1/*
2    User DMA
3
4    Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
5    Copyright (C) 2004  Chris Kennedy <c@groovy.org>
6    Copyright (C) 2005-2007  Hans Verkuil <hverkuil@xs4all.nl>
7
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 2 of the License, or
11    (at your option) any later version.
12
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17
18    You should have received a copy of the GNU General Public License
19    along with this program; if not, write to the Free Software
20    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21 */
22
23#include "ivtv-driver.h"
24#include "ivtv-streams.h"
25#include "ivtv-udma.h"
26
27void ivtv_udma_get_page_info(struct ivtv_dma_page_info *dma_page, unsigned long first, unsigned long size)
28{
29	dma_page->uaddr = first & PAGE_MASK;
30	dma_page->offset = first & ~PAGE_MASK;
31	dma_page->tail = 1 + ((first+size-1) & ~PAGE_MASK);
32	dma_page->first = (first & PAGE_MASK) >> PAGE_SHIFT;
33	dma_page->last = ((first+size-1) & PAGE_MASK) >> PAGE_SHIFT;
34	dma_page->page_count = dma_page->last - dma_page->first + 1;
35	if (dma_page->page_count == 1) dma_page->tail -= dma_page->offset;
36}
37
38int ivtv_udma_fill_sg_list (struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset)
39{
40	int i, offset;
41
42	offset = dma_page->offset;
43
44	/* Fill SG Array with new values */
45	for (i = 0; i < dma_page->page_count; i++) {
46		if (i == dma_page->page_count - 1) {
47			dma->SGlist[map_offset].length = dma_page->tail;
48		}
49		else {
50			dma->SGlist[map_offset].length = PAGE_SIZE - offset;
51		}
52		dma->SGlist[map_offset].offset = offset;
53		dma->SGlist[map_offset].page = dma->map[map_offset];
54		offset = 0;
55		map_offset++;
56	}
57	return map_offset;
58}
59
60void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32 buffer_offset_2, u32 split) {
61	int i;
62	struct scatterlist *sg;
63
64	for (i = 0, sg = dma->SGlist; i < dma->SG_length; i++, sg++) {
65		dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg));
66		dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg));
67		dma->SGarray[i].dst = cpu_to_le32(buffer_offset);
68		buffer_offset += sg_dma_len(sg);
69
70		split -= sg_dma_len(sg);
71		if (split == 0)
72			buffer_offset = buffer_offset_2;
73	}
74}
75
76/* User DMA Buffers */
77void ivtv_udma_alloc(struct ivtv *itv)
78{
79	if (itv->udma.SG_handle == 0) {
80		/* Map DMA Page Array Buffer */
81		itv->udma.SG_handle = pci_map_single(itv->dev, itv->udma.SGarray,
82			   sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE);
83		ivtv_udma_sync_for_cpu(itv);
84	}
85}
86
87int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
88		       void __user *userbuf, int size_in_bytes)
89{
90	struct ivtv_dma_page_info user_dma;
91	struct ivtv_user_dma *dma = &itv->udma;
92	int err;
93
94	IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr);
95
96	/* Still in USE */
97	if (dma->SG_length || dma->page_count) {
98		IVTV_DEBUG_WARN("ivtv_udma_setup: SG_length %d page_count %d still full?\n",
99			   dma->SG_length, dma->page_count);
100		return -EBUSY;
101	}
102
103	ivtv_udma_get_page_info(&user_dma, (unsigned long)userbuf, size_in_bytes);
104
105	if (user_dma.page_count <= 0) {
106		IVTV_DEBUG_WARN("ivtv_udma_setup: Error %d page_count from %d bytes %d offset\n",
107			   user_dma.page_count, size_in_bytes, user_dma.offset);
108		return -EINVAL;
109	}
110
111	/* Get user pages for DMA Xfer */
112	down_read(&current->mm->mmap_sem);
113	err = get_user_pages(current, current->mm,
114			user_dma.uaddr, user_dma.page_count, 0, 1, dma->map, NULL);
115	up_read(&current->mm->mmap_sem);
116
117	if (user_dma.page_count != err) {
118		IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
119			   err, user_dma.page_count);
120		return -EINVAL;
121	}
122
123	dma->page_count = user_dma.page_count;
124
125	/* Fill SG List with new values */
126	ivtv_udma_fill_sg_list(dma, &user_dma, 0);
127
128	/* Map SG List */
129	dma->SG_length = pci_map_sg(itv->dev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE);
130
131	/* Fill SG Array with new values */
132	ivtv_udma_fill_sg_array (dma, ivtv_dest_addr, 0, -1);
133
134	/* Tag SG Array with Interrupt Bit */
135	dma->SGarray[dma->SG_length - 1].size |= cpu_to_le32(0x80000000);
136
137	ivtv_udma_sync_for_device(itv);
138	return dma->page_count;
139}
140
141void ivtv_udma_unmap(struct ivtv *itv)
142{
143	struct ivtv_user_dma *dma = &itv->udma;
144	int i;
145
146	IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");
147
148	/* Nothing to free */
149	if (dma->page_count == 0)
150		return;
151
152	/* Unmap Scatterlist */
153	if (dma->SG_length) {
154		pci_unmap_sg(itv->dev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE);
155		dma->SG_length = 0;
156	}
157	/* sync DMA */
158	ivtv_udma_sync_for_cpu(itv);
159
160	/* Release User Pages */
161	for (i = 0; i < dma->page_count; i++) {
162		put_page(dma->map[i]);
163	}
164	dma->page_count = 0;
165}
166
167void ivtv_udma_free(struct ivtv *itv)
168{
169	/* Unmap SG Array */
170	if (itv->udma.SG_handle) {
171		pci_unmap_single(itv->dev, itv->udma.SG_handle,
172			 sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE);
173	}
174
175	/* Unmap Scatterlist */
176	if (itv->udma.SG_length) {
177		pci_unmap_sg(itv->dev, itv->udma.SGlist, itv->udma.page_count, PCI_DMA_TODEVICE);
178	}
179}
180
181void ivtv_udma_start(struct ivtv *itv)
182{
183	IVTV_DEBUG_DMA("start UDMA\n");
184	write_reg(itv->udma.SG_handle, IVTV_REG_DECDMAADDR);
185	write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER);
186	set_bit(IVTV_F_I_DMA, &itv->i_flags);
187	set_bit(IVTV_F_I_UDMA, &itv->i_flags);
188}
189
190void ivtv_udma_prepare(struct ivtv *itv)
191{
192	unsigned long flags;
193
194	spin_lock_irqsave(&itv->dma_reg_lock, flags);
195	if (!test_bit(IVTV_F_I_DMA, &itv->i_flags))
196		ivtv_udma_start(itv);
197	else
198		set_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
199	spin_unlock_irqrestore(&itv->dma_reg_lock, flags);
200}
201