1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2008 Freescale Semiconductor, Inc. All rights reserved.
4 *
5 * Author: John Rigby, <jrigby@freescale.com>
6 *
7 * Description:
8 * MPC5121ADS CPLD irq handling
9 */
10
11 #undef DEBUG
12
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/io.h>
17 #include <asm/prom.h>
18
19 static struct device_node *cpld_pic_node;
20 static struct irq_domain *cpld_pic_host;
21
22 /*
23 * Bits to ignore in the misc_status register
24 * 0x10 touch screen pendown is hard routed to irq1
25 * 0x02 pci status is read from pci status register
26 */
27 #define MISC_IGNORE 0x12
28
29 /*
30 * Nothing to ignore in pci status register
31 */
32 #define PCI_IGNORE 0x00
33
34 struct cpld_pic {
35 u8 pci_mask;
36 u8 pci_status;
37 u8 route;
38 u8 misc_mask;
39 u8 misc_status;
40 u8 misc_control;
41 };
42
43 static struct cpld_pic __iomem *cpld_regs;
44
45 static void __iomem *
irq_to_pic_mask(unsigned int irq)46 irq_to_pic_mask(unsigned int irq)
47 {
48 return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
49 }
50
51 static unsigned int
irq_to_pic_bit(unsigned int irq)52 irq_to_pic_bit(unsigned int irq)
53 {
54 return 1 << (irq & 0x7);
55 }
56
57 static void
cpld_mask_irq(struct irq_data * d)58 cpld_mask_irq(struct irq_data *d)
59 {
60 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
61 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
62
63 out_8(pic_mask,
64 in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
65 }
66
67 static void
cpld_unmask_irq(struct irq_data * d)68 cpld_unmask_irq(struct irq_data *d)
69 {
70 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
71 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
72
73 out_8(pic_mask,
74 in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
75 }
76
77 static struct irq_chip cpld_pic = {
78 .name = "CPLD PIC",
79 .irq_mask = cpld_mask_irq,
80 .irq_ack = cpld_mask_irq,
81 .irq_unmask = cpld_unmask_irq,
82 };
83
84 static unsigned int
cpld_pic_get_irq(int offset,u8 ignore,u8 __iomem * statusp,u8 __iomem * maskp)85 cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
86 u8 __iomem *maskp)
87 {
88 u8 status = in_8(statusp);
89 u8 mask = in_8(maskp);
90
91 /* ignore don't cares and masked irqs */
92 status |= (ignore | mask);
93
94 if (status == 0xff)
95 return ~0;
96
97 return ffz(status) + offset;
98 }
99
cpld_pic_cascade(struct irq_desc * desc)100 static void cpld_pic_cascade(struct irq_desc *desc)
101 {
102 unsigned int hwirq;
103
104 hwirq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
105 &cpld_regs->pci_mask);
106 if (hwirq != ~0) {
107 generic_handle_domain_irq(cpld_pic_host, hwirq);
108 return;
109 }
110
111 hwirq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
112 &cpld_regs->misc_mask);
113 if (hwirq != ~0) {
114 generic_handle_domain_irq(cpld_pic_host, hwirq);
115 return;
116 }
117 }
118
119 static int
cpld_pic_host_match(struct irq_domain * h,struct device_node * node,enum irq_domain_bus_token bus_token)120 cpld_pic_host_match(struct irq_domain *h, struct device_node *node,
121 enum irq_domain_bus_token bus_token)
122 {
123 return cpld_pic_node == node;
124 }
125
126 static int
cpld_pic_host_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)127 cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
128 irq_hw_number_t hw)
129 {
130 irq_set_status_flags(virq, IRQ_LEVEL);
131 irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
132 return 0;
133 }
134
135 static const struct irq_domain_ops cpld_pic_host_ops = {
136 .match = cpld_pic_host_match,
137 .map = cpld_pic_host_map,
138 };
139
140 void __init
mpc5121_ads_cpld_map(void)141 mpc5121_ads_cpld_map(void)
142 {
143 struct device_node *np = NULL;
144
145 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
146 if (!np) {
147 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
148 return;
149 }
150
151 cpld_regs = of_iomap(np, 0);
152 of_node_put(np);
153 }
154
155 void __init
mpc5121_ads_cpld_pic_init(void)156 mpc5121_ads_cpld_pic_init(void)
157 {
158 unsigned int cascade_irq;
159 struct device_node *np = NULL;
160
161 pr_debug("cpld_ic_init\n");
162
163 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
164 if (!np) {
165 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
166 return;
167 }
168
169 if (!cpld_regs)
170 goto end;
171
172 cascade_irq = irq_of_parse_and_map(np, 0);
173 if (!cascade_irq)
174 goto end;
175
176 /*
177 * statically route touch screen pendown through 1
178 * and ignore it here
179 * route all others through our cascade irq
180 */
181 out_8(&cpld_regs->route, 0xfd);
182 out_8(&cpld_regs->pci_mask, 0xff);
183 /* unmask pci ints in misc mask */
184 out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
185
186 cpld_pic_node = of_node_get(np);
187
188 cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops, NULL);
189 if (!cpld_pic_host) {
190 printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
191 goto end;
192 }
193
194 irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
195 end:
196 of_node_put(np);
197 }
198