1 /*
2 * PQ2 ADS-style PCI interrupt controller
3 *
4 * Copyright 2007 Freescale Semiconductor, Inc.
5 * Author: Scott Wood <scottwood@freescale.com>
6 *
7 * Loosely based on mpc82xx ADS support by Vitaly Bordug <vbordug@ru.mvista.com>
8 * Copyright (c) 2006 MontaVista Software, Inc.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License version 2 as published
12 * by the Free Software Foundation.
13 */
14
15 #include <linux/init.h>
16 #include <linux/spinlock.h>
17 #include <linux/irq.h>
18 #include <linux/types.h>
19 #include <linux/slab.h>
20
21 #include <asm/io.h>
22 #include <asm/prom.h>
23 #include <asm/cpm2.h>
24
25 #include "pq2.h"
26
27 static DEFINE_RAW_SPINLOCK(pci_pic_lock);
28
29 struct pq2ads_pci_pic {
30 struct device_node *node;
31 struct irq_domain *host;
32
33 struct {
34 u32 stat;
35 u32 mask;
36 } __iomem *regs;
37 };
38
39 #define NUM_IRQS 32
40
pq2ads_pci_mask_irq(struct irq_data * d)41 static void pq2ads_pci_mask_irq(struct irq_data *d)
42 {
43 struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
44 int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
45
46 if (irq != -1) {
47 unsigned long flags;
48 raw_spin_lock_irqsave(&pci_pic_lock, flags);
49
50 setbits32(&priv->regs->mask, 1 << irq);
51 mb();
52
53 raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
54 }
55 }
56
pq2ads_pci_unmask_irq(struct irq_data * d)57 static void pq2ads_pci_unmask_irq(struct irq_data *d)
58 {
59 struct pq2ads_pci_pic *priv = irq_data_get_irq_chip_data(d);
60 int irq = NUM_IRQS - irqd_to_hwirq(d) - 1;
61
62 if (irq != -1) {
63 unsigned long flags;
64
65 raw_spin_lock_irqsave(&pci_pic_lock, flags);
66 clrbits32(&priv->regs->mask, 1 << irq);
67 raw_spin_unlock_irqrestore(&pci_pic_lock, flags);
68 }
69 }
70
71 static struct irq_chip pq2ads_pci_ic = {
72 .name = "PQ2 ADS PCI",
73 .irq_mask = pq2ads_pci_mask_irq,
74 .irq_mask_ack = pq2ads_pci_mask_irq,
75 .irq_ack = pq2ads_pci_mask_irq,
76 .irq_unmask = pq2ads_pci_unmask_irq,
77 .irq_enable = pq2ads_pci_unmask_irq,
78 .irq_disable = pq2ads_pci_mask_irq
79 };
80
pq2ads_pci_irq_demux(unsigned int irq,struct irq_desc * desc)81 static void pq2ads_pci_irq_demux(unsigned int irq, struct irq_desc *desc)
82 {
83 struct pq2ads_pci_pic *priv = irq_desc_get_handler_data(desc);
84 u32 stat, mask, pend;
85 int bit;
86
87 for (;;) {
88 stat = in_be32(&priv->regs->stat);
89 mask = in_be32(&priv->regs->mask);
90
91 pend = stat & ~mask;
92
93 if (!pend)
94 break;
95
96 for (bit = 0; pend != 0; ++bit, pend <<= 1) {
97 if (pend & 0x80000000) {
98 int virq = irq_linear_revmap(priv->host, bit);
99 generic_handle_irq(virq);
100 }
101 }
102 }
103 }
104
pci_pic_host_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)105 static int pci_pic_host_map(struct irq_domain *h, unsigned int virq,
106 irq_hw_number_t hw)
107 {
108 irq_set_status_flags(virq, IRQ_LEVEL);
109 irq_set_chip_data(virq, h->host_data);
110 irq_set_chip_and_handler(virq, &pq2ads_pci_ic, handle_level_irq);
111 return 0;
112 }
113
114 static const struct irq_domain_ops pci_pic_host_ops = {
115 .map = pci_pic_host_map,
116 };
117
pq2ads_pci_init_irq(void)118 int __init pq2ads_pci_init_irq(void)
119 {
120 struct pq2ads_pci_pic *priv;
121 struct irq_domain *host;
122 struct device_node *np;
123 int ret = -ENODEV;
124 int irq;
125
126 np = of_find_compatible_node(NULL, NULL, "fsl,pq2ads-pci-pic");
127 if (!np) {
128 printk(KERN_ERR "No pci pic node in device tree.\n");
129 of_node_put(np);
130 goto out;
131 }
132
133 irq = irq_of_parse_and_map(np, 0);
134 if (irq == NO_IRQ) {
135 printk(KERN_ERR "No interrupt in pci pic node.\n");
136 of_node_put(np);
137 goto out;
138 }
139
140 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
141 if (!priv) {
142 of_node_put(np);
143 ret = -ENOMEM;
144 goto out_unmap_irq;
145 }
146
147 /* PCI interrupt controller registers: status and mask */
148 priv->regs = of_iomap(np, 0);
149 if (!priv->regs) {
150 printk(KERN_ERR "Cannot map PCI PIC registers.\n");
151 goto out_free_kmalloc;
152 }
153
154 /* mask all PCI interrupts */
155 out_be32(&priv->regs->mask, ~0);
156 mb();
157
158 host = irq_domain_add_linear(np, NUM_IRQS, &pci_pic_host_ops, priv);
159 if (!host) {
160 ret = -ENOMEM;
161 goto out_unmap_regs;
162 }
163
164 priv->host = host;
165 irq_set_handler_data(irq, priv);
166 irq_set_chained_handler(irq, pq2ads_pci_irq_demux);
167
168 of_node_put(np);
169 return 0;
170
171 out_unmap_regs:
172 iounmap(priv->regs);
173 out_free_kmalloc:
174 kfree(priv);
175 of_node_put(np);
176 out_unmap_irq:
177 irq_dispose_mapping(irq);
178 out:
179 return ret;
180 }
181