1/*
2 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
3 *
4 * Author: John Rigby, <jrigby@freescale.com>
5 *
6 * Description:
7 * MPC5121ADS CPLD irq handling
8 *
9 * This is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 */
14
15#undef DEBUG
16
17#include <linux/kernel.h>
18#include <linux/interrupt.h>
19#include <linux/irq.h>
20#include <linux/io.h>
21#include <asm/prom.h>
22
23static struct device_node *cpld_pic_node;
24static struct irq_domain *cpld_pic_host;
25
26/*
27 * Bits to ignore in the misc_status register
28 * 0x10 touch screen pendown is hard routed to irq1
29 * 0x02 pci status is read from pci status register
30 */
31#define MISC_IGNORE 0x12
32
33/*
34 * Nothing to ignore in pci status register
35 */
36#define PCI_IGNORE 0x00
37
38struct cpld_pic {
39	u8 pci_mask;
40	u8 pci_status;
41	u8 route;
42	u8 misc_mask;
43	u8 misc_status;
44	u8 misc_control;
45};
46
47static struct cpld_pic __iomem *cpld_regs;
48
49static void __iomem *
50irq_to_pic_mask(unsigned int irq)
51{
52	return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
53}
54
55static unsigned int
56irq_to_pic_bit(unsigned int irq)
57{
58	return 1 << (irq & 0x7);
59}
60
61static void
62cpld_mask_irq(struct irq_data *d)
63{
64	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
65	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
66
67	out_8(pic_mask,
68	      in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
69}
70
71static void
72cpld_unmask_irq(struct irq_data *d)
73{
74	unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
75	void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
76
77	out_8(pic_mask,
78	      in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
79}
80
81static struct irq_chip cpld_pic = {
82	.name = "CPLD PIC",
83	.irq_mask = cpld_mask_irq,
84	.irq_ack = cpld_mask_irq,
85	.irq_unmask = cpld_unmask_irq,
86};
87
88static int
89cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
90			    u8 __iomem *maskp)
91{
92	int cpld_irq;
93	u8 status = in_8(statusp);
94	u8 mask = in_8(maskp);
95
96	/* ignore don't cares and masked irqs */
97	status |= (ignore | mask);
98
99	if (status == 0xff)
100		return NO_IRQ;
101
102	cpld_irq = ffz(status) + offset;
103
104	return irq_linear_revmap(cpld_pic_host, cpld_irq);
105}
106
107static void
108cpld_pic_cascade(unsigned int irq, struct irq_desc *desc)
109{
110	irq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
111		&cpld_regs->pci_mask);
112	if (irq != NO_IRQ) {
113		generic_handle_irq(irq);
114		return;
115	}
116
117	irq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
118		&cpld_regs->misc_mask);
119	if (irq != NO_IRQ) {
120		generic_handle_irq(irq);
121		return;
122	}
123}
124
125static int
126cpld_pic_host_match(struct irq_domain *h, struct device_node *node)
127{
128	return cpld_pic_node == node;
129}
130
131static int
132cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
133			     irq_hw_number_t hw)
134{
135	irq_set_status_flags(virq, IRQ_LEVEL);
136	irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
137	return 0;
138}
139
140static const struct irq_domain_ops cpld_pic_host_ops = {
141	.match = cpld_pic_host_match,
142	.map = cpld_pic_host_map,
143};
144
145void __init
146mpc5121_ads_cpld_map(void)
147{
148	struct device_node *np = NULL;
149
150	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
151	if (!np) {
152		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
153		return;
154	}
155
156	cpld_regs = of_iomap(np, 0);
157	of_node_put(np);
158}
159
160void __init
161mpc5121_ads_cpld_pic_init(void)
162{
163	unsigned int cascade_irq;
164	struct device_node *np = NULL;
165
166	pr_debug("cpld_ic_init\n");
167
168	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
169	if (!np) {
170		printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
171		return;
172	}
173
174	if (!cpld_regs)
175		goto end;
176
177	cascade_irq = irq_of_parse_and_map(np, 0);
178	if (cascade_irq == NO_IRQ)
179		goto end;
180
181	/*
182	 * statically route touch screen pendown through 1
183	 * and ignore it here
184	 * route all others through our cascade irq
185	 */
186	out_8(&cpld_regs->route, 0xfd);
187	out_8(&cpld_regs->pci_mask, 0xff);
188	/* unmask pci ints in misc mask */
189	out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
190
191	cpld_pic_node = of_node_get(np);
192
193	cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops, NULL);
194	if (!cpld_pic_host) {
195		printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
196		goto end;
197	}
198
199	irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
200end:
201	of_node_put(np);
202}
203