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1 | /* |
2 | * Copyright 2010 Broadcom | |
3 | * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits | |
16 | * | |
17 | * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8 | |
18 | * on bank 0 is set to signify that an interrupt in bank 1 has fired, and | |
19 | * to look in the bank 1 status register for more information. | |
20 | * | |
21 | * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its | |
22 | * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1 | |
23 | * status register, but bank 0 bit 8 is _not_ set. | |
24 | * | |
25 | * Quirk 2: You can't mask the register 1/2 pending interrupts | |
26 | * | |
27 | * In a proper cascaded interrupt controller, the interrupt lines with | |
28 | * cascaded interrupt controllers on them are just normal interrupt lines. | |
29 | * You can mask the interrupts and get on with things. With this controller | |
30 | * you can't do that. | |
31 | * | |
32 | * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0 | |
33 | * | |
34 | * Those interrupts that have shortcuts can only be masked/unmasked in | |
35 | * their respective banks' enable/disable registers. Doing so in the bank 0 | |
36 | * enable/disable registers has no effect. | |
37 | * | |
38 | * The FIQ control register: | |
39 | * Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0) | |
40 | * Bit 7: Enable FIQ generation | |
41 | * Bits 8+: Unused | |
42 | * | |
43 | * An interrupt must be disabled before configuring it for FIQ generation | |
44 | * otherwise both handlers will fire at the same time! | |
45 | */ | |
46 | ||
47 | #include <linux/io.h> | |
48 | #include <linux/slab.h> | |
49 | #include <linux/of_address.h> | |
50 | #include <linux/of_irq.h> | |
51 | #include <linux/irqdomain.h> | |
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52 | |
53 | #include <asm/exception.h> | |
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54 | #include <asm/mach/irq.h> |
55 | ||
56 | #include "irqchip.h" | |
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57 | |
58 | /* Put the bank and irq (32 bits) into the hwirq */ | |
59 | #define MAKE_HWIRQ(b, n) ((b << 5) | (n)) | |
60 | #define HWIRQ_BANK(i) (i >> 5) | |
61 | #define HWIRQ_BIT(i) BIT(i & 0x1f) | |
62 | ||
63 | #define NR_IRQS_BANK0 8 | |
64 | #define BANK0_HWIRQ_MASK 0xff | |
65 | /* Shortcuts can't be disabled so any unknown new ones need to be masked */ | |
66 | #define SHORTCUT1_MASK 0x00007c00 | |
67 | #define SHORTCUT2_MASK 0x001f8000 | |
68 | #define SHORTCUT_SHIFT 10 | |
69 | #define BANK1_HWIRQ BIT(8) | |
70 | #define BANK2_HWIRQ BIT(9) | |
71 | #define BANK0_VALID_MASK (BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \ | |
72 | | SHORTCUT1_MASK | SHORTCUT2_MASK) | |
73 | ||
74 | #define REG_FIQ_CONTROL 0x0c | |
75 | ||
76 | #define NR_BANKS 3 | |
77 | #define IRQS_PER_BANK 32 | |
78 | ||
79 | static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 }; | |
80 | static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 }; | |
81 | static int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 }; | |
82 | static int bank_irqs[] __initconst = { 8, 32, 32 }; | |
83 | ||
84 | static const int shortcuts[] = { | |
85 | 7, 9, 10, 18, 19, /* Bank 1 */ | |
86 | 21, 22, 23, 24, 25, 30 /* Bank 2 */ | |
87 | }; | |
88 | ||
89 | struct armctrl_ic { | |
90 | void __iomem *base; | |
91 | void __iomem *pending[NR_BANKS]; | |
92 | void __iomem *enable[NR_BANKS]; | |
93 | void __iomem *disable[NR_BANKS]; | |
94 | struct irq_domain *domain; | |
95 | }; | |
96 | ||
97 | static struct armctrl_ic intc __read_mostly; | |
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98 | static asmlinkage void __exception_irq_entry bcm2835_handle_irq( |
99 | struct pt_regs *regs); | |
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100 | |
101 | static void armctrl_mask_irq(struct irq_data *d) | |
102 | { | |
103 | writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]); | |
104 | } | |
105 | ||
106 | static void armctrl_unmask_irq(struct irq_data *d) | |
107 | { | |
108 | writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]); | |
109 | } | |
110 | ||
111 | static struct irq_chip armctrl_chip = { | |
112 | .name = "ARMCTRL-level", | |
113 | .irq_mask = armctrl_mask_irq, | |
114 | .irq_unmask = armctrl_unmask_irq | |
115 | }; | |
116 | ||
117 | static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr, | |
118 | const u32 *intspec, unsigned int intsize, | |
119 | unsigned long *out_hwirq, unsigned int *out_type) | |
120 | { | |
121 | if (WARN_ON(intsize != 2)) | |
122 | return -EINVAL; | |
123 | ||
124 | if (WARN_ON(intspec[0] >= NR_BANKS)) | |
125 | return -EINVAL; | |
126 | ||
127 | if (WARN_ON(intspec[1] >= IRQS_PER_BANK)) | |
128 | return -EINVAL; | |
129 | ||
130 | if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0)) | |
131 | return -EINVAL; | |
132 | ||
133 | *out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]); | |
134 | *out_type = IRQ_TYPE_NONE; | |
135 | return 0; | |
136 | } | |
137 | ||
138 | static struct irq_domain_ops armctrl_ops = { | |
139 | .xlate = armctrl_xlate | |
140 | }; | |
141 | ||
142 | static int __init armctrl_of_init(struct device_node *node, | |
143 | struct device_node *parent) | |
144 | { | |
145 | void __iomem *base; | |
146 | int irq, b, i; | |
147 | ||
148 | base = of_iomap(node, 0); | |
149 | if (!base) | |
150 | panic("%s: unable to map IC registers\n", | |
151 | node->full_name); | |
152 | ||
153 | intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0), | |
154 | &armctrl_ops, NULL); | |
155 | if (!intc.domain) | |
156 | panic("%s: unable to create IRQ domain\n", node->full_name); | |
157 | ||
158 | for (b = 0; b < NR_BANKS; b++) { | |
159 | intc.pending[b] = base + reg_pending[b]; | |
160 | intc.enable[b] = base + reg_enable[b]; | |
161 | intc.disable[b] = base + reg_disable[b]; | |
162 | ||
163 | for (i = 0; i < bank_irqs[b]; i++) { | |
164 | irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i)); | |
165 | BUG_ON(irq <= 0); | |
166 | irq_set_chip_and_handler(irq, &armctrl_chip, | |
167 | handle_level_irq); | |
168 | set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); | |
169 | } | |
170 | } | |
89214f00 | 171 | |
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172 | set_handle_irq(bcm2835_handle_irq); |
173 | return 0; | |
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174 | } |
175 | ||
176 | /* | |
177 | * Handle each interrupt across the entire interrupt controller. This reads the | |
178 | * status register before handling each interrupt, which is necessary given that | |
179 | * handle_IRQ may briefly re-enable interrupts for soft IRQ handling. | |
180 | */ | |
181 | ||
182 | static void armctrl_handle_bank(int bank, struct pt_regs *regs) | |
183 | { | |
184 | u32 stat, irq; | |
185 | ||
186 | while ((stat = readl_relaxed(intc.pending[bank]))) { | |
187 | irq = MAKE_HWIRQ(bank, ffs(stat) - 1); | |
188 | handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); | |
189 | } | |
190 | } | |
191 | ||
192 | static void armctrl_handle_shortcut(int bank, struct pt_regs *regs, | |
193 | u32 stat) | |
194 | { | |
195 | u32 irq = MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]); | |
196 | handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); | |
197 | } | |
198 | ||
5702941e | 199 | static asmlinkage void __exception_irq_entry bcm2835_handle_irq( |
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200 | struct pt_regs *regs) |
201 | { | |
202 | u32 stat, irq; | |
203 | ||
204 | while ((stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK)) { | |
205 | if (stat & BANK0_HWIRQ_MASK) { | |
206 | irq = MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1); | |
207 | handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); | |
208 | } else if (stat & SHORTCUT1_MASK) { | |
209 | armctrl_handle_shortcut(1, regs, stat & SHORTCUT1_MASK); | |
210 | } else if (stat & SHORTCUT2_MASK) { | |
211 | armctrl_handle_shortcut(2, regs, stat & SHORTCUT2_MASK); | |
212 | } else if (stat & BANK1_HWIRQ) { | |
213 | armctrl_handle_bank(1, regs); | |
214 | } else if (stat & BANK2_HWIRQ) { | |
215 | armctrl_handle_bank(2, regs); | |
216 | } else { | |
217 | BUG(); | |
218 | } | |
219 | } | |
220 | } | |
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221 | |
222 | IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic", armctrl_of_init); |