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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright 2010 Broadcom
4 * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren
5 *
6 * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits
7 *
8 * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8
9 * on bank 0 is set to signify that an interrupt in bank 1 has fired, and
10 * to look in the bank 1 status register for more information.
11 *
12 * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its
13 * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1
14 * status register, but bank 0 bit 8 is _not_ set.
15 *
16 * Quirk 2: You can't mask the register 1/2 pending interrupts
17 *
18 * In a proper cascaded interrupt controller, the interrupt lines with
19 * cascaded interrupt controllers on them are just normal interrupt lines.
20 * You can mask the interrupts and get on with things. With this controller
21 * you can't do that.
22 *
23 * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0
24 *
25 * Those interrupts that have shortcuts can only be masked/unmasked in
26 * their respective banks' enable/disable registers. Doing so in the bank 0
27 * enable/disable registers has no effect.
28 *
29 * The FIQ control register:
30 * Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0)
31 * Bit 7: Enable FIQ generation
32 * Bits 8+: Unused
33 *
34 * An interrupt must be disabled before configuring it for FIQ generation
35 * otherwise both handlers will fire at the same time!
36 */
37
38#include <linux/io.h>
39#include <linux/slab.h>
40#include <linux/of_address.h>
41#include <linux/of_irq.h>
42#include <linux/irqchip.h>
43#include <linux/irqdomain.h>
44
45#include <asm/exception.h>
46
47/* Put the bank and irq (32 bits) into the hwirq */
48#define MAKE_HWIRQ(b, n) ((b << 5) | (n))
49#define HWIRQ_BANK(i) (i >> 5)
50#define HWIRQ_BIT(i) BIT(i & 0x1f)
51
52#define NR_IRQS_BANK0 8
53#define BANK0_HWIRQ_MASK 0xff
54/* Shortcuts can't be disabled so any unknown new ones need to be masked */
55#define SHORTCUT1_MASK 0x00007c00
56#define SHORTCUT2_MASK 0x001f8000
57#define SHORTCUT_SHIFT 10
58#define BANK1_HWIRQ BIT(8)
59#define BANK2_HWIRQ BIT(9)
60#define BANK0_VALID_MASK (BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \
61 | SHORTCUT1_MASK | SHORTCUT2_MASK)
62
63#define REG_FIQ_CONTROL 0x0c
64
65#define NR_BANKS 3
66#define IRQS_PER_BANK 32
67
68static const int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
69static const int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
70static const int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
71static const int bank_irqs[] __initconst = { 8, 32, 32 };
72
73static const int shortcuts[] = {
74 7, 9, 10, 18, 19, /* Bank 1 */
75 21, 22, 23, 24, 25, 30 /* Bank 2 */
76};
77
78struct armctrl_ic {
79 void __iomem *base;
80 void __iomem *pending[NR_BANKS];
81 void __iomem *enable[NR_BANKS];
82 void __iomem *disable[NR_BANKS];
83 struct irq_domain *domain;
84};
85
86static struct armctrl_ic intc __read_mostly;
87static void __exception_irq_entry bcm2835_handle_irq(
88 struct pt_regs *regs);
89static void bcm2836_chained_handle_irq(struct irq_desc *desc);
90
91static void armctrl_mask_irq(struct irq_data *d)
92{
93 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
94}
95
96static void armctrl_unmask_irq(struct irq_data *d)
97{
98 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
99}
100
101static struct irq_chip armctrl_chip = {
102 .name = "ARMCTRL-level",
103 .irq_mask = armctrl_mask_irq,
104 .irq_unmask = armctrl_unmask_irq
105};
106
107static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
108 const u32 *intspec, unsigned int intsize,
109 unsigned long *out_hwirq, unsigned int *out_type)
110{
111 if (WARN_ON(intsize != 2))
112 return -EINVAL;
113
114 if (WARN_ON(intspec[0] >= NR_BANKS))
115 return -EINVAL;
116
117 if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
118 return -EINVAL;
119
120 if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
121 return -EINVAL;
122
123 *out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
124 *out_type = IRQ_TYPE_NONE;
125 return 0;
126}
127
128static const struct irq_domain_ops armctrl_ops = {
129 .xlate = armctrl_xlate
130};
131
132static int __init armctrl_of_init(struct device_node *node,
133 struct device_node *parent,
134 bool is_2836)
135{
136 void __iomem *base;
137 int irq, b, i;
138
139 base = of_iomap(node, 0);
140 if (!base)
141 panic("%pOF: unable to map IC registers\n", node);
142
143 intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
144 &armctrl_ops, NULL);
145 if (!intc.domain)
146 panic("%pOF: unable to create IRQ domain\n", node);
147
148 for (b = 0; b < NR_BANKS; b++) {
149 intc.pending[b] = base + reg_pending[b];
150 intc.enable[b] = base + reg_enable[b];
151 intc.disable[b] = base + reg_disable[b];
152
153 for (i = 0; i < bank_irqs[b]; i++) {
154 irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
155 BUG_ON(irq <= 0);
156 irq_set_chip_and_handler(irq, &armctrl_chip,
157 handle_level_irq);
158 irq_set_probe(irq);
159 }
160 }
161
162 if (is_2836) {
163 int parent_irq = irq_of_parse_and_map(node, 0);
164
165 if (!parent_irq) {
166 panic("%pOF: unable to get parent interrupt.\n",
167 node);
168 }
169 irq_set_chained_handler(parent_irq, bcm2836_chained_handle_irq);
170 } else {
171 set_handle_irq(bcm2835_handle_irq);
172 }
173
174 return 0;
175}
176
177static int __init bcm2835_armctrl_of_init(struct device_node *node,
178 struct device_node *parent)
179{
180 return armctrl_of_init(node, parent, false);
181}
182
183static int __init bcm2836_armctrl_of_init(struct device_node *node,
184 struct device_node *parent)
185{
186 return armctrl_of_init(node, parent, true);
187}
188
189
190/*
191 * Handle each interrupt across the entire interrupt controller. This reads the
192 * status register before handling each interrupt, which is necessary given that
193 * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
194 */
195
196static u32 armctrl_translate_bank(int bank)
197{
198 u32 stat = readl_relaxed(intc.pending[bank]);
199
200 return MAKE_HWIRQ(bank, ffs(stat) - 1);
201}
202
203static u32 armctrl_translate_shortcut(int bank, u32 stat)
204{
205 return MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
206}
207
208static u32 get_next_armctrl_hwirq(void)
209{
210 u32 stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK;
211
212 if (stat == 0)
213 return ~0;
214 else if (stat & BANK0_HWIRQ_MASK)
215 return MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
216 else if (stat & SHORTCUT1_MASK)
217 return armctrl_translate_shortcut(1, stat & SHORTCUT1_MASK);
218 else if (stat & SHORTCUT2_MASK)
219 return armctrl_translate_shortcut(2, stat & SHORTCUT2_MASK);
220 else if (stat & BANK1_HWIRQ)
221 return armctrl_translate_bank(1);
222 else if (stat & BANK2_HWIRQ)
223 return armctrl_translate_bank(2);
224 else
225 BUG();
226}
227
228static void __exception_irq_entry bcm2835_handle_irq(
229 struct pt_regs *regs)
230{
231 u32 hwirq;
232
233 while ((hwirq = get_next_armctrl_hwirq()) != ~0)
234 handle_domain_irq(intc.domain, hwirq, regs);
235}
236
237static void bcm2836_chained_handle_irq(struct irq_desc *desc)
238{
239 u32 hwirq;
240
241 while ((hwirq = get_next_armctrl_hwirq()) != ~0)
242 generic_handle_irq(irq_linear_revmap(intc.domain, hwirq));
243}
244
245IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic",
246 bcm2835_armctrl_of_init);
247IRQCHIP_DECLARE(bcm2836_armctrl_ic, "brcm,bcm2836-armctrl-ic",
248 bcm2836_armctrl_of_init);
249

Warning: That file was not part of the compilation database. It may have many parsing errors.