mirror of https://gitee.com/openkylin/linux.git
287 lines
5.2 KiB
C
287 lines
5.2 KiB
C
/*
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* linux/arch/arm/kernel/dma.c
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*
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* Copyright (C) 1995-2000 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Front-end to the DMA handling. This handles the allocation/freeing
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* of DMA channels, and provides a unified interface to the machines
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* DMA facilities.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/errno.h>
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#include <linux/scatterlist.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <asm/dma.h>
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#include <asm/mach/dma.h>
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DEFINE_RAW_SPINLOCK(dma_spin_lock);
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EXPORT_SYMBOL(dma_spin_lock);
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static dma_t *dma_chan[MAX_DMA_CHANNELS];
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static inline dma_t *dma_channel(unsigned int chan)
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{
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if (chan >= MAX_DMA_CHANNELS)
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return NULL;
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return dma_chan[chan];
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}
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int __init isa_dma_add(unsigned int chan, dma_t *dma)
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{
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if (!dma->d_ops)
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return -EINVAL;
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sg_init_table(&dma->buf, 1);
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if (dma_chan[chan])
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return -EBUSY;
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dma_chan[chan] = dma;
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return 0;
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}
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/*
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* Request DMA channel
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*
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* On certain platforms, we have to allocate an interrupt as well...
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*/
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int request_dma(unsigned int chan, const char *device_id)
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{
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dma_t *dma = dma_channel(chan);
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int ret;
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if (!dma)
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goto bad_dma;
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if (xchg(&dma->lock, 1) != 0)
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goto busy;
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dma->device_id = device_id;
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dma->active = 0;
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dma->invalid = 1;
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ret = 0;
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if (dma->d_ops->request)
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ret = dma->d_ops->request(chan, dma);
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if (ret)
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xchg(&dma->lock, 0);
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return ret;
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bad_dma:
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pr_err("dma: trying to allocate DMA%d\n", chan);
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return -EINVAL;
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busy:
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return -EBUSY;
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}
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EXPORT_SYMBOL(request_dma);
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/*
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* Free DMA channel
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*
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* On certain platforms, we have to free interrupt as well...
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*/
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void free_dma(unsigned int chan)
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{
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dma_t *dma = dma_channel(chan);
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if (!dma)
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goto bad_dma;
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if (dma->active) {
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pr_err("dma%d: freeing active DMA\n", chan);
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dma->d_ops->disable(chan, dma);
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dma->active = 0;
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}
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if (xchg(&dma->lock, 0) != 0) {
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if (dma->d_ops->free)
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dma->d_ops->free(chan, dma);
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return;
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}
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pr_err("dma%d: trying to free free DMA\n", chan);
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return;
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bad_dma:
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pr_err("dma: trying to free DMA%d\n", chan);
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}
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EXPORT_SYMBOL(free_dma);
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/* Set DMA Scatter-Gather list
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*/
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void set_dma_sg (unsigned int chan, struct scatterlist *sg, int nr_sg)
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{
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dma_t *dma = dma_channel(chan);
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if (dma->active)
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pr_err("dma%d: altering DMA SG while DMA active\n", chan);
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dma->sg = sg;
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dma->sgcount = nr_sg;
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dma->invalid = 1;
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}
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EXPORT_SYMBOL(set_dma_sg);
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/* Set DMA address
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*
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* Copy address to the structure, and set the invalid bit
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*/
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void __set_dma_addr (unsigned int chan, void *addr)
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{
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dma_t *dma = dma_channel(chan);
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if (dma->active)
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pr_err("dma%d: altering DMA address while DMA active\n", chan);
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dma->sg = NULL;
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dma->addr = addr;
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dma->invalid = 1;
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}
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EXPORT_SYMBOL(__set_dma_addr);
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/* Set DMA byte count
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*
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* Copy address to the structure, and set the invalid bit
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*/
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void set_dma_count (unsigned int chan, unsigned long count)
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{
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dma_t *dma = dma_channel(chan);
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if (dma->active)
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pr_err("dma%d: altering DMA count while DMA active\n", chan);
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dma->sg = NULL;
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dma->count = count;
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dma->invalid = 1;
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}
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EXPORT_SYMBOL(set_dma_count);
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/* Set DMA direction mode
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*/
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void set_dma_mode (unsigned int chan, unsigned int mode)
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{
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dma_t *dma = dma_channel(chan);
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if (dma->active)
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pr_err("dma%d: altering DMA mode while DMA active\n", chan);
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dma->dma_mode = mode;
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dma->invalid = 1;
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}
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EXPORT_SYMBOL(set_dma_mode);
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/* Enable DMA channel
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*/
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void enable_dma (unsigned int chan)
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{
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dma_t *dma = dma_channel(chan);
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if (!dma->lock)
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goto free_dma;
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if (dma->active == 0) {
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dma->active = 1;
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dma->d_ops->enable(chan, dma);
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}
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return;
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free_dma:
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pr_err("dma%d: trying to enable free DMA\n", chan);
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BUG();
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}
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EXPORT_SYMBOL(enable_dma);
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/* Disable DMA channel
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*/
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void disable_dma (unsigned int chan)
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{
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dma_t *dma = dma_channel(chan);
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if (!dma->lock)
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goto free_dma;
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if (dma->active == 1) {
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dma->active = 0;
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dma->d_ops->disable(chan, dma);
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}
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return;
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free_dma:
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pr_err("dma%d: trying to disable free DMA\n", chan);
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BUG();
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}
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EXPORT_SYMBOL(disable_dma);
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/*
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* Is the specified DMA channel active?
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*/
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int dma_channel_active(unsigned int chan)
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{
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dma_t *dma = dma_channel(chan);
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return dma->active;
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}
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EXPORT_SYMBOL(dma_channel_active);
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void set_dma_page(unsigned int chan, char pagenr)
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{
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pr_err("dma%d: trying to set_dma_page\n", chan);
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}
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EXPORT_SYMBOL(set_dma_page);
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void set_dma_speed(unsigned int chan, int cycle_ns)
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{
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dma_t *dma = dma_channel(chan);
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int ret = 0;
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if (dma->d_ops->setspeed)
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ret = dma->d_ops->setspeed(chan, dma, cycle_ns);
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dma->speed = ret;
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}
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EXPORT_SYMBOL(set_dma_speed);
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int get_dma_residue(unsigned int chan)
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{
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dma_t *dma = dma_channel(chan);
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int ret = 0;
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if (dma->d_ops->residue)
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ret = dma->d_ops->residue(chan, dma);
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return ret;
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}
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EXPORT_SYMBOL(get_dma_residue);
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#ifdef CONFIG_PROC_FS
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static int proc_dma_show(struct seq_file *m, void *v)
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{
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int i;
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for (i = 0 ; i < MAX_DMA_CHANNELS ; i++) {
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dma_t *dma = dma_channel(i);
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if (dma && dma->lock)
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seq_printf(m, "%2d: %s\n", i, dma->device_id);
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}
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return 0;
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}
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static int __init proc_dma_init(void)
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{
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proc_create_single("dma", 0, NULL, proc_dma_show);
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return 0;
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}
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__initcall(proc_dma_init);
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#endif
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