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>
18 #include <linux/scatterlist.h>
19 #include <linux/seq_file.h>
20 #include <linux/proc_fs.h>
24 #include <asm/mach/dma.h>
26 DEFINE_RAW_SPINLOCK(dma_spin_lock);
27 EXPORT_SYMBOL(dma_spin_lock);
29 static dma_t *dma_chan[MAX_DMA_CHANNELS];
31 static inline dma_t *dma_channel(unsigned int chan)
33 if (chan >= MAX_DMA_CHANNELS)
36 return dma_chan[chan];
39 int __init isa_dma_add(unsigned int chan, dma_t *dma)
44 sg_init_table(&dma->buf, 1);
55 * On certain platforms, we have to allocate an interrupt as well...
57 int request_dma(unsigned int chan, const char *device_id)
59 dma_t *dma = dma_channel(chan);
65 if (xchg(&dma->lock, 1) != 0)
68 dma->device_id = device_id;
73 if (dma->d_ops->request)
74 ret = dma->d_ops->request(chan, dma);
82 printk(KERN_ERR "dma: trying to allocate DMA%d\n", chan);
88 EXPORT_SYMBOL(request_dma);
93 * On certain platforms, we have to free interrupt as well...
95 void free_dma(unsigned int chan)
97 dma_t *dma = dma_channel(chan);
103 printk(KERN_ERR "dma%d: freeing active DMA\n", chan);
104 dma->d_ops->disable(chan, dma);
108 if (xchg(&dma->lock, 0) != 0) {
109 if (dma->d_ops->free)
110 dma->d_ops->free(chan, dma);
114 printk(KERN_ERR "dma%d: trying to free free DMA\n", chan);
118 printk(KERN_ERR "dma: trying to free DMA%d\n", chan);
120 EXPORT_SYMBOL(free_dma);
122 /* Set DMA Scatter-Gather list
124 void set_dma_sg (unsigned int chan, struct scatterlist *sg, int nr_sg)
126 dma_t *dma = dma_channel(chan);
129 printk(KERN_ERR "dma%d: altering DMA SG while "
130 "DMA active\n", chan);
133 dma->sgcount = nr_sg;
136 EXPORT_SYMBOL(set_dma_sg);
140 * Copy address to the structure, and set the invalid bit
142 void __set_dma_addr (unsigned int chan, void *addr)
144 dma_t *dma = dma_channel(chan);
147 printk(KERN_ERR "dma%d: altering DMA address while "
148 "DMA active\n", chan);
154 EXPORT_SYMBOL(__set_dma_addr);
156 /* Set DMA byte count
158 * Copy address to the structure, and set the invalid bit
160 void set_dma_count (unsigned int chan, unsigned long count)
162 dma_t *dma = dma_channel(chan);
165 printk(KERN_ERR "dma%d: altering DMA count while "
166 "DMA active\n", chan);
172 EXPORT_SYMBOL(set_dma_count);
174 /* Set DMA direction mode
176 void set_dma_mode (unsigned int chan, unsigned int mode)
178 dma_t *dma = dma_channel(chan);
181 printk(KERN_ERR "dma%d: altering DMA mode while "
182 "DMA active\n", chan);
184 dma->dma_mode = mode;
187 EXPORT_SYMBOL(set_dma_mode);
189 /* Enable DMA channel
191 void enable_dma (unsigned int chan)
193 dma_t *dma = dma_channel(chan);
198 if (dma->active == 0) {
200 dma->d_ops->enable(chan, dma);
205 printk(KERN_ERR "dma%d: trying to enable free DMA\n", chan);
208 EXPORT_SYMBOL(enable_dma);
210 /* Disable DMA channel
212 void disable_dma (unsigned int chan)
214 dma_t *dma = dma_channel(chan);
219 if (dma->active == 1) {
221 dma->d_ops->disable(chan, dma);
226 printk(KERN_ERR "dma%d: trying to disable free DMA\n", chan);
229 EXPORT_SYMBOL(disable_dma);
232 * Is the specified DMA channel active?
234 int dma_channel_active(unsigned int chan)
236 dma_t *dma = dma_channel(chan);
239 EXPORT_SYMBOL(dma_channel_active);
241 void set_dma_page(unsigned int chan, char pagenr)
243 printk(KERN_ERR "dma%d: trying to set_dma_page\n", chan);
245 EXPORT_SYMBOL(set_dma_page);
247 void set_dma_speed(unsigned int chan, int cycle_ns)
249 dma_t *dma = dma_channel(chan);
252 if (dma->d_ops->setspeed)
253 ret = dma->d_ops->setspeed(chan, dma, cycle_ns);
256 EXPORT_SYMBOL(set_dma_speed);
258 int get_dma_residue(unsigned int chan)
260 dma_t *dma = dma_channel(chan);
263 if (dma->d_ops->residue)
264 ret = dma->d_ops->residue(chan, dma);
268 EXPORT_SYMBOL(get_dma_residue);
270 #ifdef CONFIG_PROC_FS
271 static int proc_dma_show(struct seq_file *m, void *v)
275 for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
276 dma_t *dma = dma_channel(i);
277 if (dma && dma->lock)
278 seq_printf(m, "%2d: %s\n", i, dma->device_id);
283 static int proc_dma_open(struct inode *inode, struct file *file)
285 return single_open(file, proc_dma_show, NULL);
288 static const struct file_operations proc_dma_operations = {
289 .open = proc_dma_open,
292 .release = single_release,
295 static int __init proc_dma_init(void)
297 proc_create("dma", 0, NULL, &proc_dma_operations);
301 __initcall(proc_dma_init);