1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Root interrupt controller for the BCM2836 (Raspberry Pi 2).
4 *
5 * Copyright 2015 Broadcom
6 */
7
8 #include <linux/cpu.h>
9 #include <linux/of_address.h>
10 #include <linux/of_irq.h>
11 #include <linux/irqchip.h>
12 #include <linux/irqdomain.h>
13 #include <linux/irqchip/irq-bcm2836.h>
14
15 #include <asm/exception.h>
16
17 struct bcm2836_arm_irqchip_intc {
18 struct irq_domain *domain;
19 void __iomem *base;
20 };
21
22 static struct bcm2836_arm_irqchip_intc intc __read_mostly;
23
bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,unsigned int bit,int cpu)24 static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
25 unsigned int bit,
26 int cpu)
27 {
28 void __iomem *reg = intc.base + reg_offset + 4 * cpu;
29
30 writel(readl(reg) & ~BIT(bit), reg);
31 }
32
bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,unsigned int bit,int cpu)33 static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
34 unsigned int bit,
35 int cpu)
36 {
37 void __iomem *reg = intc.base + reg_offset + 4 * cpu;
38
39 writel(readl(reg) | BIT(bit), reg);
40 }
41
bcm2836_arm_irqchip_mask_timer_irq(struct irq_data * d)42 static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
43 {
44 bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
45 d->hwirq - LOCAL_IRQ_CNTPSIRQ,
46 smp_processor_id());
47 }
48
bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data * d)49 static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
50 {
51 bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
52 d->hwirq - LOCAL_IRQ_CNTPSIRQ,
53 smp_processor_id());
54 }
55
56 static struct irq_chip bcm2836_arm_irqchip_timer = {
57 .name = "bcm2836-timer",
58 .irq_mask = bcm2836_arm_irqchip_mask_timer_irq,
59 .irq_unmask = bcm2836_arm_irqchip_unmask_timer_irq,
60 };
61
bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data * d)62 static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
63 {
64 writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
65 }
66
bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data * d)67 static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
68 {
69 writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
70 }
71
72 static struct irq_chip bcm2836_arm_irqchip_pmu = {
73 .name = "bcm2836-pmu",
74 .irq_mask = bcm2836_arm_irqchip_mask_pmu_irq,
75 .irq_unmask = bcm2836_arm_irqchip_unmask_pmu_irq,
76 };
77
bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data * d)78 static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
79 {
80 }
81
bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data * d)82 static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
83 {
84 }
85
86 static struct irq_chip bcm2836_arm_irqchip_gpu = {
87 .name = "bcm2836-gpu",
88 .irq_mask = bcm2836_arm_irqchip_mask_gpu_irq,
89 .irq_unmask = bcm2836_arm_irqchip_unmask_gpu_irq,
90 };
91
bcm2836_map(struct irq_domain * d,unsigned int irq,irq_hw_number_t hw)92 static int bcm2836_map(struct irq_domain *d, unsigned int irq,
93 irq_hw_number_t hw)
94 {
95 struct irq_chip *chip;
96
97 switch (hw) {
98 case LOCAL_IRQ_CNTPSIRQ:
99 case LOCAL_IRQ_CNTPNSIRQ:
100 case LOCAL_IRQ_CNTHPIRQ:
101 case LOCAL_IRQ_CNTVIRQ:
102 chip = &bcm2836_arm_irqchip_timer;
103 break;
104 case LOCAL_IRQ_GPU_FAST:
105 chip = &bcm2836_arm_irqchip_gpu;
106 break;
107 case LOCAL_IRQ_PMU_FAST:
108 chip = &bcm2836_arm_irqchip_pmu;
109 break;
110 default:
111 pr_warn_once("Unexpected hw irq: %lu\n", hw);
112 return -EINVAL;
113 }
114
115 irq_set_percpu_devid(irq);
116 irq_domain_set_info(d, irq, hw, chip, d->host_data,
117 handle_percpu_devid_irq, NULL, NULL);
118 irq_set_status_flags(irq, IRQ_NOAUTOEN);
119
120 return 0;
121 }
122
123 static void
bcm2836_arm_irqchip_handle_irq(struct pt_regs * regs)124 __exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
125 {
126 int cpu = smp_processor_id();
127 u32 stat;
128
129 stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
130 if (stat & BIT(LOCAL_IRQ_MAILBOX0)) {
131 #ifdef CONFIG_SMP
132 void __iomem *mailbox0 = (intc.base +
133 LOCAL_MAILBOX0_CLR0 + 16 * cpu);
134 u32 mbox_val = readl(mailbox0);
135 u32 ipi = ffs(mbox_val) - 1;
136
137 writel(1 << ipi, mailbox0);
138 handle_IPI(ipi, regs);
139 #endif
140 } else if (stat) {
141 u32 hwirq = ffs(stat) - 1;
142
143 handle_domain_irq(intc.domain, hwirq, regs);
144 }
145 }
146
147 #ifdef CONFIG_SMP
bcm2836_arm_irqchip_send_ipi(const struct cpumask * mask,unsigned int ipi)148 static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask,
149 unsigned int ipi)
150 {
151 int cpu;
152 void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;
153
154 /*
155 * Ensure that stores to normal memory are visible to the
156 * other CPUs before issuing the IPI.
157 */
158 smp_wmb();
159
160 for_each_cpu(cpu, mask) {
161 writel(1 << ipi, mailbox0_base + 16 * cpu);
162 }
163 }
164
bcm2836_cpu_starting(unsigned int cpu)165 static int bcm2836_cpu_starting(unsigned int cpu)
166 {
167 bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
168 cpu);
169 return 0;
170 }
171
bcm2836_cpu_dying(unsigned int cpu)172 static int bcm2836_cpu_dying(unsigned int cpu)
173 {
174 bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
175 cpu);
176 return 0;
177 }
178 #endif
179
180 static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
181 .xlate = irq_domain_xlate_onetwocell,
182 .map = bcm2836_map,
183 };
184
185 static void
bcm2836_arm_irqchip_smp_init(void)186 bcm2836_arm_irqchip_smp_init(void)
187 {
188 #ifdef CONFIG_SMP
189 /* Unmask IPIs to the boot CPU. */
190 cpuhp_setup_state(CPUHP_AP_IRQ_BCM2836_STARTING,
191 "irqchip/bcm2836:starting", bcm2836_cpu_starting,
192 bcm2836_cpu_dying);
193
194 set_smp_cross_call(bcm2836_arm_irqchip_send_ipi);
195 #endif
196 }
197
198 /*
199 * The LOCAL_IRQ_CNT* timer firings are based off of the external
200 * oscillator with some scaling. The firmware sets up CNTFRQ to
201 * report 19.2Mhz, but doesn't set up the scaling registers.
202 */
bcm2835_init_local_timer_frequency(void)203 static void bcm2835_init_local_timer_frequency(void)
204 {
205 /*
206 * Set the timer to source from the 19.2Mhz crystal clock (bit
207 * 8 unset), and only increment by 1 instead of 2 (bit 9
208 * unset).
209 */
210 writel(0, intc.base + LOCAL_CONTROL);
211
212 /*
213 * Set the timer prescaler to 1:1 (timer freq = input freq *
214 * 2**31 / prescaler)
215 */
216 writel(0x80000000, intc.base + LOCAL_PRESCALER);
217 }
218
bcm2836_arm_irqchip_l1_intc_of_init(struct device_node * node,struct device_node * parent)219 static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
220 struct device_node *parent)
221 {
222 intc.base = of_iomap(node, 0);
223 if (!intc.base) {
224 panic("%pOF: unable to map local interrupt registers\n", node);
225 }
226
227 bcm2835_init_local_timer_frequency();
228
229 intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
230 &bcm2836_arm_irqchip_intc_ops,
231 NULL);
232 if (!intc.domain)
233 panic("%pOF: unable to create IRQ domain\n", node);
234
235 bcm2836_arm_irqchip_smp_init();
236
237 set_handle_irq(bcm2836_arm_irqchip_handle_irq);
238 return 0;
239 }
240
241 IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
242 bcm2836_arm_irqchip_l1_intc_of_init);
243