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, ®istered_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(®istered_dmac_list))) 50 return nr; 51 52 list_for_each_entry(info, ®istered_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(®istered_dmac_list)) 171 return 0; 172 173 /* 174 * Iterate over each registered DMAC 175 */ 176 list_for_each_entry(info, ®istered_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, ®istered_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"); 275