LXR linux/arch/sh/drivers/dma/dma-isa.c

   1/*
   2 * arch/sh/drivers/dma/dma-isa.c
   3 *
   4 * Generic ISA DMA wrapper for SH DMA API
   5 *
   6 * Copyright (C) 2003, 2004  Paul Mundt
   7 *
   8 * This file is subject to the terms and conditions of the GNU General Public
   9 * License.  See the file "COPYING" in the main directory of this archive
  10 * for more details.
  11 */
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <asm/dma.h>
  15
  16/*
  17 * This implements a small wrapper set to make code using the old ISA DMA API
  18 * work with the SH DMA API. Since most of the work in the new API happens
  19 * at ops->xfer() time, we simply use the various set_dma_xxx() routines to
  20 * fill in per-channel info, and then hand hand this off to ops->xfer() at
  21 * enable_dma() time.
  22 *
  23 * For channels that are doing on-demand data transfer via cascading, the
  24 * channel itself will still need to be configured through the new API. As
  25 * such, this code is meant for only the simplest of tasks (and shouldn't be
  26 * used in any new drivers at all).
  27 *
  28 * NOTE: ops->xfer() is the preferred way of doing things. However, there
  29 * are some users of the ISA DMA API that exist in common code that we
  30 * don't necessarily want to go out of our way to break, so we still
  31 * allow for some compatibility at that level. Any new code is strongly
  32 * advised to run far away from the ISA DMA API and use the SH DMA API
  33 * directly.
  34 */
  35unsigned long claim_dma_lock(void)
  36{
  37        unsigned long flags;
  38
  39        spin_lock_irqsave(&dma_spin_lock, flags);
  40
  41        return flags;
  42}
  43EXPORT_SYMBOL(claim_dma_lock);
  44
  45void release_dma_lock(unsigned long flags)
  46{
  47        spin_unlock_irqrestore(&dma_spin_lock, flags);
  48}
  49EXPORT_SYMBOL(release_dma_lock);
  50
  51void disable_dma(unsigned int chan)
  52{
  53        /* Nothing */
  54}
  55EXPORT_SYMBOL(disable_dma);
  56
  57void enable_dma(unsigned int chan)
  58{
  59        struct dma_info *info = get_dma_info(chan);
  60        struct dma_channel *channel = &info->channels[chan];
  61
  62        info->ops->xfer(channel);
  63}
  64EXPORT_SYMBOL(enable_dma);
  65
  66void clear_dma_ff(unsigned int chan)
  67{
  68        /* Nothing */
  69}
  70EXPORT_SYMBOL(clear_dma_ff);
  71
  72void set_dma_mode(unsigned int chan, char mode)
  73{
  74        struct dma_info *info = get_dma_info(chan);
  75        struct dma_channel *channel = &info->channels[chan];
  76
  77        channel->mode = mode;
  78}
  79EXPORT_SYMBOL(set_dma_mode);
  80
  81void set_dma_addr(unsigned int chan, unsigned int addr)
  82{
  83        struct dma_info *info = get_dma_info(chan);
  84        struct dma_channel *channel = &info->channels[chan];
  85
  86        /*
  87         * Single address mode is the only thing supported through
  88         * this interface.
  89         */
  90        if ((channel->mode & DMA_MODE_MASK) == DMA_MODE_READ) {
  91                channel->sar = addr;
  92        } else {
  93                channel->dar = addr;
  94        }
  95}
  96EXPORT_SYMBOL(set_dma_addr);
  97
  98void set_dma_count(unsigned int chan, unsigned int count)
  99{
 100        struct dma_info *info = get_dma_info(chan);
 101        struct dma_channel *channel = &info->channels[chan];
 102
 103        channel->count = count;
 104}
 105EXPORT_SYMBOL(set_dma_count);
 106
 107