arch/sh/drivers/dma/dma-api.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * arch/sh/drivers/dma/dma-api.c
   4  *
   5  * SuperH-specific DMA management API
   6  *
   7  * Copyright (C) 2003, 2004, 2005  Paul Mundt
   8  */
   9 #include <linux/init.h>
  10 #include <linux/module.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/proc_fs.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/list.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/mm.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <asm/dma.h>
  20
  21 DEFINE_SPINLOCK(dma_spin_lock);
  22 static LIST_HEAD(registered_dmac_list);
  23
  24 struct dma_info *get_dma_info(unsigned int chan)
  25 {
  26         struct dma_info *info;
  27
  28         /*
  29          * Look for each DMAC's range to determine who the owner of
  30          * the channel is.
  31          */
  32         list_for_each_entry(info, &registered_dmac_list, list) {
  33                 if ((chan <  info->first_vchannel_nr) ||
  34                     (chan >= info->first_vchannel_nr + info->nr_channels))
  35                         continue;
  36
  37                 return info;
  38         }
  39
  40         return NULL;
  41 }
  42 EXPORT_SYMBOL(get_dma_info);
  43
  44 static unsigned int get_nr_channels(void)
  45 {
  46         struct dma_info *info;
  47         unsigned int nr = 0;
  48
  49         if (unlikely(list_empty(&registered_dmac_list)))
  50                 return nr;
  51
  52         list_for_each_entry(info, &registered_dmac_list, list)
  53                 nr += info->nr_channels;
  54
  55         return nr;
  56 }
  57
  58 struct dma_channel *get_dma_channel(unsigned int chan)
  59 {
  60         struct dma_info *info = get_dma_info(chan);
  61         struct dma_channel *channel;
  62         int i;
  63
  64         if (unlikely(!info))
  65                 return ERR_PTR(-EINVAL);
  66
  67         for (i = 0; i < info->nr_channels; i++) {
  68                 channel = &info->channels[i];
  69                 if (channel->vchan == chan)
  70                         return channel;
  71         }
  72
  73         return NULL;
  74 }
  75 EXPORT_SYMBOL(get_dma_channel);
  76
  77 int get_dma_residue(unsigned int chan)
  78 {
  79         struct dma_info *info = get_dma_info(chan);
  80         struct dma_channel *channel = get_dma_channel(chan);
  81
  82         if (info->ops->get_residue)
  83                 return info->ops->get_residue(channel);
  84
  85         return 0;
  86 }
  87 EXPORT_SYMBOL(get_dma_residue);
  88
  89 int request_dma(unsigned int chan, const char *dev_id)
  90 {
  91         struct dma_channel *channel = { 0 };
  92         struct dma_info *info = get_dma_info(chan);
  93         int result;
  94
  95         channel = get_dma_channel(chan);
  96         if (atomic_xchg(&channel->busy, 1))
  97                 return -EBUSY;
  98
  99         strscpy(channel->dev_id, dev_id, sizeof(channel->dev_id));
 100
 101         if (info->ops->request) {
 102                 result = info->ops->request(channel);
 103                 if (result)
 104                         atomic_set(&channel->busy, 0);
 105
 106                 return result;
 107         }
 108
 109         return 0;
 110 }
 111 EXPORT_SYMBOL(request_dma);
 112
 113 void free_dma(unsigned int chan)
 114 {
 115         struct dma_info *info = get_dma_info(chan);
 116         struct dma_channel *channel = get_dma_channel(chan);
 117
 118         if (info->ops->free)
 119                 info->ops->free(channel);
 120
 121         atomic_set(&channel->busy, 0);
 122 }
 123 EXPORT_SYMBOL(free_dma);
 124
 125 void dma_wait_for_completion(unsigned int chan)
 126 {
 127         struct dma_info *info = get_dma_info(chan);
 128         struct dma_channel *channel = get_dma_channel(chan);
 129
 130         if (channel->flags & DMA_TEI_CAPABLE) {
 131                 wait_event(channel->wait_queue,
 132                            (info->ops->get_residue(channel) == 0));
 133                 return;
 134         }
 135
 136         while (info->ops->get_residue(channel))
 137                 cpu_relax();
 138 }
 139 EXPORT_SYMBOL(dma_wait_for_completion);
 140
 141 void dma_configure_channel(unsigned int chan, unsigned long flags)
 142 {
 143         struct dma_info *info = get_dma_info(chan);
 144         struct dma_channel *channel = get_dma_channel(chan);
 145
 146         if (info->ops->configure)
 147                 info->ops->configure(channel, flags);
 148 }
 149 EXPORT_SYMBOL(dma_configure_channel);
 150
 151 int dma_xfer(unsigned int chan, unsigned long from,
 152              unsigned long to, size_t size, unsigned int mode)
 153 {
 154         struct dma_info *info = get_dma_info(chan);
 155         struct dma_channel *channel = get_dma_channel(chan);
 156
 157         channel->sar    = from;
 158         channel->dar    = to;
 159         channel->count  = size;
 160         channel->mode   = mode;
 161
 162         return info->ops->xfer(channel);
 163 }
 164 EXPORT_SYMBOL(dma_xfer);
 165
 166 static int dma_proc_show(struct seq_file *m, void *v)
 167 {
 168         struct dma_info *info = v;
 169
 170         if (list_empty(&registered_dmac_list))
 171                 return 0;
 172
 173         /*
 174          * Iterate over each registered DMAC
 175          */
 176         list_for_each_entry(info, &registered_dmac_list, list) {
 177                 int i;
 178
 179                 /*
 180                  * Iterate over each channel
 181                  */
 182                 for (i = 0; i < info->nr_channels; i++) {
 183                         struct dma_channel *channel = info->channels + i;
 184
 185                         if (!(channel->flags & DMA_CONFIGURED))
 186                                 continue;
 187
 188                         seq_printf(m, "%2d: %14s    %s\n", i,
 189                                    info->name, channel->dev_id);
 190                 }
 191         }
 192
 193         return 0;
 194 }
 195
 196 int register_dmac(struct dma_info *info)
 197 {
 198         unsigned int total_channels, i;
 199
 200         INIT_LIST_HEAD(&info->list);
 201
 202         printk(KERN_INFO "DMA: Registering %s handler (%d channel%s).\n",
 203                info->name, info->nr_channels, info->nr_channels > 1 ? "s" : "");
 204
 205         BUG_ON((info->flags & DMAC_CHANNELS_CONFIGURED) && !info->channels);
 206
 207         info->pdev = platform_device_register_simple(info->name, -1,
 208                                                      NULL, 0);
 209         if (IS_ERR(info->pdev))
 210                 return PTR_ERR(info->pdev);
 211
 212         /*
 213          * Don't touch pre-configured channels
 214          */
 215         if (!(info->flags & DMAC_CHANNELS_CONFIGURED)) {
 216                 unsigned int size;
 217
 218                 size = sizeof(struct dma_channel) * info->nr_channels;
 219
 220                 info->channels = kzalloc(size, GFP_KERNEL);
 221                 if (!info->channels)
 222                         return -ENOMEM;
 223         }
 224
 225         total_channels = get_nr_channels();
 226         info->first_vchannel_nr = total_channels;
 227         for (i = 0; i < info->nr_channels; i++) {
 228                 struct dma_channel *chan = &info->channels[i];
 229
 230                 atomic_set(&chan->busy, 0);
 231
 232                 chan->chan  = info->first_channel_nr + i;
 233                 chan->vchan = info->first_channel_nr + i + total_channels;
 234
 235                 memcpy(chan->dev_id, "Unused", 7);
 236
 237                 if (info->flags & DMAC_CHANNELS_TEI_CAPABLE)
 238                         chan->flags |= DMA_TEI_CAPABLE;
 239
 240                 init_waitqueue_head(&chan->wait_queue);
 241                 dma_create_sysfs_files(chan, info);
 242         }
 243
 244         list_add(&info->list, &registered_dmac_list);
 245
 246         return 0;
 247 }
 248 EXPORT_SYMBOL(register_dmac);
 249
 250 void unregister_dmac(struct dma_info *info)
 251 {
 252         unsigned int i;
 253
 254         for (i = 0; i < info->nr_channels; i++)
 255                 dma_remove_sysfs_files(info->channels + i, info);
 256
 257         if (!(info->flags & DMAC_CHANNELS_CONFIGURED))
 258                 kfree(info->channels);
 259
 260         list_del(&info->list);
 261         platform_device_unregister(info->pdev);
 262 }
 263 EXPORT_SYMBOL(unregister_dmac);
 264
 265 static int __init dma_api_init(void)
 266 {
 267         printk(KERN_NOTICE "DMA: Registering DMA API.\n");
 268         return proc_create_single("dma", 0, NULL, dma_proc_show) ? 0 : -ENOMEM;
 269 }
 270 subsys_initcall(dma_api_init);
 271
 272 MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
 273 MODULE_DESCRIPTION("DMA API for SuperH");
 274 MODULE_LICENSE("GPL v2");