Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * ALSA sequencer FIFO |
| 3 | * Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl> |
| 4 | * |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * along with this program; if not, write to the Free Software |
| 18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | * |
| 20 | */ |
| 21 | |
| 22 | #include <sound/driver.h> |
| 23 | #include <sound/core.h> |
| 24 | #include <linux/slab.h> |
| 25 | #include "seq_fifo.h" |
| 26 | #include "seq_lock.h" |
| 27 | |
| 28 | |
| 29 | /* FIFO */ |
| 30 | |
| 31 | /* create new fifo */ |
| 32 | fifo_t *snd_seq_fifo_new(int poolsize) |
| 33 | { |
| 34 | fifo_t *f; |
| 35 | |
| 36 | f = kcalloc(1, sizeof(*f), GFP_KERNEL); |
| 37 | if (f == NULL) { |
| 38 | snd_printd("malloc failed for snd_seq_fifo_new() \n"); |
| 39 | return NULL; |
| 40 | } |
| 41 | |
| 42 | f->pool = snd_seq_pool_new(poolsize); |
| 43 | if (f->pool == NULL) { |
| 44 | kfree(f); |
| 45 | return NULL; |
| 46 | } |
| 47 | if (snd_seq_pool_init(f->pool) < 0) { |
| 48 | snd_seq_pool_delete(&f->pool); |
| 49 | kfree(f); |
| 50 | return NULL; |
| 51 | } |
| 52 | |
| 53 | spin_lock_init(&f->lock); |
| 54 | snd_use_lock_init(&f->use_lock); |
| 55 | init_waitqueue_head(&f->input_sleep); |
| 56 | atomic_set(&f->overflow, 0); |
| 57 | |
| 58 | f->head = NULL; |
| 59 | f->tail = NULL; |
| 60 | f->cells = 0; |
| 61 | |
| 62 | return f; |
| 63 | } |
| 64 | |
| 65 | void snd_seq_fifo_delete(fifo_t **fifo) |
| 66 | { |
| 67 | fifo_t *f; |
| 68 | |
| 69 | snd_assert(fifo != NULL, return); |
| 70 | f = *fifo; |
| 71 | snd_assert(f != NULL, return); |
| 72 | *fifo = NULL; |
| 73 | |
| 74 | snd_seq_fifo_clear(f); |
| 75 | |
| 76 | /* wake up clients if any */ |
| 77 | if (waitqueue_active(&f->input_sleep)) |
| 78 | wake_up(&f->input_sleep); |
| 79 | |
| 80 | /* release resources...*/ |
| 81 | /*....................*/ |
| 82 | |
| 83 | if (f->pool) { |
| 84 | snd_seq_pool_done(f->pool); |
| 85 | snd_seq_pool_delete(&f->pool); |
| 86 | } |
| 87 | |
| 88 | kfree(f); |
| 89 | } |
| 90 | |
| 91 | static snd_seq_event_cell_t *fifo_cell_out(fifo_t *f); |
| 92 | |
| 93 | /* clear queue */ |
| 94 | void snd_seq_fifo_clear(fifo_t *f) |
| 95 | { |
| 96 | snd_seq_event_cell_t *cell; |
| 97 | unsigned long flags; |
| 98 | |
| 99 | /* clear overflow flag */ |
| 100 | atomic_set(&f->overflow, 0); |
| 101 | |
| 102 | snd_use_lock_sync(&f->use_lock); |
| 103 | spin_lock_irqsave(&f->lock, flags); |
| 104 | /* drain the fifo */ |
| 105 | while ((cell = fifo_cell_out(f)) != NULL) { |
| 106 | snd_seq_cell_free(cell); |
| 107 | } |
| 108 | spin_unlock_irqrestore(&f->lock, flags); |
| 109 | } |
| 110 | |
| 111 | |
| 112 | /* enqueue event to fifo */ |
| 113 | int snd_seq_fifo_event_in(fifo_t *f, snd_seq_event_t *event) |
| 114 | { |
| 115 | snd_seq_event_cell_t *cell; |
| 116 | unsigned long flags; |
| 117 | int err; |
| 118 | |
| 119 | snd_assert(f != NULL, return -EINVAL); |
| 120 | |
| 121 | snd_use_lock_use(&f->use_lock); |
| 122 | err = snd_seq_event_dup(f->pool, event, &cell, 1, NULL); /* always non-blocking */ |
| 123 | if (err < 0) { |
| 124 | if (err == -ENOMEM) |
| 125 | atomic_inc(&f->overflow); |
| 126 | snd_use_lock_free(&f->use_lock); |
| 127 | return err; |
| 128 | } |
| 129 | |
| 130 | /* append new cells to fifo */ |
| 131 | spin_lock_irqsave(&f->lock, flags); |
| 132 | if (f->tail != NULL) |
| 133 | f->tail->next = cell; |
| 134 | f->tail = cell; |
| 135 | if (f->head == NULL) |
| 136 | f->head = cell; |
| 137 | f->cells++; |
| 138 | spin_unlock_irqrestore(&f->lock, flags); |
| 139 | |
| 140 | /* wakeup client */ |
| 141 | if (waitqueue_active(&f->input_sleep)) |
| 142 | wake_up(&f->input_sleep); |
| 143 | |
| 144 | snd_use_lock_free(&f->use_lock); |
| 145 | |
| 146 | return 0; /* success */ |
| 147 | |
| 148 | } |
| 149 | |
| 150 | /* dequeue cell from fifo */ |
| 151 | static snd_seq_event_cell_t *fifo_cell_out(fifo_t *f) |
| 152 | { |
| 153 | snd_seq_event_cell_t *cell; |
| 154 | |
| 155 | if ((cell = f->head) != NULL) { |
| 156 | f->head = cell->next; |
| 157 | |
| 158 | /* reset tail if this was the last element */ |
| 159 | if (f->tail == cell) |
| 160 | f->tail = NULL; |
| 161 | |
| 162 | cell->next = NULL; |
| 163 | f->cells--; |
| 164 | } |
| 165 | |
| 166 | return cell; |
| 167 | } |
| 168 | |
| 169 | /* dequeue cell from fifo and copy on user space */ |
| 170 | int snd_seq_fifo_cell_out(fifo_t *f, snd_seq_event_cell_t **cellp, int nonblock) |
| 171 | { |
| 172 | snd_seq_event_cell_t *cell; |
| 173 | unsigned long flags; |
| 174 | wait_queue_t wait; |
| 175 | |
| 176 | snd_assert(f != NULL, return -EINVAL); |
| 177 | |
| 178 | *cellp = NULL; |
| 179 | init_waitqueue_entry(&wait, current); |
| 180 | spin_lock_irqsave(&f->lock, flags); |
| 181 | while ((cell = fifo_cell_out(f)) == NULL) { |
| 182 | if (nonblock) { |
| 183 | /* non-blocking - return immediately */ |
| 184 | spin_unlock_irqrestore(&f->lock, flags); |
| 185 | return -EAGAIN; |
| 186 | } |
| 187 | set_current_state(TASK_INTERRUPTIBLE); |
| 188 | add_wait_queue(&f->input_sleep, &wait); |
| 189 | spin_unlock_irq(&f->lock); |
| 190 | schedule(); |
| 191 | spin_lock_irq(&f->lock); |
| 192 | remove_wait_queue(&f->input_sleep, &wait); |
| 193 | if (signal_pending(current)) { |
| 194 | spin_unlock_irqrestore(&f->lock, flags); |
| 195 | return -ERESTARTSYS; |
| 196 | } |
| 197 | } |
| 198 | spin_unlock_irqrestore(&f->lock, flags); |
| 199 | *cellp = cell; |
| 200 | |
| 201 | return 0; |
| 202 | } |
| 203 | |
| 204 | |
| 205 | void snd_seq_fifo_cell_putback(fifo_t *f, snd_seq_event_cell_t *cell) |
| 206 | { |
| 207 | unsigned long flags; |
| 208 | |
| 209 | if (cell) { |
| 210 | spin_lock_irqsave(&f->lock, flags); |
| 211 | cell->next = f->head; |
| 212 | f->head = cell; |
| 213 | f->cells++; |
| 214 | spin_unlock_irqrestore(&f->lock, flags); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | |
| 219 | /* polling; return non-zero if queue is available */ |
| 220 | int snd_seq_fifo_poll_wait(fifo_t *f, struct file *file, poll_table *wait) |
| 221 | { |
| 222 | poll_wait(file, &f->input_sleep, wait); |
| 223 | return (f->cells > 0); |
| 224 | } |
| 225 | |
| 226 | /* change the size of pool; all old events are removed */ |
| 227 | int snd_seq_fifo_resize(fifo_t *f, int poolsize) |
| 228 | { |
| 229 | unsigned long flags; |
| 230 | pool_t *newpool, *oldpool; |
| 231 | snd_seq_event_cell_t *cell, *next, *oldhead; |
| 232 | |
| 233 | snd_assert(f != NULL && f->pool != NULL, return -EINVAL); |
| 234 | |
| 235 | /* allocate new pool */ |
| 236 | newpool = snd_seq_pool_new(poolsize); |
| 237 | if (newpool == NULL) |
| 238 | return -ENOMEM; |
| 239 | if (snd_seq_pool_init(newpool) < 0) { |
| 240 | snd_seq_pool_delete(&newpool); |
| 241 | return -ENOMEM; |
| 242 | } |
| 243 | |
| 244 | spin_lock_irqsave(&f->lock, flags); |
| 245 | /* remember old pool */ |
| 246 | oldpool = f->pool; |
| 247 | oldhead = f->head; |
| 248 | /* exchange pools */ |
| 249 | f->pool = newpool; |
| 250 | f->head = NULL; |
| 251 | f->tail = NULL; |
| 252 | f->cells = 0; |
| 253 | /* NOTE: overflow flag is not cleared */ |
| 254 | spin_unlock_irqrestore(&f->lock, flags); |
| 255 | |
| 256 | /* release cells in old pool */ |
| 257 | for (cell = oldhead; cell; cell = next) { |
| 258 | next = cell->next; |
| 259 | snd_seq_cell_free(cell); |
| 260 | } |
| 261 | snd_seq_pool_delete(&oldpool); |
| 262 | |
| 263 | return 0; |
| 264 | } |