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 <linux/sched/signal.h> |
16 | |
17 | #include <asm/mipsmtregs.h> |
18 | #include <asm/mips_mt.h> |
19 | #include <asm/processor.h> |
20 | #include <asm/rtlx.h> |
21 | #include <asm/setup.h> |
22 | #include <asm/vpe.h> |
23 | |
24 | static int sp_stopping; |
25 | struct rtlx_info *rtlx; |
26 | struct chan_waitqueues channel_wqs[RTLX_CHANNELS]; |
27 | struct vpe_notifications rtlx_notify; |
28 | void (*aprp_hook)(void) = NULL; |
29 | EXPORT_SYMBOL(aprp_hook); |
30 | |
31 | static void __used dump_rtlx(void) |
32 | { |
33 | int i; |
34 | |
35 | pr_info("id 0x%lx state %d\n" , rtlx->id, rtlx->state); |
36 | |
37 | for (i = 0; i < RTLX_CHANNELS; i++) { |
38 | struct rtlx_channel *chan = &rtlx->channel[i]; |
39 | |
40 | pr_info(" rt_state %d lx_state %d buffer_size %d\n" , |
41 | chan->rt_state, chan->lx_state, chan->buffer_size); |
42 | |
43 | pr_info(" rt_read %d rt_write %d\n" , |
44 | chan->rt_read, chan->rt_write); |
45 | |
46 | pr_info(" lx_read %d lx_write %d\n" , |
47 | chan->lx_read, chan->lx_write); |
48 | |
49 | pr_info(" rt_buffer <%s>\n" , chan->rt_buffer); |
50 | pr_info(" lx_buffer <%s>\n" , chan->lx_buffer); |
51 | } |
52 | } |
53 | |
54 | /* call when we have the address of the shared structure from the SP side. */ |
55 | static int rtlx_init(struct rtlx_info *rtlxi) |
56 | { |
57 | if (rtlxi->id != RTLX_ID) { |
58 | pr_err("no valid RTLX id at 0x%p 0x%lx\n" , rtlxi, rtlxi->id); |
59 | return -ENOEXEC; |
60 | } |
61 | |
62 | rtlx = rtlxi; |
63 | |
64 | return 0; |
65 | } |
66 | |
67 | /* notifications */ |
68 | void rtlx_starting(int vpe) |
69 | { |
70 | int i; |
71 | sp_stopping = 0; |
72 | |
73 | /* force a reload of rtlx */ |
74 | rtlx = NULL; |
75 | |
76 | /* wake up any sleeping rtlx_open's */ |
77 | for (i = 0; i < RTLX_CHANNELS; i++) |
78 | wake_up_interruptible(&channel_wqs[i].lx_queue); |
79 | } |
80 | |
81 | void rtlx_stopping(int vpe) |
82 | { |
83 | int i; |
84 | |
85 | sp_stopping = 1; |
86 | for (i = 0; i < RTLX_CHANNELS; i++) |
87 | wake_up_interruptible(&channel_wqs[i].lx_queue); |
88 | } |
89 | |
90 | |
91 | int rtlx_open(int index, int can_sleep) |
92 | { |
93 | struct rtlx_info **p; |
94 | struct rtlx_channel *chan; |
95 | enum rtlx_state state; |
96 | int ret = 0; |
97 | |
98 | if (index >= RTLX_CHANNELS) { |
99 | pr_debug("rtlx_open index out of range\n" ); |
100 | return -ENOSYS; |
101 | } |
102 | |
103 | if (atomic_inc_return(v: &channel_wqs[index].in_open) > 1) { |
104 | pr_debug("rtlx_open channel %d already opened\n" , index); |
105 | ret = -EBUSY; |
106 | goto out_fail; |
107 | } |
108 | |
109 | if (rtlx == NULL) { |
110 | p = vpe_get_shared(aprp_cpu_index()); |
111 | if (p == NULL) { |
112 | if (can_sleep) { |
113 | ret = __wait_event_interruptible( |
114 | channel_wqs[index].lx_queue, |
115 | (p = vpe_get_shared(aprp_cpu_index()))); |
116 | if (ret) |
117 | goto out_fail; |
118 | } else { |
119 | pr_debug("No SP program loaded, and device opened with O_NONBLOCK\n" ); |
120 | ret = -ENOSYS; |
121 | goto out_fail; |
122 | } |
123 | } |
124 | |
125 | smp_rmb(); |
126 | if (*p == NULL) { |
127 | if (can_sleep) { |
128 | DEFINE_WAIT(wait); |
129 | |
130 | for (;;) { |
131 | prepare_to_wait( |
132 | wq_head: &channel_wqs[index].lx_queue, |
133 | wq_entry: &wait, TASK_INTERRUPTIBLE); |
134 | smp_rmb(); |
135 | if (*p != NULL) |
136 | break; |
137 | if (!signal_pending(current)) { |
138 | schedule(); |
139 | continue; |
140 | } |
141 | ret = -ERESTARTSYS; |
142 | goto out_fail; |
143 | } |
144 | finish_wait(wq_head: &channel_wqs[index].lx_queue, |
145 | wq_entry: &wait); |
146 | } else { |
147 | pr_err(" *vpe_get_shared is NULL. Has an SP program been loaded?\n" ); |
148 | ret = -ENOSYS; |
149 | goto out_fail; |
150 | } |
151 | } |
152 | |
153 | if ((unsigned int)*p < KSEG0) { |
154 | pr_warn("vpe_get_shared returned an invalid pointer maybe an error code %d\n" , |
155 | (int)*p); |
156 | ret = -ENOSYS; |
157 | goto out_fail; |
158 | } |
159 | |
160 | ret = rtlx_init(rtlxi: *p); |
161 | if (ret < 0) |
162 | goto out_ret; |
163 | } |
164 | |
165 | chan = &rtlx->channel[index]; |
166 | |
167 | state = xchg(&chan->lx_state, RTLX_STATE_OPENED); |
168 | if (state == RTLX_STATE_OPENED) { |
169 | ret = -EBUSY; |
170 | goto out_fail; |
171 | } |
172 | |
173 | out_fail: |
174 | smp_mb(); |
175 | atomic_dec(v: &channel_wqs[index].in_open); |
176 | smp_mb(); |
177 | |
178 | out_ret: |
179 | return ret; |
180 | } |
181 | |
182 | int rtlx_release(int index) |
183 | { |
184 | if (rtlx == NULL) { |
185 | pr_err("rtlx_release() with null rtlx\n" ); |
186 | return 0; |
187 | } |
188 | rtlx->channel[index].lx_state = RTLX_STATE_UNUSED; |
189 | return 0; |
190 | } |
191 | |
192 | unsigned int rtlx_read_poll(int index, int can_sleep) |
193 | { |
194 | struct rtlx_channel *chan; |
195 | |
196 | if (rtlx == NULL) |
197 | return 0; |
198 | |
199 | chan = &rtlx->channel[index]; |
200 | |
201 | /* data available to read? */ |
202 | if (chan->lx_read == chan->lx_write) { |
203 | if (can_sleep) { |
204 | int ret = __wait_event_interruptible( |
205 | channel_wqs[index].lx_queue, |
206 | (chan->lx_read != chan->lx_write) || |
207 | sp_stopping); |
208 | if (ret) |
209 | return ret; |
210 | |
211 | if (sp_stopping) |
212 | return 0; |
213 | } else |
214 | return 0; |
215 | } |
216 | |
217 | return (chan->lx_write + chan->buffer_size - chan->lx_read) |
218 | % chan->buffer_size; |
219 | } |
220 | |
221 | static inline int write_spacefree(int read, int write, int size) |
222 | { |
223 | if (read == write) { |
224 | /* |
225 | * Never fill the buffer completely, so indexes are always |
226 | * equal if empty and only empty, or !equal if data available |
227 | */ |
228 | return size - 1; |
229 | } |
230 | |
231 | return ((read + size - write) % size) - 1; |
232 | } |
233 | |
234 | unsigned int rtlx_write_poll(int index) |
235 | { |
236 | struct rtlx_channel *chan = &rtlx->channel[index]; |
237 | |
238 | return write_spacefree(read: chan->rt_read, write: chan->rt_write, |
239 | size: chan->buffer_size); |
240 | } |
241 | |
242 | ssize_t rtlx_read(int index, void __user *buff, size_t count) |
243 | { |
244 | size_t lx_write, fl = 0L; |
245 | struct rtlx_channel *lx; |
246 | unsigned long failed; |
247 | |
248 | if (rtlx == NULL) |
249 | return -ENOSYS; |
250 | |
251 | lx = &rtlx->channel[index]; |
252 | |
253 | mutex_lock(&channel_wqs[index].mutex); |
254 | smp_rmb(); |
255 | lx_write = lx->lx_write; |
256 | |
257 | /* find out how much in total */ |
258 | count = min(count, |
259 | (size_t)(lx_write + lx->buffer_size - lx->lx_read) |
260 | % lx->buffer_size); |
261 | |
262 | /* then how much from the read pointer onwards */ |
263 | fl = min(count, (size_t)lx->buffer_size - lx->lx_read); |
264 | |
265 | failed = copy_to_user(to: buff, from: lx->lx_buffer + lx->lx_read, n: fl); |
266 | if (failed) |
267 | goto out; |
268 | |
269 | /* and if there is anything left at the beginning of the buffer */ |
270 | if (count - fl) |
271 | failed = copy_to_user(to: buff + fl, from: lx->lx_buffer, n: count - fl); |
272 | |
273 | out: |
274 | count -= failed; |
275 | |
276 | smp_wmb(); |
277 | lx->lx_read = (lx->lx_read + count) % lx->buffer_size; |
278 | smp_wmb(); |
279 | mutex_unlock(lock: &channel_wqs[index].mutex); |
280 | |
281 | return count; |
282 | } |
283 | |
284 | ssize_t rtlx_write(int index, const void __user *buffer, size_t count) |
285 | { |
286 | struct rtlx_channel *rt; |
287 | unsigned long failed; |
288 | size_t rt_read; |
289 | size_t fl; |
290 | |
291 | if (rtlx == NULL) |
292 | return -ENOSYS; |
293 | |
294 | rt = &rtlx->channel[index]; |
295 | |
296 | mutex_lock(&channel_wqs[index].mutex); |
297 | smp_rmb(); |
298 | rt_read = rt->rt_read; |
299 | |
300 | /* total number of bytes to copy */ |
301 | count = min_t(size_t, count, write_spacefree(rt_read, rt->rt_write, |
302 | rt->buffer_size)); |
303 | |
304 | /* first bit from write pointer to the end of the buffer, or count */ |
305 | fl = min(count, (size_t) rt->buffer_size - rt->rt_write); |
306 | |
307 | failed = copy_from_user(to: rt->rt_buffer + rt->rt_write, from: buffer, n: fl); |
308 | if (failed) |
309 | goto out; |
310 | |
311 | /* if there's any left copy to the beginning of the buffer */ |
312 | if (count - fl) |
313 | failed = copy_from_user(to: rt->rt_buffer, from: buffer + fl, n: count - fl); |
314 | |
315 | out: |
316 | count -= failed; |
317 | |
318 | smp_wmb(); |
319 | rt->rt_write = (rt->rt_write + count) % rt->buffer_size; |
320 | smp_wmb(); |
321 | mutex_unlock(lock: &channel_wqs[index].mutex); |
322 | |
323 | _interrupt_sp(); |
324 | |
325 | return count; |
326 | } |
327 | |
328 | |
329 | static int file_open(struct inode *inode, struct file *filp) |
330 | { |
331 | return rtlx_open(index: iminor(inode), can_sleep: (filp->f_flags & O_NONBLOCK) ? 0 : 1); |
332 | } |
333 | |
334 | static int file_release(struct inode *inode, struct file *filp) |
335 | { |
336 | return rtlx_release(index: iminor(inode)); |
337 | } |
338 | |
339 | static __poll_t file_poll(struct file *file, poll_table *wait) |
340 | { |
341 | int minor = iminor(inode: file_inode(f: file)); |
342 | __poll_t mask = 0; |
343 | |
344 | poll_wait(filp: file, wait_address: &channel_wqs[minor].rt_queue, p: wait); |
345 | poll_wait(filp: file, wait_address: &channel_wqs[minor].lx_queue, p: wait); |
346 | |
347 | if (rtlx == NULL) |
348 | return 0; |
349 | |
350 | /* data available to read? */ |
351 | if (rtlx_read_poll(index: minor, can_sleep: 0)) |
352 | mask |= EPOLLIN | EPOLLRDNORM; |
353 | |
354 | /* space to write */ |
355 | if (rtlx_write_poll(index: minor)) |
356 | mask |= EPOLLOUT | EPOLLWRNORM; |
357 | |
358 | return mask; |
359 | } |
360 | |
361 | static ssize_t file_read(struct file *file, char __user *buffer, size_t count, |
362 | loff_t *ppos) |
363 | { |
364 | int minor = iminor(inode: file_inode(f: file)); |
365 | |
366 | /* data available? */ |
367 | if (!rtlx_read_poll(index: minor, can_sleep: (file->f_flags & O_NONBLOCK) ? 0 : 1)) |
368 | return 0; /* -EAGAIN makes 'cat' whine */ |
369 | |
370 | return rtlx_read(index: minor, buff: buffer, count); |
371 | } |
372 | |
373 | static ssize_t file_write(struct file *file, const char __user *buffer, |
374 | size_t count, loff_t *ppos) |
375 | { |
376 | int minor = iminor(inode: file_inode(f: file)); |
377 | |
378 | /* any space left... */ |
379 | if (!rtlx_write_poll(index: minor)) { |
380 | int ret; |
381 | |
382 | if (file->f_flags & O_NONBLOCK) |
383 | return -EAGAIN; |
384 | |
385 | ret = __wait_event_interruptible(channel_wqs[minor].rt_queue, |
386 | rtlx_write_poll(minor)); |
387 | if (ret) |
388 | return ret; |
389 | } |
390 | |
391 | return rtlx_write(index: minor, buffer, count); |
392 | } |
393 | |
394 | const struct file_operations rtlx_fops = { |
395 | .owner = THIS_MODULE, |
396 | .open = file_open, |
397 | .release = file_release, |
398 | .write = file_write, |
399 | .read = file_read, |
400 | .poll = file_poll, |
401 | .llseek = noop_llseek, |
402 | }; |
403 | |
404 | module_init(rtlx_module_init); |
405 | module_exit(rtlx_module_exit); |
406 | |
407 | MODULE_DESCRIPTION("MIPS RTLX" ); |
408 | MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc." ); |
409 | MODULE_LICENSE("GPL" ); |
410 | |