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  */
  35 unsigned long claim_dma_lock(void)
  36 {
  37         unsigned long flags;
  38
  39         spin_lock_irqsave(&dma_spin_lock, flags);
  40
  41         return flags;
  42 }
  43 EXPORT_SYMBOL(claim_dma_lock);
  44
  45 void release_dma_lock(unsigned long flags)
  46 {
  47         spin_unlock_irqrestore(&dma_spin_lock, flags);
  48 }
  49 EXPORT_SYMBOL(release_dma_lock);
  50
  51 void disable_dma(unsigned int chan)
  52 {
  53         /* Nothing */
  54 }
  55 EXPORT_SYMBOL(disable_dma);
  56
  57 void 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 }
  64 EXPORT_SYMBOL(enable_dma);
  65
  66 void clear_dma_ff(unsigned int chan)
  67 {
  68         /* Nothing */
  69 }
  70 EXPORT_SYMBOL(clear_dma_ff);
  71
  72 void 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 }
  79 EXPORT_SYMBOL(set_dma_mode);
  80
  81 void 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 }
  96 EXPORT_SYMBOL(set_dma_addr);
  97
  98 void 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 }
 105 EXPORT_SYMBOL(set_dma_count);
 106