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Paul Mackerrasf9bd1702005-10-26 16:47:42 +10001/*
2 * i8259 interrupt controller driver.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 */
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +10009#undef DEBUG
10
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/init.h>
12#include <linux/ioport.h>
13#include <linux/interrupt.h>
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100014#include <linux/kernel.h>
15#include <linux/delay.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <asm/io.h>
17#include <asm/i8259.h>
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100018#include <asm/prom.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100020static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100022static unsigned char cached_8259[2] = { 0xff, 0xff };
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#define cached_A1 (cached_8259[0])
24#define cached_21 (cached_8259[1])
25
26static DEFINE_SPINLOCK(i8259_lock);
27
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100028static struct device_node *i8259_node;
29static struct irq_host *i8259_host;
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31/*
32 * Acknowledge the IRQ using either the PCI host bridge's interrupt
33 * acknowledge feature or poll. How i8259_init() is called determines
34 * which is called. It should be noted that polling is broken on some
35 * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
36 */
Olaf Hering35a84c22006-10-07 22:08:26 +100037unsigned int i8259_irq(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070038{
39 int irq;
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100040 int lock = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041
42 /* Either int-ack or poll for the IRQ */
43 if (pci_intack)
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100044 irq = readb(pci_intack);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 else {
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100046 spin_lock(&i8259_lock);
47 lock = 1;
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 /* Perform an interrupt acknowledge cycle on controller 1. */
50 outb(0x0C, 0x20); /* prepare for poll */
51 irq = inb(0x20) & 7;
52 if (irq == 2 ) {
53 /*
54 * Interrupt is cascaded so perform interrupt
55 * acknowledge on controller 2.
56 */
57 outb(0x0C, 0xA0); /* prepare for poll */
58 irq = (inb(0xA0) & 7) + 8;
59 }
60 }
61
62 if (irq == 7) {
63 /*
64 * This may be a spurious interrupt.
65 *
66 * Read the interrupt status register (ISR). If the most
67 * significant bit is not set then there is no valid
68 * interrupt.
69 */
70 if (!pci_intack)
71 outb(0x0B, 0x20); /* ISR register */
72 if(~inb(0x20) & 0x80)
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100073 irq = NO_IRQ;
74 } else if (irq == 0xff)
75 irq = NO_IRQ;
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100077 if (lock)
78 spin_unlock(&i8259_lock);
79 return irq;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100080}
81
Linus Torvalds1da177e2005-04-16 15:20:36 -070082static void i8259_mask_and_ack_irq(unsigned int irq_nr)
83{
84 unsigned long flags;
85
86 spin_lock_irqsave(&i8259_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 if (irq_nr > 7) {
88 cached_A1 |= 1 << (irq_nr-8);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100089 inb(0xA1); /* DUMMY */
90 outb(cached_A1, 0xA1);
91 outb(0x20, 0xA0); /* Non-specific EOI */
92 outb(0x20, 0x20); /* Non-specific EOI to cascade */
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 } else {
94 cached_21 |= 1 << irq_nr;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100095 inb(0x21); /* DUMMY */
96 outb(cached_21, 0x21);
97 outb(0x20, 0x20); /* Non-specific EOI */
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 }
99 spin_unlock_irqrestore(&i8259_lock, flags);
100}
101
102static void i8259_set_irq_mask(int irq_nr)
103{
104 outb(cached_A1,0xA1);
105 outb(cached_21,0x21);
106}
107
108static void i8259_mask_irq(unsigned int irq_nr)
109{
110 unsigned long flags;
111
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000112 pr_debug("i8259_mask_irq(%d)\n", irq_nr);
113
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000115 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 cached_21 |= 1 << irq_nr;
117 else
118 cached_A1 |= 1 << (irq_nr-8);
119 i8259_set_irq_mask(irq_nr);
120 spin_unlock_irqrestore(&i8259_lock, flags);
121}
122
123static void i8259_unmask_irq(unsigned int irq_nr)
124{
125 unsigned long flags;
126
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000127 pr_debug("i8259_unmask_irq(%d)\n", irq_nr);
128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000130 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 cached_21 &= ~(1 << irq_nr);
132 else
133 cached_A1 &= ~(1 << (irq_nr-8));
134 i8259_set_irq_mask(irq_nr);
135 spin_unlock_irqrestore(&i8259_lock, flags);
136}
137
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000138static struct irq_chip i8259_pic = {
139 .typename = " i8259 ",
140 .mask = i8259_mask_irq,
141 .unmask = i8259_unmask_irq,
142 .mask_ack = i8259_mask_and_ack_irq,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143};
144
145static struct resource pic1_iores = {
146 .name = "8259 (master)",
147 .start = 0x20,
148 .end = 0x21,
149 .flags = IORESOURCE_BUSY,
150};
151
152static struct resource pic2_iores = {
153 .name = "8259 (slave)",
154 .start = 0xa0,
155 .end = 0xa1,
156 .flags = IORESOURCE_BUSY,
157};
158
159static struct resource pic_edgectrl_iores = {
160 .name = "8259 edge control",
161 .start = 0x4d0,
162 .end = 0x4d1,
163 .flags = IORESOURCE_BUSY,
164};
165
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000166static int i8259_host_match(struct irq_host *h, struct device_node *node)
167{
168 return i8259_node == NULL || i8259_node == node;
169}
170
171static int i8259_host_map(struct irq_host *h, unsigned int virq,
Benjamin Herrenschmidt6e99e452006-07-10 04:44:42 -0700172 irq_hw_number_t hw)
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000173{
174 pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
175
176 /* We block the internal cascade */
177 if (hw == 2)
178 get_irq_desc(virq)->status |= IRQ_NOREQUEST;
179
Benjamin Herrenschmidt6e99e452006-07-10 04:44:42 -0700180 /* We use the level handler only for now, we might want to
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000181 * be more cautious here but that works for now
182 */
183 get_irq_desc(virq)->status |= IRQ_LEVEL;
184 set_irq_chip_and_handler(virq, &i8259_pic, handle_level_irq);
185 return 0;
186}
187
188static void i8259_host_unmap(struct irq_host *h, unsigned int virq)
189{
190 /* Make sure irq is masked in hardware */
191 i8259_mask_irq(virq);
192
193 /* remove chip and handler */
194 set_irq_chip_and_handler(virq, NULL, NULL);
195
196 /* Make sure it's completed */
197 synchronize_irq(virq);
198}
199
200static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
201 u32 *intspec, unsigned int intsize,
202 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
203{
204 static unsigned char map_isa_senses[4] = {
205 IRQ_TYPE_LEVEL_LOW,
206 IRQ_TYPE_LEVEL_HIGH,
207 IRQ_TYPE_EDGE_FALLING,
208 IRQ_TYPE_EDGE_RISING,
209 };
210
211 *out_hwirq = intspec[0];
212 if (intsize > 1 && intspec[1] < 4)
213 *out_flags = map_isa_senses[intspec[1]];
214 else
215 *out_flags = IRQ_TYPE_NONE;
216
217 return 0;
218}
219
220static struct irq_host_ops i8259_host_ops = {
221 .match = i8259_host_match,
222 .map = i8259_host_map,
223 .unmap = i8259_host_unmap,
224 .xlate = i8259_host_xlate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225};
226
Benjamin Herrenschmidtf4d4c352006-10-25 13:22:27 +1000227struct irq_host *i8259_get_host(void)
228{
229 return i8259_host;
230}
231
Michael Ellerman40681b92006-08-02 11:13:50 +1000232/**
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000233 * i8259_init - Initialize the legacy controller
234 * @node: device node of the legacy PIC (can be NULL, but then, it will match
235 * all interrupts, so beware)
236 * @intack_addr: PCI interrupt acknowledge (real) address which will return
237 * the active irq from the 8259
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 */
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000239void i8259_init(struct device_node *node, unsigned long intack_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
241 unsigned long flags;
242
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000243 /* initialize the controller */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 spin_lock_irqsave(&i8259_lock, flags);
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000245
246 /* Mask all first */
247 outb(0xff, 0xA1);
248 outb(0xff, 0x21);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 /* init master interrupt controller */
251 outb(0x11, 0x20); /* Start init sequence */
252 outb(0x00, 0x21); /* Vector base */
253 outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
254 outb(0x01, 0x21); /* Select 8086 mode */
255
256 /* init slave interrupt controller */
257 outb(0x11, 0xA0); /* Start init sequence */
258 outb(0x08, 0xA1); /* Vector base */
259 outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
260 outb(0x01, 0xA1); /* Select 8086 mode */
261
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000262 /* That thing is slow */
263 udelay(100);
264
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 /* always read ISR */
266 outb(0x0B, 0x20);
267 outb(0x0B, 0xA0);
268
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000269 /* Unmask the internal cascade */
270 cached_21 &= ~(1 << 2);
271
272 /* Set interrupt masks */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 outb(cached_A1, 0xA1);
274 outb(cached_21, 0x21);
275
276 spin_unlock_irqrestore(&i8259_lock, flags);
277
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000278 /* create a legacy host */
279 if (node)
280 i8259_node = of_node_get(node);
281 i8259_host = irq_alloc_host(IRQ_HOST_MAP_LEGACY, 0, &i8259_host_ops, 0);
282 if (i8259_host == NULL) {
283 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
284 return;
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000285 }
David Woodhouse9d2ba6f2005-11-05 17:54:22 +0000286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 /* reserve our resources */
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000288 /* XXX should we continue doing that ? it seems to cause problems
289 * with further requesting of PCI IO resources for that range...
290 * need to look into it.
291 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 request_resource(&ioport_resource, &pic1_iores);
293 request_resource(&ioport_resource, &pic2_iores);
294 request_resource(&ioport_resource, &pic_edgectrl_iores);
295
296 if (intack_addr != 0)
297 pci_intack = ioremap(intack_addr, 1);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000298
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000299 printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}