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fead4dd4 JN |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | // Copyright 2021 Jonathan Neuschäfer | |
3 | ||
4 | #include <linux/irqchip.h> | |
5 | #include <linux/of_address.h> | |
6 | #include <linux/of_irq.h> | |
7 | #include <linux/printk.h> | |
8 | ||
9 | #include <asm/exception.h> | |
10 | ||
11 | #define AIC_SCR(x) ((x)*4) /* Source control registers */ | |
12 | #define AIC_GEN 0x84 /* Interrupt group enable control register */ | |
13 | #define AIC_GRSR 0x88 /* Interrupt group raw status register */ | |
14 | #define AIC_IRSR 0x100 /* Interrupt raw status register */ | |
15 | #define AIC_IASR 0x104 /* Interrupt active status register */ | |
16 | #define AIC_ISR 0x108 /* Interrupt status register */ | |
17 | #define AIC_IPER 0x10c /* Interrupt priority encoding register */ | |
18 | #define AIC_ISNR 0x110 /* Interrupt source number register */ | |
19 | #define AIC_IMR 0x114 /* Interrupt mask register */ | |
20 | #define AIC_OISR 0x118 /* Output interrupt status register */ | |
21 | #define AIC_MECR 0x120 /* Mask enable command register */ | |
22 | #define AIC_MDCR 0x124 /* Mask disable command register */ | |
23 | #define AIC_SSCR 0x128 /* Source set command register */ | |
24 | #define AIC_SCCR 0x12c /* Source clear command register */ | |
25 | #define AIC_EOSCR 0x130 /* End of service command register */ | |
26 | ||
27 | #define AIC_SCR_SRCTYPE_LOW_LEVEL (0 << 6) | |
28 | #define AIC_SCR_SRCTYPE_HIGH_LEVEL (1 << 6) | |
29 | #define AIC_SCR_SRCTYPE_NEG_EDGE (2 << 6) | |
30 | #define AIC_SCR_SRCTYPE_POS_EDGE (3 << 6) | |
31 | #define AIC_SCR_PRIORITY(x) (x) | |
32 | #define AIC_SCR_PRIORITY_MASK 0x7 | |
33 | ||
34 | #define AIC_NUM_IRQS 32 | |
35 | ||
36 | struct wpcm450_aic { | |
37 | void __iomem *regs; | |
38 | struct irq_domain *domain; | |
39 | }; | |
40 | ||
41 | static struct wpcm450_aic *aic; | |
42 | ||
43 | static void wpcm450_aic_init_hw(void) | |
44 | { | |
45 | int i; | |
46 | ||
47 | /* Disable (mask) all interrupts */ | |
48 | writel(0xffffffff, aic->regs + AIC_MDCR); | |
49 | ||
50 | /* | |
51 | * Make sure the interrupt controller is ready to serve new interrupts. | |
52 | * Reading from IPER indicates that the nIRQ signal may be deasserted, | |
53 | * and writing to EOSCR indicates that interrupt handling has finished. | |
54 | */ | |
55 | readl(aic->regs + AIC_IPER); | |
56 | writel(0, aic->regs + AIC_EOSCR); | |
57 | ||
58 | /* Initialize trigger mode and priority of each interrupt source */ | |
59 | for (i = 0; i < AIC_NUM_IRQS; i++) | |
60 | writel(AIC_SCR_SRCTYPE_HIGH_LEVEL | AIC_SCR_PRIORITY(7), | |
61 | aic->regs + AIC_SCR(i)); | |
62 | } | |
63 | ||
64 | static void __exception_irq_entry wpcm450_aic_handle_irq(struct pt_regs *regs) | |
65 | { | |
66 | int hwirq; | |
67 | ||
68 | /* Determine the interrupt source */ | |
69 | /* Read IPER to signal that nIRQ can be de-asserted */ | |
70 | hwirq = readl(aic->regs + AIC_IPER) / 4; | |
71 | ||
0953fb26 | 72 | generic_handle_domain_irq(aic->domain, hwirq); |
fead4dd4 JN |
73 | } |
74 | ||
75 | static void wpcm450_aic_eoi(struct irq_data *d) | |
76 | { | |
77 | /* Signal end-of-service */ | |
78 | writel(0, aic->regs + AIC_EOSCR); | |
79 | } | |
80 | ||
81 | static void wpcm450_aic_mask(struct irq_data *d) | |
82 | { | |
83 | unsigned int mask = BIT(d->hwirq); | |
84 | ||
85 | /* Disable (mask) the interrupt */ | |
86 | writel(mask, aic->regs + AIC_MDCR); | |
87 | } | |
88 | ||
89 | static void wpcm450_aic_unmask(struct irq_data *d) | |
90 | { | |
91 | unsigned int mask = BIT(d->hwirq); | |
92 | ||
93 | /* Enable (unmask) the interrupt */ | |
94 | writel(mask, aic->regs + AIC_MECR); | |
95 | } | |
96 | ||
97 | static int wpcm450_aic_set_type(struct irq_data *d, unsigned int flow_type) | |
98 | { | |
99 | /* | |
100 | * The hardware supports high/low level, as well as rising/falling edge | |
101 | * modes, and the DT binding accommodates for that, but as long as | |
102 | * other modes than high level mode are not used and can't be tested, | |
103 | * they are rejected in this driver. | |
104 | */ | |
105 | if ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH) | |
106 | return -EINVAL; | |
107 | ||
108 | return 0; | |
109 | } | |
110 | ||
111 | static struct irq_chip wpcm450_aic_chip = { | |
112 | .name = "wpcm450-aic", | |
113 | .irq_eoi = wpcm450_aic_eoi, | |
114 | .irq_mask = wpcm450_aic_mask, | |
115 | .irq_unmask = wpcm450_aic_unmask, | |
116 | .irq_set_type = wpcm450_aic_set_type, | |
117 | }; | |
118 | ||
119 | static int wpcm450_aic_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq) | |
120 | { | |
121 | if (hwirq >= AIC_NUM_IRQS) | |
122 | return -EPERM; | |
123 | ||
124 | irq_set_chip_and_handler(irq, &wpcm450_aic_chip, handle_fasteoi_irq); | |
125 | irq_set_chip_data(irq, aic); | |
126 | irq_set_probe(irq); | |
127 | ||
128 | return 0; | |
129 | } | |
130 | ||
131 | static const struct irq_domain_ops wpcm450_aic_ops = { | |
132 | .map = wpcm450_aic_map, | |
133 | .xlate = irq_domain_xlate_twocell, | |
134 | }; | |
135 | ||
136 | static int __init wpcm450_aic_of_init(struct device_node *node, | |
137 | struct device_node *parent) | |
138 | { | |
139 | if (parent) | |
140 | return -EINVAL; | |
141 | ||
142 | aic = kzalloc(sizeof(*aic), GFP_KERNEL); | |
143 | if (!aic) | |
144 | return -ENOMEM; | |
145 | ||
146 | aic->regs = of_iomap(node, 0); | |
147 | if (!aic->regs) { | |
148 | pr_err("Failed to map WPCM450 AIC registers\n"); | |
149 | return -ENOMEM; | |
150 | } | |
151 | ||
152 | wpcm450_aic_init_hw(); | |
153 | ||
154 | set_handle_irq(wpcm450_aic_handle_irq); | |
155 | ||
156 | aic->domain = irq_domain_add_linear(node, AIC_NUM_IRQS, &wpcm450_aic_ops, aic); | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | IRQCHIP_DECLARE(wpcm450_aic, "nuvoton,wpcm450-aic", wpcm450_aic_of_init); |