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
22static struct device_node *cpld_pic_node;
23static 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
37struct 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
46static struct cpld_pic __iomem *cpld_regs;
47
48static void __iomem *
49irq_to_pic_mask(unsigned int irq)
50{
51 return irq <= 7 ? &cpld_regs->pci_mask : &cpld_regs->misc_mask;
52}
53
54static unsigned int
55irq_to_pic_bit(unsigned int irq)
56{
57 return 1 << (irq & 0x7);
58}
59
60static void
61cpld_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(irq: cpld_irq);
65
66 out_8(pic_mask,
67 in_8(pic_mask) | irq_to_pic_bit(irq: cpld_irq));
68}
69
70static void
71cpld_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(irq: cpld_irq);
75
76 out_8(pic_mask,
77 in_8(pic_mask) & ~irq_to_pic_bit(irq: cpld_irq));
78}
79
80static 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
87static unsigned int
88cpld_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
103static void cpld_pic_cascade(struct irq_desc *desc)
104{
105 unsigned int hwirq;
106
107 hwirq = cpld_pic_get_irq(offset: 0, PCI_IGNORE, statusp: &cpld_regs->pci_status,
108 maskp: &cpld_regs->pci_mask);
109 if (hwirq != ~0) {
110 generic_handle_domain_irq(domain: cpld_pic_host, hwirq);
111 return;
112 }
113
114 hwirq = cpld_pic_get_irq(offset: 8, MISC_IGNORE, statusp: &cpld_regs->misc_status,
115 maskp: &cpld_regs->misc_mask);
116 if (hwirq != ~0) {
117 generic_handle_domain_irq(domain: cpld_pic_host, hwirq);
118 return;
119 }
120}
121
122static int
123cpld_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
129static int
130cpld_pic_host_map(struct irq_domain *h, unsigned int virq,
131 irq_hw_number_t hw)
132{
133 irq_set_status_flags(irq: virq, set: IRQ_LEVEL);
134 irq_set_chip_and_handler(irq: virq, chip: &cpld_pic, handle: handle_level_irq);
135 return 0;
136}
137
138static const struct irq_domain_ops cpld_pic_host_ops = {
139 .match = cpld_pic_host_match,
140 .map = cpld_pic_host_map,
141};
142
143void __init
144mpc5121_ads_cpld_map(void)
145{
146 struct device_node *np = NULL;
147
148 np = of_find_compatible_node(NULL, NULL, compat: "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(node: np, index: 0);
155 of_node_put(node: np);
156}
157
158void __init
159mpc5121_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, compat: "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(node: np, index: 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(node: np);
190
191 cpld_pic_host = irq_domain_create_linear(of_fwnode_handle(np), size: 16,
192 ops: &cpld_pic_host_ops, NULL);
193 if (!cpld_pic_host) {
194 printk(KERN_ERR "CPLD PIC: failed to allocate irq host!\n");
195 goto end;
196 }
197
198 irq_set_chained_handler(irq: cascade_irq, handle: cpld_pic_cascade);
199end:
200 of_node_put(node: np);
201}
202

source code of linux/arch/powerpc/platforms/512x/mpc5121_ads_cpld.c