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1da177e4 LT |
1 | /* |
2 | * linux/arch/i386/mach_visws/visws_apic.c | |
3 | * | |
4 | * Copyright (C) 1999 Bent Hagemark, Ingo Molnar | |
5 | * | |
6 | * SGI Visual Workstation interrupt controller | |
7 | * | |
8 | * The Cobalt system ASIC in the Visual Workstation contains a "Cobalt" APIC | |
9 | * which serves as the main interrupt controller in the system. Non-legacy | |
10 | * hardware in the system uses this controller directly. Legacy devices | |
11 | * are connected to the PIIX4 which in turn has its 8259(s) connected to | |
12 | * a of the Cobalt APIC entry. | |
13 | * | |
14 | * 09/02/2000 - Updated for 2.4 by jbarnes@sgi.com | |
15 | * | |
16 | * 25/11/2002 - Updated for 2.5 by Andrey Panin <pazke@orbita1.ru> | |
17 | */ | |
18 | ||
19 | #include <linux/config.h> | |
20 | #include <linux/kernel_stat.h> | |
21 | #include <linux/interrupt.h> | |
1da177e4 LT |
22 | #include <linux/smp_lock.h> |
23 | #include <linux/init.h> | |
24 | ||
25 | #include <asm/io.h> | |
26 | #include <asm/apic.h> | |
27 | #include <asm/i8259.h> | |
28 | ||
29 | #include "cobalt.h" | |
30 | #include "irq_vectors.h" | |
31 | ||
32 | ||
33 | static DEFINE_SPINLOCK(cobalt_lock); | |
34 | ||
35 | /* | |
36 | * Set the given Cobalt APIC Redirection Table entry to point | |
37 | * to the given IDT vector/index. | |
38 | */ | |
39 | static inline void co_apic_set(int entry, int irq) | |
40 | { | |
41 | co_apic_write(CO_APIC_LO(entry), CO_APIC_LEVEL | (irq + FIRST_EXTERNAL_VECTOR)); | |
42 | co_apic_write(CO_APIC_HI(entry), 0); | |
43 | } | |
44 | ||
45 | /* | |
46 | * Cobalt (IO)-APIC functions to handle PCI devices. | |
47 | */ | |
48 | static inline int co_apic_ide0_hack(void) | |
49 | { | |
50 | extern char visws_board_type; | |
51 | extern char visws_board_rev; | |
52 | ||
53 | if (visws_board_type == VISWS_320 && visws_board_rev == 5) | |
54 | return 5; | |
55 | return CO_APIC_IDE0; | |
56 | } | |
57 | ||
58 | static int is_co_apic(unsigned int irq) | |
59 | { | |
60 | if (IS_CO_APIC(irq)) | |
61 | return CO_APIC(irq); | |
62 | ||
63 | switch (irq) { | |
64 | case 0: return CO_APIC_CPU; | |
65 | case CO_IRQ_IDE0: return co_apic_ide0_hack(); | |
66 | case CO_IRQ_IDE1: return CO_APIC_IDE1; | |
67 | default: return -1; | |
68 | } | |
69 | } | |
70 | ||
71 | ||
72 | /* | |
73 | * This is the SGI Cobalt (IO-)APIC: | |
74 | */ | |
75 | ||
76 | static void enable_cobalt_irq(unsigned int irq) | |
77 | { | |
78 | co_apic_set(is_co_apic(irq), irq); | |
79 | } | |
80 | ||
81 | static void disable_cobalt_irq(unsigned int irq) | |
82 | { | |
83 | int entry = is_co_apic(irq); | |
84 | ||
85 | co_apic_write(CO_APIC_LO(entry), CO_APIC_MASK); | |
86 | co_apic_read(CO_APIC_LO(entry)); | |
87 | } | |
88 | ||
89 | /* | |
90 | * "irq" really just serves to identify the device. Here is where we | |
91 | * map this to the Cobalt APIC entry where it's physically wired. | |
92 | * This is called via request_irq -> setup_irq -> irq_desc->startup() | |
93 | */ | |
94 | static unsigned int startup_cobalt_irq(unsigned int irq) | |
95 | { | |
96 | unsigned long flags; | |
97 | ||
98 | spin_lock_irqsave(&cobalt_lock, flags); | |
99 | if ((irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS | IRQ_WAITING))) | |
100 | irq_desc[irq].status &= ~(IRQ_DISABLED | IRQ_INPROGRESS | IRQ_WAITING); | |
101 | enable_cobalt_irq(irq); | |
102 | spin_unlock_irqrestore(&cobalt_lock, flags); | |
103 | return 0; | |
104 | } | |
105 | ||
106 | static void ack_cobalt_irq(unsigned int irq) | |
107 | { | |
108 | unsigned long flags; | |
109 | ||
110 | spin_lock_irqsave(&cobalt_lock, flags); | |
111 | disable_cobalt_irq(irq); | |
112 | apic_write(APIC_EOI, APIC_EIO_ACK); | |
113 | spin_unlock_irqrestore(&cobalt_lock, flags); | |
114 | } | |
115 | ||
116 | static void end_cobalt_irq(unsigned int irq) | |
117 | { | |
118 | unsigned long flags; | |
119 | ||
120 | spin_lock_irqsave(&cobalt_lock, flags); | |
121 | if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) | |
122 | enable_cobalt_irq(irq); | |
123 | spin_unlock_irqrestore(&cobalt_lock, flags); | |
124 | } | |
125 | ||
126 | static struct hw_interrupt_type cobalt_irq_type = { | |
127 | .typename = "Cobalt-APIC", | |
128 | .startup = startup_cobalt_irq, | |
129 | .shutdown = disable_cobalt_irq, | |
130 | .enable = enable_cobalt_irq, | |
131 | .disable = disable_cobalt_irq, | |
132 | .ack = ack_cobalt_irq, | |
133 | .end = end_cobalt_irq, | |
134 | }; | |
135 | ||
136 | ||
137 | /* | |
138 | * This is the PIIX4-based 8259 that is wired up indirectly to Cobalt | |
139 | * -- not the manner expected by the code in i8259.c. | |
140 | * | |
141 | * there is a 'master' physical interrupt source that gets sent to | |
142 | * the CPU. But in the chipset there are various 'virtual' interrupts | |
143 | * waiting to be handled. We represent this to Linux through a 'master' | |
144 | * interrupt controller type, and through a special virtual interrupt- | |
145 | * controller. Device drivers only see the virtual interrupt sources. | |
146 | */ | |
147 | static unsigned int startup_piix4_master_irq(unsigned int irq) | |
148 | { | |
149 | init_8259A(0); | |
150 | ||
151 | return startup_cobalt_irq(irq); | |
152 | } | |
153 | ||
154 | static void end_piix4_master_irq(unsigned int irq) | |
155 | { | |
156 | unsigned long flags; | |
157 | ||
158 | spin_lock_irqsave(&cobalt_lock, flags); | |
159 | enable_cobalt_irq(irq); | |
160 | spin_unlock_irqrestore(&cobalt_lock, flags); | |
161 | } | |
162 | ||
163 | static struct hw_interrupt_type piix4_master_irq_type = { | |
164 | .typename = "PIIX4-master", | |
165 | .startup = startup_piix4_master_irq, | |
166 | .ack = ack_cobalt_irq, | |
167 | .end = end_piix4_master_irq, | |
168 | }; | |
169 | ||
170 | ||
171 | static struct hw_interrupt_type piix4_virtual_irq_type = { | |
172 | .typename = "PIIX4-virtual", | |
173 | .startup = startup_8259A_irq, | |
174 | .shutdown = disable_8259A_irq, | |
175 | .enable = enable_8259A_irq, | |
176 | .disable = disable_8259A_irq, | |
177 | }; | |
178 | ||
179 | ||
180 | /* | |
181 | * PIIX4-8259 master/virtual functions to handle interrupt requests | |
182 | * from legacy devices: floppy, parallel, serial, rtc. | |
183 | * | |
184 | * None of these get Cobalt APIC entries, neither do they have IDT | |
185 | * entries. These interrupts are purely virtual and distributed from | |
186 | * the 'master' interrupt source: CO_IRQ_8259. | |
187 | * | |
188 | * When the 8259 interrupts its handler figures out which of these | |
189 | * devices is interrupting and dispatches to its handler. | |
190 | * | |
191 | * CAREFUL: devices see the 'virtual' interrupt only. Thus disable/ | |
192 | * enable_irq gets the right irq. This 'master' irq is never directly | |
193 | * manipulated by any driver. | |
194 | */ | |
195 | static irqreturn_t piix4_master_intr(int irq, void *dev_id, struct pt_regs * regs) | |
196 | { | |
197 | int realirq; | |
198 | irq_desc_t *desc; | |
199 | unsigned long flags; | |
200 | ||
201 | spin_lock_irqsave(&i8259A_lock, flags); | |
202 | ||
203 | /* Find out what's interrupting in the PIIX4 master 8259 */ | |
204 | outb(0x0c, 0x20); /* OCW3 Poll command */ | |
205 | realirq = inb(0x20); | |
206 | ||
207 | /* | |
208 | * Bit 7 == 0 means invalid/spurious | |
209 | */ | |
210 | if (unlikely(!(realirq & 0x80))) | |
211 | goto out_unlock; | |
212 | ||
213 | realirq &= 7; | |
214 | ||
215 | if (unlikely(realirq == 2)) { | |
216 | outb(0x0c, 0xa0); | |
217 | realirq = inb(0xa0); | |
218 | ||
219 | if (unlikely(!(realirq & 0x80))) | |
220 | goto out_unlock; | |
221 | ||
222 | realirq = (realirq & 7) + 8; | |
223 | } | |
224 | ||
225 | /* mask and ack interrupt */ | |
226 | cached_irq_mask |= 1 << realirq; | |
227 | if (unlikely(realirq > 7)) { | |
228 | inb(0xa1); | |
229 | outb(cached_slave_mask, 0xa1); | |
230 | outb(0x60 + (realirq & 7), 0xa0); | |
231 | outb(0x60 + 2, 0x20); | |
232 | } else { | |
233 | inb(0x21); | |
234 | outb(cached_master_mask, 0x21); | |
235 | outb(0x60 + realirq, 0x20); | |
236 | } | |
237 | ||
238 | spin_unlock_irqrestore(&i8259A_lock, flags); | |
239 | ||
240 | desc = irq_desc + realirq; | |
241 | ||
242 | /* | |
243 | * handle this 'virtual interrupt' as a Cobalt one now. | |
244 | */ | |
245 | kstat_cpu(smp_processor_id()).irqs[realirq]++; | |
246 | ||
247 | if (likely(desc->action != NULL)) | |
248 | handle_IRQ_event(realirq, regs, desc->action); | |
249 | ||
250 | if (!(desc->status & IRQ_DISABLED)) | |
251 | enable_8259A_irq(realirq); | |
252 | ||
253 | return IRQ_HANDLED; | |
254 | ||
255 | out_unlock: | |
256 | spin_unlock_irqrestore(&i8259A_lock, flags); | |
257 | return IRQ_NONE; | |
258 | } | |
259 | ||
260 | static struct irqaction master_action = { | |
261 | .handler = piix4_master_intr, | |
262 | .name = "PIIX4-8259", | |
263 | }; | |
264 | ||
265 | static struct irqaction cascade_action = { | |
266 | .handler = no_action, | |
267 | .name = "cascade", | |
268 | }; | |
269 | ||
270 | ||
271 | void init_VISWS_APIC_irqs(void) | |
272 | { | |
273 | int i; | |
274 | ||
275 | for (i = 0; i < CO_IRQ_APIC0 + CO_APIC_LAST + 1; i++) { | |
276 | irq_desc[i].status = IRQ_DISABLED; | |
277 | irq_desc[i].action = 0; | |
278 | irq_desc[i].depth = 1; | |
279 | ||
280 | if (i == 0) { | |
281 | irq_desc[i].handler = &cobalt_irq_type; | |
282 | } | |
283 | else if (i == CO_IRQ_IDE0) { | |
284 | irq_desc[i].handler = &cobalt_irq_type; | |
285 | } | |
286 | else if (i == CO_IRQ_IDE1) { | |
287 | irq_desc[i].handler = &cobalt_irq_type; | |
288 | } | |
289 | else if (i == CO_IRQ_8259) { | |
290 | irq_desc[i].handler = &piix4_master_irq_type; | |
291 | } | |
292 | else if (i < CO_IRQ_APIC0) { | |
293 | irq_desc[i].handler = &piix4_virtual_irq_type; | |
294 | } | |
295 | else if (IS_CO_APIC(i)) { | |
296 | irq_desc[i].handler = &cobalt_irq_type; | |
297 | } | |
298 | } | |
299 | ||
300 | setup_irq(CO_IRQ_8259, &master_action); | |
301 | setup_irq(2, &cascade_action); | |
302 | } |