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1/*
2 * OpenRISC Linux
3 *
4 * Linux architectural port borrowing liberally from similar works of
5 * others. All original copyrights apply as per the original source
6 * declaration.
7 *
8 * Modifications for the OpenRISC architecture:
9 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version
15 * 2 of the License, or (at your option) any later version.
16 *
17 * DMA mapping callbacks...
18 * As alloc_coherent is the only DMA callback being used currently, that's
19 * the only thing implemented properly. The rest need looking into...
20 */
21
22#include <linux/dma-mapping.h>
23#include <linux/dma-debug.h>
24#include <linux/export.h>
25
26#include <asm/cpuinfo.h>
27#include <asm/spr_defs.h>
28#include <asm/tlbflush.h>
29
30static int
31page_set_nocache(pte_t *pte, unsigned long addr,
32 unsigned long next, struct mm_walk *walk)
33{
34 unsigned long cl;
35 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
36
37 pte_val(*pte) |= _PAGE_CI;
38
39 /*
40 * Flush the page out of the TLB so that the new page flags get
41 * picked up next time there's an access
42 */
43 flush_tlb_page(NULL, addr);
44
45 /* Flush page out of dcache */
46 for (cl = __pa(addr); cl < __pa(next); cl += cpuinfo->dcache_block_size)
47 mtspr(SPR_DCBFR, cl);
48
49 return 0;
50}
51
52static int
53page_clear_nocache(pte_t *pte, unsigned long addr,
54 unsigned long next, struct mm_walk *walk)
55{
56 pte_val(*pte) &= ~_PAGE_CI;
57
58 /*
59 * Flush the page out of the TLB so that the new page flags get
60 * picked up next time there's an access
61 */
62 flush_tlb_page(NULL, addr);
63
64 return 0;
65}
66
67/*
68 * Alloc "coherent" memory, which for OpenRISC means simply uncached.
69 *
70 * This function effectively just calls __get_free_pages, sets the
71 * cache-inhibit bit on those pages, and makes sure that the pages are
72 * flushed out of the cache before they are used.
73 *
74 * If the NON_CONSISTENT attribute is set, then this function just
75 * returns "normal", cachable memory.
76 *
77 * There are additional flags WEAK_ORDERING and WRITE_COMBINE to take
78 * into consideration here, too. All current known implementations of
79 * the OR1K support only strongly ordered memory accesses, so that flag
80 * is being ignored for now; uncached but write-combined memory is a
81 * missing feature of the OR1K.
82 */
83static void *
84or1k_dma_alloc(struct device *dev, size_t size,
85 dma_addr_t *dma_handle, gfp_t gfp,
86 unsigned long attrs)
87{
88 unsigned long va;
89 void *page;
90 struct mm_walk walk = {
91 .pte_entry = page_set_nocache,
92 .mm = &init_mm
93 };
94
95 page = alloc_pages_exact(size, gfp);
96 if (!page)
97 return NULL;
98
99 /* This gives us the real physical address of the first page. */
100 *dma_handle = __pa(page);
101
102 va = (unsigned long)page;
103
104 if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
105 /*
106 * We need to iterate through the pages, clearing the dcache for
107 * them and setting the cache-inhibit bit.
108 */
109 if (walk_page_range(va, va + size, &walk)) {
110 free_pages_exact(page, size);
111 return NULL;
112 }
113 }
114
115 return (void *)va;
116}
117
118static void
119or1k_dma_free(struct device *dev, size_t size, void *vaddr,
120 dma_addr_t dma_handle, unsigned long attrs)
121{
122 unsigned long va = (unsigned long)vaddr;
123 struct mm_walk walk = {
124 .pte_entry = page_clear_nocache,
125 .mm = &init_mm
126 };
127
128 if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
129 /* walk_page_range shouldn't be able to fail here */
130 WARN_ON(walk_page_range(va, va + size, &walk));
131 }
132
133 free_pages_exact(vaddr, size);
134}
135
136static dma_addr_t
137or1k_map_page(struct device *dev, struct page *page,
138 unsigned long offset, size_t size,
139 enum dma_data_direction dir,
140 unsigned long attrs)
141{
142 unsigned long cl;
143 dma_addr_t addr = page_to_phys(page) + offset;
144 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
145
146 if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
147 return addr;
148
149 switch (dir) {
150 case DMA_TO_DEVICE:
151 /* Flush the dcache for the requested range */
152 for (cl = addr; cl < addr + size;
153 cl += cpuinfo->dcache_block_size)
154 mtspr(SPR_DCBFR, cl);
155 break;
156 case DMA_FROM_DEVICE:
157 /* Invalidate the dcache for the requested range */
158 for (cl = addr; cl < addr + size;
159 cl += cpuinfo->dcache_block_size)
160 mtspr(SPR_DCBIR, cl);
161 break;
162 default:
163 /*
164 * NOTE: If dir == DMA_BIDIRECTIONAL then there's no need to
165 * flush nor invalidate the cache here as the area will need
166 * to be manually synced anyway.
167 */
168 break;
169 }
170
171 return addr;
172}
173
174static void
175or1k_unmap_page(struct device *dev, dma_addr_t dma_handle,
176 size_t size, enum dma_data_direction dir,
177 unsigned long attrs)
178{
179 /* Nothing special to do here... */
180}
181
182static int
183or1k_map_sg(struct device *dev, struct scatterlist *sg,
184 int nents, enum dma_data_direction dir,
185 unsigned long attrs)
186{
187 struct scatterlist *s;
188 int i;
189
190 for_each_sg(sg, s, nents, i) {
191 s->dma_address = or1k_map_page(dev, sg_page(s), s->offset,
192 s->length, dir, 0);
193 }
194
195 return nents;
196}
197
198static void
199or1k_unmap_sg(struct device *dev, struct scatterlist *sg,
200 int nents, enum dma_data_direction dir,
201 unsigned long attrs)
202{
203 struct scatterlist *s;
204 int i;
205
206 for_each_sg(sg, s, nents, i) {
207 or1k_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, 0);
208 }
209}
210
211static void
212or1k_sync_single_for_cpu(struct device *dev,
213 dma_addr_t dma_handle, size_t size,
214 enum dma_data_direction dir)
215{
216 unsigned long cl;
217 dma_addr_t addr = dma_handle;
218 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
219
220 /* Invalidate the dcache for the requested range */
221 for (cl = addr; cl < addr + size; cl += cpuinfo->dcache_block_size)
222 mtspr(SPR_DCBIR, cl);
223}
224
225static void
226or1k_sync_single_for_device(struct device *dev,
227 dma_addr_t dma_handle, size_t size,
228 enum dma_data_direction dir)
229{
230 unsigned long cl;
231 dma_addr_t addr = dma_handle;
232 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
233
234 /* Flush the dcache for the requested range */
235 for (cl = addr; cl < addr + size; cl += cpuinfo->dcache_block_size)
236 mtspr(SPR_DCBFR, cl);
237}
238
239const struct dma_map_ops or1k_dma_map_ops = {
240 .alloc = or1k_dma_alloc,
241 .free = or1k_dma_free,
242 .map_page = or1k_map_page,
243 .unmap_page = or1k_unmap_page,
244 .map_sg = or1k_map_sg,
245 .unmap_sg = or1k_unmap_sg,
246 .sync_single_for_cpu = or1k_sync_single_for_cpu,
247 .sync_single_for_device = or1k_sync_single_for_device,
248};
249EXPORT_SYMBOL(or1k_dma_map_ops);
250
251/* Number of entries preallocated for DMA-API debugging */
252#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
253
254static int __init dma_init(void)
255{
256 dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
257
258 return 0;
259}
260fs_initcall(dma_init);
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC Linux
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
12 *
13 * DMA mapping callbacks...
14 * As alloc_coherent is the only DMA callback being used currently, that's
15 * the only thing implemented properly. The rest need looking into...
16 */
17
18#include <linux/dma-noncoherent.h>
19#include <linux/pagewalk.h>
20
21#include <asm/cpuinfo.h>
22#include <asm/spr_defs.h>
23#include <asm/tlbflush.h>
24
25static int
26page_set_nocache(pte_t *pte, unsigned long addr,
27 unsigned long next, struct mm_walk *walk)
28{
29 unsigned long cl;
30 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
31
32 pte_val(*pte) |= _PAGE_CI;
33
34 /*
35 * Flush the page out of the TLB so that the new page flags get
36 * picked up next time there's an access
37 */
38 flush_tlb_page(NULL, addr);
39
40 /* Flush page out of dcache */
41 for (cl = __pa(addr); cl < __pa(next); cl += cpuinfo->dcache_block_size)
42 mtspr(SPR_DCBFR, cl);
43
44 return 0;
45}
46
47static const struct mm_walk_ops set_nocache_walk_ops = {
48 .pte_entry = page_set_nocache,
49};
50
51static int
52page_clear_nocache(pte_t *pte, unsigned long addr,
53 unsigned long next, struct mm_walk *walk)
54{
55 pte_val(*pte) &= ~_PAGE_CI;
56
57 /*
58 * Flush the page out of the TLB so that the new page flags get
59 * picked up next time there's an access
60 */
61 flush_tlb_page(NULL, addr);
62
63 return 0;
64}
65
66static const struct mm_walk_ops clear_nocache_walk_ops = {
67 .pte_entry = page_clear_nocache,
68};
69
70/*
71 * Alloc "coherent" memory, which for OpenRISC means simply uncached.
72 *
73 * This function effectively just calls __get_free_pages, sets the
74 * cache-inhibit bit on those pages, and makes sure that the pages are
75 * flushed out of the cache before they are used.
76 *
77 * If the NON_CONSISTENT attribute is set, then this function just
78 * returns "normal", cachable memory.
79 *
80 * There are additional flags WEAK_ORDERING and WRITE_COMBINE to take
81 * into consideration here, too. All current known implementations of
82 * the OR1K support only strongly ordered memory accesses, so that flag
83 * is being ignored for now; uncached but write-combined memory is a
84 * missing feature of the OR1K.
85 */
86void *
87arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
88 gfp_t gfp, unsigned long attrs)
89{
90 unsigned long va;
91 void *page;
92
93 page = alloc_pages_exact(size, gfp | __GFP_ZERO);
94 if (!page)
95 return NULL;
96
97 /* This gives us the real physical address of the first page. */
98 *dma_handle = __pa(page);
99
100 va = (unsigned long)page;
101
102 /*
103 * We need to iterate through the pages, clearing the dcache for
104 * them and setting the cache-inhibit bit.
105 */
106 if (walk_page_range(&init_mm, va, va + size, &set_nocache_walk_ops,
107 NULL)) {
108 free_pages_exact(page, size);
109 return NULL;
110 }
111
112 return (void *)va;
113}
114
115void
116arch_dma_free(struct device *dev, size_t size, void *vaddr,
117 dma_addr_t dma_handle, unsigned long attrs)
118{
119 unsigned long va = (unsigned long)vaddr;
120
121 /* walk_page_range shouldn't be able to fail here */
122 WARN_ON(walk_page_range(&init_mm, va, va + size,
123 &clear_nocache_walk_ops, NULL));
124
125 free_pages_exact(vaddr, size);
126}
127
128void arch_sync_dma_for_device(struct device *dev, phys_addr_t addr, size_t size,
129 enum dma_data_direction dir)
130{
131 unsigned long cl;
132 struct cpuinfo_or1k *cpuinfo = &cpuinfo_or1k[smp_processor_id()];
133
134 switch (dir) {
135 case DMA_TO_DEVICE:
136 /* Flush the dcache for the requested range */
137 for (cl = addr; cl < addr + size;
138 cl += cpuinfo->dcache_block_size)
139 mtspr(SPR_DCBFR, cl);
140 break;
141 case DMA_FROM_DEVICE:
142 /* Invalidate the dcache for the requested range */
143 for (cl = addr; cl < addr + size;
144 cl += cpuinfo->dcache_block_size)
145 mtspr(SPR_DCBIR, cl);
146 break;
147 default:
148 /*
149 * NOTE: If dir == DMA_BIDIRECTIONAL then there's no need to
150 * flush nor invalidate the cache here as the area will need
151 * to be manually synced anyway.
152 */
153 break;
154 }
155}