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
dump_rtlx(void)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. */
rtlx_init(struct rtlx_info * rtlxi)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 */
rtlx_starting(int vpe)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
rtlx_stopping(int vpe)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
rtlx_open(int index,int can_sleep)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("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("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
rtlx_release(int index)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
rtlx_read_poll(int index,int can_sleep)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
write_spacefree(int read,int write,int size)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
rtlx_write_poll(int index)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
rtlx_read(int index,void __user * buff,size_t count)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
rtlx_write(int index,const void __user * buffer,size_t count)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
file_open(struct inode * inode,struct file * filp)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
file_release(struct inode * inode,struct file * filp)332 static int file_release(struct inode *inode, struct file *filp)
333 {
334 return rtlx_release(iminor(inode));
335 }
336
file_poll(struct file * file,poll_table * wait)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
file_read(struct file * file,char __user * buffer,size_t count,loff_t * ppos)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
file_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)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