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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
46DECLARE_PER_CPU(PTBI, pTBI);
47
48void *secondary_data_stack;
49
50/*
51 * structures for inter-processor calls
52 * - A collection of single bit ipi messages.
53 */
54struct ipi_data {
55 spinlock_t lock;
56 unsigned long ipi_count;
57 unsigned long bits;
58};
59
60static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
61 .lock = __SPIN_LOCK_UNLOCKED(ipi_data.lock),
62};
63
64static DEFINE_SPINLOCK(boot_lock);
65
66static DECLARE_COMPLETION(cpu_running);
67
68/*
69 * "thread" is assumed to be a valid Meta hardware thread ID.
70 */
71static 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 */
121static 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 */
171static 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
216int __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 */
268int __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 */
299void __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 */
311void cpu_die(void)
312{
313 local_irq_disable();
314 idle_task_exit();
315 irq_ctx_exit(smp_processor_id());
316
317 (void)cpu_report_death();
318
319 asm ("XOR TXENABLE, D0Re0,D0Re0\n");
320}
321#endif /* CONFIG_HOTPLUG_CPU */
322
323/*
324 * Called by both boot and secondaries to move global data into
325 * per-processor storage.
326 */
327void smp_store_cpu_info(unsigned int cpuid)
328{
329 struct cpuinfo_metag *cpu_info = &per_cpu(cpu_data, cpuid);
330
331 cpu_info->loops_per_jiffy = loops_per_jiffy;
332}
333
334/*
335 * This is the secondary CPU boot entry. We're using this CPUs
336 * idle thread stack and the global page tables.
337 */
338asmlinkage void secondary_start_kernel(void)
339{
340 struct mm_struct *mm = &init_mm;
341 unsigned int cpu = smp_processor_id();
342
343 /*
344 * All kernel threads share the same mm context; grab a
345 * reference and switch to it.
346 */
347 atomic_inc(&mm->mm_users);
348 atomic_inc(&mm->mm_count);
349 current->active_mm = mm;
350 cpumask_set_cpu(cpu, mm_cpumask(mm));
351 enter_lazy_tlb(mm, current);
352 local_flush_tlb_all();
353
354 /*
355 * TODO: Some day it might be useful for each Linux CPU to
356 * have its own TBI structure. That would allow each Linux CPU
357 * to run different interrupt handlers for the same IRQ
358 * number.
359 *
360 * For now, simply copying the pointer to the boot CPU's TBI
361 * structure is sufficient because we always want to run the
362 * same interrupt handler whatever CPU takes the interrupt.
363 */
364 per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
365
366 if (!per_cpu(pTBI, cpu))
367 panic("No TBI found!");
368
369 per_cpu_trap_init(cpu);
370 irq_ctx_init(cpu);
371
372 preempt_disable();
373
374 setup_priv();
375
376 notify_cpu_starting(cpu);
377
378 pr_info("CPU%u (thread %u): Booted secondary processor\n",
379 cpu, cpu_2_hwthread_id[cpu]);
380
381 calibrate_delay();
382 smp_store_cpu_info(cpu);
383
384 /*
385 * OK, now it's safe to let the boot CPU continue
386 */
387 set_cpu_online(cpu, true);
388 complete(&cpu_running);
389
390 /*
391 * Enable local interrupts.
392 */
393 tbi_startup_interrupt(TBID_SIGNUM_TRT);
394 local_irq_enable();
395
396 /*
397 * OK, it's off to the idle thread for us
398 */
399 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
400}
401
402void __init smp_cpus_done(unsigned int max_cpus)
403{
404 int cpu;
405 unsigned long bogosum = 0;
406
407 for_each_online_cpu(cpu)
408 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
409
410 pr_info("SMP: Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
411 num_online_cpus(),
412 bogosum / (500000/HZ),
413 (bogosum / (5000/HZ)) % 100);
414}
415
416void __init smp_prepare_cpus(unsigned int max_cpus)
417{
418 unsigned int cpu = smp_processor_id();
419
420 init_new_context(current, &init_mm);
421 current_thread_info()->cpu = cpu;
422
423 smp_store_cpu_info(cpu);
424 init_cpu_present(cpu_possible_mask);
425}
426
427void __init smp_prepare_boot_cpu(void)
428{
429 unsigned int cpu = smp_processor_id();
430
431 per_cpu(pTBI, cpu) = __TBI(TBID_ISTAT_BIT);
432
433 if (!per_cpu(pTBI, cpu))
434 panic("No TBI found!");
435}
436
437static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg);
438
439static void send_ipi_message(const struct cpumask *mask, enum ipi_msg_type msg)
440{
441 unsigned long flags;
442 unsigned int cpu;
443 cpumask_t map;
444
445 cpumask_clear(&map);
446 local_irq_save(flags);
447
448 for_each_cpu(cpu, mask) {
449 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
450
451 spin_lock(&ipi->lock);
452
453 /*
454 * KICK interrupts are queued in hardware so we'll get
455 * multiple interrupts if we call smp_cross_call()
456 * multiple times for one msg. The problem is that we
457 * only have one bit for each message - we can't queue
458 * them in software.
459 *
460 * The first time through ipi_handler() we'll clear
461 * the msg bit, having done all the work. But when we
462 * return we'll get _another_ interrupt (and another,
463 * and another until we've handled all the queued
464 * KICKs). Running ipi_handler() when there's no work
465 * to do is bad because that's how kick handler
466 * chaining detects who the KICK was intended for.
467 * See arch/metag/kernel/kick.c for more details.
468 *
469 * So only add 'cpu' to 'map' if we haven't already
470 * queued a KICK interrupt for 'msg'.
471 */
472 if (!(ipi->bits & (1 << msg))) {
473 ipi->bits |= 1 << msg;
474 cpumask_set_cpu(cpu, &map);
475 }
476
477 spin_unlock(&ipi->lock);
478 }
479
480 /*
481 * Call the platform specific cross-CPU call function.
482 */
483 smp_cross_call(map, msg);
484
485 local_irq_restore(flags);
486}
487
488void arch_send_call_function_ipi_mask(const struct cpumask *mask)
489{
490 send_ipi_message(mask, IPI_CALL_FUNC);
491}
492
493void arch_send_call_function_single_ipi(int cpu)
494{
495 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
496}
497
498void show_ipi_list(struct seq_file *p)
499{
500 unsigned int cpu;
501
502 seq_puts(p, "IPI:");
503
504 for_each_present_cpu(cpu)
505 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
506
507 seq_putc(p, '\n');
508}
509
510static DEFINE_SPINLOCK(stop_lock);
511
512/*
513 * Main handler for inter-processor interrupts
514 *
515 * For Meta, the ipimask now only identifies a single
516 * category of IPI (Bit 1 IPIs have been replaced by a
517 * different mechanism):
518 *
519 * Bit 0 - Inter-processor function call
520 */
521static int do_IPI(void)
522{
523 unsigned int cpu = smp_processor_id();
524 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
525 unsigned long msgs, nextmsg;
526 int handled = 0;
527
528 ipi->ipi_count++;
529
530 spin_lock(&ipi->lock);
531 msgs = ipi->bits;
532 nextmsg = msgs & -msgs;
533 ipi->bits &= ~nextmsg;
534 spin_unlock(&ipi->lock);
535
536 if (nextmsg) {
537 handled = 1;
538
539 nextmsg = ffz(~nextmsg);
540 switch (nextmsg) {
541 case IPI_RESCHEDULE:
542 scheduler_ipi();
543 break;
544
545 case IPI_CALL_FUNC:
546 generic_smp_call_function_interrupt();
547 break;
548
549 default:
550 pr_crit("CPU%u: Unknown IPI message 0x%lx\n",
551 cpu, nextmsg);
552 break;
553 }
554 }
555
556 return handled;
557}
558
559void smp_send_reschedule(int cpu)
560{
561 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
562}
563
564static void stop_this_cpu(void *data)
565{
566 unsigned int cpu = smp_processor_id();
567
568 if (system_state == SYSTEM_BOOTING ||
569 system_state == SYSTEM_RUNNING) {
570 spin_lock(&stop_lock);
571 pr_crit("CPU%u: stopping\n", cpu);
572 dump_stack();
573 spin_unlock(&stop_lock);
574 }
575
576 set_cpu_online(cpu, false);
577
578 local_irq_disable();
579
580 hard_processor_halt(HALT_OK);
581}
582
583void smp_send_stop(void)
584{
585 smp_call_function(stop_this_cpu, NULL, 0);
586}
587
588/*
589 * not supported here
590 */
591int setup_profiling_timer(unsigned int multiplier)
592{
593 return -EINVAL;
594}
595
596/*
597 * We use KICKs for inter-processor interrupts.
598 *
599 * For every CPU in "callmap" the IPI data must already have been
600 * stored in that CPU's "ipi_data" member prior to calling this
601 * function.
602 */
603static void kick_raise_softirq(cpumask_t callmap, unsigned int irq)
604{
605 int cpu;
606
607 for_each_cpu(cpu, &callmap) {
608 unsigned int thread;
609
610 thread = cpu_2_hwthread_id[cpu];
611
612 BUG_ON(thread == BAD_HWTHREAD_ID);
613
614 metag_out32(1, T0KICKI + (thread * TnXKICK_STRIDE));
615 }
616}
617
618static TBIRES ipi_handler(TBIRES State, int SigNum, int Triggers,
619 int Inst, PTBI pTBI, int *handled)
620{
621 *handled = do_IPI();
622
623 return State;
624}
625
626static struct kick_irq_handler ipi_irq = {
627 .func = ipi_handler,
628};
629
630static void smp_cross_call(cpumask_t callmap, enum ipi_msg_type msg)
631{
632 kick_raise_softirq(callmap, 1);
633}
634
635static inline unsigned int get_core_count(void)
636{
637 int i;
638 unsigned int ret = 0;
639
640 for (i = 0; i < CONFIG_NR_CPUS; i++) {
641 if (core_reg_read(TXUCT_ID, TXENABLE_REGNUM, i))
642 ret++;
643 }
644
645 return ret;
646}
647
648/*
649 * Initialise the CPU possible map early - this describes the CPUs
650 * which may be present or become present in the system.
651 */
652void __init smp_init_cpus(void)
653{
654 unsigned int i, ncores = get_core_count();
655
656 /* If no hwthread_map early param was set use default mapping */
657 for (i = 0; i < NR_CPUS; i++)
658 if (cpu_2_hwthread_id[i] == BAD_HWTHREAD_ID) {
659 cpu_2_hwthread_id[i] = i;
660 hwthread_id_2_cpu[i] = i;
661 }
662
663 for (i = 0; i < ncores; i++)
664 set_cpu_possible(i, true);
665
666 kick_register_func(&ipi_irq);
667}