/* * linux/arch/arm26/kernel/dma.c * * Copyright (C) 1995-2000 Russell King * 2003 Ian Molton * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Front-end to the DMA handling. This handles the allocation/freeing * of DMA channels, and provides a unified interface to the machines * DMA facilities. */ #include <linux/module.h> #include <linux/slab.h> #include <linux/sched.h> #include <linux/mman.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/errno.h> #include <asm/dma.h> DEFINE_SPINLOCK(dma_spin_lock); static dma_t dma_chan[MAX_DMA_CHANNELS]; /* * Get dma list for /proc/dma */ int get_dma_list(char *buf) { dma_t *dma; char *p = buf; int i; for (i = 0, dma = dma_chan; i < MAX_DMA_CHANNELS; i++, dma++) if (dma->lock) p += sprintf(p, "%2d: %14s %s\n", i, dma->d_ops->type, dma->device_id); return p - buf; } /* * Request DMA channel * * On certain platforms, we have to allocate an interrupt as well... */ int request_dma(dmach_t channel, const char *device_id) { dma_t *dma = dma_chan + channel; int ret; if (channel >= MAX_DMA_CHANNELS || !dma->d_ops) goto bad_dma; if (xchg(&dma->lock, 1) != 0) goto busy; dma->device_id = device_id; dma->active = 0; dma->invalid = 1; ret = 0; if (dma->d_ops->request) ret = dma->d_ops->request(channel, dma); if (ret) xchg(&dma->lock, 0); return ret; bad_dma: printk(KERN_ERR "dma: trying to allocate DMA%d\n", channel); return -EINVAL; busy: return -EBUSY; } /* * Free DMA channel * * On certain platforms, we have to free interrupt as well... */ void free_dma(dmach_t channel) { dma_t *dma = dma_chan + channel; if (channel >= MAX_DMA_CHANNELS || !dma->d_ops) goto bad_dma; if (dma->active) { printk(KERN_ERR "dma%d: freeing active DMA\n", channel); dma->d_ops->disable(channel, dma); dma->active = 0; } if (xchg(&dma->lock, 0) != 0) { if (dma->d_ops->free) dma->d_ops->free(channel, dma); return; } printk(KERN_ERR "dma%d: trying to free free DMA\n", channel); return; bad_dma: printk(KERN_ERR "dma: trying to free DMA%d\n", channel); } /* Set DMA Scatter-Gather list */ void set_dma_sg (dmach_t channel, struct scatterlist *sg, int nr_sg) { dma_t *dma = dma_chan + channel; if (dma->active) printk(KERN_ERR "dma%d: altering DMA SG while " "DMA active\n", channel); dma->sg = sg; dma->sgcount = nr_sg; dma->using_sg = 1; dma->invalid = 1; } /* Set DMA address * * Copy address to the structure, and set the invalid bit */ void set_dma_addr (dmach_t channel, unsigned long physaddr) { dma_t *dma = dma_chan + channel; if (dma->active) printk(KERN_ERR "dma%d: altering DMA address while " "DMA active\n", channel); dma->sg = &dma->buf; dma->sgcount = 1; dma->buf.__address = (char *)physaddr;//FIXME - not pretty dma->using_sg = 0; dma->invalid = 1; } /* Set DMA byte count * * Copy address to the structure, and set the invalid bit */ void set_dma_count (dmach_t channel, unsigned long count) { dma_t *dma = dma_chan + channel; if (dma->active) printk(KERN_ERR "dma%d: altering DMA count while " "DMA active\n", channel); dma->sg = &dma->buf; dma->sgcount = 1; dma->buf.length = count; dma->using_sg = 0; dma->invalid = 1; } /* Set DMA direction mode */ void set_dma_mode (dmach_t channel, dmamode_t mode) { dma_t *dma = dma_chan + channel; if (dma->active) printk(KERN_ERR "dma%d: altering DMA mode while " "DMA active\n", channel); dma->dma_mode = mode; dma->invalid = 1; } /* Enable DMA channel */ void enable_dma (dmach_t channel) { dma_t *dma = dma_chan + channel; if (!dma->lock) goto free_dma; if (dma->active == 0) { dma->active = 1; dma->d_ops->enable(channel, dma); } return; free_dma: printk(KERN_ERR "dma%d: trying to enable free DMA\n", channel); BUG(); } /* Disable DMA channel */ void disable_dma (dmach_t channel) { dma_t *dma = dma_chan + channel; if (!dma->lock) goto free_dma; if (dma->active == 1) { dma->active = 0; dma->d_ops->disable(channel, dma); } return; free_dma: printk(KERN_ERR "dma%d: trying to disable free DMA\n", channel); BUG(); } /* * Is the specified DMA channel active? */ int dma_channel_active(dmach_t channel) { return dma_chan[channel].active; } void set_dma_page(dmach_t channel, char pagenr) { printk(KERN_ERR "dma%d: trying to set_dma_page\n", channel); } void set_dma_speed(dmach_t channel, int cycle_ns) { dma_t *dma = dma_chan + channel; int ret = 0; if (dma->d_ops->setspeed) ret = dma->d_ops->setspeed(channel, dma, cycle_ns); dma->speed = ret; } int get_dma_residue(dmach_t channel) { dma_t *dma = dma_chan + channel; int ret = 0; if (dma->d_ops->residue) ret = dma->d_ops->residue(channel, dma); return ret; } void __init init_dma(void) { arch_dma_init(dma_chan); } EXPORT_SYMBOL(request_dma); EXPORT_SYMBOL(free_dma); EXPORT_SYMBOL(enable_dma); EXPORT_SYMBOL(disable_dma); EXPORT_SYMBOL(set_dma_addr); EXPORT_SYMBOL(set_dma_count); EXPORT_SYMBOL(set_dma_mode); EXPORT_SYMBOL(set_dma_page); EXPORT_SYMBOL(get_dma_residue); EXPORT_SYMBOL(set_dma_sg); EXPORT_SYMBOL(set_dma_speed); EXPORT_SYMBOL(dma_spin_lock);