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1da177e4 LT |
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 | * Code to handle x86 style IRQs plus some generic interrupt stuff. | |
7 | * | |
8 | * Copyright (C) 1992 Linus Torvalds | |
9 | * Copyright (C) 1994 - 2000 Ralf Baechle | |
10 | */ | |
11 | #include <linux/delay.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/ioport.h> | |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/spinlock.h> | |
84652e83 | 17 | #include <linux/syscore_ops.h> |
ca4d3e67 | 18 | #include <linux/irq.h> |
1da177e4 LT |
19 | |
20 | #include <asm/i8259.h> | |
21 | #include <asm/io.h> | |
22 | ||
1da177e4 LT |
23 | /* |
24 | * This is the 'legacy' 8259A Programmable Interrupt Controller, | |
25 | * present in the majority of PC/AT boxes. | |
26 | * plus some generic x86 specific things if generic specifics makes | |
27 | * any sense at all. | |
28 | * this file should become arch/i386/kernel/irq.c when the old irq.c | |
29 | * moves to arch independent land | |
30 | */ | |
31 | ||
a0be2f79 | 32 | static int i8259A_auto_eoi = -1; |
89650870 | 33 | DEFINE_RAW_SPINLOCK(i8259A_lock); |
7c8d948f TG |
34 | static void disable_8259A_irq(struct irq_data *d); |
35 | static void enable_8259A_irq(struct irq_data *d); | |
36 | static void mask_and_ack_8259A(struct irq_data *d); | |
d80c1c0b | 37 | static void init_8259A(int auto_eoi); |
1da177e4 | 38 | |
2cafe978 | 39 | static struct irq_chip i8259A_chip = { |
7c8d948f TG |
40 | .name = "XT-PIC", |
41 | .irq_mask = disable_8259A_irq, | |
42 | .irq_disable = disable_8259A_irq, | |
43 | .irq_unmask = enable_8259A_irq, | |
44 | .irq_mask_ack = mask_and_ack_8259A, | |
1da177e4 LT |
45 | }; |
46 | ||
47 | /* | |
48 | * 8259A PIC functions to handle ISA devices: | |
49 | */ | |
50 | ||
51 | /* | |
52 | * This contains the irq mask for both 8259A irq controllers, | |
53 | */ | |
54 | static unsigned int cached_irq_mask = 0xffff; | |
55 | ||
2cafe978 AN |
56 | #define cached_master_mask (cached_irq_mask) |
57 | #define cached_slave_mask (cached_irq_mask >> 8) | |
1da177e4 | 58 | |
7c8d948f | 59 | static void disable_8259A_irq(struct irq_data *d) |
1da177e4 | 60 | { |
7c8d948f | 61 | unsigned int mask, irq = d->irq - I8259A_IRQ_BASE; |
1da177e4 LT |
62 | unsigned long flags; |
63 | ||
2fa7937b | 64 | mask = 1 << irq; |
89650870 | 65 | raw_spin_lock_irqsave(&i8259A_lock, flags); |
1da177e4 LT |
66 | cached_irq_mask |= mask; |
67 | if (irq & 8) | |
2cafe978 | 68 | outb(cached_slave_mask, PIC_SLAVE_IMR); |
1da177e4 | 69 | else |
2cafe978 | 70 | outb(cached_master_mask, PIC_MASTER_IMR); |
89650870 | 71 | raw_spin_unlock_irqrestore(&i8259A_lock, flags); |
1da177e4 LT |
72 | } |
73 | ||
7c8d948f | 74 | static void enable_8259A_irq(struct irq_data *d) |
1da177e4 | 75 | { |
7c8d948f | 76 | unsigned int mask, irq = d->irq - I8259A_IRQ_BASE; |
1da177e4 LT |
77 | unsigned long flags; |
78 | ||
2fa7937b | 79 | mask = ~(1 << irq); |
89650870 | 80 | raw_spin_lock_irqsave(&i8259A_lock, flags); |
1da177e4 LT |
81 | cached_irq_mask &= mask; |
82 | if (irq & 8) | |
2cafe978 | 83 | outb(cached_slave_mask, PIC_SLAVE_IMR); |
1da177e4 | 84 | else |
2cafe978 | 85 | outb(cached_master_mask, PIC_MASTER_IMR); |
89650870 | 86 | raw_spin_unlock_irqrestore(&i8259A_lock, flags); |
1da177e4 LT |
87 | } |
88 | ||
89 | int i8259A_irq_pending(unsigned int irq) | |
90 | { | |
2fa7937b | 91 | unsigned int mask; |
1da177e4 LT |
92 | unsigned long flags; |
93 | int ret; | |
94 | ||
2fa7937b AN |
95 | irq -= I8259A_IRQ_BASE; |
96 | mask = 1 << irq; | |
89650870 | 97 | raw_spin_lock_irqsave(&i8259A_lock, flags); |
1da177e4 | 98 | if (irq < 8) |
2cafe978 | 99 | ret = inb(PIC_MASTER_CMD) & mask; |
1da177e4 | 100 | else |
2cafe978 | 101 | ret = inb(PIC_SLAVE_CMD) & (mask >> 8); |
89650870 | 102 | raw_spin_unlock_irqrestore(&i8259A_lock, flags); |
1da177e4 LT |
103 | |
104 | return ret; | |
105 | } | |
106 | ||
107 | void make_8259A_irq(unsigned int irq) | |
108 | { | |
109 | disable_irq_nosync(irq); | |
e4ec7989 | 110 | irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq); |
1da177e4 LT |
111 | enable_irq(irq); |
112 | } | |
113 | ||
114 | /* | |
115 | * This function assumes to be called rarely. Switching between | |
116 | * 8259A registers is slow. | |
117 | * This has to be protected by the irq controller spinlock | |
118 | * before being called. | |
119 | */ | |
120 | static inline int i8259A_irq_real(unsigned int irq) | |
121 | { | |
122 | int value; | |
123 | int irqmask = 1 << irq; | |
124 | ||
125 | if (irq < 8) { | |
21a151d8 | 126 | outb(0x0B, PIC_MASTER_CMD); /* ISR register */ |
2cafe978 | 127 | value = inb(PIC_MASTER_CMD) & irqmask; |
21a151d8 | 128 | outb(0x0A, PIC_MASTER_CMD); /* back to the IRR register */ |
1da177e4 LT |
129 | return value; |
130 | } | |
21a151d8 | 131 | outb(0x0B, PIC_SLAVE_CMD); /* ISR register */ |
2cafe978 | 132 | value = inb(PIC_SLAVE_CMD) & (irqmask >> 8); |
21a151d8 | 133 | outb(0x0A, PIC_SLAVE_CMD); /* back to the IRR register */ |
1da177e4 LT |
134 | return value; |
135 | } | |
136 | ||
137 | /* | |
138 | * Careful! The 8259A is a fragile beast, it pretty | |
139 | * much _has_ to be done exactly like this (mask it | |
140 | * first, _then_ send the EOI, and the order of EOI | |
141 | * to the two 8259s is important! | |
142 | */ | |
7c8d948f | 143 | static void mask_and_ack_8259A(struct irq_data *d) |
1da177e4 | 144 | { |
7c8d948f | 145 | unsigned int irqmask, irq = d->irq - I8259A_IRQ_BASE; |
1da177e4 LT |
146 | unsigned long flags; |
147 | ||
2fa7937b | 148 | irqmask = 1 << irq; |
89650870 | 149 | raw_spin_lock_irqsave(&i8259A_lock, flags); |
1da177e4 | 150 | /* |
2cafe978 AN |
151 | * Lightweight spurious IRQ detection. We do not want |
152 | * to overdo spurious IRQ handling - it's usually a sign | |
153 | * of hardware problems, so we only do the checks we can | |
154 | * do without slowing down good hardware unnecessarily. | |
1da177e4 | 155 | * |
2cafe978 AN |
156 | * Note that IRQ7 and IRQ15 (the two spurious IRQs |
157 | * usually resulting from the 8259A-1|2 PICs) occur | |
158 | * even if the IRQ is masked in the 8259A. Thus we | |
159 | * can check spurious 8259A IRQs without doing the | |
160 | * quite slow i8259A_irq_real() call for every IRQ. | |
161 | * This does not cover 100% of spurious interrupts, | |
162 | * but should be enough to warn the user that there | |
163 | * is something bad going on ... | |
1da177e4 LT |
164 | */ |
165 | if (cached_irq_mask & irqmask) | |
166 | goto spurious_8259A_irq; | |
167 | cached_irq_mask |= irqmask; | |
168 | ||
169 | handle_real_irq: | |
170 | if (irq & 8) { | |
2cafe978 AN |
171 | inb(PIC_SLAVE_IMR); /* DUMMY - (do we need this?) */ |
172 | outb(cached_slave_mask, PIC_SLAVE_IMR); | |
21a151d8 RB |
173 | outb(0x60+(irq&7), PIC_SLAVE_CMD);/* 'Specific EOI' to slave */ |
174 | outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD); /* 'Specific EOI' to master-IRQ2 */ | |
1da177e4 | 175 | } else { |
2cafe978 AN |
176 | inb(PIC_MASTER_IMR); /* DUMMY - (do we need this?) */ |
177 | outb(cached_master_mask, PIC_MASTER_IMR); | |
70342287 | 178 | outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */ |
1da177e4 | 179 | } |
89650870 | 180 | raw_spin_unlock_irqrestore(&i8259A_lock, flags); |
1da177e4 LT |
181 | return; |
182 | ||
183 | spurious_8259A_irq: | |
184 | /* | |
185 | * this is the slow path - should happen rarely. | |
186 | */ | |
187 | if (i8259A_irq_real(irq)) | |
188 | /* | |
189 | * oops, the IRQ _is_ in service according to the | |
190 | * 8259A - not spurious, go handle it. | |
191 | */ | |
192 | goto handle_real_irq; | |
193 | ||
194 | { | |
2cafe978 | 195 | static int spurious_irq_mask; |
1da177e4 LT |
196 | /* |
197 | * At this point we can be sure the IRQ is spurious, | |
198 | * lets ACK and report it. [once per IRQ] | |
199 | */ | |
200 | if (!(spurious_irq_mask & irqmask)) { | |
201 | printk(KERN_DEBUG "spurious 8259A interrupt: IRQ%d.\n", irq); | |
202 | spurious_irq_mask |= irqmask; | |
203 | } | |
204 | atomic_inc(&irq_err_count); | |
205 | /* | |
206 | * Theoretically we do not have to handle this IRQ, | |
207 | * but in Linux this does not cause problems and is | |
208 | * simpler for us. | |
209 | */ | |
210 | goto handle_real_irq; | |
211 | } | |
212 | } | |
213 | ||
84652e83 | 214 | static void i8259A_resume(void) |
1da177e4 | 215 | { |
a0be2f79 AN |
216 | if (i8259A_auto_eoi >= 0) |
217 | init_8259A(i8259A_auto_eoi); | |
2cafe978 AN |
218 | } |
219 | ||
84652e83 | 220 | static void i8259A_shutdown(void) |
2cafe978 AN |
221 | { |
222 | /* Put the i8259A into a quiescent state that | |
223 | * the kernel initialization code can get it | |
224 | * out of. | |
225 | */ | |
a0be2f79 AN |
226 | if (i8259A_auto_eoi >= 0) { |
227 | outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */ | |
fe0b030c | 228 | outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */ |
a0be2f79 | 229 | } |
1da177e4 LT |
230 | } |
231 | ||
84652e83 | 232 | static struct syscore_ops i8259_syscore_ops = { |
1da177e4 | 233 | .resume = i8259A_resume, |
2cafe978 | 234 | .shutdown = i8259A_shutdown, |
1da177e4 LT |
235 | }; |
236 | ||
1da177e4 LT |
237 | static int __init i8259A_init_sysfs(void) |
238 | { | |
84652e83 RW |
239 | register_syscore_ops(&i8259_syscore_ops); |
240 | return 0; | |
1da177e4 LT |
241 | } |
242 | ||
243 | device_initcall(i8259A_init_sysfs); | |
244 | ||
d80c1c0b | 245 | static void init_8259A(int auto_eoi) |
1da177e4 LT |
246 | { |
247 | unsigned long flags; | |
248 | ||
2cafe978 AN |
249 | i8259A_auto_eoi = auto_eoi; |
250 | ||
89650870 | 251 | raw_spin_lock_irqsave(&i8259A_lock, flags); |
1da177e4 | 252 | |
2cafe978 AN |
253 | outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */ |
254 | outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */ | |
1da177e4 LT |
255 | |
256 | /* | |
257 | * outb_p - this has to work on a wide range of PC hardware. | |
258 | */ | |
2cafe978 AN |
259 | outb_p(0x11, PIC_MASTER_CMD); /* ICW1: select 8259A-1 init */ |
260 | outb_p(I8259A_IRQ_BASE + 0, PIC_MASTER_IMR); /* ICW2: 8259A-1 IR0 mapped to I8259A_IRQ_BASE + 0x00 */ | |
261 | outb_p(1U << PIC_CASCADE_IR, PIC_MASTER_IMR); /* 8259A-1 (the master) has a slave on IR2 */ | |
262 | if (auto_eoi) /* master does Auto EOI */ | |
263 | outb_p(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR); | |
264 | else /* master expects normal EOI */ | |
265 | outb_p(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR); | |
266 | ||
267 | outb_p(0x11, PIC_SLAVE_CMD); /* ICW1: select 8259A-2 init */ | |
268 | outb_p(I8259A_IRQ_BASE + 8, PIC_SLAVE_IMR); /* ICW2: 8259A-2 IR0 mapped to I8259A_IRQ_BASE + 0x08 */ | |
269 | outb_p(PIC_CASCADE_IR, PIC_SLAVE_IMR); /* 8259A-2 is a slave on master's IR2 */ | |
270 | outb_p(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR); /* (slave's support for AEOI in flat mode is to be investigated) */ | |
1da177e4 LT |
271 | if (auto_eoi) |
272 | /* | |
2cafe978 | 273 | * In AEOI mode we just have to mask the interrupt |
1da177e4 LT |
274 | * when acking. |
275 | */ | |
7c8d948f | 276 | i8259A_chip.irq_mask_ack = disable_8259A_irq; |
1da177e4 | 277 | else |
7c8d948f | 278 | i8259A_chip.irq_mask_ack = mask_and_ack_8259A; |
1da177e4 LT |
279 | |
280 | udelay(100); /* wait for 8259A to initialize */ | |
281 | ||
2cafe978 AN |
282 | outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */ |
283 | outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */ | |
1da177e4 | 284 | |
89650870 | 285 | raw_spin_unlock_irqrestore(&i8259A_lock, flags); |
1da177e4 LT |
286 | } |
287 | ||
288 | /* | |
289 | * IRQ2 is cascade interrupt to second interrupt controller | |
290 | */ | |
291 | static struct irqaction irq2 = { | |
4e45171c | 292 | .handler = no_action, |
4e45171c | 293 | .name = "cascade", |
5c22cd40 | 294 | .flags = IRQF_NO_THREAD, |
1da177e4 LT |
295 | }; |
296 | ||
297 | static struct resource pic1_io_resource = { | |
2cafe978 AN |
298 | .name = "pic1", |
299 | .start = PIC_MASTER_CMD, | |
300 | .end = PIC_MASTER_IMR, | |
301 | .flags = IORESOURCE_BUSY | |
1da177e4 LT |
302 | }; |
303 | ||
304 | static struct resource pic2_io_resource = { | |
2cafe978 AN |
305 | .name = "pic2", |
306 | .start = PIC_SLAVE_CMD, | |
307 | .end = PIC_SLAVE_IMR, | |
308 | .flags = IORESOURCE_BUSY | |
1da177e4 LT |
309 | }; |
310 | ||
311 | /* | |
312 | * On systems with i8259-style interrupt controllers we assume for | |
28a7879d | 313 | * driver compatibility reasons interrupts 0 - 15 to be the i8259 |
1da177e4 LT |
314 | * interrupts even if the hardware uses a different interrupt numbering. |
315 | */ | |
49a89efb | 316 | void __init init_i8259_irqs(void) |
1da177e4 LT |
317 | { |
318 | int i; | |
319 | ||
639702bd TB |
320 | insert_resource(&ioport_resource, &pic1_io_resource); |
321 | insert_resource(&ioport_resource, &pic2_io_resource); | |
1da177e4 LT |
322 | |
323 | init_8259A(0); | |
324 | ||
24649c00 | 325 | for (i = I8259A_IRQ_BASE; i < I8259A_IRQ_BASE + 16; i++) { |
e4ec7989 TG |
326 | irq_set_chip_and_handler(i, &i8259A_chip, handle_level_irq); |
327 | irq_set_probe(i); | |
24649c00 | 328 | } |
1da177e4 | 329 | |
2fa7937b | 330 | setup_irq(I8259A_IRQ_BASE + PIC_CASCADE_IR, &irq2); |
1da177e4 | 331 | } |