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 <linux/of_address.h>
18 #include <linux/of_irq.h>
19
20 #include "mpc5121_ads.h"
21
22 static struct device_node *cpld_pic_node;
23 static struct irq_domain *cpld_pic_host;
24
25 /*
26 * Bits to ignore in the misc_status register
27 * 0x10 touch screen pendown is hard routed to irq1
28 * 0x02 pci status is read from pci status register
29 */
30 #define MISC_IGNORE 0x12
31
32 /*
33 * Nothing to ignore in pci status register
34 */
35 #define PCI_IGNORE 0x00
36
37 struct cpld_pic {
38 u8 pci_mask;
39 u8 pci_status;
40 u8 route;
41 u8 misc_mask;
42 u8 misc_status;
43 u8 misc_control;
44 };
45
46 static struct cpld_pic __iomem *cpld_regs;
47
48 static void __iomem *
irq_to_pic_mask(unsigned int irq)49 irq_to_pic_mask(unsigned int irq)
50 {
51 return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
52 }
53
54 static unsigned int
irq_to_pic_bit(unsigned int irq)55 irq_to_pic_bit(unsigned int irq)
56 {
57 return 1 << (irq & 0x7);
58 }
59
60 static void
cpld_mask_irq(struct irq_data * d)61 cpld_mask_irq(struct irq_data *d)
62 {
63 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
64 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
65
66 out_8(pic_mask,
67 in_8(pic_mask) | irq_to_pic_bit(cpld_irq));
68 }
69
70 static void
cpld_unmask_irq(struct irq_data * d)71 cpld_unmask_irq(struct irq_data *d)
72 {
73 unsigned int cpld_irq = (unsigned int)irqd_to_hwirq(d);
74 void __iomem *pic_mask = irq_to_pic_mask(cpld_irq);
75
76 out_8(pic_mask,
77 in_8(pic_mask) & ~irq_to_pic_bit(cpld_irq));
78 }
79
80 static struct irq_chip cpld_pic = {
81 .name = "CPLD PIC",
82 .irq_mask = cpld_mask_irq,
83 .irq_ack = cpld_mask_irq,
84 .irq_unmask = cpld_unmask_irq,
85 };
86
87 static unsigned int
cpld_pic_get_irq(int offset,u8 ignore,u8 __iomem * statusp,u8 __iomem * maskp)88 cpld_pic_get_irq(int offset, u8 ignore, u8 __iomem *statusp,
89 u8 __iomem *maskp)
90 {
91 u8 status = in_8(statusp);
92 u8 mask = in_8(maskp);
93
94 /* ignore don't cares and masked irqs */
95 status |= (ignore | mask);
96
97 if (status == 0xff)
98 return ~0;
99
100 return ffz(status) + offset;
101 }
102
cpld_pic_cascade(struct irq_desc * desc)103 static void cpld_pic_cascade(struct irq_desc *desc)
104 {
105 unsigned int hwirq;
106
107 hwirq = cpld_pic_get_irq(0, PCI_IGNORE, &cpld_regs->pci_status,
108 &cpld_regs->pci_mask);
109 if (hwirq != ~0) {
110 generic_handle_domain_irq(cpld_pic_host, hwirq);
111 return;
112 }
113
114 hwirq = cpld_pic_get_irq(8, MISC_IGNORE, &cpld_regs->misc_status,
115 &cpld_regs->misc_mask);
116 if (hwirq != ~0) {
117 generic_handle_domain_irq(cpld_pic_host, hwirq);
118 return;
119 }
120 }
121
122 static int
cpld_pic_host_match(struct irq_domain * h,struct device_node * node,enum irq_domain_bus_token bus_token)123 cpld_pic_host_match(struct irq_domain *h, struct device_node *node,
124 enum irq_domain_bus_token bus_token)
125 {
126 return cpld_pic_node == node;
127 }
128
129 static int
cpld_pic_host_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)130 cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
131 irq_hw_number_t hw)
132 {
133 irq_set_status_flags(virq, IRQ_LEVEL);
134 irq_set_chip_and_handler(virq, &cpld_pic, handle_level_irq);
135 return 0;
136 }
137
138 static const struct irq_domain_ops cpld_pic_host_ops = {
139 .match = cpld_pic_host_match,
140 .map = cpld_pic_host_map,
141 };
142
143 void __init
mpc5121_ads_cpld_map(void)144 mpc5121_ads_cpld_map(void)
145 {
146 struct device_node *np = NULL;
147
148 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
149 if (!np) {
150 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
151 return;
152 }
153
154 cpld_regs = of_iomap(np, 0);
155 of_node_put(np);
156 }
157
158 void __init
mpc5121_ads_cpld_pic_init(void)159 mpc5121_ads_cpld_pic_init(void)
160 {
161 unsigned int cascade_irq;
162 struct device_node *np = NULL;
163
164 pr_debug("cpld_ic_init\n");
165
166 np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121ads-cpld-pic");
167 if (!np) {
168 printk(KERN_ERR "CPLD PIC init: can not find cpld-pic node\n");
169 return;
170 }
171
172 if (!cpld_regs)
173 goto end;
174
175 cascade_irq = irq_of_parse_and_map(np, 0);
176 if (!cascade_irq)
177 goto end;
178
179 /*
180 * statically route touch screen pendown through 1
181 * and ignore it here
182 * route all others through our cascade irq
183 */
184 out_8(&cpld_regs->route, 0xfd);
185 out_8(&cpld_regs->pci_mask, 0xff);
186 /* unmask pci ints in misc mask */
187 out_8(&cpld_regs->misc_mask, ~(MISC_IGNORE));
188
189 cpld_pic_node = of_node_get(np);
190
191 cpld_pic_host = irq_domain_add_linear(np, 16, &cpld_pic_host_ops, NULL);
192 if (!cpld_pic_host) {
193 printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
194 goto end;
195 }
196
197 irq_set_chained_handler(cascade_irq, cpld_pic_cascade);
198 end:
199 of_node_put(np);
200 }
201