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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) 2004, 2005 MIPS Technologies, Inc. All rights reserved.
7 * Copyright (C) 2013 Imagination Technologies Ltd.
8 */
9#include <linux/kernel.h>
10#include <linux/device.h>
11#include <linux/fs.h>
12#include <linux/slab.h>
13#include <linux/export.h>
14
15#include <asm/mipsregs.h>
16#include <asm/mipsmtregs.h>
17#include <asm/mips_mt.h>
18#include <asm/vpe.h>
19
20static int major;
21
22/* The number of TCs and VPEs physically available on the core */
23static int hw_tcs, hw_vpes;
24
25/* We are prepared so configure and start the VPE... */
26int vpe_run(struct vpe *v)
27{
28 unsigned long flags, val, dmt_flag;
29 struct vpe_notifications *notifier;
30 unsigned int vpeflags;
31 struct tc *t;
32
33 /* check we are the Master VPE */
34 local_irq_save(flags);
35 val = read_c0_vpeconf0();
36 if (!(val & VPECONF0_MVP)) {
37 pr_warn("VPE loader: only Master VPE's are able to config MT\n");
38 local_irq_restore(flags);
39
40 return -1;
41 }
42
43 dmt_flag = dmt();
44 vpeflags = dvpe();
45
46 if (list_empty(&v->tc)) {
47 evpe(vpeflags);
48 emt(dmt_flag);
49 local_irq_restore(flags);
50
51 pr_warn("VPE loader: No TC's associated with VPE %d\n",
52 v->minor);
53
54 return -ENOEXEC;
55 }
56
57 t = list_first_entry(&v->tc, struct tc, tc);
58
59 /* Put MVPE's into 'configuration state' */
60 set_c0_mvpcontrol(MVPCONTROL_VPC);
61
62 settc(t->index);
63
64 /* should check it is halted, and not activated */
65 if ((read_tc_c0_tcstatus() & TCSTATUS_A) ||
66 !(read_tc_c0_tchalt() & TCHALT_H)) {
67 evpe(vpeflags);
68 emt(dmt_flag);
69 local_irq_restore(flags);
70
71 pr_warn("VPE loader: TC %d is already active!\n",
72 t->index);
73
74 return -ENOEXEC;
75 }
76
77 /*
78 * Write the address we want it to start running from in the TCPC
79 * register.
80 */
81 write_tc_c0_tcrestart((unsigned long)v->__start);
82 write_tc_c0_tccontext((unsigned long)0);
83
84 /*
85 * Mark the TC as activated, not interrupt exempt and not dynamically
86 * allocatable
87 */
88 val = read_tc_c0_tcstatus();
89 val = (val & ~(TCSTATUS_DA | TCSTATUS_IXMT)) | TCSTATUS_A;
90 write_tc_c0_tcstatus(val);
91
92 write_tc_c0_tchalt(read_tc_c0_tchalt() & ~TCHALT_H);
93
94 /*
95 * We don't pass the memsize here, so VPE programs need to be
96 * compiled with DFLT_STACK_SIZE and DFLT_HEAP_SIZE defined.
97 */
98 mttgpr($7, 0);
99 mttgpr($6, v->ntcs);
100
101 /* set up VPE1 */
102 /*
103 * bind the TC to VPE 1 as late as possible so we only have the final
104 * VPE registers to set up, and so an EJTAG probe can trigger on it
105 */
106 write_tc_c0_tcbind((read_tc_c0_tcbind() & ~TCBIND_CURVPE) | 1);
107
108 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~(VPECONF0_VPA));
109
110 back_to_back_c0_hazard();
111
112 /* Set up the XTC bit in vpeconf0 to point at our tc */
113 write_vpe_c0_vpeconf0((read_vpe_c0_vpeconf0() & ~(VPECONF0_XTC))
114 | (t->index << VPECONF0_XTC_SHIFT));
115
116 back_to_back_c0_hazard();
117
118 /* enable this VPE */
119 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
120
121 /* clear out any left overs from a previous program */
122 write_vpe_c0_status(0);
123 write_vpe_c0_cause(0);
124
125 /* take system out of configuration state */
126 clear_c0_mvpcontrol(MVPCONTROL_VPC);
127
128 /*
129 * SMVP kernels manage VPE enable independently, but uniprocessor
130 * kernels need to turn it on, even if that wasn't the pre-dvpe() state.
131 */
132#ifdef CONFIG_SMP
133 evpe(vpeflags);
134#else
135 evpe(EVPE_ENABLE);
136#endif
137 emt(dmt_flag);
138 local_irq_restore(flags);
139
140 list_for_each_entry(notifier, &v->notify, list)
141 notifier->start(VPE_MODULE_MINOR);
142
143 return 0;
144}
145
146void cleanup_tc(struct tc *tc)
147{
148 unsigned long flags;
149 unsigned int mtflags, vpflags;
150 int tmp;
151
152 local_irq_save(flags);
153 mtflags = dmt();
154 vpflags = dvpe();
155 /* Put MVPE's into 'configuration state' */
156 set_c0_mvpcontrol(MVPCONTROL_VPC);
157
158 settc(tc->index);
159 tmp = read_tc_c0_tcstatus();
160
161 /* mark not allocated and not dynamically allocatable */
162 tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
163 tmp |= TCSTATUS_IXMT; /* interrupt exempt */
164 write_tc_c0_tcstatus(tmp);
165
166 write_tc_c0_tchalt(TCHALT_H);
167 mips_ihb();
168
169 clear_c0_mvpcontrol(MVPCONTROL_VPC);
170 evpe(vpflags);
171 emt(mtflags);
172 local_irq_restore(flags);
173}
174
175/* module wrapper entry points */
176/* give me a vpe */
177void *vpe_alloc(void)
178{
179 int i;
180 struct vpe *v;
181
182 /* find a vpe */
183 for (i = 1; i < MAX_VPES; i++) {
184 v = get_vpe(i);
185 if (v != NULL) {
186 v->state = VPE_STATE_INUSE;
187 return v;
188 }
189 }
190 return NULL;
191}
192EXPORT_SYMBOL(vpe_alloc);
193
194/* start running from here */
195int vpe_start(void *vpe, unsigned long start)
196{
197 struct vpe *v = vpe;
198
199 v->__start = start;
200 return vpe_run(v);
201}
202EXPORT_SYMBOL(vpe_start);
203
204/* halt it for now */
205int vpe_stop(void *vpe)
206{
207 struct vpe *v = vpe;
208 struct tc *t;
209 unsigned int evpe_flags;
210
211 evpe_flags = dvpe();
212
213 t = list_entry(v->tc.next, struct tc, tc);
214 if (t != NULL) {
215 settc(t->index);
216 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
217 }
218
219 evpe(evpe_flags);
220
221 return 0;
222}
223EXPORT_SYMBOL(vpe_stop);
224
225/* I've done with it thank you */
226int vpe_free(void *vpe)
227{
228 struct vpe *v = vpe;
229 struct tc *t;
230 unsigned int evpe_flags;
231
232 t = list_entry(v->tc.next, struct tc, tc);
233 if (t == NULL)
234 return -ENOEXEC;
235
236 evpe_flags = dvpe();
237
238 /* Put MVPE's into 'configuration state' */
239 set_c0_mvpcontrol(MVPCONTROL_VPC);
240
241 settc(t->index);
242 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
243
244 /* halt the TC */
245 write_tc_c0_tchalt(TCHALT_H);
246 mips_ihb();
247
248 /* mark the TC unallocated */
249 write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
250
251 v->state = VPE_STATE_UNUSED;
252
253 clear_c0_mvpcontrol(MVPCONTROL_VPC);
254 evpe(evpe_flags);
255
256 return 0;
257}
258EXPORT_SYMBOL(vpe_free);
259
260static ssize_t store_kill(struct device *dev, struct device_attribute *attr,
261 const char *buf, size_t len)
262{
263 struct vpe *vpe = get_vpe(aprp_cpu_index());
264 struct vpe_notifications *notifier;
265
266 list_for_each_entry(notifier, &vpe->notify, list)
267 notifier->stop(aprp_cpu_index());
268
269 release_progmem(vpe->load_addr);
270 cleanup_tc(get_tc(aprp_cpu_index()));
271 vpe_stop(vpe);
272 vpe_free(vpe);
273
274 return len;
275}
276static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
277
278static ssize_t ntcs_show(struct device *cd, struct device_attribute *attr,
279 char *buf)
280{
281 struct vpe *vpe = get_vpe(aprp_cpu_index());
282
283 return sprintf(buf, "%d\n", vpe->ntcs);
284}
285
286static ssize_t ntcs_store(struct device *dev, struct device_attribute *attr,
287 const char *buf, size_t len)
288{
289 struct vpe *vpe = get_vpe(aprp_cpu_index());
290 unsigned long new;
291 int ret;
292
293 ret = kstrtoul(buf, 0, &new);
294 if (ret < 0)
295 return ret;
296
297 if (new == 0 || new > (hw_tcs - aprp_cpu_index()))
298 return -EINVAL;
299
300 vpe->ntcs = new;
301
302 return len;
303}
304static DEVICE_ATTR_RW(ntcs);
305
306static struct attribute *vpe_attrs[] = {
307 &dev_attr_kill.attr,
308 &dev_attr_ntcs.attr,
309 NULL,
310};
311ATTRIBUTE_GROUPS(vpe);
312
313static void vpe_device_release(struct device *cd)
314{
315}
316
317static struct class vpe_class = {
318 .name = "vpe",
319 .dev_release = vpe_device_release,
320 .dev_groups = vpe_groups,
321};
322
323static struct device vpe_device;
324
325int __init vpe_module_init(void)
326{
327 unsigned int mtflags, vpflags;
328 unsigned long flags, val;
329 struct vpe *v = NULL;
330 struct tc *t;
331 int tc, err;
332
333 if (!cpu_has_mipsmt) {
334 pr_warn("VPE loader: not a MIPS MT capable processor\n");
335 return -ENODEV;
336 }
337
338 if (vpelimit == 0) {
339 pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
340 "Pass maxvpes=<n> argument as kernel argument\n");
341
342 return -ENODEV;
343 }
344
345 if (aprp_cpu_index() == 0) {
346 pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
347 "Pass maxtcs=<n> argument as kernel argument\n");
348
349 return -ENODEV;
350 }
351
352 major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
353 if (major < 0) {
354 pr_warn("VPE loader: unable to register character device\n");
355 return major;
356 }
357
358 err = class_register(&vpe_class);
359 if (err) {
360 pr_err("vpe_class registration failed\n");
361 goto out_chrdev;
362 }
363
364 device_initialize(&vpe_device);
365 vpe_device.class = &vpe_class;
366 vpe_device.parent = NULL;
367 dev_set_name(&vpe_device, "vpe1");
368 vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
369 err = device_add(&vpe_device);
370 if (err) {
371 pr_err("Adding vpe_device failed\n");
372 goto out_class;
373 }
374
375 local_irq_save(flags);
376 mtflags = dmt();
377 vpflags = dvpe();
378
379 /* Put MVPE's into 'configuration state' */
380 set_c0_mvpcontrol(MVPCONTROL_VPC);
381
382 val = read_c0_mvpconf0();
383 hw_tcs = (val & MVPCONF0_PTC) + 1;
384 hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
385
386 for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
387 /*
388 * Must re-enable multithreading temporarily or in case we
389 * reschedule send IPIs or similar we might hang.
390 */
391 clear_c0_mvpcontrol(MVPCONTROL_VPC);
392 evpe(vpflags);
393 emt(mtflags);
394 local_irq_restore(flags);
395 t = alloc_tc(tc);
396 if (!t) {
397 err = -ENOMEM;
398 goto out_dev;
399 }
400
401 local_irq_save(flags);
402 mtflags = dmt();
403 vpflags = dvpe();
404 set_c0_mvpcontrol(MVPCONTROL_VPC);
405
406 /* VPE's */
407 if (tc < hw_tcs) {
408 settc(tc);
409
410 v = alloc_vpe(tc);
411 if (v == NULL) {
412 pr_warn("VPE: unable to allocate VPE\n");
413 goto out_reenable;
414 }
415
416 v->ntcs = hw_tcs - aprp_cpu_index();
417
418 /* add the tc to the list of this vpe's tc's. */
419 list_add(&t->tc, &v->tc);
420
421 /* deactivate all but vpe0 */
422 if (tc >= aprp_cpu_index()) {
423 unsigned long tmp = read_vpe_c0_vpeconf0();
424
425 tmp &= ~VPECONF0_VPA;
426
427 /* master VPE */
428 tmp |= VPECONF0_MVP;
429 write_vpe_c0_vpeconf0(tmp);
430 }
431
432 /* disable multi-threading with TC's */
433 write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
434 ~VPECONTROL_TE);
435
436 if (tc >= vpelimit) {
437 /*
438 * Set config to be the same as vpe0,
439 * particularly kseg0 coherency alg
440 */
441 write_vpe_c0_config(read_c0_config());
442 }
443 }
444
445 /* TC's */
446 t->pvpe = v; /* set the parent vpe */
447
448 if (tc >= aprp_cpu_index()) {
449 unsigned long tmp;
450
451 settc(tc);
452
453 /*
454 * A TC that is bound to any other VPE gets bound to
455 * VPE0, ideally I'd like to make it homeless but it
456 * doesn't appear to let me bind a TC to a non-existent
457 * VPE. Which is perfectly reasonable.
458 *
459 * The (un)bound state is visible to an EJTAG probe so
460 * may notify GDB...
461 */
462 tmp = read_tc_c0_tcbind();
463 if (tmp & TCBIND_CURVPE) {
464 /* tc is bound >vpe0 */
465 write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
466
467 t->pvpe = get_vpe(0); /* set the parent vpe */
468 }
469
470 /* halt the TC */
471 write_tc_c0_tchalt(TCHALT_H);
472 mips_ihb();
473
474 tmp = read_tc_c0_tcstatus();
475
476 /* mark not activated and not dynamically allocatable */
477 tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
478 tmp |= TCSTATUS_IXMT; /* interrupt exempt */
479 write_tc_c0_tcstatus(tmp);
480 }
481 }
482
483out_reenable:
484 /* release config state */
485 clear_c0_mvpcontrol(MVPCONTROL_VPC);
486
487 evpe(vpflags);
488 emt(mtflags);
489 local_irq_restore(flags);
490
491 return 0;
492
493out_dev:
494 device_del(&vpe_device);
495
496out_class:
497 put_device(&vpe_device);
498 class_unregister(&vpe_class);
499
500out_chrdev:
501 unregister_chrdev(major, VPE_MODULE_NAME);
502
503 return err;
504}
505
506void __exit vpe_module_exit(void)
507{
508 struct vpe *v, *n;
509
510 device_unregister(&vpe_device);
511 class_unregister(&vpe_class);
512 unregister_chrdev(major, VPE_MODULE_NAME);
513
514 /* No locking needed here */
515 list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
516 if (v->state != VPE_STATE_UNUSED)
517 release_vpe(v);
518 }
519}