1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 User DMA
4
5 Copyright (C) 2003-2004 Kevin Thayer <nufan_wfk at yahoo.com>
6 Copyright (C) 2004 Chris Kennedy <c@groovy.org>
7 Copyright (C) 2005-2007 Hans Verkuil <hverkuil@xs4all.nl>
8
9 */
10
11#include "ivtv-driver.h"
12#include "ivtv-udma.h"
13
14void ivtv_udma_get_page_info(struct ivtv_dma_page_info *dma_page, unsigned long first, unsigned long size)
15{
16 dma_page->uaddr = first & PAGE_MASK;
17 dma_page->offset = first & ~PAGE_MASK;
18 dma_page->tail = 1 + ((first+size-1) & ~PAGE_MASK);
19 dma_page->first = (first & PAGE_MASK) >> PAGE_SHIFT;
20 dma_page->last = ((first+size-1) & PAGE_MASK) >> PAGE_SHIFT;
21 dma_page->page_count = dma_page->last - dma_page->first + 1;
22 if (dma_page->page_count == 1) dma_page->tail -= dma_page->offset;
23}
24
25int ivtv_udma_fill_sg_list (struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset)
26{
27 int i, offset;
28 unsigned long flags;
29
30 if (map_offset < 0)
31 return map_offset;
32
33 offset = dma_page->offset;
34
35 /* Fill SG Array with new values */
36 for (i = 0; i < dma_page->page_count; i++) {
37 unsigned int len = (i == dma_page->page_count - 1) ?
38 dma_page->tail : PAGE_SIZE - offset;
39
40 if (PageHighMem(page: dma->map[map_offset])) {
41 void *src;
42
43 if (dma->bouncemap[map_offset] == NULL)
44 dma->bouncemap[map_offset] = alloc_page(GFP_KERNEL);
45 if (dma->bouncemap[map_offset] == NULL)
46 return -1;
47 local_irq_save(flags);
48 src = kmap_atomic(page: dma->map[map_offset]) + offset;
49 memcpy(page_address(dma->bouncemap[map_offset]) + offset, src, len);
50 kunmap_atomic(src);
51 local_irq_restore(flags);
52 sg_set_page(sg: &dma->SGlist[map_offset], page: dma->bouncemap[map_offset], len, offset);
53 }
54 else {
55 sg_set_page(sg: &dma->SGlist[map_offset], page: dma->map[map_offset], len, offset);
56 }
57 offset = 0;
58 map_offset++;
59 }
60 return map_offset;
61}
62
63void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32 buffer_offset_2, u32 split) {
64 int i;
65 struct scatterlist *sg;
66
67 for_each_sg(dma->SGlist, sg, dma->SG_length, i) {
68 dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg));
69 dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg));
70 dma->SGarray[i].dst = cpu_to_le32(buffer_offset);
71 buffer_offset += sg_dma_len(sg);
72
73 split -= sg_dma_len(sg);
74 if (split == 0)
75 buffer_offset = buffer_offset_2;
76 }
77}
78
79/* User DMA Buffers */
80void ivtv_udma_alloc(struct ivtv *itv)
81{
82 if (itv->udma.SG_handle == 0) {
83 /* Map DMA Page Array Buffer */
84 itv->udma.SG_handle = dma_map_single(&itv->pdev->dev,
85 itv->udma.SGarray,
86 sizeof(itv->udma.SGarray),
87 DMA_TO_DEVICE);
88 ivtv_udma_sync_for_cpu(itv);
89 }
90}
91
92int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
93 void __user *userbuf, int size_in_bytes)
94{
95 struct ivtv_dma_page_info user_dma;
96 struct ivtv_user_dma *dma = &itv->udma;
97 int err;
98
99 IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr);
100
101 /* Still in USE */
102 if (dma->SG_length || dma->page_count) {
103 IVTV_DEBUG_WARN("ivtv_udma_setup: SG_length %d page_count %d still full?\n",
104 dma->SG_length, dma->page_count);
105 return -EBUSY;
106 }
107
108 ivtv_udma_get_page_info(dma_page: &user_dma, first: (unsigned long)userbuf, size: size_in_bytes);
109
110 if (user_dma.page_count <= 0) {
111 IVTV_DEBUG_WARN("ivtv_udma_setup: Error %d page_count from %d bytes %d offset\n",
112 user_dma.page_count, size_in_bytes, user_dma.offset);
113 return -EINVAL;
114 }
115
116 /* Pin user pages for DMA Xfer */
117 err = pin_user_pages_unlocked(start: user_dma.uaddr, nr_pages: user_dma.page_count,
118 pages: dma->map, gup_flags: 0);
119
120 if (user_dma.page_count != err) {
121 IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
122 err, user_dma.page_count);
123 if (err >= 0) {
124 unpin_user_pages(pages: dma->map, npages: err);
125 return -EINVAL;
126 }
127 return err;
128 }
129
130 dma->page_count = user_dma.page_count;
131
132 /* Fill SG List with new values */
133 if (ivtv_udma_fill_sg_list(dma, dma_page: &user_dma, map_offset: 0) < 0) {
134 unpin_user_pages(pages: dma->map, npages: dma->page_count);
135 dma->page_count = 0;
136 return -ENOMEM;
137 }
138
139 /* Map SG List */
140 dma->SG_length = dma_map_sg(&itv->pdev->dev, dma->SGlist,
141 dma->page_count, DMA_TO_DEVICE);
142
143 /* Fill SG Array with new values */
144 ivtv_udma_fill_sg_array (dma, buffer_offset: ivtv_dest_addr, buffer_offset_2: 0, split: -1);
145
146 /* Tag SG Array with Interrupt Bit */
147 dma->SGarray[dma->SG_length - 1].size |= cpu_to_le32(0x80000000);
148
149 ivtv_udma_sync_for_device(itv);
150 return dma->page_count;
151}
152
153void ivtv_udma_unmap(struct ivtv *itv)
154{
155 struct ivtv_user_dma *dma = &itv->udma;
156
157 IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");
158
159 /* Nothing to free */
160 if (dma->page_count == 0)
161 return;
162
163 /* Unmap Scatterlist */
164 if (dma->SG_length) {
165 dma_unmap_sg(&itv->pdev->dev, dma->SGlist, dma->page_count,
166 DMA_TO_DEVICE);
167 dma->SG_length = 0;
168 }
169 /* sync DMA */
170 ivtv_udma_sync_for_cpu(itv);
171
172 unpin_user_pages(pages: dma->map, npages: dma->page_count);
173 dma->page_count = 0;
174}
175
176void ivtv_udma_free(struct ivtv *itv)
177{
178 int i;
179
180 /* Unmap SG Array */
181 if (itv->udma.SG_handle) {
182 dma_unmap_single(&itv->pdev->dev, itv->udma.SG_handle,
183 sizeof(itv->udma.SGarray), DMA_TO_DEVICE);
184 }
185
186 /* Unmap Scatterlist */
187 if (itv->udma.SG_length) {
188 dma_unmap_sg(&itv->pdev->dev, itv->udma.SGlist,
189 itv->udma.page_count, DMA_TO_DEVICE);
190 }
191
192 for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) {
193 if (itv->udma.bouncemap[i])
194 __free_page(itv->udma.bouncemap[i]);
195 }
196}
197
198void ivtv_udma_start(struct ivtv *itv)
199{
200 IVTV_DEBUG_DMA("start UDMA\n");
201 write_reg(itv->udma.SG_handle, IVTV_REG_DECDMAADDR);
202 write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER);
203 set_bit(IVTV_F_I_DMA, addr: &itv->i_flags);
204 set_bit(IVTV_F_I_UDMA, addr: &itv->i_flags);
205 clear_bit(IVTV_F_I_UDMA_PENDING, addr: &itv->i_flags);
206}
207
208void ivtv_udma_prepare(struct ivtv *itv)
209{
210 unsigned long flags;
211
212 spin_lock_irqsave(&itv->dma_reg_lock, flags);
213 if (!test_bit(IVTV_F_I_DMA, &itv->i_flags))
214 ivtv_udma_start(itv);
215 else
216 set_bit(IVTV_F_I_UDMA_PENDING, addr: &itv->i_flags);
217 spin_unlock_irqrestore(lock: &itv->dma_reg_lock, flags);
218}
219

source code of linux/drivers/media/pci/ivtv/ivtv-udma.c