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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 irq_host *i8259_host;
Linus Torvalds1da177e2005-04-16 15:20:36 -070029
30/*
31 * Acknowledge the IRQ using either the PCI host bridge's interrupt
32 * acknowledge feature or poll. How i8259_init() is called determines
33 * which is called. It should be noted that polling is broken on some
34 * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
35 */
Olaf Hering35a84c22006-10-07 22:08:26 +100036unsigned int i8259_irq(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -070037{
38 int irq;
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100039 int lock = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41 /* Either int-ack or poll for the IRQ */
42 if (pci_intack)
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100043 irq = readb(pci_intack);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 else {
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100045 spin_lock(&i8259_lock);
46 lock = 1;
47
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 /* Perform an interrupt acknowledge cycle on controller 1. */
49 outb(0x0C, 0x20); /* prepare for poll */
50 irq = inb(0x20) & 7;
51 if (irq == 2 ) {
52 /*
53 * Interrupt is cascaded so perform interrupt
54 * acknowledge on controller 2.
55 */
56 outb(0x0C, 0xA0); /* prepare for poll */
57 irq = (inb(0xA0) & 7) + 8;
58 }
59 }
60
61 if (irq == 7) {
62 /*
63 * This may be a spurious interrupt.
64 *
65 * Read the interrupt status register (ISR). If the most
66 * significant bit is not set then there is no valid
67 * interrupt.
68 */
69 if (!pci_intack)
70 outb(0x0B, 0x20); /* ISR register */
71 if(~inb(0x20) & 0x80)
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100072 irq = NO_IRQ;
73 } else if (irq == 0xff)
74 irq = NO_IRQ;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +100076 if (lock)
77 spin_unlock(&i8259_lock);
78 return irq;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100079}
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081static void i8259_mask_and_ack_irq(unsigned int irq_nr)
82{
83 unsigned long flags;
84
85 spin_lock_irqsave(&i8259_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 if (irq_nr > 7) {
87 cached_A1 |= 1 << (irq_nr-8);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100088 inb(0xA1); /* DUMMY */
89 outb(cached_A1, 0xA1);
90 outb(0x20, 0xA0); /* Non-specific EOI */
91 outb(0x20, 0x20); /* Non-specific EOI to cascade */
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 } else {
93 cached_21 |= 1 << irq_nr;
Paul Mackerrasf9bd1702005-10-26 16:47:42 +100094 inb(0x21); /* DUMMY */
95 outb(cached_21, 0x21);
96 outb(0x20, 0x20); /* Non-specific EOI */
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 }
98 spin_unlock_irqrestore(&i8259_lock, flags);
99}
100
101static void i8259_set_irq_mask(int irq_nr)
102{
103 outb(cached_A1,0xA1);
104 outb(cached_21,0x21);
105}
106
107static void i8259_mask_irq(unsigned int irq_nr)
108{
109 unsigned long flags;
110
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000111 pr_debug("i8259_mask_irq(%d)\n", irq_nr);
112
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000114 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 cached_21 |= 1 << irq_nr;
116 else
117 cached_A1 |= 1 << (irq_nr-8);
118 i8259_set_irq_mask(irq_nr);
119 spin_unlock_irqrestore(&i8259_lock, flags);
120}
121
122static void i8259_unmask_irq(unsigned int irq_nr)
123{
124 unsigned long flags;
125
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000126 pr_debug("i8259_unmask_irq(%d)\n", irq_nr);
127
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 spin_lock_irqsave(&i8259_lock, flags);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000129 if (irq_nr < 8)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 cached_21 &= ~(1 << irq_nr);
131 else
132 cached_A1 &= ~(1 << (irq_nr-8));
133 i8259_set_irq_mask(irq_nr);
134 spin_unlock_irqrestore(&i8259_lock, flags);
135}
136
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000137static struct irq_chip i8259_pic = {
138 .typename = " i8259 ",
139 .mask = i8259_mask_irq,
140 .unmask = i8259_unmask_irq,
141 .mask_ack = i8259_mask_and_ack_irq,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142};
143
144static struct resource pic1_iores = {
145 .name = "8259 (master)",
146 .start = 0x20,
147 .end = 0x21,
148 .flags = IORESOURCE_BUSY,
149};
150
151static struct resource pic2_iores = {
152 .name = "8259 (slave)",
153 .start = 0xa0,
154 .end = 0xa1,
155 .flags = IORESOURCE_BUSY,
156};
157
158static struct resource pic_edgectrl_iores = {
159 .name = "8259 edge control",
160 .start = 0x4d0,
161 .end = 0x4d1,
162 .flags = IORESOURCE_BUSY,
163};
164
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000165static int i8259_host_match(struct irq_host *h, struct device_node *node)
166{
Michael Ellerman52964f82007-08-28 18:47:54 +1000167 return h->of_node == NULL || h->of_node == node;
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000168}
169
170static int i8259_host_map(struct irq_host *h, unsigned int virq,
Benjamin Herrenschmidt6e99e452006-07-10 04:44:42 -0700171 irq_hw_number_t hw)
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000172{
173 pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
174
175 /* We block the internal cascade */
176 if (hw == 2)
177 get_irq_desc(virq)->status |= IRQ_NOREQUEST;
178
Benjamin Herrenschmidt6e99e452006-07-10 04:44:42 -0700179 /* We use the level handler only for now, we might want to
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000180 * be more cautious here but that works for now
181 */
182 get_irq_desc(virq)->status |= IRQ_LEVEL;
183 set_irq_chip_and_handler(virq, &i8259_pic, handle_level_irq);
184 return 0;
185}
186
187static void i8259_host_unmap(struct irq_host *h, unsigned int virq)
188{
189 /* Make sure irq is masked in hardware */
190 i8259_mask_irq(virq);
191
192 /* remove chip and handler */
193 set_irq_chip_and_handler(virq, NULL, NULL);
194
195 /* Make sure it's completed */
196 synchronize_irq(virq);
197}
198
199static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
200 u32 *intspec, unsigned int intsize,
201 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
202{
203 static unsigned char map_isa_senses[4] = {
204 IRQ_TYPE_LEVEL_LOW,
205 IRQ_TYPE_LEVEL_HIGH,
206 IRQ_TYPE_EDGE_FALLING,
207 IRQ_TYPE_EDGE_RISING,
208 };
209
210 *out_hwirq = intspec[0];
211 if (intsize > 1 && intspec[1] < 4)
212 *out_flags = map_isa_senses[intspec[1]];
213 else
214 *out_flags = IRQ_TYPE_NONE;
215
216 return 0;
217}
218
219static struct irq_host_ops i8259_host_ops = {
220 .match = i8259_host_match,
221 .map = i8259_host_map,
222 .unmap = i8259_host_unmap,
223 .xlate = i8259_host_xlate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224};
225
Benjamin Herrenschmidtf4d4c352006-10-25 13:22:27 +1000226struct irq_host *i8259_get_host(void)
227{
228 return i8259_host;
229}
230
Michael Ellerman40681b92006-08-02 11:13:50 +1000231/**
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000232 * i8259_init - Initialize the legacy controller
233 * @node: device node of the legacy PIC (can be NULL, but then, it will match
234 * all interrupts, so beware)
235 * @intack_addr: PCI interrupt acknowledge (real) address which will return
236 * the active irq from the 8259
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 */
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000238void i8259_init(struct device_node *node, unsigned long intack_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
240 unsigned long flags;
241
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000242 /* initialize the controller */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 spin_lock_irqsave(&i8259_lock, flags);
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000244
245 /* Mask all first */
246 outb(0xff, 0xA1);
247 outb(0xff, 0x21);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000248
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 /* init master interrupt controller */
250 outb(0x11, 0x20); /* Start init sequence */
251 outb(0x00, 0x21); /* Vector base */
252 outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
253 outb(0x01, 0x21); /* Select 8086 mode */
254
255 /* init slave interrupt controller */
256 outb(0x11, 0xA0); /* Start init sequence */
257 outb(0x08, 0xA1); /* Vector base */
258 outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
259 outb(0x01, 0xA1); /* Select 8086 mode */
260
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000261 /* That thing is slow */
262 udelay(100);
263
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264 /* always read ISR */
265 outb(0x0B, 0x20);
266 outb(0x0B, 0xA0);
267
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000268 /* Unmask the internal cascade */
269 cached_21 &= ~(1 << 2);
270
271 /* Set interrupt masks */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 outb(cached_A1, 0xA1);
273 outb(cached_21, 0x21);
274
275 spin_unlock_irqrestore(&i8259_lock, flags);
276
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000277 /* create a legacy host */
Michael Ellerman52964f82007-08-28 18:47:54 +1000278 i8259_host = irq_alloc_host(of_node_get(node), IRQ_HOST_MAP_LEGACY,
279 0, &i8259_host_ops, 0);
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000280 if (i8259_host == NULL) {
281 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
282 return;
Benjamin Herrenschmidtb9e5b4e2006-07-03 19:32:51 +1000283 }
David Woodhouse9d2ba6f2005-11-05 17:54:22 +0000284
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285 /* reserve our resources */
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000286 /* XXX should we continue doing that ? it seems to cause problems
287 * with further requesting of PCI IO resources for that range...
288 * need to look into it.
289 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 request_resource(&ioport_resource, &pic1_iores);
291 request_resource(&ioport_resource, &pic2_iores);
292 request_resource(&ioport_resource, &pic_edgectrl_iores);
293
294 if (intack_addr != 0)
295 pci_intack = ioremap(intack_addr, 1);
Paul Mackerrasf9bd1702005-10-26 16:47:42 +1000296
Benjamin Herrenschmidt0ebfff12006-07-03 21:36:01 +1000297 printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298}