xref: /linux/drivers/dma-buf/heaps/cma_heap.c (revision 46040ea8a6a58e5645d91ffa3ead7ed8fd633d56)
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 
cma_heap_attach(struct dma_buf * dmabuf,struct dma_buf_attachment * attachment)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 
cma_heap_detach(struct dma_buf * dmabuf,struct dma_buf_attachment * attachment)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 
cma_heap_map_dma_buf(struct dma_buf_attachment * attachment,enum dma_data_direction direction)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 
cma_heap_unmap_dma_buf(struct dma_buf_attachment * attachment,struct sg_table * table,enum dma_data_direction direction)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 
cma_heap_dma_buf_begin_cpu_access(struct dma_buf * dmabuf,enum dma_data_direction direction)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 
cma_heap_dma_buf_end_cpu_access(struct dma_buf * dmabuf,enum dma_data_direction direction)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 
cma_heap_vm_fault(struct vm_fault * vmf)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 
cma_heap_mmap(struct dma_buf * dmabuf,struct vm_area_struct * vma)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 
cma_heap_do_vmap(struct cma_heap_buffer * buffer)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 
cma_heap_vmap(struct dma_buf * dmabuf,struct iosys_map * map)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 
cma_heap_vunmap(struct dma_buf * dmabuf,struct iosys_map * map)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 
cma_heap_dma_buf_release(struct dma_buf * dmabuf)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 
cma_heap_allocate(struct dma_heap * heap,unsigned long len,u32 fd_flags,u64 heap_flags)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_atomic(page);
313 
314 			memset(vaddr, 0, PAGE_SIZE);
315 			kunmap_atomic(vaddr);
316 			/*
317 			 * Avoid wasting time zeroing memory if the process
318 			 * has been killed by 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 
__add_cma_heap(struct cma * cma,void * data)369 static int __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 
add_default_cma_heap(void)394 static int 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");
406