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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Realtek Interrupt controller.
4 *
5 * The Realtek Interrupt controller is a big endian device found in the
6 * Realtek MIPS SoCs.
7 *
8 * Copyright (C) 2020 Birger Koblitz <[email protected]>
9 * Copyright (C) 2020 Bert Vermeulen <[email protected]>
10 * Copyright (C) 2020 John Crispin <[email protected]>
11 */
12
13#include <linux/of_irq.h>
14#include <linux/irqchip.h>
15#include <linux/spinlock.h>
16#include <linux/of_address.h>
17#include <linux/irqchip/chained_irq.h>
18
19/* Global Interrupt Mask Register */
20#define RTL_ICTL_GIMR 0x00
21/* Global Interrupt Status Register */
22#define RTL_ICTL_GISR 0x04
23/* Interrupt Routing Registers */
24#define RTL_ICTL_IRR0 0x08
25#define RTL_ICTL_IRR1 0x0c
26#define RTL_ICTL_IRR2 0x10
27#define RTL_ICTL_IRR3 0x14
28
29#define RTL_ICTL_NUM_INPUTS 32
30
31#define REG(cpu, x) (realtek_ictl_base[cpu] + x)
32
33struct realtek_ictl_output {
34 struct fwnode_handle *fwnode;
35 struct irq_domain *domain;
36 unsigned int parent_irq;
37 unsigned int parent_hwirq;
38 unsigned int index;
39 u32 mask;
40};
41
42static DEFINE_RAW_SPINLOCK(irq_lock);
43static void __iomem *realtek_ictl_base[NR_CPUS];
44
45/*
46 * IRR0-IRR3 store 4 bits per interrupt, but Realtek uses inverted numbering,
47 * placing IRQ 31 in the first four bits. A routing value of '0' means the
48 * interrupt is left disconnected. Routing values {1..15} connect to output
49 * lines {0..14}.
50 */
51#define IRR_OFFSET(idx) (4 * (3 - (idx * 4) / 32))
52#define IRR_SHIFT(idx) ((idx * 4) % 32)
53
54static inline void enable_gimr(unsigned int cpu, unsigned int hw_irq)
55{
56 u32 gimr;
57
58 gimr = readl_be(REG(cpu, RTL_ICTL_GIMR));
59 gimr |= BIT(hw_irq);
60 writel_be(gimr, REG(cpu, RTL_ICTL_GIMR));
61}
62
63static inline void disable_gimr(unsigned int cpu, unsigned int hw_irq)
64{
65 u32 gimr;
66
67 gimr = readl_be(REG(cpu, RTL_ICTL_GIMR));
68 gimr &= ~BIT(hw_irq);
69 writel_be(gimr, REG(cpu, RTL_ICTL_GIMR));
70}
71
72static void write_irr(unsigned int cpu, int hw_irq, u32 value)
73{
74 void __iomem *irr0 = REG(cpu, RTL_ICTL_IRR0);
75 unsigned int offset = IRR_OFFSET(hw_irq);
76 unsigned int shift = IRR_SHIFT(hw_irq);
77 u32 irr;
78
79 irr = readl_be(irr0 + offset) & ~(0xf << shift);
80 irr |= (value & 0xf) << shift;
81 writel_be(irr, irr0 + offset);
82}
83
84static void realtek_ictl_unmask_irq(struct irq_data *i)
85{
86 unsigned int cpu;
87
88 guard(raw_spinlock)(&irq_lock);
89 for_each_cpu(cpu, irq_data_get_effective_affinity_mask(i))
90 enable_gimr(cpu, i->hwirq);
91}
92
93static void realtek_ictl_mask_irq(struct irq_data *i)
94{
95 unsigned int cpu;
96
97 guard(raw_spinlock)(&irq_lock);
98 for_each_cpu(cpu, irq_data_get_effective_affinity_mask(i))
99 disable_gimr(cpu, i->hwirq);
100}
101
102static int realtek_ictl_irq_affinity(struct irq_data *i, const struct cpumask *dest, bool force)
103{
104 if (!irqd_irq_masked(i))
105 realtek_ictl_mask_irq(i);
106
107 irq_data_update_effective_affinity(i, dest);
108
109 if (!irqd_irq_masked(i))
110 realtek_ictl_unmask_irq(i);
111
112 return IRQ_SET_MASK_OK;
113}
114
115static struct irq_chip realtek_ictl_irq = {
116 .name = "realtek-rtl-intc",
117 .irq_mask = realtek_ictl_mask_irq,
118 .irq_unmask = realtek_ictl_unmask_irq,
119 .irq_set_affinity = realtek_ictl_irq_affinity,
120};
121
122static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw_irq)
123{
124 struct realtek_ictl_output *output = d->host_data;
125 unsigned int cpu;
126
127 irq_set_chip_and_handler(irq, &realtek_ictl_irq, handle_level_irq);
128
129 guard(raw_spinlock_irqsave)(&irq_lock);
130 output->mask |= BIT(hw_irq);
131 for_each_present_cpu(cpu)
132 write_irr(cpu, hw_irq, output->parent_hwirq - 1);
133
134 return 0;
135}
136
137static int intc_select(struct irq_domain *d, struct irq_fwspec *fwspec,
138 enum irq_domain_bus_token bus_token)
139{
140 struct realtek_ictl_output *output = d->host_data;
141 unsigned int index = 0;
142
143 if (fwspec->fwnode != output->fwnode)
144 return false;
145
146 if (fwspec->param_count == 2)
147 index = fwspec->param[1];
148
149 return index == output->index;
150}
151
152static const struct irq_domain_ops irq_domain_ops = {
153 .map = intc_map,
154 .select = intc_select,
155 .xlate = irq_domain_xlate_onecell,
156};
157
158static void realtek_irq_dispatch(struct irq_desc *desc)
159{
160 struct realtek_ictl_output *output = irq_desc_get_handler_data(desc);
161 struct irq_chip *chip = irq_desc_get_chip(desc);
162 unsigned int cpu = smp_processor_id();
163 unsigned long pending;
164 unsigned int hw_irq;
165
166 chained_irq_enter(chip, desc);
167 pending = readl_be(REG(cpu, RTL_ICTL_GIMR)) &
168 readl_be(REG(cpu, RTL_ICTL_GISR)) & output->mask;
169
170 if (unlikely(!pending)) {
171 spurious_interrupt();
172 goto out;
173 }
174
175 for_each_set_bit(hw_irq, &pending, RTL_ICTL_NUM_INPUTS)
176 generic_handle_domain_irq(output->domain, hw_irq);
177
178out:
179 chained_irq_exit(chip, desc);
180}
181
182static int __init realtek_setup_parents(struct device_node *node)
183{
184 int p, cnt, err, parent_irq, num_parents = of_irq_count(node);
185 struct realtek_ictl_output *output;
186 struct irq_data *parent_data;
187 struct of_phandle_args oirq;
188 struct irq_domain *domain;
189
190 cnt = max(1, num_parents);
191 output = kzalloc_objs(*output, cnt);
192 if (!output)
193 return -ENOMEM;
194
195 for (p = 0; p < cnt; p++) {
196 if (WARN_ON(!num_parents)) {
197 /*
198 * If DT contains no parent interrupts, assume MIPS IRQ 2 (HW0) is
199 * connected to the first output. This is the case for all known hardware.
200 */
201 oirq.np = of_find_compatible_node(NULL, NULL,
202 "mti,cpu-interrupt-controller");
203 if (!oirq.np) {
204 err = -EINVAL;
205 goto err_out;
206 }
207
208 oirq.args_count = 1;
209 oirq.args[0] = 2;
210 parent_irq = irq_create_of_mapping(&oirq);
211 of_node_put(oirq.np);
212 } else {
213 parent_irq = of_irq_get(node, p);
214 }
215
216 if (parent_irq <= 0) {
217 err = parent_irq ? parent_irq : -ENODEV;
218 goto err_out;
219 }
220
221 parent_data = irq_get_irq_data(parent_irq);
222 if (!parent_data) {
223 err = -EINVAL;
224 goto err_out;
225 }
226
227 domain = irq_domain_create_linear(of_fwnode_handle(node), RTL_ICTL_NUM_INPUTS,
228 &irq_domain_ops, &output[p]);
229 if (!domain) {
230 err = -ENOMEM;
231 goto err_out;
232 }
233
234 output[p].domain = domain;
235 output[p].fwnode = of_fwnode_handle(node);
236 output[p].index = p;
237 output[p].parent_irq = parent_irq;
238 output[p].parent_hwirq = irqd_to_hwirq(parent_data);
239 irq_set_chained_handler_and_data(parent_irq, realtek_irq_dispatch, &output[p]);
240 }
241
242 return 0;
243
244err_out:
245 while (p--) {
246 irq_set_chained_handler_and_data(output[p].parent_irq, NULL, NULL);
247 irq_domain_remove(output[p].domain);
248 }
249
250 kfree(output);
251
252 return err;
253}
254
255static int __init realtek_rtl_of_init(struct device_node *node, struct device_node *parent)
256{
257 unsigned int cpu;
258
259 for_each_present_cpu(cpu) {
260 realtek_ictl_base[cpu] = of_iomap(node, cpu);
261 if (!realtek_ictl_base[cpu])
262 return -ENXIO;
263
264 /* Disable all cascaded interrupts and clear routing */
265 for (unsigned int hw_irq = 0; hw_irq < RTL_ICTL_NUM_INPUTS; hw_irq++) {
266 disable_gimr(cpu, hw_irq);
267 write_irr(cpu, hw_irq, 0);
268 }
269 }
270
271 return realtek_setup_parents(node);
272}
273
274IRQCHIP_DECLARE(realtek_rtl_intc, "realtek,rtl-intc", realtek_rtl_of_init);