summaryrefslogtreecommitdiff
path: root/arch/parisc/kernel/irq.c
blob: e255db0bb7619cf92e8581cae017f01f20c4718d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
/* 
 * Code to handle x86 style IRQs plus some generic interrupt stuff.
 *
 * Copyright (C) 1992 Linus Torvalds
 * Copyright (C) 1994, 1995, 1996, 1997, 1998 Ralf Baechle
 * Copyright (C) 1999 SuSE GmbH (Philipp Rumpf, prumpf@tux.org)
 * Copyright (C) 1999-2000 Grant Grundler
 * Copyright (c) 2005 Matthew Wilcox
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2, or (at your option)
 *    any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/seq_file.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <asm/io.h>

#include <asm/smp.h>

#undef PARISC_IRQ_CR16_COUNTS

extern irqreturn_t timer_interrupt(int, void *);
extern irqreturn_t ipi_interrupt(int, void *);

#define EIEM_MASK(irq)       (1UL<<(CPU_IRQ_MAX - irq))

/* Bits in EIEM correlate with cpu_irq_action[].
** Numbered *Big Endian*! (ie bit 0 is MSB)
*/
static volatile unsigned long cpu_eiem = 0;

/*
** local ACK bitmap ... habitually set to 1, but reset to zero
** between ->ack() and ->end() of the interrupt to prevent
** re-interruption of a processing interrupt.
*/
static DEFINE_PER_CPU(unsigned long, local_ack_eiem) = ~0UL;

static void cpu_mask_irq(struct irq_data *d)
{
	unsigned long eirr_bit = EIEM_MASK(d->irq);

	cpu_eiem &= ~eirr_bit;
	/* Do nothing on the other CPUs.  If they get this interrupt,
	 * The & cpu_eiem in the do_cpu_irq_mask() ensures they won't
	 * handle it, and the set_eiem() at the bottom will ensure it
	 * then gets disabled */
}

static void __cpu_unmask_irq(unsigned int irq)
{
	unsigned long eirr_bit = EIEM_MASK(irq);

	cpu_eiem |= eirr_bit;

	/* This is just a simple NOP IPI.  But what it does is cause
	 * all the other CPUs to do a set_eiem(cpu_eiem) at the end
	 * of the interrupt handler */
	smp_send_all_nop();
}

static void cpu_unmask_irq(struct irq_data *d)
{
	__cpu_unmask_irq(d->irq);
}

void cpu_ack_irq(struct irq_data *d)
{
	unsigned long mask = EIEM_MASK(d->irq);
	int cpu = smp_processor_id();

	/* Clear in EIEM so we can no longer process */
	per_cpu(local_ack_eiem, cpu) &= ~mask;

	/* disable the interrupt */
	set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));

	/* and now ack it */
	mtctl(mask, 23);
}

void cpu_eoi_irq(struct irq_data *d)
{
	unsigned long mask = EIEM_MASK(d->irq);
	int cpu = smp_processor_id();

	/* set it in the eiems---it's no longer in process */
	per_cpu(local_ack_eiem, cpu) |= mask;

	/* enable the interrupt */
	set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
}

#ifdef CONFIG_SMP
int cpu_check_affinity(struct irq_data *d, const struct cpumask *dest)
{
	int cpu_dest;

	/* timer and ipi have to always be received on all CPUs */
	if (irqd_is_per_cpu(d))
		return -EINVAL;

	/* whatever mask they set, we just allow one CPU */
	cpu_dest = first_cpu(*dest);

	return cpu_dest;
}

static int cpu_set_affinity_irq(struct irq_data *d, const struct cpumask *dest,
				bool force)
{
	int cpu_dest;

	cpu_dest = cpu_check_affinity(d, dest);
	if (cpu_dest < 0)
		return -1;

	cpumask_copy(d->affinity, dest);

	return 0;
}
#endif

static struct irq_chip cpu_interrupt_type = {
	.name			= "CPU",
	.irq_mask		= cpu_mask_irq,
	.irq_unmask		= cpu_unmask_irq,
	.irq_ack		= cpu_ack_irq,
	.irq_eoi		= cpu_eoi_irq,
#ifdef CONFIG_SMP
	.irq_set_affinity	= cpu_set_affinity_irq,
#endif
	/* XXX: Needs to be written.  We managed without it so far, but
	 * we really ought to write it.
	 */
	.irq_retrigger	= NULL,
};

DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
#define irq_stats(x)		(&per_cpu(irq_stat, x))

/*
 * /proc/interrupts printing for arch specific interrupts
 */
int arch_show_interrupts(struct seq_file *p, int prec)
{
	int j;

#ifdef CONFIG_DEBUG_STACKOVERFLOW
	seq_printf(p, "%*s: ", prec, "STK");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", irq_stats(j)->kernel_stack_usage);
	seq_printf(p, "  Kernel stack usage\n");
#endif
#ifdef CONFIG_SMP
	seq_printf(p, "%*s: ", prec, "RES");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", irq_stats(j)->irq_resched_count);
	seq_printf(p, "  Rescheduling interrupts\n");
	seq_printf(p, "%*s: ", prec, "CAL");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", irq_stats(j)->irq_call_count);
	seq_printf(p, "  Function call interrupts\n");
#endif
	seq_printf(p, "%*s: ", prec, "TLB");
	for_each_online_cpu(j)
		seq_printf(p, "%10u ", irq_stats(j)->irq_tlb_count);
	seq_printf(p, "  TLB shootdowns\n");
	return 0;
}

int show_interrupts(struct seq_file *p, void *v)
{
	int i = *(loff_t *) v, j;
	unsigned long flags;

	if (i == 0) {
		seq_puts(p, "    ");
		for_each_online_cpu(j)
			seq_printf(p, "       CPU%d", j);

#ifdef PARISC_IRQ_CR16_COUNTS
		seq_printf(p, " [min/avg/max] (CPU cycle counts)");
#endif
		seq_putc(p, '\n');
	}

	if (i < NR_IRQS) {
		struct irq_desc *desc = irq_to_desc(i);
		struct irqaction *action;

		raw_spin_lock_irqsave(&desc->lock, flags);
		action = desc->action;
		if (!action)
			goto skip;
		seq_printf(p, "%3d: ", i);
#ifdef CONFIG_SMP
		for_each_online_cpu(j)
			seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
#else
		seq_printf(p, "%10u ", kstat_irqs(i));
#endif

		seq_printf(p, " %14s", irq_desc_get_chip(desc)->name);
#ifndef PARISC_IRQ_CR16_COUNTS
		seq_printf(p, "  %s", action->name);

		while ((action = action->next))
			seq_printf(p, ", %s", action->name);
#else
		for ( ;action; action = action->next) {
			unsigned int k, avg, min, max;

			min = max = action->cr16_hist[0];

			for (avg = k = 0; k < PARISC_CR16_HIST_SIZE; k++) {
				int hist = action->cr16_hist[k];

				if (hist) {
					avg += hist;
				} else
					break;

				if (hist > max) max = hist;
				if (hist < min) min = hist;
			}

			avg /= k;
			seq_printf(p, " %s[%d/%d/%d]", action->name,
					min,avg,max);
		}
#endif

		seq_putc(p, '\n');
 skip:
		raw_spin_unlock_irqrestore(&desc->lock, flags);
	}

	if (i == NR_IRQS)
		arch_show_interrupts(p, 3);

	return 0;
}



/*
** The following form a "set": Virtual IRQ, Transaction Address, Trans Data.
** Respectively, these map to IRQ region+EIRR, Processor HPA, EIRR bit.
**
** To use txn_XXX() interfaces, get a Virtual IRQ first.
** Then use that to get the Transaction address and data.
*/

int cpu_claim_irq(unsigned int irq, struct irq_chip *type, void *data)
{
	if (irq_has_action(irq))
		return -EBUSY;
	if (irq_get_chip(irq) != &cpu_interrupt_type)
		return -EBUSY;

	/* for iosapic interrupts */
	if (type) {
		irq_set_chip_and_handler(irq, type, handle_percpu_irq);
		irq_set_chip_data(irq, data);
		__cpu_unmask_irq(irq);
	}
	return 0;
}

int txn_claim_irq(int irq)
{
	return cpu_claim_irq(irq, NULL, NULL) ? -1 : irq;
}

/*
 * The bits_wide parameter accommodates the limitations of the HW/SW which
 * use these bits:
 * Legacy PA I/O (GSC/NIO): 5 bits (architected EIM register)
 * V-class (EPIC):          6 bits
 * N/L/A-class (iosapic):   8 bits
 * PCI 2.2 MSI:            16 bits
 * Some PCI devices:       32 bits (Symbios SCSI/ATM/HyperFabric)
 *
 * On the service provider side:
 * o PA 1.1 (and PA2.0 narrow mode)     5-bits (width of EIR register)
 * o PA 2.0 wide mode                   6-bits (per processor)
 * o IA64                               8-bits (0-256 total)
 *
 * So a Legacy PA I/O device on a PA 2.0 box can't use all the bits supported
 * by the processor...and the N/L-class I/O subsystem supports more bits than
 * PA2.0 has. The first case is the problem.
 */
int txn_alloc_irq(unsigned int bits_wide)
{
	int irq;

	/* never return irq 0 cause that's the interval timer */
	for (irq = CPU_IRQ_BASE + 1; irq <= CPU_IRQ_MAX; irq++) {
		if (cpu_claim_irq(irq, NULL, NULL) < 0)
			continue;
		if ((irq - CPU_IRQ_BASE) >= (1 << bits_wide))
			continue;
		return irq;
	}

	/* unlikely, but be prepared */
	return -1;
}


unsigned long txn_affinity_addr(unsigned int irq, int cpu)
{
#ifdef CONFIG_SMP
	struct irq_data *d = irq_get_irq_data(irq);
	cpumask_copy(d->affinity, cpumask_of(cpu));
#endif

	return per_cpu(cpu_data, cpu).txn_addr;
}


unsigned long txn_alloc_addr(unsigned int virt_irq)
{
	static int next_cpu = -1;

	next_cpu++; /* assign to "next" CPU we want this bugger on */

	/* validate entry */
	while ((next_cpu < nr_cpu_ids) &&
		(!per_cpu(cpu_data, next_cpu).txn_addr ||
		 !cpu_online(next_cpu)))
		next_cpu++;

	if (next_cpu >= nr_cpu_ids) 
		next_cpu = 0;	/* nothing else, assign monarch */

	return txn_affinity_addr(virt_irq, next_cpu);
}


unsigned int txn_alloc_data(unsigned int virt_irq)
{
	return virt_irq - CPU_IRQ_BASE;
}

static inline int eirr_to_irq(unsigned long eirr)
{
	int bit = fls_long(eirr);
	return (BITS_PER_LONG - bit) + TIMER_IRQ;
}

int sysctl_panic_on_stackoverflow = 1;

static inline void stack_overflow_check(struct pt_regs *regs)
{
#ifdef CONFIG_DEBUG_STACKOVERFLOW
	#define STACK_MARGIN	(256*6)

	/* Our stack starts directly behind the thread_info struct. */
	unsigned long stack_start = (unsigned long) current_thread_info();
	unsigned long sp = regs->gr[30];
	unsigned long stack_usage;
	unsigned int *last_usage;

	/* if sr7 != 0, we interrupted a userspace process which we do not want
	 * to check for stack overflow. We will only check the kernel stack. */
	if (regs->sr[7])
		return;

	/* calculate kernel stack usage */
	stack_usage = sp - stack_start;
	last_usage = &per_cpu(irq_stat.kernel_stack_usage, smp_processor_id());

	if (unlikely(stack_usage > *last_usage))
		*last_usage = stack_usage;

	if (likely(stack_usage < (THREAD_SIZE - STACK_MARGIN)))
		return;

	pr_emerg("stackcheck: %s will most likely overflow kernel stack "
		 "(sp:%lx, stk bottom-top:%lx-%lx)\n",
		current->comm, sp, stack_start, stack_start + THREAD_SIZE);

	if (sysctl_panic_on_stackoverflow)
		panic("low stack detected by irq handler - check messages\n");
#endif
}

#ifdef CONFIG_IRQSTACKS
DEFINE_PER_CPU(union irq_stack_union, irq_stack_union);

static void execute_on_irq_stack(void *func, unsigned long param1)
{
	unsigned long *irq_stack_start;
	unsigned long irq_stack;
	int cpu = smp_processor_id();

	irq_stack_start = &per_cpu(irq_stack_union, cpu).stack[0];
	irq_stack = (unsigned long) irq_stack_start;
	irq_stack = ALIGN(irq_stack, 16); /* align for stack frame usage */

	BUG_ON(*irq_stack_start); /* report bug if we were called recursive. */
	*irq_stack_start = 1;

	/* This is where we switch to the IRQ stack. */
	call_on_stack(param1, func, irq_stack);

	*irq_stack_start = 0;
}
#endif /* CONFIG_IRQSTACKS */

/* ONLY called from entry.S:intr_extint() */
void do_cpu_irq_mask(struct pt_regs *regs)
{
	struct pt_regs *old_regs;
	unsigned long eirr_val;
	int irq, cpu = smp_processor_id();
#ifdef CONFIG_SMP
	struct irq_desc *desc;
	cpumask_t dest;
#endif

	old_regs = set_irq_regs(regs);
	local_irq_disable();
	irq_enter();

	eirr_val = mfctl(23) & cpu_eiem & per_cpu(local_ack_eiem, cpu);
	if (!eirr_val)
		goto set_out;
	irq = eirr_to_irq(eirr_val);

#ifdef CONFIG_SMP
	desc = irq_to_desc(irq);
	cpumask_copy(&dest, desc->irq_data.affinity);
	if (irqd_is_per_cpu(&desc->irq_data) &&
	    !cpu_isset(smp_processor_id(), dest)) {
		int cpu = first_cpu(dest);

		printk(KERN_DEBUG "redirecting irq %d from CPU %d to %d\n",
		       irq, smp_processor_id(), cpu);
		gsc_writel(irq + CPU_IRQ_BASE,
			   per_cpu(cpu_data, cpu).hpa);
		goto set_out;
	}
#endif
	stack_overflow_check(regs);

#ifdef CONFIG_IRQSTACKS
	execute_on_irq_stack(&generic_handle_irq, irq);
#else
	generic_handle_irq(irq);
#endif /* CONFIG_IRQSTACKS */

 out:
	irq_exit();
	set_irq_regs(old_regs);
	return;

 set_out:
	set_eiem(cpu_eiem & per_cpu(local_ack_eiem, cpu));
	goto out;
}

static struct irqaction timer_action = {
	.handler = timer_interrupt,
	.name = "timer",
	.flags = IRQF_TIMER | IRQF_PERCPU | IRQF_IRQPOLL,
};

#ifdef CONFIG_SMP
static struct irqaction ipi_action = {
	.handler = ipi_interrupt,
	.name = "IPI",
	.flags = IRQF_PERCPU,
};
#endif

static void claim_cpu_irqs(void)
{
	int i;
	for (i = CPU_IRQ_BASE; i <= CPU_IRQ_MAX; i++) {
		irq_set_chip_and_handler(i, &cpu_interrupt_type,
					 handle_percpu_irq);
	}

	irq_set_handler(TIMER_IRQ, handle_percpu_irq);
	setup_irq(TIMER_IRQ, &timer_action);
#ifdef CONFIG_SMP
	irq_set_handler(IPI_IRQ, handle_percpu_irq);
	setup_irq(IPI_IRQ, &ipi_action);
#endif
}

void __init init_IRQ(void)
{
	local_irq_disable();	/* PARANOID - should already be disabled */
	mtctl(~0UL, 23);	/* EIRR : clear all pending external intr */
#ifdef CONFIG_SMP
	if (!cpu_eiem) {
		claim_cpu_irqs();
		cpu_eiem = EIEM_MASK(IPI_IRQ) | EIEM_MASK(TIMER_IRQ);
	}
#else
	claim_cpu_irqs();
	cpu_eiem = EIEM_MASK(TIMER_IRQ);
#endif
        set_eiem(cpu_eiem);	/* EIEM : enable all external intr */
}