1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 2005 MIPS Technologies, Inc. All rights reserved. 7 * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org) 8 * Copyright (C) 2013 Imagination Technologies Ltd. 9 */ 10 #include <linux/kernel.h> 11 #include <linux/fs.h> 12 #include <linux/syscalls.h> 13 #include <linux/moduleloader.h> 14 #include <linux/atomic.h> 15 #include <asm/mipsmtregs.h> 16 #include <asm/mips_mt.h> 17 #include <asm/processor.h> 18 #include <asm/rtlx.h> 19 #include <asm/setup.h> 20 #include <asm/vpe.h> 21 22 static int sp_stopping; 23 struct rtlx_info *rtlx; 24 struct chan_waitqueues channel_wqs[RTLX_CHANNELS]; 25 struct vpe_notifications rtlx_notify; 26 void (*aprp_hook)(void) = NULL; 27 EXPORT_SYMBOL(aprp_hook); 28 29 static void __used dump_rtlx(void) 30 { 31 int i; 32 33 pr_info("id 0x%lx state %d\n", rtlx->id, rtlx->state); 34 35 for (i = 0; i < RTLX_CHANNELS; i++) { 36 struct rtlx_channel *chan = &rtlx->channel[i]; 37 38 pr_info(" rt_state %d lx_state %d buffer_size %d\n", 39 chan->rt_state, chan->lx_state, chan->buffer_size); 40 41 pr_info(" rt_read %d rt_write %d\n", 42 chan->rt_read, chan->rt_write); 43 44 pr_info(" lx_read %d lx_write %d\n", 45 chan->lx_read, chan->lx_write); 46 47 pr_info(" rt_buffer <%s>\n", chan->rt_buffer); 48 pr_info(" lx_buffer <%s>\n", chan->lx_buffer); 49 } 50 } 51 52 /* call when we have the address of the shared structure from the SP side. */ 53 static int rtlx_init(struct rtlx_info *rtlxi) 54 { 55 if (rtlxi->id != RTLX_ID) { 56 pr_err("no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id); 57 return -ENOEXEC; 58 } 59 60 rtlx = rtlxi; 61 62 return 0; 63 } 64 65 /* notifications */ 66 void rtlx_starting(int vpe) 67 { 68 int i; 69 sp_stopping = 0; 70 71 /* force a reload of rtlx */ 72 rtlx = NULL; 73 74 /* wake up any sleeping rtlx_open's */ 75 for (i = 0; i < RTLX_CHANNELS; i++) 76 wake_up_interruptible(&channel_wqs[i].lx_queue); 77 } 78 79 void rtlx_stopping(int vpe) 80 { 81 int i; 82 83 sp_stopping = 1; 84 for (i = 0; i < RTLX_CHANNELS; i++) 85 wake_up_interruptible(&channel_wqs[i].lx_queue); 86 } 87 88 89 int rtlx_open(int index, int can_sleep) 90 { 91 struct rtlx_info **p; 92 struct rtlx_channel *chan; 93 enum rtlx_state state; 94 int ret = 0; 95 96 if (index >= RTLX_CHANNELS) { 97 pr_debug(KERN_DEBUG "rtlx_open index out of range\n"); 98 return -ENOSYS; 99 } 100 101 if (atomic_inc_return(&channel_wqs[index].in_open) > 1) { 102 pr_debug(KERN_DEBUG "rtlx_open channel %d already opened\n", index); 103 ret = -EBUSY; 104 goto out_fail; 105 } 106 107 if (rtlx == NULL) { 108 p = vpe_get_shared(aprp_cpu_index()); 109 if (p == NULL) { 110 if (can_sleep) { 111 ret = __wait_event_interruptible( 112 channel_wqs[index].lx_queue, 113 (p = vpe_get_shared(aprp_cpu_index()))); 114 if (ret) 115 goto out_fail; 116 } else { 117 pr_debug("No SP program loaded, and device opened with O_NONBLOCK\n"); 118 ret = -ENOSYS; 119 goto out_fail; 120 } 121 } 122 123 smp_rmb(); 124 if (*p == NULL) { 125 if (can_sleep) { 126 DEFINE_WAIT(wait); 127 128 for (;;) { 129 prepare_to_wait( 130 &channel_wqs[index].lx_queue, 131 &wait, TASK_INTERRUPTIBLE); 132 smp_rmb(); 133 if (*p != NULL) 134 break; 135 if (!signal_pending(current)) { 136 schedule(); 137 continue; 138 } 139 ret = -ERESTARTSYS; 140 goto out_fail; 141 } 142 finish_wait(&channel_wqs[index].lx_queue, 143 &wait); 144 } else { 145 pr_err(" *vpe_get_shared is NULL. Has an SP program been loaded?\n"); 146 ret = -ENOSYS; 147 goto out_fail; 148 } 149 } 150 151 if ((unsigned int)*p < KSEG0) { 152 pr_warn("vpe_get_shared returned an invalid pointer maybe an error code %d\n", 153 (int)*p); 154 ret = -ENOSYS; 155 goto out_fail; 156 } 157 158 ret = rtlx_init(*p); 159 if (ret < 0) 160 goto out_ret; 161 } 162 163 chan = &rtlx->channel[index]; 164 165 state = xchg(&chan->lx_state, RTLX_STATE_OPENED); 166 if (state == RTLX_STATE_OPENED) { 167 ret = -EBUSY; 168 goto out_fail; 169 } 170 171 out_fail: 172 smp_mb(); 173 atomic_dec(&channel_wqs[index].in_open); 174 smp_mb(); 175 176 out_ret: 177 return ret; 178 } 179 180 int rtlx_release(int index) 181 { 182 if (rtlx == NULL) { 183 pr_err("rtlx_release() with null rtlx\n"); 184 return 0; 185 } 186 rtlx->channel[index].lx_state = RTLX_STATE_UNUSED; 187 return 0; 188 } 189 190 unsigned int rtlx_read_poll(int index, int can_sleep) 191 { 192 struct rtlx_channel *chan; 193 194 if (rtlx == NULL) 195 return 0; 196 197 chan = &rtlx->channel[index]; 198 199 /* data available to read? */ 200 if (chan->lx_read == chan->lx_write) { 201 if (can_sleep) { 202 int ret = __wait_event_interruptible( 203 channel_wqs[index].lx_queue, 204 (chan->lx_read != chan->lx_write) || 205 sp_stopping); 206 if (ret) 207 return ret; 208 209 if (sp_stopping) 210 return 0; 211 } else 212 return 0; 213 } 214 215 return (chan->lx_write + chan->buffer_size - chan->lx_read) 216 % chan->buffer_size; 217 } 218 219 static inline int write_spacefree(int read, int write, int size) 220 { 221 if (read == write) { 222 /* 223 * Never fill the buffer completely, so indexes are always 224 * equal if empty and only empty, or !equal if data available 225 */ 226 return size - 1; 227 } 228 229 return ((read + size - write) % size) - 1; 230 } 231 232 unsigned int rtlx_write_poll(int index) 233 { 234 struct rtlx_channel *chan = &rtlx->channel[index]; 235 236 return write_spacefree(chan->rt_read, chan->rt_write, 237 chan->buffer_size); 238 } 239 240 ssize_t rtlx_read(int index, void __user *buff, size_t count) 241 { 242 size_t lx_write, fl = 0L; 243 struct rtlx_channel *lx; 244 unsigned long failed; 245 246 if (rtlx == NULL) 247 return -ENOSYS; 248 249 lx = &rtlx->channel[index]; 250 251 mutex_lock(&channel_wqs[index].mutex); 252 smp_rmb(); 253 lx_write = lx->lx_write; 254 255 /* find out how much in total */ 256 count = min(count, 257 (size_t)(lx_write + lx->buffer_size - lx->lx_read) 258 % lx->buffer_size); 259 260 /* then how much from the read pointer onwards */ 261 fl = min(count, (size_t)lx->buffer_size - lx->lx_read); 262 263 failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl); 264 if (failed) 265 goto out; 266 267 /* and if there is anything left at the beginning of the buffer */ 268 if (count - fl) 269 failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl); 270 271 out: 272 count -= failed; 273 274 smp_wmb(); 275 lx->lx_read = (lx->lx_read + count) % lx->buffer_size; 276 smp_wmb(); 277 mutex_unlock(&channel_wqs[index].mutex); 278 279 return count; 280 } 281 282 ssize_t rtlx_write(int index, const void __user *buffer, size_t count) 283 { 284 struct rtlx_channel *rt; 285 unsigned long failed; 286 size_t rt_read; 287 size_t fl; 288 289 if (rtlx == NULL) 290 return -ENOSYS; 291 292 rt = &rtlx->channel[index]; 293 294 mutex_lock(&channel_wqs[index].mutex); 295 smp_rmb(); 296 rt_read = rt->rt_read; 297 298 /* total number of bytes to copy */ 299 count = min_t(size_t, count, write_spacefree(rt_read, rt->rt_write, 300 rt->buffer_size)); 301 302 /* first bit from write pointer to the end of the buffer, or count */ 303 fl = min(count, (size_t) rt->buffer_size - rt->rt_write); 304 305 failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl); 306 if (failed) 307 goto out; 308 309 /* if there's any left copy to the beginning of the buffer */ 310 if (count - fl) 311 failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl); 312 313 out: 314 count -= failed; 315 316 smp_wmb(); 317 rt->rt_write = (rt->rt_write + count) % rt->buffer_size; 318 smp_wmb(); 319 mutex_unlock(&channel_wqs[index].mutex); 320 321 _interrupt_sp(); 322 323 return count; 324 } 325 326 327 static int file_open(struct inode *inode, struct file *filp) 328 { 329 return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1); 330 } 331 332 static int file_release(struct inode *inode, struct file *filp) 333 { 334 return rtlx_release(iminor(inode)); 335 } 336 337 static unsigned int file_poll(struct file *file, poll_table *wait) 338 { 339 int minor = iminor(file_inode(file)); 340 unsigned int mask = 0; 341 342 poll_wait(file, &channel_wqs[minor].rt_queue, wait); 343 poll_wait(file, &channel_wqs[minor].lx_queue, wait); 344 345 if (rtlx == NULL) 346 return 0; 347 348 /* data available to read? */ 349 if (rtlx_read_poll(minor, 0)) 350 mask |= POLLIN | POLLRDNORM; 351 352 /* space to write */ 353 if (rtlx_write_poll(minor)) 354 mask |= POLLOUT | POLLWRNORM; 355 356 return mask; 357 } 358 359 static ssize_t file_read(struct file *file, char __user *buffer, size_t count, 360 loff_t *ppos) 361 { 362 int minor = iminor(file_inode(file)); 363 364 /* data available? */ 365 if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) 366 return 0; /* -EAGAIN makes 'cat' whine */ 367 368 return rtlx_read(minor, buffer, count); 369 } 370 371 static ssize_t file_write(struct file *file, const char __user *buffer, 372 size_t count, loff_t *ppos) 373 { 374 int minor = iminor(file_inode(file)); 375 376 /* any space left... */ 377 if (!rtlx_write_poll(minor)) { 378 int ret; 379 380 if (file->f_flags & O_NONBLOCK) 381 return -EAGAIN; 382 383 ret = __wait_event_interruptible(channel_wqs[minor].rt_queue, 384 rtlx_write_poll(minor)); 385 if (ret) 386 return ret; 387 } 388 389 return rtlx_write(minor, buffer, count); 390 } 391 392 const struct file_operations rtlx_fops = { 393 .owner = THIS_MODULE, 394 .open = file_open, 395 .release = file_release, 396 .write = file_write, 397 .read = file_read, 398 .poll = file_poll, 399 .llseek = noop_llseek, 400 }; 401 402 module_init(rtlx_module_init); 403 module_exit(rtlx_module_exit); 404 405 MODULE_DESCRIPTION("MIPS RTLX"); 406 MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc."); 407 MODULE_LICENSE("GPL"); 408