1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Support for Versatile FPGA-based IRQ controllers
4 */
5#include <linux/bitops.h>
6#include <linux/irq.h>
7#include <linux/io.h>
8#include <linux/irqchip.h>
9#include <linux/irqchip/chained_irq.h>
10#include <linux/irqdomain.h>
11#include <linux/module.h>
12#include <linux/of.h>
13#include <linux/of_address.h>
14#include <linux/of_irq.h>
15#include <linux/seq_file.h>
16
17#include <asm/exception.h>
18#include <asm/mach/irq.h>
19
20#define IRQ_STATUS 0x00
21#define IRQ_RAW_STATUS 0x04
22#define IRQ_ENABLE_SET 0x08
23#define IRQ_ENABLE_CLEAR 0x0c
24#define INT_SOFT_SET 0x10
25#define INT_SOFT_CLEAR 0x14
26#define FIQ_STATUS 0x20
27#define FIQ_RAW_STATUS 0x24
28#define FIQ_ENABLE 0x28
29#define FIQ_ENABLE_SET 0x28
30#define FIQ_ENABLE_CLEAR 0x2C
31
32#define PIC_ENABLES 0x20 /* set interrupt pass through bits */
33
34/**
35 * struct fpga_irq_data - irq data container for the FPGA IRQ controller
36 * @base: memory offset in virtual memory
37 * @domain: IRQ domain for this instance
38 * @valid: mask for valid IRQs on this controller
39 * @used_irqs: number of active IRQs on this controller
40 */
41struct fpga_irq_data {
42 void __iomem *base;
43 u32 valid;
44 struct irq_domain *domain;
45 u8 used_irqs;
46};
47
48/* we cannot allocate memory when the controllers are initially registered */
49static struct fpga_irq_data fpga_irq_devices[CONFIG_VERSATILE_FPGA_IRQ_NR];
50static int fpga_irq_id;
51
52static void fpga_irq_mask(struct irq_data *d)
53{
54 struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
55 u32 mask = 1 << d->hwirq;
56
57 writel(val: mask, addr: f->base + IRQ_ENABLE_CLEAR);
58}
59
60static void fpga_irq_unmask(struct irq_data *d)
61{
62 struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
63 u32 mask = 1 << d->hwirq;
64
65 writel(val: mask, addr: f->base + IRQ_ENABLE_SET);
66}
67
68static void fpga_irq_print_chip(struct irq_data *d, struct seq_file *p)
69{
70 struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
71
72 seq_puts(m: p, s: irq_domain_get_of_node(d: f->domain)->name);
73}
74
75static const struct irq_chip fpga_chip = {
76 .irq_ack = fpga_irq_mask,
77 .irq_mask = fpga_irq_mask,
78 .irq_unmask = fpga_irq_unmask,
79 .irq_print_chip = fpga_irq_print_chip,
80};
81
82static void fpga_irq_handle(struct irq_desc *desc)
83{
84 struct irq_chip *chip = irq_desc_get_chip(desc);
85 struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
86 u32 status;
87
88 chained_irq_enter(chip, desc);
89
90 status = readl(addr: f->base + IRQ_STATUS);
91 if (status == 0) {
92 do_bad_IRQ(desc);
93 goto out;
94 }
95
96 do {
97 unsigned int irq = ffs(status) - 1;
98
99 status &= ~(1 << irq);
100 generic_handle_domain_irq(domain: f->domain, hwirq: irq);
101 } while (status);
102
103out:
104 chained_irq_exit(chip, desc);
105}
106
107/*
108 * Handle each interrupt in a single FPGA IRQ controller. Returns non-zero
109 * if we've handled at least one interrupt. This does a single read of the
110 * status register and handles all interrupts in order from LSB first.
111 */
112static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs)
113{
114 int handled = 0;
115 int irq;
116 u32 status;
117
118 while ((status = readl(addr: f->base + IRQ_STATUS))) {
119 irq = ffs(status) - 1;
120 generic_handle_domain_irq(domain: f->domain, hwirq: irq);
121 handled = 1;
122 }
123
124 return handled;
125}
126
127/*
128 * Keep iterating over all registered FPGA IRQ controllers until there are
129 * no pending interrupts.
130 */
131static void __exception_irq_entry fpga_handle_irq(struct pt_regs *regs)
132{
133 int i, handled;
134
135 do {
136 for (i = 0, handled = 0; i < fpga_irq_id; ++i)
137 handled |= handle_one_fpga(&fpga_irq_devices[i], regs);
138 } while (handled);
139}
140
141static int fpga_irqdomain_map(struct irq_domain *d, unsigned int irq,
142 irq_hw_number_t hwirq)
143{
144 struct fpga_irq_data *f = d->host_data;
145
146 /* Skip invalid IRQs, only register handlers for the real ones */
147 if (!(f->valid & BIT(hwirq)))
148 return -EPERM;
149 irq_set_chip_data(irq, data: f);
150 irq_set_chip_and_handler(irq, chip: &fpga_chip, handle: handle_level_irq);
151 irq_set_probe(irq);
152 return 0;
153}
154
155static const struct irq_domain_ops fpga_irqdomain_ops = {
156 .map = fpga_irqdomain_map,
157 .xlate = irq_domain_xlate_onetwocell,
158};
159
160static void __init fpga_irq_init(void __iomem *base, int parent_irq,
161 u32 valid, struct device_node *node)
162{
163 struct fpga_irq_data *f;
164 int i;
165
166 if (fpga_irq_id >= ARRAY_SIZE(fpga_irq_devices)) {
167 pr_err("%s: too few FPGA IRQ controllers, increase CONFIG_VERSATILE_FPGA_IRQ_NR\n", __func__);
168 return;
169 }
170 f = &fpga_irq_devices[fpga_irq_id];
171 f->base = base;
172 f->valid = valid;
173
174 if (parent_irq != -1) {
175 irq_set_chained_handler_and_data(irq: parent_irq, handle: fpga_irq_handle,
176 data: f);
177 }
178
179 f->domain = irq_domain_create_linear(of_fwnode_handle(node), size: fls(x: valid),
180 ops: &fpga_irqdomain_ops, host_data: f);
181
182 /* This will allocate all valid descriptors in the linear case */
183 for (i = 0; i < fls(x: valid); i++)
184 if (valid & BIT(i)) {
185 /* Is this still required? */
186 irq_create_mapping(domain: f->domain, hwirq: i);
187 f->used_irqs++;
188 }
189
190 pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs",
191 fpga_irq_id, node->name, base, f->used_irqs);
192 if (parent_irq != -1)
193 pr_cont(", parent IRQ: %d\n", parent_irq);
194 else
195 pr_cont("\n");
196
197 fpga_irq_id++;
198}
199
200#ifdef CONFIG_OF
201static int __init fpga_irq_of_init(struct device_node *node,
202 struct device_node *parent)
203{
204 void __iomem *base;
205 u32 clear_mask;
206 u32 valid_mask;
207 int parent_irq;
208
209 if (WARN_ON(!node))
210 return -ENODEV;
211
212 base = of_iomap(node, index: 0);
213 WARN(!base, "unable to map fpga irq registers\n");
214
215 if (of_property_read_u32(np: node, propname: "clear-mask", out_value: &clear_mask))
216 clear_mask = 0;
217
218 if (of_property_read_u32(np: node, propname: "valid-mask", out_value: &valid_mask))
219 valid_mask = 0;
220
221 writel(val: clear_mask, addr: base + IRQ_ENABLE_CLEAR);
222 writel(val: clear_mask, addr: base + FIQ_ENABLE_CLEAR);
223
224 /* Some chips are cascaded from a parent IRQ */
225 parent_irq = irq_of_parse_and_map(node, index: 0);
226 if (!parent_irq) {
227 set_handle_irq(fpga_handle_irq);
228 parent_irq = -1;
229 }
230
231 fpga_irq_init(base, parent_irq, valid: valid_mask, node);
232
233 /*
234 * On Versatile AB/PB, some secondary interrupts have a direct
235 * pass-thru to the primary controller for IRQs 20 and 22-31 which need
236 * to be enabled. See section 3.10 of the Versatile AB user guide.
237 */
238 if (of_device_is_compatible(device: node, "arm,versatile-sic"))
239 writel(val: 0xffd00000, addr: base + PIC_ENABLES);
240
241 return 0;
242}
243IRQCHIP_DECLARE(arm_fpga, "arm,versatile-fpga-irq", fpga_irq_of_init);
244IRQCHIP_DECLARE(arm_fpga_sic, "arm,versatile-sic", fpga_irq_of_init);
245#endif
246

source code of linux/drivers/irqchip/irq-versatile-fpga.c