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 #define FIQ_CONTROL_ENABLE BIT(7)
65
66 #define NR_BANKS 3
67 #define IRQS_PER_BANK 32
68
69 static const int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
70 static const int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
71 static const int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 };
72 static const int bank_irqs[] __initconst = { 8, 32, 32 };
73
74 static const int shortcuts[] = {
75 7, 9, 10, 18, 19, /* Bank 1 */
76 21, 22, 23, 24, 25, 30 /* Bank 2 */
77 };
78
79 struct armctrl_ic {
80 void __iomem *base;
81 void __iomem *pending[NR_BANKS];
82 void __iomem *enable[NR_BANKS];
83 void __iomem *disable[NR_BANKS];
84 struct irq_domain *domain;
85 };
86
87 static struct armctrl_ic intc __read_mostly;
88 static void __exception_irq_entry bcm2835_handle_irq(
89 struct pt_regs *regs);
90 static void bcm2836_chained_handle_irq(struct irq_desc *desc);
91
armctrl_mask_irq(struct irq_data * d)92 static void armctrl_mask_irq(struct irq_data *d)
93 {
94 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
95 }
96
armctrl_unmask_irq(struct irq_data * d)97 static void armctrl_unmask_irq(struct irq_data *d)
98 {
99 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
100 }
101
102 static struct irq_chip armctrl_chip = {
103 .name = "ARMCTRL-level",
104 .irq_mask = armctrl_mask_irq,
105 .irq_unmask = armctrl_unmask_irq
106 };
107
armctrl_xlate(struct irq_domain * d,struct device_node * ctrlr,const u32 * intspec,unsigned int intsize,unsigned long * out_hwirq,unsigned int * out_type)108 static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr,
109 const u32 *intspec, unsigned int intsize,
110 unsigned long *out_hwirq, unsigned int *out_type)
111 {
112 if (WARN_ON(intsize != 2))
113 return -EINVAL;
114
115 if (WARN_ON(intspec[0] >= NR_BANKS))
116 return -EINVAL;
117
118 if (WARN_ON(intspec[1] >= IRQS_PER_BANK))
119 return -EINVAL;
120
121 if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0))
122 return -EINVAL;
123
124 *out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]);
125 *out_type = IRQ_TYPE_NONE;
126 return 0;
127 }
128
129 static const struct irq_domain_ops armctrl_ops = {
130 .xlate = armctrl_xlate
131 };
132
armctrl_of_init(struct device_node * node,struct device_node * parent,bool is_2836)133 static int __init armctrl_of_init(struct device_node *node,
134 struct device_node *parent,
135 bool is_2836)
136 {
137 void __iomem *base;
138 int irq, b, i;
139 u32 reg;
140
141 base = of_iomap(node, 0);
142 if (!base)
143 panic("%pOF: unable to map IC registers\n", node);
144
145 intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
146 &armctrl_ops, NULL);
147 if (!intc.domain)
148 panic("%pOF: unable to create IRQ domain\n", node);
149
150 for (b = 0; b < NR_BANKS; b++) {
151 intc.pending[b] = base + reg_pending[b];
152 intc.enable[b] = base + reg_enable[b];
153 intc.disable[b] = base + reg_disable[b];
154
155 for (i = 0; i < bank_irqs[b]; i++) {
156 irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i));
157 BUG_ON(irq <= 0);
158 irq_set_chip_and_handler(irq, &armctrl_chip,
159 handle_level_irq);
160 irq_set_probe(irq);
161 }
162
163 reg = readl_relaxed(intc.enable[b]);
164 if (reg) {
165 writel_relaxed(reg, intc.disable[b]);
166 pr_err(FW_BUG "Bootloader left irq enabled: "
167 "bank %d irq %*pbl\n", b, IRQS_PER_BANK, ®);
168 }
169 }
170
171 reg = readl_relaxed(base + REG_FIQ_CONTROL);
172 if (reg & FIQ_CONTROL_ENABLE) {
173 writel_relaxed(0, base + REG_FIQ_CONTROL);
174 pr_err(FW_BUG "Bootloader left fiq enabled\n");
175 }
176
177 if (is_2836) {
178 int parent_irq = irq_of_parse_and_map(node, 0);
179
180 if (!parent_irq) {
181 panic("%pOF: unable to get parent interrupt.\n",
182 node);
183 }
184 irq_set_chained_handler(parent_irq, bcm2836_chained_handle_irq);
185 } else {
186 set_handle_irq(bcm2835_handle_irq);
187 }
188
189 return 0;
190 }
191
bcm2835_armctrl_of_init(struct device_node * node,struct device_node * parent)192 static int __init bcm2835_armctrl_of_init(struct device_node *node,
193 struct device_node *parent)
194 {
195 return armctrl_of_init(node, parent, false);
196 }
197
bcm2836_armctrl_of_init(struct device_node * node,struct device_node * parent)198 static int __init bcm2836_armctrl_of_init(struct device_node *node,
199 struct device_node *parent)
200 {
201 return armctrl_of_init(node, parent, true);
202 }
203
204
205 /*
206 * Handle each interrupt across the entire interrupt controller. This reads the
207 * status register before handling each interrupt, which is necessary given that
208 * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.
209 */
210
armctrl_translate_bank(int bank)211 static u32 armctrl_translate_bank(int bank)
212 {
213 u32 stat = readl_relaxed(intc.pending[bank]);
214
215 return MAKE_HWIRQ(bank, ffs(stat) - 1);
216 }
217
armctrl_translate_shortcut(int bank,u32 stat)218 static u32 armctrl_translate_shortcut(int bank, u32 stat)
219 {
220 return MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]);
221 }
222
get_next_armctrl_hwirq(void)223 static u32 get_next_armctrl_hwirq(void)
224 {
225 u32 stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK;
226
227 if (stat == 0)
228 return ~0;
229 else if (stat & BANK0_HWIRQ_MASK)
230 return MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1);
231 else if (stat & SHORTCUT1_MASK)
232 return armctrl_translate_shortcut(1, stat & SHORTCUT1_MASK);
233 else if (stat & SHORTCUT2_MASK)
234 return armctrl_translate_shortcut(2, stat & SHORTCUT2_MASK);
235 else if (stat & BANK1_HWIRQ)
236 return armctrl_translate_bank(1);
237 else if (stat & BANK2_HWIRQ)
238 return armctrl_translate_bank(2);
239 else
240 BUG();
241 }
242
bcm2835_handle_irq(struct pt_regs * regs)243 static void __exception_irq_entry bcm2835_handle_irq(
244 struct pt_regs *regs)
245 {
246 u32 hwirq;
247
248 while ((hwirq = get_next_armctrl_hwirq()) != ~0)
249 generic_handle_domain_irq(intc.domain, hwirq);
250 }
251
bcm2836_chained_handle_irq(struct irq_desc * desc)252 static void bcm2836_chained_handle_irq(struct irq_desc *desc)
253 {
254 u32 hwirq;
255
256 while ((hwirq = get_next_armctrl_hwirq()) != ~0)
257 generic_handle_domain_irq(intc.domain, hwirq);
258 }
259
260 IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic",
261 bcm2835_armctrl_of_init);
262 IRQCHIP_DECLARE(bcm2836_armctrl_ic, "brcm,bcm2836-armctrl-ic",
263 bcm2836_armctrl_of_init);
264