err.no Git - linux-2.6/blob

1 /*

2 * linux/arch/arm/kernel/dma.c

3 *

5 *

6 * This program is free software; you can redistribute it and/or modify

7 * it under the terms of the GNU General Public License version 2 as

8 * published by the Free Software Foundation.

9 *

10 * Front-end to the DMA handling. This handles the allocation/freeing

11 * of DMA channels, and provides a unified interface to the machines

12 * DMA facilities.

13 */

14 #include <linux/module.h>

15 #include <linux/slab.h>

16 #include <linux/mman.h>

17 #include <linux/init.h>

18 #include <linux/spinlock.h>

19 #include <linux/errno.h>

21 #include <asm/dma.h>

23 #include <asm/mach/dma.h>

25 DEFINE_SPINLOCK(dma_spin_lock);

27 #if MAX_DMA_CHANNELS > 0

29 static dma_t dma_chan[MAX_DMA_CHANNELS];

31 /*

32 * Get dma list for /proc/dma

33 */

34 int get_dma_list(char *buf)

35 {

36 dma_t *dma;

37 char *p = buf;

38 int i;

40 for (i = 0, dma = dma_chan; i < MAX_DMA_CHANNELS; i++, dma++)

41 if (dma->lock)

42 p += sprintf(p, "%2d: %14s %s\n", i,

43 dma->d_ops->type, dma->device_id);

45 return p - buf;

46 }

48 /*

49 * Request DMA channel

50 *

51 * On certain platforms, we have to allocate an interrupt as well...

52 */

53 int request_dma(dmach_t channel, const char *device_id)

54 {

55 dma_t *dma = dma_chan + channel;

56 int ret;

58 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)

59 goto bad_dma;

61 if (xchg(&dma->lock, 1) != 0)

62 goto busy;

64 dma->device_id = device_id;

65 dma->active = 0;

66 dma->invalid = 1;

68 ret = 0;

69 if (dma->d_ops->request)

70 ret = dma->d_ops->request(channel, dma);

72 if (ret)

73 xchg(&dma->lock, 0);

75 return ret;

77 bad_dma:

78 printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel);

79 return -EINVAL;

81 busy:

82 return -EBUSY;

83 }

85 /*

86 * Free DMA channel

87 *

88 * On certain platforms, we have to free interrupt as well...

89 */

90 void free_dma(dmach_t channel)

91 {

92 dma_t *dma = dma_chan + channel;

94 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)

95 goto bad_dma;

97 if (dma->active) {

98 printk(KERN_ERR "dma%d: freeing active DMA\n", channel);

99 dma->d_ops->disable(channel, dma);

100 dma->active = 0;

101 }

102

103 if (xchg(&dma->lock, 0) != 0) {

104 if (dma->d_ops->free)

105 dma->d_ops->free(channel, dma);

106 return;

107 }

108

109 printk(KERN_ERR "dma%d: trying to free free DMA\n", channel);

110 return;

111

112 bad_dma:

113 printk(KERN_ERR "dma: trying to free DMA%d\n", channel);

114 }

115

116 /* Set DMA Scatter-Gather list

117 */

118 void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg)

119 {

120 dma_t *dma = dma_chan + channel;

121

122 if (dma->active)

123 printk(KERN_ERR "dma%d: altering DMA SG while "

124 "DMA active\n", channel);

125

126 dma->sg = sg;

127 dma->sgcount = nr_sg;

128 dma->using_sg = 1;

129 dma->invalid = 1;

130 }

131

132 /* Set DMA address

133 *

134 * Copy address to the structure, and set the invalid bit

135 */

136 void set_dma_addr (dmach_t channel, unsigned long physaddr)

137 {

138 dma_t *dma = dma_chan + channel;

139

140 if (dma->active)

141 printk(KERN_ERR "dma%d: altering DMA address while "

142 "DMA active\n", channel);

143

144 dma->sg = &dma->buf;

145 dma->sgcount = 1;

146 dma->buf.__address = bus_to_virt(physaddr);

147 dma->using_sg = 0;

148 dma->invalid = 1;

149 }

150

151 /* Set DMA byte count

152 *

153 * Copy address to the structure, and set the invalid bit

154 */

155 void set_dma_count (dmach_t channel, unsigned long count)

156 {

157 dma_t *dma = dma_chan + channel;

158

159 if (dma->active)

160 printk(KERN_ERR "dma%d: altering DMA count while "

161 "DMA active\n", channel);

162

163 dma->sg = &dma->buf;

164 dma->sgcount = 1;

165 dma->buf.length = count;

166 dma->using_sg = 0;

167 dma->invalid = 1;

168 }

169

170 /* Set DMA direction mode

171 */

172 void set_dma_mode (dmach_t channel, dmamode_t mode)

173 {

174 dma_t *dma = dma_chan + channel;

175

176 if (dma->active)

177 printk(KERN_ERR "dma%d: altering DMA mode while "

178 "DMA active\n", channel);

179

180 dma->dma_mode = mode;

181 dma->invalid = 1;

182 }

183

184 /* Enable DMA channel

185 */

186 void enable_dma (dmach_t channel)

187 {

188 dma_t *dma = dma_chan + channel;

189

190 if (!dma->lock)

191 goto free_dma;

192

193 if (dma->active == 0) {

194 dma->active = 1;

195 dma->d_ops->enable(channel, dma);

196 }

197 return;

198

199 free_dma:

200 printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel);

201 BUG();

202 }

203

204 /* Disable DMA channel

205 */

206 void disable_dma (dmach_t channel)

207 {

208 dma_t *dma = dma_chan + channel;

209

210 if (!dma->lock)

211 goto free_dma;

212

213 if (dma->active == 1) {

214 dma->active = 0;

215 dma->d_ops->disable(channel, dma);

216 }

217 return;

218

219 free_dma:

220 printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel);

221 BUG();

222 }

223

224 /*

225 * Is the specified DMA channel active?

226 */

227 int dma_channel_active(dmach_t channel)

228 {

229 return dma_chan[channel].active;

230 }

231

232 void set_dma_page(dmach_t channel, char pagenr)

233 {

234 printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel);

235 }

236

237 void set_dma_speed(dmach_t channel, int cycle_ns)

238 {

239 dma_t *dma = dma_chan + channel;

240 int ret = 0;

241

242 if (dma->d_ops->setspeed)

243 ret = dma->d_ops->setspeed(channel, dma, cycle_ns);

244 dma->speed = ret;

245 }

246

247 int get_dma_residue(dmach_t channel)

248 {

249 dma_t *dma = dma_chan + channel;

250 int ret = 0;

251

252 if (dma->d_ops->residue)

253 ret = dma->d_ops->residue(channel, dma);

254

255 return ret;

256 }

257

258 void __init init_dma(void)

259 {

260 arch_dma_init(dma_chan);

261 }

262

263 #else

264

265 int request_dma(dmach_t channel, const char *device_id)

266 {

267 return -EINVAL;

268 }

269

270 int get_dma_residue(dmach_t channel)

271 {

272 return 0;

273 }

274

275 #define GLOBAL_ALIAS(_a,_b) asm (".set " #_a "," #_b "; .globl " #_a)

276 GLOBAL_ALIAS(disable_dma, get_dma_residue);

277 GLOBAL_ALIAS(enable_dma, get_dma_residue);

278 GLOBAL_ALIAS(free_dma, get_dma_residue);

279 GLOBAL_ALIAS(get_dma_list, get_dma_residue);

280 GLOBAL_ALIAS(set_dma_mode, get_dma_residue);

281 GLOBAL_ALIAS(set_dma_page, get_dma_residue);

282 GLOBAL_ALIAS(set_dma_count, get_dma_residue);

283 GLOBAL_ALIAS(set_dma_addr, get_dma_residue);

284 GLOBAL_ALIAS(set_dma_sg, get_dma_residue);

285 GLOBAL_ALIAS(set_dma_speed, get_dma_residue);

286 GLOBAL_ALIAS(init_dma, get_dma_residue);

287

288 #endif

289

290 EXPORT_SYMBOL(request_dma);

291 EXPORT_SYMBOL(free_dma);

292 EXPORT_SYMBOL(enable_dma);

293 EXPORT_SYMBOL(disable_dma);

294 EXPORT_SYMBOL(set_dma_addr);

295 EXPORT_SYMBOL(set_dma_count);

296 EXPORT_SYMBOL(set_dma_mode);

297 EXPORT_SYMBOL(set_dma_page);

298 EXPORT_SYMBOL(get_dma_residue);

299 EXPORT_SYMBOL(set_dma_sg);

300 EXPORT_SYMBOL(set_dma_speed);

301

302 EXPORT_SYMBOL(dma_spin_lock);