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
23 static struct device_node *cpld_pic_node;
24 static 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
38 struct 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
47 static struct cpld_pic __iomem *cpld_regs;
48
49 static void __iomem *
irq_to_pic_mask(unsigned int irq)50 irq_to_pic_mask(unsigned int irq)
51 {
52 return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
53 }
54
55 static unsigned int
irq_to_pic_bit(unsigned int irq)56 irq_to_pic_bit(unsigned int irq)
57 {
58 return 1 << (irq & 0x7);
59 }
60
61 static void
cpld_mask_irq(struct irq_data * d)62 cpld_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
71 static void
cpld_unmask_irq(struct irq_data * d)72 cpld_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
81 static 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
88 static int
cpld_pic_get_irq(int offset,u8 ignore,u8 __iomem * statusp,u8 __iomem * maskp)89 cpld_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
107 static void
cpld_pic_cascade(unsigned int irq,struct irq_desc * desc)108 cpld_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
125 static int
cpld_pic_host_match(struct irq_domain * h,struct device_node * node)126 cpld_pic_host_match(struct irq_domain *h, struct device_node *node)
127 {
128 return cpld_pic_node == node;
129 }
130
131 static int
cpld_pic_host_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)132 cpld_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
140 static const struct irq_domain_ops cpld_pic_host_ops = {
141 .match = cpld_pic_host_match,
142 .map = cpld_pic_host_map,
143 };
144
145 void __init
mpc5121_ads_cpld_map(void)146 mpc5121_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
160 void __init
mpc5121_ads_cpld_pic_init(void)161 mpc5121_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);
200 end:
201 of_node_put(np);
202 }
203