1/*
  2 * drm gem CMA (contiguous memory allocator) helper functions
  3 *
  4 * Copyright (C) 2012 Sascha Hauer, Pengutronix
  5 *
  6 * Based on Samsung Exynos code
  7 *
  8 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
  9 *
 10 * This program is free software; you can redistribute it and/or
 11 * modify it under the terms of the GNU General Public License
 12 * as published by the Free Software Foundation; either version 2
 13 * of the License, or (at your option) any later version.
 14 * This program is distributed in the hope that it will be useful,
 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 17 * GNU General Public License for more details.
 18 */
 19
 20#include <linux/mm.h>
 21#include <linux/slab.h>
 22#include <linux/mutex.h>
 23#include <linux/export.h>
 24#include <linux/dma-buf.h>
 25#include <linux/dma-mapping.h>
 26
 27#include <drm/drmP.h>
 28#include <drm/drm.h>
 29#include <drm/drm_gem_cma_helper.h>
 30#include <drm/drm_vma_manager.h>
 31
 32/*
 33 * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
 34 * @drm: The drm device
 35 * @size: The GEM object size
 36 *
 37 * This function creates and initializes a GEM CMA object of the given size, but
 38 * doesn't allocate any memory to back the object.
 39 *
 40 * Return a struct drm_gem_cma_object* on success or ERR_PTR values on failure.
 41 */
 42static struct drm_gem_cma_object *
 43__drm_gem_cma_create(struct drm_device *drm, unsigned int size)
 44{
 45	struct drm_gem_cma_object *cma_obj;
 46	struct drm_gem_object *gem_obj;
 47	int ret;
 48
 49	cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
 50	if (!cma_obj)
 51		return ERR_PTR(-ENOMEM);
 52
 53	gem_obj = &cma_obj->base;
 54
 55	ret = drm_gem_object_init(drm, gem_obj, size);
 56	if (ret)
 57		goto error;
 58
 59	ret = drm_gem_create_mmap_offset(gem_obj);
 60	if (ret) {
 61		drm_gem_object_release(gem_obj);
 62		goto error;
 63	}
 64
 65	return cma_obj;
 66
 67error:
 68	kfree(cma_obj);
 69	return ERR_PTR(ret);
 70}
 71
 72/*
 73 * drm_gem_cma_create - allocate an object with the given size
 74 *
 75 * returns a struct drm_gem_cma_object* on success or ERR_PTR values
 76 * on failure.
 77 */
 78struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
 79		unsigned int size)
 80{
 81	struct drm_gem_cma_object *cma_obj;
 82	int ret;
 83
 84	size = round_up(size, PAGE_SIZE);
 85
 86	cma_obj = __drm_gem_cma_create(drm, size);
 87	if (IS_ERR(cma_obj))
 88		return cma_obj;
 89
 90	cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
 91			&cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
 92	if (!cma_obj->vaddr) {
 93		dev_err(drm->dev, "failed to allocate buffer with size %d\n",
 94			size);
 95		ret = -ENOMEM;
 96		goto error;
 97	}
 98
 99	return cma_obj;
100
101error:
102	drm_gem_cma_free_object(&cma_obj->base);
103	return ERR_PTR(ret);
104}
105EXPORT_SYMBOL_GPL(drm_gem_cma_create);
106
107/*
108 * drm_gem_cma_create_with_handle - allocate an object with the given
109 * size and create a gem handle on it
110 *
111 * returns a struct drm_gem_cma_object* on success or ERR_PTR values
112 * on failure.
113 */
114static struct drm_gem_cma_object *drm_gem_cma_create_with_handle(
115		struct drm_file *file_priv,
116		struct drm_device *drm, unsigned int size,
117		unsigned int *handle)
118{
119	struct drm_gem_cma_object *cma_obj;
120	struct drm_gem_object *gem_obj;
121	int ret;
122
123	cma_obj = drm_gem_cma_create(drm, size);
124	if (IS_ERR(cma_obj))
125		return cma_obj;
126
127	gem_obj = &cma_obj->base;
128
129	/*
130	 * allocate a id of idr table where the obj is registered
131	 * and handle has the id what user can see.
132	 */
133	ret = drm_gem_handle_create(file_priv, gem_obj, handle);
134	if (ret)
135		goto err_handle_create;
136
137	/* drop reference from allocate - handle holds it now. */
138	drm_gem_object_unreference_unlocked(gem_obj);
139
140	return cma_obj;
141
142err_handle_create:
143	drm_gem_cma_free_object(gem_obj);
144
145	return ERR_PTR(ret);
146}
147
148/*
149 * drm_gem_cma_free_object - (struct drm_driver)->gem_free_object callback
150 * function
151 */
152void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
153{
154	struct drm_gem_cma_object *cma_obj;
155
156	drm_gem_free_mmap_offset(gem_obj);
157
158	cma_obj = to_drm_gem_cma_obj(gem_obj);
159
160	if (cma_obj->vaddr) {
161		dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
162				      cma_obj->vaddr, cma_obj->paddr);
163	} else if (gem_obj->import_attach) {
164		drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
165	}
166
167	drm_gem_object_release(gem_obj);
168
169	kfree(cma_obj);
170}
171EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
172
173/*
174 * drm_gem_cma_dumb_create - (struct drm_driver)->dumb_create callback
175 * function
176 *
177 * This aligns the pitch and size arguments to the minimum required. wrap
178 * this into your own function if you need bigger alignment.
179 */
180int drm_gem_cma_dumb_create(struct drm_file *file_priv,
181		struct drm_device *dev, struct drm_mode_create_dumb *args)
182{
183	struct drm_gem_cma_object *cma_obj;
184	int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
185
186	if (args->pitch < min_pitch)
187		args->pitch = min_pitch;
188
189	if (args->size < args->pitch * args->height)
190		args->size = args->pitch * args->height;
191
192	cma_obj = drm_gem_cma_create_with_handle(file_priv, dev,
193			args->size, &args->handle);
194	return PTR_ERR_OR_ZERO(cma_obj);
195}
196EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
197
198/*
199 * drm_gem_cma_dumb_map_offset - (struct drm_driver)->dumb_map_offset callback
200 * function
201 */
202int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
203		struct drm_device *drm, uint32_t handle, uint64_t *offset)
204{
205	struct drm_gem_object *gem_obj;
206
207	mutex_lock(&drm->struct_mutex);
208
209	gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
210	if (!gem_obj) {
211		dev_err(drm->dev, "failed to lookup gem object\n");
212		mutex_unlock(&drm->struct_mutex);
213		return -EINVAL;
214	}
215
216	*offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
217
218	drm_gem_object_unreference(gem_obj);
219
220	mutex_unlock(&drm->struct_mutex);
221
222	return 0;
223}
224EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
225
226const struct vm_operations_struct drm_gem_cma_vm_ops = {
227	.open = drm_gem_vm_open,
228	.close = drm_gem_vm_close,
229};
230EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
231
232static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
233				struct vm_area_struct *vma)
234{
235	int ret;
236
237	/*
238	 * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
239	 * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
240	 * the whole buffer.
241	 */
242	vma->vm_flags &= ~VM_PFNMAP;
243	vma->vm_pgoff = 0;
244
245	ret = dma_mmap_writecombine(cma_obj->base.dev->dev, vma,
246				    cma_obj->vaddr, cma_obj->paddr,
247				    vma->vm_end - vma->vm_start);
248	if (ret)
249		drm_gem_vm_close(vma);
250
251	return ret;
252}
253
254/*
255 * drm_gem_cma_mmap - (struct file_operation)->mmap callback function
256 */
257int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
258{
259	struct drm_gem_cma_object *cma_obj;
260	struct drm_gem_object *gem_obj;
261	int ret;
262
263	ret = drm_gem_mmap(filp, vma);
264	if (ret)
265		return ret;
266
267	gem_obj = vma->vm_private_data;
268	cma_obj = to_drm_gem_cma_obj(gem_obj);
269
270	return drm_gem_cma_mmap_obj(cma_obj, vma);
271}
272EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
273
274#ifdef CONFIG_DEBUG_FS
275void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m)
276{
277	struct drm_gem_object *obj = &cma_obj->base;
278	struct drm_device *dev = obj->dev;
279	uint64_t off;
280
281	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
282
283	off = drm_vma_node_start(&obj->vma_node);
284
285	seq_printf(m, "%2d (%2d) %08llx %pad %p %d",
286			obj->name, obj->refcount.refcount.counter,
287			off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
288
289	seq_printf(m, "\n");
290}
291EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
292#endif
293
294/* low-level interface prime helpers */
295struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
296{
297	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
298	struct sg_table *sgt;
299	int ret;
300
301	sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
302	if (!sgt)
303		return NULL;
304
305	ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
306			      cma_obj->paddr, obj->size);
307	if (ret < 0)
308		goto out;
309
310	return sgt;
311
312out:
313	kfree(sgt);
314	return NULL;
315}
316EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
317
318struct drm_gem_object *
319drm_gem_cma_prime_import_sg_table(struct drm_device *dev, size_t size,
320				  struct sg_table *sgt)
321{
322	struct drm_gem_cma_object *cma_obj;
323
324	if (sgt->nents != 1)
325		return ERR_PTR(-EINVAL);
326
327	/* Create a CMA GEM buffer. */
328	cma_obj = __drm_gem_cma_create(dev, size);
329	if (IS_ERR(cma_obj))
330		return ERR_PTR(PTR_ERR(cma_obj));
331
332	cma_obj->paddr = sg_dma_address(sgt->sgl);
333	cma_obj->sgt = sgt;
334
335	DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, size);
336
337	return &cma_obj->base;
338}
339EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
340
341int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
342			   struct vm_area_struct *vma)
343{
344	struct drm_gem_cma_object *cma_obj;
345	struct drm_device *dev = obj->dev;
346	int ret;
347
348	mutex_lock(&dev->struct_mutex);
349	ret = drm_gem_mmap_obj(obj, obj->size, vma);
350	mutex_unlock(&dev->struct_mutex);
351	if (ret < 0)
352		return ret;
353
354	cma_obj = to_drm_gem_cma_obj(obj);
355	return drm_gem_cma_mmap_obj(cma_obj, vma);
356}
357EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
358
359void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
360{
361	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
362
363	return cma_obj->vaddr;
364}
365EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
366
367void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
368{
369	/* Nothing to do */
370}
371EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);