Eric Anholt | 1a15aaa | 2015-08-06 16:00:33 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Root interrupt controller for the BCM2836 (Raspberry Pi 2). |
| 3 | * |
| 4 | * Copyright 2015 Broadcom |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation; either version 2 of the License, or |
| 9 | * (at your option) any later version. |
| 10 | * |
| 11 | * This program is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | * GNU General Public License for more details. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/cpu.h> |
| 18 | #include <linux/of_address.h> |
| 19 | #include <linux/of_irq.h> |
| 20 | #include <linux/irqchip.h> |
| 21 | #include <linux/irqdomain.h> |
| 22 | #include <asm/exception.h> |
| 23 | |
Eric Anholt | 401667b | 2015-12-26 13:47:21 -0800 | [diff] [blame^] | 24 | #define LOCAL_CONTROL 0x000 |
| 25 | #define LOCAL_PRESCALER 0x008 |
| 26 | |
Eric Anholt | 1a15aaa | 2015-08-06 16:00:33 -0700 | [diff] [blame] | 27 | /* |
| 28 | * The low 2 bits identify the CPU that the GPU IRQ goes to, and the |
| 29 | * next 2 bits identify the CPU that the GPU FIQ goes to. |
| 30 | */ |
| 31 | #define LOCAL_GPU_ROUTING 0x00c |
| 32 | /* When setting bits 0-3, enables PMU interrupts on that CPU. */ |
| 33 | #define LOCAL_PM_ROUTING_SET 0x010 |
| 34 | /* When setting bits 0-3, disables PMU interrupts on that CPU. */ |
| 35 | #define LOCAL_PM_ROUTING_CLR 0x014 |
| 36 | /* |
| 37 | * The low 4 bits of this are the CPU's timer IRQ enables, and the |
| 38 | * next 4 bits are the CPU's timer FIQ enables (which override the IRQ |
| 39 | * bits). |
| 40 | */ |
| 41 | #define LOCAL_TIMER_INT_CONTROL0 0x040 |
| 42 | /* |
| 43 | * The low 4 bits of this are the CPU's per-mailbox IRQ enables, and |
| 44 | * the next 4 bits are the CPU's per-mailbox FIQ enables (which |
| 45 | * override the IRQ bits). |
| 46 | */ |
| 47 | #define LOCAL_MAILBOX_INT_CONTROL0 0x050 |
| 48 | /* |
| 49 | * The CPU's interrupt status register. Bits are defined by the the |
| 50 | * LOCAL_IRQ_* bits below. |
| 51 | */ |
| 52 | #define LOCAL_IRQ_PENDING0 0x060 |
| 53 | /* Same status bits as above, but for FIQ. */ |
| 54 | #define LOCAL_FIQ_PENDING0 0x070 |
| 55 | /* |
| 56 | * Mailbox0 write-to-set bits. There are 16 mailboxes, 4 per CPU, and |
| 57 | * these bits are organized by mailbox number and then CPU number. We |
| 58 | * use mailbox 0 for IPIs. The mailbox's interrupt is raised while |
| 59 | * any bit is set. |
| 60 | */ |
| 61 | #define LOCAL_MAILBOX0_SET0 0x080 |
| 62 | /* Mailbox0 write-to-clear bits. */ |
| 63 | #define LOCAL_MAILBOX0_CLR0 0x0c0 |
| 64 | |
| 65 | #define LOCAL_IRQ_CNTPSIRQ 0 |
| 66 | #define LOCAL_IRQ_CNTPNSIRQ 1 |
| 67 | #define LOCAL_IRQ_CNTHPIRQ 2 |
| 68 | #define LOCAL_IRQ_CNTVIRQ 3 |
| 69 | #define LOCAL_IRQ_MAILBOX0 4 |
| 70 | #define LOCAL_IRQ_MAILBOX1 5 |
| 71 | #define LOCAL_IRQ_MAILBOX2 6 |
| 72 | #define LOCAL_IRQ_MAILBOX3 7 |
| 73 | #define LOCAL_IRQ_GPU_FAST 8 |
| 74 | #define LOCAL_IRQ_PMU_FAST 9 |
| 75 | #define LAST_IRQ LOCAL_IRQ_PMU_FAST |
| 76 | |
| 77 | struct bcm2836_arm_irqchip_intc { |
| 78 | struct irq_domain *domain; |
| 79 | void __iomem *base; |
| 80 | }; |
| 81 | |
| 82 | static struct bcm2836_arm_irqchip_intc intc __read_mostly; |
| 83 | |
| 84 | static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset, |
| 85 | unsigned int bit, |
| 86 | int cpu) |
| 87 | { |
| 88 | void __iomem *reg = intc.base + reg_offset + 4 * cpu; |
| 89 | |
| 90 | writel(readl(reg) & ~BIT(bit), reg); |
| 91 | } |
| 92 | |
| 93 | static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset, |
| 94 | unsigned int bit, |
| 95 | int cpu) |
| 96 | { |
| 97 | void __iomem *reg = intc.base + reg_offset + 4 * cpu; |
| 98 | |
| 99 | writel(readl(reg) | BIT(bit), reg); |
| 100 | } |
| 101 | |
| 102 | static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d) |
| 103 | { |
| 104 | bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0, |
| 105 | d->hwirq - LOCAL_IRQ_CNTPSIRQ, |
| 106 | smp_processor_id()); |
| 107 | } |
| 108 | |
| 109 | static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d) |
| 110 | { |
| 111 | bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0, |
| 112 | d->hwirq - LOCAL_IRQ_CNTPSIRQ, |
| 113 | smp_processor_id()); |
| 114 | } |
| 115 | |
| 116 | static struct irq_chip bcm2836_arm_irqchip_timer = { |
| 117 | .name = "bcm2836-timer", |
| 118 | .irq_mask = bcm2836_arm_irqchip_mask_timer_irq, |
| 119 | .irq_unmask = bcm2836_arm_irqchip_unmask_timer_irq, |
| 120 | }; |
| 121 | |
| 122 | static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d) |
| 123 | { |
| 124 | writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR); |
| 125 | } |
| 126 | |
| 127 | static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d) |
| 128 | { |
| 129 | writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET); |
| 130 | } |
| 131 | |
| 132 | static struct irq_chip bcm2836_arm_irqchip_pmu = { |
| 133 | .name = "bcm2836-pmu", |
| 134 | .irq_mask = bcm2836_arm_irqchip_mask_pmu_irq, |
| 135 | .irq_unmask = bcm2836_arm_irqchip_unmask_pmu_irq, |
| 136 | }; |
| 137 | |
| 138 | static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d) |
| 139 | { |
| 140 | } |
| 141 | |
| 142 | static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d) |
| 143 | { |
| 144 | } |
| 145 | |
| 146 | static struct irq_chip bcm2836_arm_irqchip_gpu = { |
| 147 | .name = "bcm2836-gpu", |
| 148 | .irq_mask = bcm2836_arm_irqchip_mask_gpu_irq, |
| 149 | .irq_unmask = bcm2836_arm_irqchip_unmask_gpu_irq, |
| 150 | }; |
| 151 | |
| 152 | static void bcm2836_arm_irqchip_register_irq(int hwirq, struct irq_chip *chip) |
| 153 | { |
| 154 | int irq = irq_create_mapping(intc.domain, hwirq); |
| 155 | |
| 156 | irq_set_percpu_devid(irq); |
| 157 | irq_set_chip_and_handler(irq, chip, handle_percpu_devid_irq); |
| 158 | irq_set_status_flags(irq, IRQ_NOAUTOEN); |
| 159 | } |
| 160 | |
| 161 | static void |
| 162 | __exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs) |
| 163 | { |
| 164 | int cpu = smp_processor_id(); |
| 165 | u32 stat; |
| 166 | |
| 167 | stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu); |
| 168 | if (stat & 0x10) { |
| 169 | #ifdef CONFIG_SMP |
| 170 | void __iomem *mailbox0 = (intc.base + |
| 171 | LOCAL_MAILBOX0_CLR0 + 16 * cpu); |
| 172 | u32 mbox_val = readl(mailbox0); |
| 173 | u32 ipi = ffs(mbox_val) - 1; |
| 174 | |
| 175 | writel(1 << ipi, mailbox0); |
| 176 | handle_IPI(ipi, regs); |
| 177 | #endif |
| 178 | } else { |
| 179 | u32 hwirq = ffs(stat) - 1; |
| 180 | |
| 181 | handle_IRQ(irq_linear_revmap(intc.domain, hwirq), regs); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | #ifdef CONFIG_SMP |
| 186 | static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask, |
| 187 | unsigned int ipi) |
| 188 | { |
| 189 | int cpu; |
| 190 | void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0; |
| 191 | |
| 192 | /* |
| 193 | * Ensure that stores to normal memory are visible to the |
| 194 | * other CPUs before issuing the IPI. |
| 195 | */ |
| 196 | dsb(); |
| 197 | |
| 198 | for_each_cpu(cpu, mask) { |
| 199 | writel(1 << ipi, mailbox0_base + 16 * cpu); |
| 200 | } |
| 201 | } |
| 202 | |
| 203 | /* Unmasks the IPI on the CPU when it's online. */ |
| 204 | static int bcm2836_arm_irqchip_cpu_notify(struct notifier_block *nfb, |
| 205 | unsigned long action, void *hcpu) |
| 206 | { |
| 207 | unsigned int cpu = (unsigned long)hcpu; |
| 208 | unsigned int int_reg = LOCAL_MAILBOX_INT_CONTROL0; |
| 209 | unsigned int mailbox = 0; |
| 210 | |
| 211 | if (action == CPU_STARTING || action == CPU_STARTING_FROZEN) |
| 212 | bcm2836_arm_irqchip_unmask_per_cpu_irq(int_reg, mailbox, cpu); |
| 213 | else if (action == CPU_DYING) |
| 214 | bcm2836_arm_irqchip_mask_per_cpu_irq(int_reg, mailbox, cpu); |
| 215 | |
| 216 | return NOTIFY_OK; |
| 217 | } |
| 218 | |
| 219 | static struct notifier_block bcm2836_arm_irqchip_cpu_notifier = { |
| 220 | .notifier_call = bcm2836_arm_irqchip_cpu_notify, |
| 221 | .priority = 100, |
| 222 | }; |
| 223 | #endif |
| 224 | |
| 225 | static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = { |
| 226 | .xlate = irq_domain_xlate_onecell |
| 227 | }; |
| 228 | |
| 229 | static void |
| 230 | bcm2836_arm_irqchip_smp_init(void) |
| 231 | { |
| 232 | #ifdef CONFIG_SMP |
| 233 | /* Unmask IPIs to the boot CPU. */ |
| 234 | bcm2836_arm_irqchip_cpu_notify(&bcm2836_arm_irqchip_cpu_notifier, |
| 235 | CPU_STARTING, |
| 236 | (void *)smp_processor_id()); |
| 237 | register_cpu_notifier(&bcm2836_arm_irqchip_cpu_notifier); |
| 238 | |
| 239 | set_smp_cross_call(bcm2836_arm_irqchip_send_ipi); |
| 240 | #endif |
| 241 | } |
| 242 | |
Eric Anholt | 401667b | 2015-12-26 13:47:21 -0800 | [diff] [blame^] | 243 | /* |
| 244 | * The LOCAL_IRQ_CNT* timer firings are based off of the external |
| 245 | * oscillator with some scaling. The firmware sets up CNTFRQ to |
| 246 | * report 19.2Mhz, but doesn't set up the scaling registers. |
| 247 | */ |
| 248 | static void bcm2835_init_local_timer_frequency(void) |
| 249 | { |
| 250 | /* |
| 251 | * Set the timer to source from the 19.2Mhz crystal clock (bit |
| 252 | * 8 unset), and only increment by 1 instead of 2 (bit 9 |
| 253 | * unset). |
| 254 | */ |
| 255 | writel(0, intc.base + LOCAL_CONTROL); |
| 256 | |
| 257 | /* |
| 258 | * Set the timer prescaler to 1:1 (timer freq = input freq * |
| 259 | * 2**31 / prescaler) |
| 260 | */ |
| 261 | writel(0x80000000, intc.base + LOCAL_PRESCALER); |
| 262 | } |
| 263 | |
Eric Anholt | 1a15aaa | 2015-08-06 16:00:33 -0700 | [diff] [blame] | 264 | static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node, |
| 265 | struct device_node *parent) |
| 266 | { |
| 267 | intc.base = of_iomap(node, 0); |
| 268 | if (!intc.base) { |
| 269 | panic("%s: unable to map local interrupt registers\n", |
| 270 | node->full_name); |
| 271 | } |
| 272 | |
Eric Anholt | 401667b | 2015-12-26 13:47:21 -0800 | [diff] [blame^] | 273 | bcm2835_init_local_timer_frequency(); |
| 274 | |
Eric Anholt | 1a15aaa | 2015-08-06 16:00:33 -0700 | [diff] [blame] | 275 | intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1, |
| 276 | &bcm2836_arm_irqchip_intc_ops, |
| 277 | NULL); |
| 278 | if (!intc.domain) |
| 279 | panic("%s: unable to create IRQ domain\n", node->full_name); |
| 280 | |
| 281 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPSIRQ, |
| 282 | &bcm2836_arm_irqchip_timer); |
| 283 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPNSIRQ, |
| 284 | &bcm2836_arm_irqchip_timer); |
| 285 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTHPIRQ, |
| 286 | &bcm2836_arm_irqchip_timer); |
| 287 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTVIRQ, |
| 288 | &bcm2836_arm_irqchip_timer); |
| 289 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_GPU_FAST, |
| 290 | &bcm2836_arm_irqchip_gpu); |
| 291 | bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_PMU_FAST, |
| 292 | &bcm2836_arm_irqchip_pmu); |
| 293 | |
| 294 | bcm2836_arm_irqchip_smp_init(); |
| 295 | |
| 296 | set_handle_irq(bcm2836_arm_irqchip_handle_irq); |
| 297 | return 0; |
| 298 | } |
| 299 | |
| 300 | IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc", |
| 301 | bcm2836_arm_irqchip_l1_intc_of_init); |