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
20 static int major;
21
22 /* The number of TCs and VPEs physically available on the core */
23 static int hw_tcs, hw_vpes;
24
25 /* We are prepared so configure and start the VPE... */
vpe_run(struct vpe * v)26 int 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
cleanup_tc(struct tc * tc)146 void 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 */
vpe_alloc(void)177 void *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 }
192 EXPORT_SYMBOL(vpe_alloc);
193
194 /* start running from here */
vpe_start(void * vpe,unsigned long start)195 int vpe_start(void *vpe, unsigned long start)
196 {
197 struct vpe *v = vpe;
198
199 v->__start = start;
200 return vpe_run(v);
201 }
202 EXPORT_SYMBOL(vpe_start);
203
204 /* halt it for now */
vpe_stop(void * vpe)205 int 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 }
223 EXPORT_SYMBOL(vpe_stop);
224
225 /* I've done with it thank you */
vpe_free(void * vpe)226 int 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 }
258 EXPORT_SYMBOL(vpe_free);
259
store_kill(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)260 static 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 }
276 static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
277
ntcs_show(struct device * cd,struct device_attribute * attr,char * buf)278 static 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
ntcs_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)286 static 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 }
304 static DEVICE_ATTR_RW(ntcs);
305
306 static struct attribute *vpe_attrs[] = {
307 &dev_attr_kill.attr,
308 &dev_attr_ntcs.attr,
309 NULL,
310 };
311 ATTRIBUTE_GROUPS(vpe);
312
vpe_device_release(struct device * cd)313 static void vpe_device_release(struct device *cd)
314 {
315 }
316
317 static struct class vpe_class = {
318 .name = "vpe",
319 .owner = THIS_MODULE,
320 .dev_release = vpe_device_release,
321 .dev_groups = vpe_groups,
322 };
323
324 static struct device vpe_device;
325
vpe_module_init(void)326 int __init vpe_module_init(void)
327 {
328 unsigned int mtflags, vpflags;
329 unsigned long flags, val;
330 struct vpe *v = NULL;
331 struct tc *t;
332 int tc, err;
333
334 if (!cpu_has_mipsmt) {
335 pr_warn("VPE loader: not a MIPS MT capable processor\n");
336 return -ENODEV;
337 }
338
339 if (vpelimit == 0) {
340 pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
341 "Pass maxvpes=<n> argument as kernel argument\n");
342
343 return -ENODEV;
344 }
345
346 if (aprp_cpu_index() == 0) {
347 pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
348 "Pass maxtcs=<n> argument as kernel argument\n");
349
350 return -ENODEV;
351 }
352
353 major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
354 if (major < 0) {
355 pr_warn("VPE loader: unable to register character device\n");
356 return major;
357 }
358
359 err = class_register(&vpe_class);
360 if (err) {
361 pr_err("vpe_class registration failed\n");
362 goto out_chrdev;
363 }
364
365 device_initialize(&vpe_device);
366 vpe_device.class = &vpe_class,
367 vpe_device.parent = NULL,
368 dev_set_name(&vpe_device, "vpe1");
369 vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
370 err = device_add(&vpe_device);
371 if (err) {
372 pr_err("Adding vpe_device failed\n");
373 goto out_class;
374 }
375
376 local_irq_save(flags);
377 mtflags = dmt();
378 vpflags = dvpe();
379
380 /* Put MVPE's into 'configuration state' */
381 set_c0_mvpcontrol(MVPCONTROL_VPC);
382
383 val = read_c0_mvpconf0();
384 hw_tcs = (val & MVPCONF0_PTC) + 1;
385 hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
386
387 for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
388 /*
389 * Must re-enable multithreading temporarily or in case we
390 * reschedule send IPIs or similar we might hang.
391 */
392 clear_c0_mvpcontrol(MVPCONTROL_VPC);
393 evpe(vpflags);
394 emt(mtflags);
395 local_irq_restore(flags);
396 t = alloc_tc(tc);
397 if (!t) {
398 err = -ENOMEM;
399 goto out_dev;
400 }
401
402 local_irq_save(flags);
403 mtflags = dmt();
404 vpflags = dvpe();
405 set_c0_mvpcontrol(MVPCONTROL_VPC);
406
407 /* VPE's */
408 if (tc < hw_tcs) {
409 settc(tc);
410
411 v = alloc_vpe(tc);
412 if (v == NULL) {
413 pr_warn("VPE: unable to allocate VPE\n");
414 goto out_reenable;
415 }
416
417 v->ntcs = hw_tcs - aprp_cpu_index();
418
419 /* add the tc to the list of this vpe's tc's. */
420 list_add(&t->tc, &v->tc);
421
422 /* deactivate all but vpe0 */
423 if (tc >= aprp_cpu_index()) {
424 unsigned long tmp = read_vpe_c0_vpeconf0();
425
426 tmp &= ~VPECONF0_VPA;
427
428 /* master VPE */
429 tmp |= VPECONF0_MVP;
430 write_vpe_c0_vpeconf0(tmp);
431 }
432
433 /* disable multi-threading with TC's */
434 write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
435 ~VPECONTROL_TE);
436
437 if (tc >= vpelimit) {
438 /*
439 * Set config to be the same as vpe0,
440 * particularly kseg0 coherency alg
441 */
442 write_vpe_c0_config(read_c0_config());
443 }
444 }
445
446 /* TC's */
447 t->pvpe = v; /* set the parent vpe */
448
449 if (tc >= aprp_cpu_index()) {
450 unsigned long tmp;
451
452 settc(tc);
453
454 /*
455 * A TC that is bound to any other VPE gets bound to
456 * VPE0, ideally I'd like to make it homeless but it
457 * doesn't appear to let me bind a TC to a non-existent
458 * VPE. Which is perfectly reasonable.
459 *
460 * The (un)bound state is visible to an EJTAG probe so
461 * may notify GDB...
462 */
463 tmp = read_tc_c0_tcbind();
464 if (tmp & TCBIND_CURVPE) {
465 /* tc is bound >vpe0 */
466 write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
467
468 t->pvpe = get_vpe(0); /* set the parent vpe */
469 }
470
471 /* halt the TC */
472 write_tc_c0_tchalt(TCHALT_H);
473 mips_ihb();
474
475 tmp = read_tc_c0_tcstatus();
476
477 /* mark not activated and not dynamically allocatable */
478 tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
479 tmp |= TCSTATUS_IXMT; /* interrupt exempt */
480 write_tc_c0_tcstatus(tmp);
481 }
482 }
483
484 out_reenable:
485 /* release config state */
486 clear_c0_mvpcontrol(MVPCONTROL_VPC);
487
488 evpe(vpflags);
489 emt(mtflags);
490 local_irq_restore(flags);
491
492 return 0;
493
494 out_dev:
495 device_del(&vpe_device);
496
497 out_class:
498 put_device(&vpe_device);
499 class_unregister(&vpe_class);
500
501 out_chrdev:
502 unregister_chrdev(major, VPE_MODULE_NAME);
503
504 return err;
505 }
506
vpe_module_exit(void)507 void __exit vpe_module_exit(void)
508 {
509 struct vpe *v, *n;
510
511 device_unregister(&vpe_device);
512 class_unregister(&vpe_class);
513 unregister_chrdev(major, VPE_MODULE_NAME);
514
515 /* No locking needed here */
516 list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
517 if (v->state != VPE_STATE_UNUSED)
518 release_vpe(v);
519 }
520 }
521