]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - arch/arc/mm/dma.c
Merge remote-tracking branches 'asoc/topic/inntel', 'asoc/topic/input', 'asoc/topic...
[mirror_ubuntu-bionic-kernel.git] / arch / arc / mm / dma.c
1 /*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 /*
10 * DMA Coherent API Notes
11 *
12 * I/O is inherently non-coherent on ARC. So a coherent DMA buffer is
13 * implemented by accessing it using a kernel virtual address, with
14 * Cache bit off in the TLB entry.
15 *
16 * The default DMA address == Phy address which is 0x8000_0000 based.
17 */
18
19 #include <linux/dma-mapping.h>
20 #include <asm/cache.h>
21 #include <asm/cacheflush.h>
22
23
24 static void *arc_dma_alloc(struct device *dev, size_t size,
25 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
26 {
27 unsigned long order = get_order(size);
28 struct page *page;
29 phys_addr_t paddr;
30 void *kvaddr;
31 int need_coh = 1, need_kvaddr = 0;
32
33 page = alloc_pages(gfp, order);
34 if (!page)
35 return NULL;
36
37 /*
38 * IOC relies on all data (even coherent DMA data) being in cache
39 * Thus allocate normal cached memory
40 *
41 * The gains with IOC are two pronged:
42 * -For streaming data, elides need for cache maintenance, saving
43 * cycles in flush code, and bus bandwidth as all the lines of a
44 * buffer need to be flushed out to memory
45 * -For coherent data, Read/Write to buffers terminate early in cache
46 * (vs. always going to memory - thus are faster)
47 */
48 if ((is_isa_arcv2() && ioc_enable) ||
49 (attrs & DMA_ATTR_NON_CONSISTENT))
50 need_coh = 0;
51
52 /*
53 * - A coherent buffer needs MMU mapping to enforce non-cachability
54 * - A highmem page needs a virtual handle (hence MMU mapping)
55 * independent of cachability
56 */
57 if (PageHighMem(page) || need_coh)
58 need_kvaddr = 1;
59
60 /* This is linear addr (0x8000_0000 based) */
61 paddr = page_to_phys(page);
62
63 *dma_handle = plat_phys_to_dma(dev, paddr);
64
65 /* This is kernel Virtual address (0x7000_0000 based) */
66 if (need_kvaddr) {
67 kvaddr = ioremap_nocache(paddr, size);
68 if (kvaddr == NULL) {
69 __free_pages(page, order);
70 return NULL;
71 }
72 } else {
73 kvaddr = (void *)(u32)paddr;
74 }
75
76 /*
77 * Evict any existing L1 and/or L2 lines for the backing page
78 * in case it was used earlier as a normal "cached" page.
79 * Yeah this bit us - STAR 9000898266
80 *
81 * Although core does call flush_cache_vmap(), it gets kvaddr hence
82 * can't be used to efficiently flush L1 and/or L2 which need paddr
83 * Currently flush_cache_vmap nukes the L1 cache completely which
84 * will be optimized as a separate commit
85 */
86 if (need_coh)
87 dma_cache_wback_inv(paddr, size);
88
89 return kvaddr;
90 }
91
92 static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
93 dma_addr_t dma_handle, unsigned long attrs)
94 {
95 phys_addr_t paddr = plat_dma_to_phys(dev, dma_handle);
96 struct page *page = virt_to_page(paddr);
97 int is_non_coh = 1;
98
99 is_non_coh = (attrs & DMA_ATTR_NON_CONSISTENT) ||
100 (is_isa_arcv2() && ioc_enable);
101
102 if (PageHighMem(page) || !is_non_coh)
103 iounmap((void __force __iomem *)vaddr);
104
105 __free_pages(page, get_order(size));
106 }
107
108 static int arc_dma_mmap(struct device *dev, struct vm_area_struct *vma,
109 void *cpu_addr, dma_addr_t dma_addr, size_t size,
110 unsigned long attrs)
111 {
112 unsigned long user_count = vma_pages(vma);
113 unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
114 unsigned long pfn = __phys_to_pfn(plat_dma_to_phys(dev, dma_addr));
115 unsigned long off = vma->vm_pgoff;
116 int ret = -ENXIO;
117
118 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
119
120 if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))
121 return ret;
122
123 if (off < count && user_count <= (count - off)) {
124 ret = remap_pfn_range(vma, vma->vm_start,
125 pfn + off,
126 user_count << PAGE_SHIFT,
127 vma->vm_page_prot);
128 }
129
130 return ret;
131 }
132
133 /*
134 * streaming DMA Mapping API...
135 * CPU accesses page via normal paddr, thus needs to explicitly made
136 * consistent before each use
137 */
138 static void _dma_cache_sync(phys_addr_t paddr, size_t size,
139 enum dma_data_direction dir)
140 {
141 switch (dir) {
142 case DMA_FROM_DEVICE:
143 dma_cache_inv(paddr, size);
144 break;
145 case DMA_TO_DEVICE:
146 dma_cache_wback(paddr, size);
147 break;
148 case DMA_BIDIRECTIONAL:
149 dma_cache_wback_inv(paddr, size);
150 break;
151 default:
152 pr_err("Invalid DMA dir [%d] for OP @ %pa[p]\n", dir, &paddr);
153 }
154 }
155
156 static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
157 unsigned long offset, size_t size, enum dma_data_direction dir,
158 unsigned long attrs)
159 {
160 phys_addr_t paddr = page_to_phys(page) + offset;
161 _dma_cache_sync(paddr, size, dir);
162 return plat_phys_to_dma(dev, paddr);
163 }
164
165 static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
166 int nents, enum dma_data_direction dir, unsigned long attrs)
167 {
168 struct scatterlist *s;
169 int i;
170
171 for_each_sg(sg, s, nents, i)
172 s->dma_address = dma_map_page(dev, sg_page(s), s->offset,
173 s->length, dir);
174
175 return nents;
176 }
177
178 static void arc_dma_sync_single_for_cpu(struct device *dev,
179 dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
180 {
181 _dma_cache_sync(plat_dma_to_phys(dev, dma_handle), size, DMA_FROM_DEVICE);
182 }
183
184 static void arc_dma_sync_single_for_device(struct device *dev,
185 dma_addr_t dma_handle, size_t size, enum dma_data_direction dir)
186 {
187 _dma_cache_sync(plat_dma_to_phys(dev, dma_handle), size, DMA_TO_DEVICE);
188 }
189
190 static void arc_dma_sync_sg_for_cpu(struct device *dev,
191 struct scatterlist *sglist, int nelems,
192 enum dma_data_direction dir)
193 {
194 int i;
195 struct scatterlist *sg;
196
197 for_each_sg(sglist, sg, nelems, i)
198 _dma_cache_sync(sg_phys(sg), sg->length, dir);
199 }
200
201 static void arc_dma_sync_sg_for_device(struct device *dev,
202 struct scatterlist *sglist, int nelems,
203 enum dma_data_direction dir)
204 {
205 int i;
206 struct scatterlist *sg;
207
208 for_each_sg(sglist, sg, nelems, i)
209 _dma_cache_sync(sg_phys(sg), sg->length, dir);
210 }
211
212 static int arc_dma_supported(struct device *dev, u64 dma_mask)
213 {
214 /* Support 32 bit DMA mask exclusively */
215 return dma_mask == DMA_BIT_MASK(32);
216 }
217
218 struct dma_map_ops arc_dma_ops = {
219 .alloc = arc_dma_alloc,
220 .free = arc_dma_free,
221 .mmap = arc_dma_mmap,
222 .map_page = arc_dma_map_page,
223 .map_sg = arc_dma_map_sg,
224 .sync_single_for_device = arc_dma_sync_single_for_device,
225 .sync_single_for_cpu = arc_dma_sync_single_for_cpu,
226 .sync_sg_for_cpu = arc_dma_sync_sg_for_cpu,
227 .sync_sg_for_device = arc_dma_sync_sg_for_device,
228 .dma_supported = arc_dma_supported,
229 };
230 EXPORT_SYMBOL(arc_dma_ops);