1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Aspeed AST24XX, AST25XX, and AST26XX SCU Interrupt Controller
4 * Copyright 2019 IBM Corporation
5 *
6 * Eddie James <eajames@linux.ibm.com>
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/irq.h>
11 #include <linux/irqchip.h>
12 #include <linux/irqchip/chained_irq.h>
13 #include <linux/irqdomain.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/of_irq.h>
16 #include <linux/regmap.h>
17
18 #define ASPEED_SCU_IC_REG 0x018
19 #define ASPEED_SCU_IC_SHIFT 0
20 #define ASPEED_SCU_IC_ENABLE GENMASK(6, ASPEED_SCU_IC_SHIFT)
21 #define ASPEED_SCU_IC_NUM_IRQS 7
22 #define ASPEED_SCU_IC_STATUS_SHIFT 16
23
24 #define ASPEED_AST2600_SCU_IC0_REG 0x560
25 #define ASPEED_AST2600_SCU_IC0_SHIFT 0
26 #define ASPEED_AST2600_SCU_IC0_ENABLE \
27 GENMASK(5, ASPEED_AST2600_SCU_IC0_SHIFT)
28 #define ASPEED_AST2600_SCU_IC0_NUM_IRQS 6
29
30 #define ASPEED_AST2600_SCU_IC1_REG 0x570
31 #define ASPEED_AST2600_SCU_IC1_SHIFT 4
32 #define ASPEED_AST2600_SCU_IC1_ENABLE \
33 GENMASK(5, ASPEED_AST2600_SCU_IC1_SHIFT)
34 #define ASPEED_AST2600_SCU_IC1_NUM_IRQS 2
35
36 struct aspeed_scu_ic {
37 unsigned long irq_enable;
38 unsigned long irq_shift;
39 unsigned int num_irqs;
40 unsigned int reg;
41 struct regmap *scu;
42 struct irq_domain *irq_domain;
43 };
44
aspeed_scu_ic_irq_handler(struct irq_desc * desc)45 static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
46 {
47 unsigned int sts;
48 unsigned long bit;
49 unsigned long enabled;
50 unsigned long max;
51 unsigned long status;
52 struct aspeed_scu_ic *scu_ic = irq_desc_get_handler_data(desc);
53 struct irq_chip *chip = irq_desc_get_chip(desc);
54 unsigned int mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
55
56 chained_irq_enter(chip, desc);
57
58 /*
59 * The SCU IC has just one register to control its operation and read
60 * status. The interrupt enable bits occupy the lower 16 bits of the
61 * register, while the interrupt status bits occupy the upper 16 bits.
62 * The status bit for a given interrupt is always 16 bits shifted from
63 * the enable bit for the same interrupt.
64 * Therefore, perform the IRQ operations in the enable bit space by
65 * shifting the status down to get the mapping and then back up to
66 * clear the bit.
67 */
68 regmap_read(scu_ic->scu, scu_ic->reg, &sts);
69 enabled = sts & scu_ic->irq_enable;
70 status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
71
72 bit = scu_ic->irq_shift;
73 max = scu_ic->num_irqs + bit;
74
75 for_each_set_bit_from(bit, &status, max) {
76 generic_handle_domain_irq(scu_ic->irq_domain,
77 bit - scu_ic->irq_shift);
78
79 regmap_write_bits(scu_ic->scu, scu_ic->reg, mask,
80 BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
81 }
82
83 chained_irq_exit(chip, desc);
84 }
85
aspeed_scu_ic_irq_mask(struct irq_data * data)86 static void aspeed_scu_ic_irq_mask(struct irq_data *data)
87 {
88 struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
89 unsigned int mask = BIT(data->hwirq + scu_ic->irq_shift) |
90 (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
91
92 /*
93 * Status bits are cleared by writing 1. In order to prevent the mask
94 * operation from clearing the status bits, they should be under the
95 * mask and written with 0.
96 */
97 regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, 0);
98 }
99
aspeed_scu_ic_irq_unmask(struct irq_data * data)100 static void aspeed_scu_ic_irq_unmask(struct irq_data *data)
101 {
102 struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
103 unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
104 unsigned int mask = bit |
105 (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
106
107 /*
108 * Status bits are cleared by writing 1. In order to prevent the unmask
109 * operation from clearing the status bits, they should be under the
110 * mask and written with 0.
111 */
112 regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
113 }
114
aspeed_scu_ic_irq_set_affinity(struct irq_data * data,const struct cpumask * dest,bool force)115 static int aspeed_scu_ic_irq_set_affinity(struct irq_data *data,
116 const struct cpumask *dest,
117 bool force)
118 {
119 return -EINVAL;
120 }
121
122 static struct irq_chip aspeed_scu_ic_chip = {
123 .name = "aspeed-scu-ic",
124 .irq_mask = aspeed_scu_ic_irq_mask,
125 .irq_unmask = aspeed_scu_ic_irq_unmask,
126 .irq_set_affinity = aspeed_scu_ic_irq_set_affinity,
127 };
128
aspeed_scu_ic_map(struct irq_domain * domain,unsigned int irq,irq_hw_number_t hwirq)129 static int aspeed_scu_ic_map(struct irq_domain *domain, unsigned int irq,
130 irq_hw_number_t hwirq)
131 {
132 irq_set_chip_and_handler(irq, &aspeed_scu_ic_chip, handle_level_irq);
133 irq_set_chip_data(irq, domain->host_data);
134
135 return 0;
136 }
137
138 static const struct irq_domain_ops aspeed_scu_ic_domain_ops = {
139 .map = aspeed_scu_ic_map,
140 };
141
aspeed_scu_ic_of_init_common(struct aspeed_scu_ic * scu_ic,struct device_node * node)142 static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
143 struct device_node *node)
144 {
145 int irq;
146 int rc = 0;
147
148 if (!node->parent) {
149 rc = -ENODEV;
150 goto err;
151 }
152
153 scu_ic->scu = syscon_node_to_regmap(node->parent);
154 if (IS_ERR(scu_ic->scu)) {
155 rc = PTR_ERR(scu_ic->scu);
156 goto err;
157 }
158
159 irq = irq_of_parse_and_map(node, 0);
160 if (irq < 0) {
161 rc = irq;
162 goto err;
163 }
164
165 scu_ic->irq_domain = irq_domain_add_linear(node, scu_ic->num_irqs,
166 &aspeed_scu_ic_domain_ops,
167 scu_ic);
168 if (!scu_ic->irq_domain) {
169 rc = -ENOMEM;
170 goto err;
171 }
172
173 irq_set_chained_handler_and_data(irq, aspeed_scu_ic_irq_handler,
174 scu_ic);
175
176 return 0;
177
178 err:
179 kfree(scu_ic);
180
181 return rc;
182 }
183
aspeed_scu_ic_of_init(struct device_node * node,struct device_node * parent)184 static int __init aspeed_scu_ic_of_init(struct device_node *node,
185 struct device_node *parent)
186 {
187 struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
188
189 if (!scu_ic)
190 return -ENOMEM;
191
192 scu_ic->irq_enable = ASPEED_SCU_IC_ENABLE;
193 scu_ic->irq_shift = ASPEED_SCU_IC_SHIFT;
194 scu_ic->num_irqs = ASPEED_SCU_IC_NUM_IRQS;
195 scu_ic->reg = ASPEED_SCU_IC_REG;
196
197 return aspeed_scu_ic_of_init_common(scu_ic, node);
198 }
199
aspeed_ast2600_scu_ic0_of_init(struct device_node * node,struct device_node * parent)200 static int __init aspeed_ast2600_scu_ic0_of_init(struct device_node *node,
201 struct device_node *parent)
202 {
203 struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
204
205 if (!scu_ic)
206 return -ENOMEM;
207
208 scu_ic->irq_enable = ASPEED_AST2600_SCU_IC0_ENABLE;
209 scu_ic->irq_shift = ASPEED_AST2600_SCU_IC0_SHIFT;
210 scu_ic->num_irqs = ASPEED_AST2600_SCU_IC0_NUM_IRQS;
211 scu_ic->reg = ASPEED_AST2600_SCU_IC0_REG;
212
213 return aspeed_scu_ic_of_init_common(scu_ic, node);
214 }
215
aspeed_ast2600_scu_ic1_of_init(struct device_node * node,struct device_node * parent)216 static int __init aspeed_ast2600_scu_ic1_of_init(struct device_node *node,
217 struct device_node *parent)
218 {
219 struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
220
221 if (!scu_ic)
222 return -ENOMEM;
223
224 scu_ic->irq_enable = ASPEED_AST2600_SCU_IC1_ENABLE;
225 scu_ic->irq_shift = ASPEED_AST2600_SCU_IC1_SHIFT;
226 scu_ic->num_irqs = ASPEED_AST2600_SCU_IC1_NUM_IRQS;
227 scu_ic->reg = ASPEED_AST2600_SCU_IC1_REG;
228
229 return aspeed_scu_ic_of_init_common(scu_ic, node);
230 }
231
232 IRQCHIP_DECLARE(ast2400_scu_ic, "aspeed,ast2400-scu-ic", aspeed_scu_ic_of_init);
233 IRQCHIP_DECLARE(ast2500_scu_ic, "aspeed,ast2500-scu-ic", aspeed_scu_ic_of_init);
234 IRQCHIP_DECLARE(ast2600_scu_ic0, "aspeed,ast2600-scu-ic0",
235 aspeed_ast2600_scu_ic0_of_init);
236 IRQCHIP_DECLARE(ast2600_scu_ic1, "aspeed,ast2600-scu-ic1",
237 aspeed_ast2600_scu_ic1_of_init);
238