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1 /*
2 * Copyright (C) 2009,2010,2011 Imagination Technologies Ltd.
3 *
4 * Copyright (C) 2002 ARM Limited, All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10 #include <linux/atomic.h>
11 #include <linux/completion.h>
12 #include <linux/delay.h>
13 #include <linux/init.h>
14 #include <linux/spinlock.h>
15 #include <linux/sched.h>
16 #include <linux/interrupt.h>
17 #include <linux/cache.h>
18 #include <linux/profile.h>
19 #include <linux/errno.h>
20 #include <linux/mm.h>
21 #include <linux/err.h>
22 #include <linux/cpu.h>
23 #include <linux/smp.h>
24 #include <linux/seq_file.h>
25 #include <linux/irq.h>
26 #include <linux/bootmem.h>
27
28 #include <asm/cacheflush.h>
29 #include <asm/cachepart.h>
30 #include <asm/core_reg.h>
31 #include <asm/cpu.h>
32 #include <asm/global_lock.h>
33 #include <asm/metag_mem.h>
34 #include <asm/mmu_context.h>
35 #include <asm/pgtable.h>
36 #include <asm/pgalloc.h>
37 #include <asm/processor.h>
38 #include <asm/setup.h>
39 #include <asm/tlbflush.h>
40 #include <asm/hwthread.h>
41 #include <asm/traps.h>
42
43 #define SYSC_DCPART(n) (SYSC_DCPART0 + SYSC_xCPARTn_STRIDE * (n))
44 #define SYSC_ICPART(n) (SYSC_ICPART0 + SYSC_xCPARTn_STRIDE * (n))
45
46 DECLARE_PER_CPU(PTBI, pTBI);
47
48 void *secondary_data_stack;
49
50 /*
51 * structures for inter-processor calls
52 * - A collection of single bit ipi messages.
53 */
54 struct ipi_data {
55 spinlock_t lock;
56 unsigned long ipi_count;
57 unsigned long bits;
58 };
59
60 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
61 .lock = __SPIN_LOCK_UNLOCKED(ipi_data.lock),
62 };
63
64 static DEFINE_SPINLOCK(boot_lock);
65
66 static DECLARE_COMPLETION(cpu_running);
67
68 /*
69 * "thread" is assumed to be a valid Meta hardware thread ID.
70 */
71 static int boot_secondary(unsigned int thread, struct task_struct *idle)
72 {
73 u32 val;
74
75 /*
76 * set synchronisation state between this boot processor
77 * and the secondary one
78 */
79 spin_lock(&boot_lock);
80
81 core_reg_write(TXUPC_ID, 0, thread, (unsigned int)secondary_startup);
82 core_reg_write(TXUPC_ID, 1, thread, 0);
83
84 /*
85 * Give the thread privilege (PSTAT) and clear potentially problematic
86 * bits in the process (namely ISTAT, CBMarker, CBMarkerI, LSM_STEP).
87 */
88 core_reg_write(TXUCT_ID, TXSTATUS_REGNUM, thread, TXSTATUS_PSTAT_BIT);
89
90 /* Clear the minim enable bit. */
91 val = core_reg_read(TXUCT_ID, TXPRIVEXT_REGNUM, thread);
92 core_reg_write(TXUCT_ID, TXPRIVEXT_REGNUM, thread, val & ~0x80);
93
94 /*
95 * set the ThreadEnable bit (0x1) in the TXENABLE register
96 * for the specified thread - off it goes!
97 */
98 val = core_reg_read(TXUCT_ID, TXENABLE_REGNUM, thread);
99 core_reg_write(TXUCT_ID, TXENABLE_REGNUM, thread, val | 0x1);
100
101 /*
102 * now the secondary core is starting up let it run its
103 * calibrations, then wait for it to finish
104 */
105 spin_unlock(&boot_lock);
106
107 return 0;
108 }
109
110 /**
111 * describe_cachepart_change: describe a change to cache partitions.
112 * @thread: Hardware thread number.
113 * @label: Label of cache type, e.g. "dcache" or "icache".
114 * @sz: Total size of the cache.
115 * @old: Old cache partition configuration (*CPART* register).
116 * @new: New cache partition configuration (*CPART* register).
117 *
118 * If the cache partition has changed, prints a message to the log describing
119 * those changes.
120 */
121 static void describe_cachepart_change(unsigned int thread, const char *label,
122 unsigned int sz, unsigned int old,
123 unsigned int new)
124 {
125 unsigned int lor1, land1, gor1, gand1;
126 unsigned int lor2, land2, gor2, gand2;
127 unsigned int diff = old ^ new;
128
129 if (!diff)
130 return;
131
132 pr_info("Thread %d: %s partition changed:", thread, label);
133 if (diff & (SYSC_xCPARTL_OR_BITS | SYSC_xCPARTL_AND_BITS)) {
134 lor1 = (old & SYSC_xCPARTL_OR_BITS) >> SYSC_xCPARTL_OR_S;
135 lor2 = (new & SYSC_xCPARTL_OR_BITS) >> SYSC_xCPARTL_OR_S;
136 land1 = (old & SYSC_xCPARTL_AND_BITS) >> SYSC_xCPARTL_AND_S;
137 land2 = (new & SYSC_xCPARTL_AND_BITS) >> SYSC_xCPARTL_AND_S;
138 pr_cont(" L:%#x+%#x->%#x+%#x",
139 (lor1 * sz) >> 4,
140 ((land1 + 1) * sz) >> 4,
141 (lor2 * sz) >> 4,
142 ((land2 + 1) * sz) >> 4);
143 }
144 if (diff & (SYSC_xCPARTG_OR_BITS | SYSC_xCPARTG_AND_BITS)) {
145 gor1 = (old & SYSC_xCPARTG_OR_BITS) >> SYSC_xCPARTG_OR_S;
146 gor2 = (new & SYSC_xCPARTG_OR_BITS) >> SYSC_xCPARTG_OR_S;
147 gand1 = (old & SYSC_xCPARTG_AND_BITS) >> SYSC_xCPARTG_AND_S;
148 gand2 = (new & SYSC_xCPARTG_AND_BITS) >> SYSC_xCPARTG_AND_S;
149 pr_cont(" G:%#x+%#x->%#x+%#x",
150 (gor1 * sz) >> 4,
151 ((gand1 + 1) * sz) >> 4,
152 (gor2 * sz) >> 4,
153 ((gand2 + 1) * sz) >> 4);
154 }
155 if (diff & SYSC_CWRMODE_BIT)
156 pr_cont(" %sWR",
157 (new & SYSC_CWRMODE_BIT) ? "+" : "-");
158 if (diff & SYSC_DCPART_GCON_BIT)
159 pr_cont(" %sGCOn",
160 (new & SYSC_DCPART_GCON_BIT) ? "+" : "-");
161 pr_cont("\n");
162 }
163
164 /**
165 * setup_smp_cache: ensure cache coherency for new SMP thread.
166 * @thread: New hardware thread number.
167 *
168 * Ensures that coherency is enabled and that the threads share the same cache
169 * partitions.
170 */
171 static void setup_smp_cache(unsigned int thread)
172 {
173 unsigned int this_thread, lflags;
174 unsigned int dcsz, dcpart_this, dcpart_old, dcpart_new;
175 unsigned int icsz, icpart_old, icpart_new;
176
177 /*
178 * Copy over the current thread's cache partition configuration to the
179 * new thread so that they share cache partitions.
180 */
181 __global_lock2(lflags);
182 this_thread = hard_processor_id();
183 /* Share dcache partition */
184 dcpart_this = metag_in32(SYSC_DCPART(this_thread));
185 dcpart_old = metag_in32(SYSC_DCPART(thread));
186 dcpart_new = dcpart_this;
187 #if PAGE_OFFSET < LINGLOBAL_BASE
188 /*
189 * For the local data cache to be coherent the threads must also have
190 * GCOn enabled.
191 */
192 dcpart_new |= SYSC_DCPART_GCON_BIT;
193 metag_out32(dcpart_new, SYSC_DCPART(this_thread));
194 #endif
195 metag_out32(dcpart_new, SYSC_DCPART(thread));
196 /* Share icache partition too */
197 icpart_new = metag_in32(SYSC_ICPART(this_thread));
198 icpart_old = metag_in32(SYSC_ICPART(thread));
199 metag_out32(icpart_new, SYSC_ICPART(thread));
200 __global_unlock2(lflags);
201
202 /*
203 * Log if the cache partitions were altered so the user is aware of any
204 * potential unintentional cache wastage.
205 */
206 dcsz = get_dcache_size();
207 icsz = get_dcache_size();
208 describe_cachepart_change(this_thread, "dcache", dcsz,
209 dcpart_this, dcpart_new);
210 describe_cachepart_change(thread, "dcache", dcsz,
211 dcpart_old, dcpart_new);
212 describe_cachepart_change(thread, "icache", icsz,
213 icpart_old, icpart_new);
214 }
215
216 int __cpu_up(unsigned int cpu, struct task_struct *idle)
217 {
218 unsigned int thread = cpu_2_hwthread_id[cpu];
219 int ret;
220
221 load_pgd(swapper_pg_dir, thread);
222
223 flush_tlb_all();
224
225 setup_smp_cache(thread);
226
227 /*
228 * Tell the secondary CPU where to find its idle thread's stack.
229 */
230 secondary_data_stack = task_stack_page(idle);
231
232 wmb();
233
234 /*
235 * Now bring the CPU into our world.
236 */
237 ret = boot_secondary(thread, idle);
238 if (ret == 0) {
239 /*
240 * CPU was successfully started, wait for it
241 * to come online or time out.
242 */
243 wait_for_completion_timeout(&cpu_running,
244 msecs_to_jiffies(1000));
245
246 if (!cpu_online(cpu))
247 ret = -EIO;
248 }
249
250 secondary_data_stack = NULL;
251
252 if (ret) {
253 pr_crit("CPU%u: processor failed to boot\n", cpu);
254
255 /*
256 * FIXME: We need to clean up the new idle thread. --rmk
257 */
258 }
259
260 return ret;
261 }
262
263 #ifdef CONFIG_HOTPLUG_CPU
264
265 /*
266 * __cpu_disable runs on the processor to be shutdown.
267 */
268 int __cpu_disable(void)
269 {
270 unsigned int cpu = smp_processor_id();
271
272 /*
273 * Take this CPU offline. Once we clear this, we can't return,
274 * and we must not schedule until we're ready to give up the cpu.
275 */
276 set_cpu_online(cpu, false);
277
278 /*
279 * OK - migrate IRQs away from this CPU
280 */
281 migrate_irqs();
282
283 /*
284 * Flush user cache and TLB mappings, and then remove this CPU
285 * from the vm mask set of all processes.
286 */
287 flush_cache_all();
288 local_flush_tlb_all();
289
290 clear_tasks_mm_cpumask(cpu);
291
292 return 0;
293 }
294
295 /*
296 * called on the thread which is asking for a CPU to be shutdown -
297 * waits until shutdown has completed, or it is timed out.
298 */
299 void __cpu_die(unsigned int cpu)
300 {
301 if (!cpu_wait_death(cpu, 1))
302 pr_err("CPU%u: unable to kill\n", cpu);
303 }
304
305 /*
306 * Called from the idle thread for the CPU which has been shutdown.
307 *
308 * Note that we do not return from this function. If this cpu is
309 * brought online again it will need to run secondary_startup().
310 */
311 void cpu_die(void)
312 {
313 local_irq_disable();
314 idle_task_exit();
315
316 (void)cpu_report_death();
317
318 asm ("XOR TXENABLE, D0Re0,D0Re0\n");
319 }
320 #endif /* CONFIG_HOTPLUG_CPU */
321
322 /*
323 * Called by both boot and secondaries to move global data into
324 * per-processor storage.
325 */
326 void smp_store_cpu_info(unsigned int cpuid)
327 {
328 struct cpuinfo_metag *cpu_info = &per_cpu(cpu_data, cpuid);
329
330 cpu_info->loops_per_jiffy = loops_per_jiffy;
331 }
332
333 /*
334 * This is the secondary CPU boot entry. We're using this CPUs
335 * idle thread stack and the global page tables.
336 */
337 asmlinkage void secondary_start_kernel(void)
338 {
339 struct mm_struct *mm = &init_mm;
340 unsigned int cpu = smp_processor_id();
341
342 /*
343 * All kernel threads share the same mm context; grab a
344 * reference and switch to it.
345 */
346 atomic_inc(&mm->mm_users);
347 atomic_inc(&mm->mm_count);
348 current->active_mm = mm;
349 cpumask_set_cpu(cpu, mm_cpumask(mm));
350 enter_lazy_tlb(mm, current);
351 local_flush_tlb_all();
352
353 /*
354 * TODO: Some day it might be useful for each Linux CPU to
355 * have its own TBI structure. That would allow each Linux CPU
356 * to run different interrupt handlers for the same IRQ
357 * number.
358 *
359 * For now, simply copying the pointer to the boot CPU's TBI
360 * structure is sufficient because we always want to run the
361 * same interrupt handler whatever CPU takes the interrupt.
362 */
363 per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
364
365 if (!per_cpu(pTBI, cpu))
366 panic("No TBI found!");
367
368 per_cpu_trap_init(cpu);
369
370 preempt_disable();
371
372 setup_priv();
373
374 notify_cpu_starting(cpu);
375
376 pr_info("CPU%u (thread %u): Booted secondary processor\n",
377 cpu, cpu_2_hwthread_id[cpu]);
378
379 calibrate_delay();
380 smp_store_cpu_info(cpu);
381
382 /*
383 * OK, now it's safe to let the boot CPU continue
384 */
385 set_cpu_online(cpu, true);
386 complete(&cpu_running);
387
388 /*
389 * Enable local interrupts.
390 */
391 tbi_startup_interrupt(TBID_SIGNUM_TRT);
392 local_irq_enable();
393
394 /*
395 * OK, it's off to the idle thread for us
396 */
397 cpu_startup_entry(CPUHP_ONLINE);
398 }
399
400 void __init smp_cpus_done(unsigned int max_cpus)
401 {
402 int cpu;
403 unsigned long bogosum = 0;
404
405 for_each_online_cpu(cpu)
406 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
407
408 pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
409 num_online_cpus(),
410 bogosum / (500000/HZ),
411 (bogosum / (5000/HZ)) % 100);
412 }
413
414 void __init smp_prepare_cpus(unsigned int max_cpus)
415 {
416 unsigned int cpu = smp_processor_id();
417
418 init_new_context(current, &init_mm);
419 current_thread_info()->cpu = cpu;
420
421 smp_store_cpu_info(cpu);
422 init_cpu_present(cpu_possible_mask);
423 }
424
425 void __init smp_prepare_boot_cpu(void)
426 {
427 unsigned int cpu = smp_processor_id();
428
429 per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
430
431 if (!per_cpu(pTBI, cpu))
432 panic("No TBI found!");
433 }
434
435 static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg);
436
437 static void send_ipi_message(const struct cpumask *mask, enum ipi_msg_type msg)
438 {
439 unsigned long flags;
440 unsigned int cpu;
441 cpumask_t map;
442
443 cpumask_clear(&map);
444 local_irq_save(flags);
445
446 for_each_cpu(cpu, mask) {
447 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
448
449 spin_lock(&ipi->lock);
450
451 /*
452 * KICK interrupts are queued in hardware so we'll get
453 * multiple interrupts if we call smp_cross_call()
454 * multiple times for one msg. The problem is that we
455 * only have one bit for each message - we can't queue
456 * them in software.
457 *
458 * The first time through ipi_handler() we'll clear
459 * the msg bit, having done all the work. But when we
460 * return we'll get _another_ interrupt (and another,
461 * and another until we've handled all the queued
462 * KICKs). Running ipi_handler() when there's no work
463 * to do is bad because that's how kick handler
464 * chaining detects who the KICK was intended for.
465 * See arch/metag/kernel/kick.c for more details.
466 *
467 * So only add 'cpu' to 'map' if we haven't already
468 * queued a KICK interrupt for 'msg'.
469 */
470 if (!(ipi->bits & (1 << msg))) {
471 ipi->bits |= 1 << msg;
472 cpumask_set_cpu(cpu, &map);
473 }
474
475 spin_unlock(&ipi->lock);
476 }
477
478 /*
479 * Call the platform specific cross-CPU call function.
480 */
481 smp_cross_call(map, msg);
482
483 local_irq_restore(flags);
484 }
485
486 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
487 {
488 send_ipi_message(mask, IPI_CALL_FUNC);
489 }
490
491 void arch_send_call_function_single_ipi(int cpu)
492 {
493 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
494 }
495
496 void show_ipi_list(struct seq_file *p)
497 {
498 unsigned int cpu;
499
500 seq_puts(p, "IPI:");
501
502 for_each_present_cpu(cpu)
503 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
504
505 seq_putc(p, '\n');
506 }
507
508 static DEFINE_SPINLOCK(stop_lock);
509
510 /*
511 * Main handler for inter-processor interrupts
512 *
513 * For Meta, the ipimask now only identifies a single
514 * category of IPI (Bit 1 IPIs have been replaced by a
515 * different mechanism):
516 *
517 * Bit 0 - Inter-processor function call
518 */
519 static int do_IPI(void)
520 {
521 unsigned int cpu = smp_processor_id();
522 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
523 unsigned long msgs, nextmsg;
524 int handled = 0;
525
526 ipi->ipi_count++;
527
528 spin_lock(&ipi->lock);
529 msgs = ipi->bits;
530 nextmsg = msgs & -msgs;
531 ipi->bits &= ~nextmsg;
532 spin_unlock(&ipi->lock);
533
534 if (nextmsg) {
535 handled = 1;
536
537 nextmsg = ffz(~nextmsg);
538 switch (nextmsg) {
539 case IPI_RESCHEDULE:
540 scheduler_ipi();
541 break;
542
543 case IPI_CALL_FUNC:
544 generic_smp_call_function_interrupt();
545 break;
546
547 default:
548 pr_crit("CPU%u: Unknown IPI message 0x%lx\n",
549 cpu, nextmsg);
550 break;
551 }
552 }
553
554 return handled;
555 }
556
557 void smp_send_reschedule(int cpu)
558 {
559 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
560 }
561
562 static void stop_this_cpu(void *data)
563 {
564 unsigned int cpu = smp_processor_id();
565
566 if (system_state == SYSTEM_BOOTING ||
567 system_state == SYSTEM_RUNNING) {
568 spin_lock(&stop_lock);
569 pr_crit("CPU%u: stopping\n", cpu);
570 dump_stack();
571 spin_unlock(&stop_lock);
572 }
573
574 set_cpu_online(cpu, false);
575
576 local_irq_disable();
577
578 hard_processor_halt(HALT_OK);
579 }
580
581 void smp_send_stop(void)
582 {
583 smp_call_function(stop_this_cpu, NULL, 0);
584 }
585
586 /*
587 * not supported here
588 */
589 int setup_profiling_timer(unsigned int multiplier)
590 {
591 return -EINVAL;
592 }
593
594 /*
595 * We use KICKs for inter-processor interrupts.
596 *
597 * For every CPU in "callmap" the IPI data must already have been
598 * stored in that CPU's "ipi_data" member prior to calling this
599 * function.
600 */
601 static void kick_raise_softirq(cpumask_t callmap, unsigned int irq)
602 {
603 int cpu;
604
605 for_each_cpu(cpu, &callmap) {
606 unsigned int thread;
607
608 thread = cpu_2_hwthread_id[cpu];
609
610 BUG_ON(thread == BAD_HWTHREAD_ID);
611
612 metag_out32(1, T0KICKI + (thread * TnXKICK_STRIDE));
613 }
614 }
615
616 static TBIRES ipi_handler(TBIRES State, int SigNum, int Triggers,
617 int Inst, PTBI pTBI, int *handled)
618 {
619 *handled = do_IPI();
620
621 return State;
622 }
623
624 static struct kick_irq_handler ipi_irq = {
625 .func = ipi_handler,
626 };
627
628 static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg)
629 {
630 kick_raise_softirq(callmap, 1);
631 }
632
633 static inline unsigned int get_core_count(void)
634 {
635 int i;
636 unsigned int ret = 0;
637
638 for (i = 0; i < CONFIG_NR_CPUS; i++) {
639 if (core_reg_read(TXUCT_ID, TXENABLE_REGNUM, i))
640 ret++;
641 }
642
643 return ret;
644 }
645
646 /*
647 * Initialise the CPU possible map early - this describes the CPUs
648 * which may be present or become present in the system.
649 */
650 void __init smp_init_cpus(void)
651 {
652 unsigned int i, ncores = get_core_count();
653
654 /* If no hwthread_map early param was set use default mapping */
655 for (i = 0; i < NR_CPUS; i++)
656 if (cpu_2_hwthread_id[i] == BAD_HWTHREAD_ID) {
657 cpu_2_hwthread_id[i] = i;
658 hwthread_id_2_cpu[i] = i;
659 }
660
661 for (i = 0; i < ncores; i++)
662 set_cpu_possible(i, true);
663
664 kick_register_func(&ipi_irq);
665 }