2 * DMA implementation for Hexagon
4 * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 and
8 * only version 2 as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 #include <linux/dma-mapping.h>
22 #include <linux/bootmem.h>
23 #include <linux/genalloc.h>
24 #include <asm/dma-mapping.h>
25 #include <linux/module.h>
28 const struct dma_map_ops *dma_ops;
29 EXPORT_SYMBOL(dma_ops);
31 int bad_dma_address; /* globals are automatically initialized to zero */
33 static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
35 return phys_to_virt((unsigned long) dma_addr);
38 int dma_supported(struct device *dev, u64 mask)
40 if (mask == DMA_BIT_MASK(32))
45 EXPORT_SYMBOL(dma_supported);
47 static struct gen_pool *coherent_pool;
50 /* Allocates from a pool of uncached memory that was reserved at boot time */
52 static void *hexagon_dma_alloc_coherent(struct device *dev, size_t size,
53 dma_addr_t *dma_addr, gfp_t flag,
59 * Our max_low_pfn should have been backed off by 16MB in
60 * mm/init.c to create DMA coherent space. Use that as the VA
64 if (coherent_pool == NULL) {
65 coherent_pool = gen_pool_create(PAGE_SHIFT, -1);
67 if (coherent_pool == NULL)
68 panic("Can't create %s() memory pool!", __func__);
70 gen_pool_add(coherent_pool,
71 pfn_to_virt(max_low_pfn),
72 hexagon_coherent_pool_size, -1);
75 ret = (void *) gen_pool_alloc(coherent_pool, size);
79 *dma_addr = (dma_addr_t) virt_to_phys(ret);
86 static void hexagon_free_coherent(struct device *dev, size_t size, void *vaddr,
87 dma_addr_t dma_addr, unsigned long attrs)
89 gen_pool_free(coherent_pool, (unsigned long) vaddr, size);
92 static int check_addr(const char *name, struct device *hwdev,
93 dma_addr_t bus, size_t size)
95 if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) {
96 if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
98 "%s: overflow %Lx+%zu of device mask %Lx\n",
99 name, (long long)bus, size,
100 (long long)*hwdev->dma_mask);
106 static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,
107 int nents, enum dma_data_direction dir,
110 struct scatterlist *s;
113 WARN_ON(nents == 0 || sg[0].length == 0);
115 for_each_sg(sg, s, nents, i) {
116 s->dma_address = sg_phys(s);
117 if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
120 s->dma_length = s->length;
122 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
125 flush_dcache_range(dma_addr_to_virt(s->dma_address),
126 dma_addr_to_virt(s->dma_address + s->length));
135 static inline void dma_sync(void *addr, size_t size,
136 enum dma_data_direction dir)
140 hexagon_clean_dcache_range((unsigned long) addr,
141 (unsigned long) addr + size);
143 case DMA_FROM_DEVICE:
144 hexagon_inv_dcache_range((unsigned long) addr,
145 (unsigned long) addr + size);
147 case DMA_BIDIRECTIONAL:
148 flush_dcache_range((unsigned long) addr,
149 (unsigned long) addr + size);
157 * hexagon_map_page() - maps an address for device DMA
158 * @dev: pointer to DMA device
159 * @page: pointer to page struct of DMA memory
160 * @offset: offset within page
161 * @size: size of memory to map
162 * @dir: transfer direction
163 * @attrs: pointer to DMA attrs (not used)
165 * Called to map a memory address to a DMA address prior
166 * to accesses to/from device.
168 * We don't particularly have many hoops to jump through
169 * so far. Straight translation between phys and virtual.
171 * DMA is not cache coherent so sync is necessary; this
172 * seems to be a convenient place to do it.
175 static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
176 unsigned long offset, size_t size,
177 enum dma_data_direction dir,
180 dma_addr_t bus = page_to_phys(page) + offset;
183 if (!check_addr("map_single", dev, bus, size))
184 return bad_dma_address;
186 if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
187 dma_sync(dma_addr_to_virt(bus), size, dir);
192 static void hexagon_sync_single_for_cpu(struct device *dev,
193 dma_addr_t dma_handle, size_t size,
194 enum dma_data_direction dir)
196 dma_sync(dma_addr_to_virt(dma_handle), size, dir);
199 static void hexagon_sync_single_for_device(struct device *dev,
200 dma_addr_t dma_handle, size_t size,
201 enum dma_data_direction dir)
203 dma_sync(dma_addr_to_virt(dma_handle), size, dir);
206 const struct dma_map_ops hexagon_dma_ops = {
207 .alloc = hexagon_dma_alloc_coherent,
208 .free = hexagon_free_coherent,
209 .map_sg = hexagon_map_sg,
210 .map_page = hexagon_map_page,
211 .sync_single_for_cpu = hexagon_sync_single_for_cpu,
212 .sync_single_for_device = hexagon_sync_single_for_device,
216 void __init hexagon_dma_init(void)
221 dma_ops = &hexagon_dma_ops;