obj = buffer->priv; 124 struct page **pages; 125 omap_gem_get_pages(obj, &pages, false); 126 omap_gem_cpu_sync(obj, page_num); 127 return kmap(pages[page_num]); 128 } 129 130 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer, 131 unsigned long page_num, void *addr) 132 { 133 struct drm_gem_object *obj = buffer->priv; 134 struct page **pages; 135 omap_gem_get_pages(obj, &pages, false); 136 kunmap(pages[page_num]); 137 } 138 139 /* 140 * TODO maybe we can split up drm_gem_mmap to avoid duplicating 141 * some here.. or at least have a drm_dmabuf_mmap helper. 142 */ 143 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer, 144 struct vm_area_struct *vma) 145 { 146 struct drm_gem_object *obj = buffer->priv; 147 int ret = 0; 148 149 if (WARN_ON(!obj->filp)) 150 return -EINVAL; 151 152 /* Check for valid size. */ 153 if (omap_gem_mmap_size(obj) < vma->vm_end - vma->vm_start) { 154 ret = -EINVAL; 155 goto out_unlock; 156 } 157 158 if (!obj->dev->driver->gem_vm_ops) { 159 ret = -EINVAL; 160 goto out_unlock; 161 } 162 163 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; 164 vma->vm_ops = obj->dev->driver->gem_vm_ops; 165 vma->vm_private_data = obj; 166 vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); 167 168 /* Take a ref for this mapping of the object, so that the fault 169 * handler can dereference the mmap offset's pointer to the object. 170 * This reference is cleaned up by the corresponding vm_close 171 * (which should happen whether the vma was created by this call, or 172 * by a vm_open due to mremap or partial unmap or whatever). 173 */ 174 vma->vm_ops->open(vma); 175 176 out_unlock: 177 178 return omap_gem_mmap_obj(obj, vma); 179 } 180 181 static struct dma_buf_ops omap_dmabuf_ops = { 182 .map_dma_buf = omap_gem_map_dma_buf, 183 .unmap_dma_buf = omap_gem_unmap_dma_buf, 184 .release = omap_gem_dmabuf_release, 185 .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access, 186 .end_cpu_access = omap_gem_dmabuf_end_cpu_access, 187 .kmap_atomic = omap_gem_dmabuf_kmap_atomic, 188 .kunmap_atomic = omap_gem_dmabuf_kunmap_atomic, 189 .kmap = omap_gem_dmabuf_kmap, 190 .kunmap = omap_gem_dmabuf_kunmap, 191 .mmap = omap_gem_dmabuf_mmap, 192 }; 193 194 struct dma_buf *omap_gem_prime_export(struct drm_device *dev, 195 struct drm_gem_object *obj, int flags) 196 { 197 return dma_buf_export(obj, &omap_dmabuf_ops, obj->size, flags); 198 } 199 200 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev, 201 struct dma_buf *buffer) 202 { 203 struct drm_gem_object *obj; 204 205 /* is this one of own objects? */ 206 if (buffer->ops == &omap_dmabuf_ops) { 207 obj = buffer->priv; 208 /* is it from our device? */ 209 if (obj->dev == dev) { 210 /* 211 * Importing dmabuf exported from out own gem increases 212 * refcount on gem itself instead of f_count of dmabuf. 213 */ 214 drm_gem_object_reference(obj); 215 return obj; 216 } 217 } 218 219 /* 220 * TODO add support for importing buffers from other devices.. 221 * for now we don't need this but would be nice to add eventually 222 */ 223 return ERR_PTR(-EINVAL); 224 } 225