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 
ivtv_udma_get_page_info(struct ivtv_dma_page_info * dma_page,unsigned long first,unsigned long size)14 void 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 
ivtv_udma_fill_sg_list(struct ivtv_user_dma * dma,struct ivtv_dma_page_info * dma_page,int map_offset)25 int 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(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(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(&dma->SGlist[map_offset], dma->bouncemap[map_offset], len, offset);
53 		}
54 		else {
55 			sg_set_page(&dma->SGlist[map_offset], dma->map[map_offset], len, offset);
56 		}
57 		offset = 0;
58 		map_offset++;
59 	}
60 	return map_offset;
61 }
62 
ivtv_udma_fill_sg_array(struct ivtv_user_dma * dma,u32 buffer_offset,u32 buffer_offset_2,u32 split)63 void 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 */
ivtv_udma_alloc(struct ivtv * itv)80 void 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 
ivtv_udma_setup(struct ivtv * itv,unsigned long ivtv_dest_addr,void __user * userbuf,int size_in_bytes)92 int 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(&user_dma, (unsigned long)userbuf, 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(user_dma.uaddr, user_dma.page_count,
118 			dma->map, 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(dma->map, 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, &user_dma, 0) < 0) {
134 		unpin_user_pages(dma->map, 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, ivtv_dest_addr, 0, -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 
ivtv_udma_unmap(struct ivtv * itv)153 void 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(dma->map, dma->page_count);
173 	dma->page_count = 0;
174 }
175 
ivtv_udma_free(struct ivtv * itv)176 void 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 
ivtv_udma_start(struct ivtv * itv)198 void 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, &itv->i_flags);
204 	set_bit(IVTV_F_I_UDMA, &itv->i_flags);
205 	clear_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
206 }
207 
ivtv_udma_prepare(struct ivtv * itv)208 void 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, &itv->i_flags);
217 	spin_unlock_irqrestore(&itv->dma_reg_lock, flags);
218 }
219