xref: /linux/arch/powerpc/kernel/irq.c (revision 9ce7677cfd7cd871adb457c80bea3b581b839641) 
1 /*
2  *  arch/ppc/kernel/irq.c
3  *
4  *  Derived from arch/i386/kernel/irq.c
5  *    Copyright (C) 1992 Linus Torvalds
6  *  Adapted from arch/i386 by Gary Thomas
7  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8  *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
9  *    Copyright (C) 1996-2001 Cort Dougan
10  *  Adapted for Power Macintosh by Paul Mackerras
11  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
12  *  Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
13  *
14  * This program is free software; you can redistribute it and/or
15  * modify it under the terms of the GNU General Public License
16  * as published by the Free Software Foundation; either version
17  * 2 of the License, or (at your option) any later version.
18  *
19  * This file contains the code used by various IRQ handling routines:
20  * asking for different IRQ's should be done through these routines
21  * instead of just grabbing them. Thus setups with different IRQ numbers
22  * shouldn't result in any weird surprises, and installing new handlers
23  * should be easier.
24  *
25  * The MPC8xx has an interrupt mask in the SIU.  If a bit is set, the
26  * interrupt is _enabled_.  As expected, IRQ0 is bit 0 in the 32-bit
27  * mask register (of which only 16 are defined), hence the weird shifting
28  * and complement of the cached_irq_mask.  I want to be able to stuff
29  * this right into the SIU SMASK register.
30  * Many of the prep/chrp functions are conditional compiled on CONFIG_8xx
31  * to reduce code space and undefined function references.
32  */
33 
34 #include <linux/errno.h>
35 #include <linux/module.h>
36 #include <linux/threads.h>
37 #include <linux/kernel_stat.h>
38 #include <linux/signal.h>
39 #include <linux/sched.h>
40 #include <linux/ptrace.h>
41 #include <linux/ioport.h>
42 #include <linux/interrupt.h>
43 #include <linux/timex.h>
44 #include <linux/config.h>
45 #include <linux/init.h>
46 #include <linux/slab.h>
47 #include <linux/pci.h>
48 #include <linux/delay.h>
49 #include <linux/irq.h>
50 #include <linux/proc_fs.h>
51 #include <linux/random.h>
52 #include <linux/seq_file.h>
53 #include <linux/cpumask.h>
54 #include <linux/profile.h>
55 #include <linux/bitops.h>
56 #ifdef CONFIG_PPC64
57 #include <linux/kallsyms.h>
58 #endif
59 
60 #include <asm/uaccess.h>
61 #include <asm/system.h>
62 #include <asm/io.h>
63 #include <asm/pgtable.h>
64 #include <asm/irq.h>
65 #include <asm/cache.h>
66 #include <asm/prom.h>
67 #include <asm/ptrace.h>
68 #include <asm/machdep.h>
69 #ifdef CONFIG_PPC64
70 #include <asm/iseries/it_lp_queue.h>
71 #include <asm/paca.h>
72 #endif
73 
74 int __irq_offset_value;
75 #ifdef CONFIG_PPC32
76 EXPORT_SYMBOL(__irq_offset_value);
77 #endif
78 
79 static int ppc_spurious_interrupts;
80 
81 #if defined(CONFIG_PPC_ISERIES) && defined(CONFIG_SMP)
82 extern void iSeries_smp_message_recv(struct pt_regs *);
83 #endif
84 
85 #ifdef CONFIG_PPC32
86 #define NR_MASK_WORDS	((NR_IRQS + 31) / 32)
87 
88 unsigned long ppc_cached_irq_mask[NR_MASK_WORDS];
89 atomic_t ppc_n_lost_interrupts;
90 
91 #ifdef CONFIG_TAU_INT
92 extern int tau_initialized;
93 extern int tau_interrupts(int);
94 #endif
95 
96 #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
97 extern atomic_t ipi_recv;
98 extern atomic_t ipi_sent;
99 #endif
100 #endif /* CONFIG_PPC32 */
101 
102 #ifdef CONFIG_PPC64
103 EXPORT_SYMBOL(irq_desc);
104 
105 int distribute_irqs = 1;
106 u64 ppc64_interrupt_controller;
107 #endif /* CONFIG_PPC64 */
108 
109 int show_interrupts(struct seq_file *p, void *v)
110 {
111 	int i = *(loff_t *)v, j;
112 	struct irqaction *action;
113 	irq_desc_t *desc;
114 	unsigned long flags;
115 
116 	if (i == 0) {
117 		seq_puts(p, "           ");
118 		for_each_online_cpu(j)
119 			seq_printf(p, "CPU%d       ", j);
120 		seq_putc(p, '\n');
121 	}
122 
123 	if (i < NR_IRQS) {
124 		desc = get_irq_desc(i);
125 		spin_lock_irqsave(&desc->lock, flags);
126 		action = desc->action;
127 		if (!action || !action->handler)
128 			goto skip;
129 		seq_printf(p, "%3d: ", i);
130 #ifdef CONFIG_SMP
131 		for_each_online_cpu(j)
132 			seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
133 #else
134 		seq_printf(p, "%10u ", kstat_irqs(i));
135 #endif /* CONFIG_SMP */
136 		if (desc->handler)
137 			seq_printf(p, " %s ", desc->handler->typename);
138 		else
139 			seq_puts(p, "  None      ");
140 		seq_printf(p, "%s", (desc->status & IRQ_LEVEL) ? "Level " : "Edge  ");
141 		seq_printf(p, "    %s", action->name);
142 		for (action = action->next; action; action = action->next)
143 			seq_printf(p, ", %s", action->name);
144 		seq_putc(p, '\n');
145 skip:
146 		spin_unlock_irqrestore(&desc->lock, flags);
147 	} else if (i == NR_IRQS) {
148 #ifdef CONFIG_PPC32
149 #ifdef CONFIG_TAU_INT
150 		if (tau_initialized){
151 			seq_puts(p, "TAU: ");
152 			for (j = 0; j < NR_CPUS; j++)
153 				if (cpu_online(j))
154 					seq_printf(p, "%10u ", tau_interrupts(j));
155 			seq_puts(p, "  PowerPC             Thermal Assist (cpu temp)\n");
156 		}
157 #endif
158 #if defined(CONFIG_SMP) && !defined(CONFIG_PPC_MERGE)
159 		/* should this be per processor send/receive? */
160 		seq_printf(p, "IPI (recv/sent): %10u/%u\n",
161 				atomic_read(&ipi_recv), atomic_read(&ipi_sent));
162 #endif
163 #endif /* CONFIG_PPC32 */
164 		seq_printf(p, "BAD: %10u\n", ppc_spurious_interrupts);
165 	}
166 	return 0;
167 }
168 
169 #ifdef CONFIG_HOTPLUG_CPU
170 void fixup_irqs(cpumask_t map)
171 {
172 	unsigned int irq;
173 	static int warned;
174 
175 	for_each_irq(irq) {
176 		cpumask_t mask;
177 
178 		if (irq_desc[irq].status & IRQ_PER_CPU)
179 			continue;
180 
181 		cpus_and(mask, irq_affinity[irq], map);
182 		if (any_online_cpu(mask) == NR_CPUS) {
183 			printk("Breaking affinity for irq %i\n", irq);
184 			mask = map;
185 		}
186 		if (irq_desc[irq].handler->set_affinity)
187 			irq_desc[irq].handler->set_affinity(irq, mask);
188 		else if (irq_desc[irq].action && !(warned++))
189 			printk("Cannot set affinity for irq %i\n", irq);
190 	}
191 
192 	local_irq_enable();
193 	mdelay(1);
194 	local_irq_disable();
195 }
196 #endif
197 
198 #ifdef CONFIG_PPC_ISERIES
199 void do_IRQ(struct pt_regs *regs)
200 {
201 	struct paca_struct *lpaca;
202 
203 	irq_enter();
204 
205 #ifdef CONFIG_DEBUG_STACKOVERFLOW
206 	/* Debugging check for stack overflow: is there less than 2KB free? */
207 	{
208 		long sp;
209 
210 		sp = __get_SP() & (THREAD_SIZE-1);
211 
212 		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
213 			printk("do_IRQ: stack overflow: %ld\n",
214 				sp - sizeof(struct thread_info));
215 			dump_stack();
216 		}
217 	}
218 #endif
219 
220 	lpaca = get_paca();
221 #ifdef CONFIG_SMP
222 	if (lpaca->lppaca.int_dword.fields.ipi_cnt) {
223 		lpaca->lppaca.int_dword.fields.ipi_cnt = 0;
224 		iSeries_smp_message_recv(regs);
225 	}
226 #endif /* CONFIG_SMP */
227 	if (hvlpevent_is_pending())
228 		process_hvlpevents(regs);
229 
230 	irq_exit();
231 
232 	if (lpaca->lppaca.int_dword.fields.decr_int) {
233 		lpaca->lppaca.int_dword.fields.decr_int = 0;
234 		/* Signal a fake decrementer interrupt */
235 		timer_interrupt(regs);
236 	}
237 }
238 
239 #else	/* CONFIG_PPC_ISERIES */
240 
241 void do_IRQ(struct pt_regs *regs)
242 {
243 	int irq;
244 #ifdef CONFIG_IRQSTACKS
245 	struct thread_info *curtp, *irqtp;
246 #endif
247 
248         irq_enter();
249 
250 #ifdef CONFIG_DEBUG_STACKOVERFLOW
251 	/* Debugging check for stack overflow: is there less than 2KB free? */
252 	{
253 		long sp;
254 
255 		sp = __get_SP() & (THREAD_SIZE-1);
256 
257 		if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
258 			printk("do_IRQ: stack overflow: %ld\n",
259 				sp - sizeof(struct thread_info));
260 			dump_stack();
261 		}
262 	}
263 #endif
264 
265 	/*
266 	 * Every platform is required to implement ppc_md.get_irq.
267 	 * This function will either return an irq number or -1 to
268 	 * indicate there are no more pending.
269 	 * The value -2 is for buggy hardware and means that this IRQ
270 	 * has already been handled. -- Tom
271 	 */
272 	irq = ppc_md.get_irq(regs);
273 
274 	if (irq >= 0) {
275 #ifdef CONFIG_IRQSTACKS
276 		/* Switch to the irq stack to handle this */
277 		curtp = current_thread_info();
278 		irqtp = hardirq_ctx[smp_processor_id()];
279 		if (curtp != irqtp) {
280 			irqtp->task = curtp->task;
281 			irqtp->flags = 0;
282 			call___do_IRQ(irq, regs, irqtp);
283 			irqtp->task = NULL;
284 			if (irqtp->flags)
285 				set_bits(irqtp->flags, &curtp->flags);
286 		} else
287 #endif
288 			__do_IRQ(irq, regs);
289 	} else
290 #ifdef CONFIG_PPC32
291 		if (irq != -2)
292 #endif
293 			/* That's not SMP safe ... but who cares ? */
294 			ppc_spurious_interrupts++;
295         irq_exit();
296 }
297 
298 #endif	/* CONFIG_PPC_ISERIES */
299 
300 void __init init_IRQ(void)
301 {
302 #ifdef CONFIG_PPC64
303 	static int once = 0;
304 
305 	if (once)
306 		return;
307 
308 	once++;
309 
310 #endif
311 	ppc_md.init_IRQ();
312 #ifdef CONFIG_PPC64
313 	irq_ctx_init();
314 #endif
315 }
316 
317 #ifdef CONFIG_PPC64
318 /*
319  * Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
320  */
321 
322 #define UNDEFINED_IRQ 0xffffffff
323 unsigned int virt_irq_to_real_map[NR_IRQS];
324 
325 /*
326  * Don't use virtual irqs 0, 1, 2 for devices.
327  * The pcnet32 driver considers interrupt numbers < 2 to be invalid,
328  * and 2 is the XICS IPI interrupt.
329  * We limit virtual irqs to 17 less than NR_IRQS so that when we
330  * offset them by 16 (to reserve the first 16 for ISA interrupts)
331  * we don't end up with an interrupt number >= NR_IRQS.
332  */
333 #define MIN_VIRT_IRQ	3
334 #define MAX_VIRT_IRQ	(NR_IRQS - NUM_ISA_INTERRUPTS - 1)
335 #define NR_VIRT_IRQS	(MAX_VIRT_IRQ - MIN_VIRT_IRQ + 1)
336 
337 void
338 virt_irq_init(void)
339 {
340 	int i;
341 	for (i = 0; i < NR_IRQS; i++)
342 		virt_irq_to_real_map[i] = UNDEFINED_IRQ;
343 }
344 
345 /* Create a mapping for a real_irq if it doesn't already exist.
346  * Return the virtual irq as a convenience.
347  */
348 int virt_irq_create_mapping(unsigned int real_irq)
349 {
350 	unsigned int virq, first_virq;
351 	static int warned;
352 
353 	if (ppc64_interrupt_controller == IC_OPEN_PIC)
354 		return real_irq;	/* no mapping for openpic (for now) */
355 
356 	if (ppc64_interrupt_controller == IC_CELL_PIC)
357 		return real_irq;	/* no mapping for iic either */
358 
359 	/* don't map interrupts < MIN_VIRT_IRQ */
360 	if (real_irq < MIN_VIRT_IRQ) {
361 		virt_irq_to_real_map[real_irq] = real_irq;
362 		return real_irq;
363 	}
364 
365 	/* map to a number between MIN_VIRT_IRQ and MAX_VIRT_IRQ */
366 	virq = real_irq;
367 	if (virq > MAX_VIRT_IRQ)
368 		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
369 
370 	/* search for this number or a free slot */
371 	first_virq = virq;
372 	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
373 		if (virt_irq_to_real_map[virq] == real_irq)
374 			return virq;
375 		if (++virq > MAX_VIRT_IRQ)
376 			virq = MIN_VIRT_IRQ;
377 		if (virq == first_virq)
378 			goto nospace;	/* oops, no free slots */
379 	}
380 
381 	virt_irq_to_real_map[virq] = real_irq;
382 	return virq;
383 
384  nospace:
385 	if (!warned) {
386 		printk(KERN_CRIT "Interrupt table is full\n");
387 		printk(KERN_CRIT "Increase NR_IRQS (currently %d) "
388 		       "in your kernel sources and rebuild.\n", NR_IRQS);
389 		warned = 1;
390 	}
391 	return NO_IRQ;
392 }
393 
394 /*
395  * In most cases will get a hit on the very first slot checked in the
396  * virt_irq_to_real_map.  Only when there are a large number of
397  * IRQs will this be expensive.
398  */
399 unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
400 {
401 	unsigned int virq;
402 	unsigned int first_virq;
403 
404 	virq = real_irq;
405 
406 	if (virq > MAX_VIRT_IRQ)
407 		virq = (virq % NR_VIRT_IRQS) + MIN_VIRT_IRQ;
408 
409 	first_virq = virq;
410 
411 	do {
412 		if (virt_irq_to_real_map[virq] == real_irq)
413 			return virq;
414 
415 		virq++;
416 
417 		if (virq >= MAX_VIRT_IRQ)
418 			virq = 0;
419 
420 	} while (first_virq != virq);
421 
422 	return NO_IRQ;
423 
424 }
425 
426 #ifdef CONFIG_IRQSTACKS
427 struct thread_info *softirq_ctx[NR_CPUS];
428 struct thread_info *hardirq_ctx[NR_CPUS];
429 
430 void irq_ctx_init(void)
431 {
432 	struct thread_info *tp;
433 	int i;
434 
435 	for_each_cpu(i) {
436 		memset((void *)softirq_ctx[i], 0, THREAD_SIZE);
437 		tp = softirq_ctx[i];
438 		tp->cpu = i;
439 		tp->preempt_count = SOFTIRQ_OFFSET;
440 
441 		memset((void *)hardirq_ctx[i], 0, THREAD_SIZE);
442 		tp = hardirq_ctx[i];
443 		tp->cpu = i;
444 		tp->preempt_count = HARDIRQ_OFFSET;
445 	}
446 }
447 
448 void do_softirq(void)
449 {
450 	unsigned long flags;
451 	struct thread_info *curtp, *irqtp;
452 
453 	if (in_interrupt())
454 		return;
455 
456 	local_irq_save(flags);
457 
458 	if (local_softirq_pending()) {
459 		curtp = current_thread_info();
460 		irqtp = softirq_ctx[smp_processor_id()];
461 		irqtp->task = curtp->task;
462 		call_do_softirq(irqtp);
463 		irqtp->task = NULL;
464 	}
465 
466 	local_irq_restore(flags);
467 }
468 EXPORT_SYMBOL(do_softirq);
469 
470 #endif /* CONFIG_IRQSTACKS */
471 
472 static int __init setup_noirqdistrib(char *str)
473 {
474 	distribute_irqs = 0;
475 	return 1;
476 }
477 
478 __setup("noirqdistrib", setup_noirqdistrib);
479 #endif /* CONFIG_PPC64 */
480