2 * linux/arch/arm/kernel/dma.c
4 * Copyright (C) 1995-2000 Russell King
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.
10 * Front-end to the DMA handling. This handles the allocation/freeing
11 * of DMA channels, and provides a unified interface to the machines
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/errno.h>
21 #include <asm/mach/dma.h>
23 DEFINE_SPINLOCK(dma_spin_lock);
25 static dma_t dma_chan[MAX_DMA_CHANNELS];
28 * Get dma list for /proc/dma
30 int get_dma_list(char *buf)
36 for (i = 0, dma = dma_chan; i < MAX_DMA_CHANNELS; i++, dma++)
38 p += sprintf(p, "%2d: %14s %s\n", i,
39 dma->d_ops->type, dma->device_id);
47 * On certain platforms, we have to allocate an interrupt as well...
49 int request_dma(dmach_t channel, const char *device_id)
51 dma_t *dma = dma_chan + channel;
54 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
57 if (xchg(&dma->lock, 1) != 0)
60 dma->device_id = device_id;
65 if (dma->d_ops->request)
66 ret = dma->d_ops->request(channel, dma);
74 printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel);
84 * On certain platforms, we have to free interrupt as well...
86 void free_dma(dmach_t channel)
88 dma_t *dma = dma_chan + channel;
90 if (channel >= MAX_DMA_CHANNELS || !dma->d_ops)
94 printk(KERN_ERR "dma%d: freeing active DMA\n", channel);
95 dma->d_ops->disable(channel, dma);
99 if (xchg(&dma->lock, 0) != 0) {
100 if (dma->d_ops->free)
101 dma->d_ops->free(channel, dma);
105 printk(KERN_ERR "dma%d: trying to free free DMA\n", channel);
109 printk(KERN_ERR "dma: trying to free DMA%d\n", channel);
112 /* Set DMA Scatter-Gather list
114 void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg)
116 dma_t *dma = dma_chan + channel;
119 printk(KERN_ERR "dma%d: altering DMA SG while "
120 "DMA active\n", channel);
123 dma->sgcount = nr_sg;
129 * Copy address to the structure, and set the invalid bit
131 void __set_dma_addr (dmach_t channel, void *addr)
133 dma_t *dma = dma_chan + channel;
136 printk(KERN_ERR "dma%d: altering DMA address while "
137 "DMA active\n", channel);
144 /* Set DMA byte count
146 * Copy address to the structure, and set the invalid bit
148 void set_dma_count (dmach_t channel, unsigned long count)
150 dma_t *dma = dma_chan + channel;
153 printk(KERN_ERR "dma%d: altering DMA count while "
154 "DMA active\n", channel);
161 /* Set DMA direction mode
163 void set_dma_mode (dmach_t channel, dmamode_t mode)
165 dma_t *dma = dma_chan + channel;
168 printk(KERN_ERR "dma%d: altering DMA mode while "
169 "DMA active\n", channel);
171 dma->dma_mode = mode;
175 /* Enable DMA channel
177 void enable_dma (dmach_t channel)
179 dma_t *dma = dma_chan + channel;
184 if (dma->active == 0) {
186 dma->d_ops->enable(channel, dma);
191 printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel);
195 /* Disable DMA channel
197 void disable_dma (dmach_t channel)
199 dma_t *dma = dma_chan + channel;
204 if (dma->active == 1) {
206 dma->d_ops->disable(channel, dma);
211 printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel);
216 * Is the specified DMA channel active?
218 int dma_channel_active(dmach_t channel)
220 return dma_chan[channel].active;
223 void set_dma_page(dmach_t channel, char pagenr)
225 printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel);
228 void set_dma_speed(dmach_t channel, int cycle_ns)
230 dma_t *dma = dma_chan + channel;
233 if (dma->d_ops->setspeed)
234 ret = dma->d_ops->setspeed(channel, dma, cycle_ns);
238 int get_dma_residue(dmach_t channel)
240 dma_t *dma = dma_chan + channel;
243 if (dma->d_ops->residue)
244 ret = dma->d_ops->residue(channel, dma);
249 static int __init init_dma(void)
251 arch_dma_init(dma_chan);
255 core_initcall(init_dma);
257 EXPORT_SYMBOL(request_dma);
258 EXPORT_SYMBOL(free_dma);
259 EXPORT_SYMBOL(enable_dma);
260 EXPORT_SYMBOL(disable_dma);
261 EXPORT_SYMBOL(__set_dma_addr);
262 EXPORT_SYMBOL(set_dma_count);
263 EXPORT_SYMBOL(set_dma_mode);
264 EXPORT_SYMBOL(set_dma_page);
265 EXPORT_SYMBOL(get_dma_residue);
266 EXPORT_SYMBOL(set_dma_sg);
267 EXPORT_SYMBOL(set_dma_speed);
269 EXPORT_SYMBOL(dma_spin_lock);