drivers/irqchip/irq-bcm2836.c

   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
  24 #define LOCAL_CONTROL                   0x000
  25 #define LOCAL_PRESCALER                 0x008
  26
  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  * Mailbox 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 #define LOCAL_MAILBOX3_SET0             0x08c
  63 /* Mailbox write-to-clear bits. */
  64 #define LOCAL_MAILBOX0_CLR0             0x0c0
  65 #define LOCAL_MAILBOX3_CLR0             0x0cc
  66
  67 #define LOCAL_IRQ_CNTPSIRQ      0
  68 #define LOCAL_IRQ_CNTPNSIRQ     1
  69 #define LOCAL_IRQ_CNTHPIRQ      2
  70 #define LOCAL_IRQ_CNTVIRQ       3
  71 #define LOCAL_IRQ_MAILBOX0      4
  72 #define LOCAL_IRQ_MAILBOX1      5
  73 #define LOCAL_IRQ_MAILBOX2      6
  74 #define LOCAL_IRQ_MAILBOX3      7
  75 #define LOCAL_IRQ_GPU_FAST      8
  76 #define LOCAL_IRQ_PMU_FAST      9
  77 #define LAST_IRQ                LOCAL_IRQ_PMU_FAST
  78
  79 struct bcm2836_arm_irqchip_intc {
  80         struct irq_domain *domain;
  81         void __iomem *base;
  82 };
  83
  84 static struct bcm2836_arm_irqchip_intc intc  __read_mostly;
  85
  86 static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
  87                                                  unsigned int bit,
  88                                                  int cpu)
  89 {
  90         void __iomem *reg = intc.base + reg_offset + 4 * cpu;
  91
  92         writel(readl(reg) & ~BIT(bit), reg);
  93 }
  94
  95 static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
  96                                                    unsigned int bit,
  97                                                  int cpu)
  98 {
  99         void __iomem *reg = intc.base + reg_offset + 4 * cpu;
 100
 101         writel(readl(reg) | BIT(bit), reg);
 102 }
 103
 104 static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
 105 {
 106         bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
 107                                              d->hwirq - LOCAL_IRQ_CNTPSIRQ,
 108                                              smp_processor_id());
 109 }
 110
 111 static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
 112 {
 113         bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
 114                                                d->hwirq - LOCAL_IRQ_CNTPSIRQ,
 115                                                smp_processor_id());
 116 }
 117
 118 static struct irq_chip bcm2836_arm_irqchip_timer = {
 119         .name           = "bcm2836-timer",
 120         .irq_mask       = bcm2836_arm_irqchip_mask_timer_irq,
 121         .irq_unmask     = bcm2836_arm_irqchip_unmask_timer_irq,
 122 };
 123
 124 static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
 125 {
 126         writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
 127 }
 128
 129 static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
 130 {
 131         writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
 132 }
 133
 134 static struct irq_chip bcm2836_arm_irqchip_pmu = {
 135         .name           = "bcm2836-pmu",
 136         .irq_mask       = bcm2836_arm_irqchip_mask_pmu_irq,
 137         .irq_unmask     = bcm2836_arm_irqchip_unmask_pmu_irq,
 138 };
 139
 140 static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
 141 {
 142 }
 143
 144 static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
 145 {
 146 }
 147
 148 static struct irq_chip bcm2836_arm_irqchip_gpu = {
 149         .name           = "bcm2836-gpu",
 150         .irq_mask       = bcm2836_arm_irqchip_mask_gpu_irq,
 151         .irq_unmask     = bcm2836_arm_irqchip_unmask_gpu_irq,
 152 };
 153
 154 static void bcm2836_arm_irqchip_register_irq(int hwirq, struct irq_chip *chip)
 155 {
 156         int irq = irq_create_mapping(intc.domain, hwirq);
 157
 158         irq_set_percpu_devid(irq);
 159         irq_set_chip_and_handler(irq, chip, handle_percpu_devid_irq);
 160         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 161 }
 162
 163 static void
 164 __exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
 165 {
 166         int cpu = smp_processor_id();
 167         u32 stat;
 168
 169         stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
 170         if (stat & BIT(LOCAL_IRQ_MAILBOX0)) {
 171 #ifdef CONFIG_SMP
 172                 void __iomem *mailbox0 = (intc.base +
 173                                           LOCAL_MAILBOX0_CLR0 + 16 * cpu);
 174                 u32 mbox_val = readl(mailbox0);
 175                 u32 ipi = ffs(mbox_val) - 1;
 176
 177                 writel(1 << ipi, mailbox0);
 178                 handle_IPI(ipi, regs);
 179 #endif
 180         } else if (stat) {
 181                 u32 hwirq = ffs(stat) - 1;
 182
 183                 handle_IRQ(irq_linear_revmap(intc.domain, hwirq), regs);
 184         }
 185 }
 186
 187 #ifdef CONFIG_SMP
 188 static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask,
 189                                          unsigned int ipi)
 190 {
 191         int cpu;
 192         void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;
 193
 194         /*
 195          * Ensure that stores to normal memory are visible to the
 196          * other CPUs before issuing the IPI.
 197          */
 198         smp_wmb();
 199
 200         for_each_cpu(cpu, mask) {
 201                 writel(1 << ipi, mailbox0_base + 16 * cpu);
 202         }
 203 }
 204
 205 /* Unmasks the IPI on the CPU when it's online. */
 206 static int bcm2836_arm_irqchip_cpu_notify(struct notifier_block *nfb,
 207                                           unsigned long action, void *hcpu)
 208 {
 209         unsigned int cpu = (unsigned long)hcpu;
 210         unsigned int int_reg = LOCAL_MAILBOX_INT_CONTROL0;
 211         unsigned int mailbox = 0;
 212
 213         if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
 214                 bcm2836_arm_irqchip_unmask_per_cpu_irq(int_reg, mailbox, cpu);
 215         else if (action == CPU_DYING)
 216                 bcm2836_arm_irqchip_mask_per_cpu_irq(int_reg, mailbox, cpu);
 217
 218         return NOTIFY_OK;
 219 }
 220
 221 static struct notifier_block bcm2836_arm_irqchip_cpu_notifier = {
 222         .notifier_call = bcm2836_arm_irqchip_cpu_notify,
 223         .priority = 100,
 224 };
 225
 226 #ifdef CONFIG_ARM
 227 int __init bcm2836_smp_boot_secondary(unsigned int cpu,
 228                                       struct task_struct *idle)
 229 {
 230         unsigned long secondary_startup_phys =
 231                 (unsigned long)virt_to_phys((void *)secondary_startup);
 232
 233         writel(secondary_startup_phys,
 234                intc.base + LOCAL_MAILBOX3_SET0 + 16 * cpu);
 235
 236         return 0;
 237 }
 238
 239 static const struct smp_operations bcm2836_smp_ops __initconst = {
 240         .smp_boot_secondary     = bcm2836_smp_boot_secondary,
 241 };
 242 #endif
 243 #endif
 244
 245 static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
 246         .xlate = irq_domain_xlate_onecell
 247 };
 248
 249 static void
 250 bcm2836_arm_irqchip_smp_init(void)
 251 {
 252 #ifdef CONFIG_SMP
 253         /* Unmask IPIs to the boot CPU. */
 254         bcm2836_arm_irqchip_cpu_notify(&bcm2836_arm_irqchip_cpu_notifier,
 255                                        CPU_STARTING,
 256                                        (void *)(uintptr_t)smp_processor_id());
 257         register_cpu_notifier(&bcm2836_arm_irqchip_cpu_notifier);
 258
 259         set_smp_cross_call(bcm2836_arm_irqchip_send_ipi);
 260
 261 #ifdef CONFIG_ARM
 262         smp_set_ops(&bcm2836_smp_ops);
 263 #endif
 264 #endif
 265 }
 266
 267 /*
 268  * The LOCAL_IRQ_CNT* timer firings are based off of the external
 269  * oscillator with some scaling.  The firmware sets up CNTFRQ to
 270  * report 19.2Mhz, but doesn't set up the scaling registers.
 271  */
 272 static void bcm2835_init_local_timer_frequency(void)
 273 {
 274         /*
 275          * Set the timer to source from the 19.2Mhz crystal clock (bit
 276          * 8 unset), and only increment by 1 instead of 2 (bit 9
 277          * unset).
 278          */
 279         writel(0, intc.base + LOCAL_CONTROL);
 280
 281         /*
 282          * Set the timer prescaler to 1:1 (timer freq = input freq *
 283          * 2**31 / prescaler)
 284          */
 285         writel(0x80000000, intc.base + LOCAL_PRESCALER);
 286 }
 287
 288 static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
 289                                                       struct device_node *parent)
 290 {
 291         intc.base = of_iomap(node, 0);
 292         if (!intc.base) {
 293                 panic("%s: unable to map local interrupt registers\n",
 294                         node->full_name);
 295         }
 296
 297         bcm2835_init_local_timer_frequency();
 298
 299         intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
 300                                             &bcm2836_arm_irqchip_intc_ops,
 301                                             NULL);
 302         if (!intc.domain)
 303                 panic("%s: unable to create IRQ domain\n", node->full_name);
 304
 305         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPSIRQ,
 306                                          &bcm2836_arm_irqchip_timer);
 307         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPNSIRQ,
 308                                          &bcm2836_arm_irqchip_timer);
 309         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTHPIRQ,
 310                                          &bcm2836_arm_irqchip_timer);
 311         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTVIRQ,
 312                                          &bcm2836_arm_irqchip_timer);
 313         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_GPU_FAST,
 314                                          &bcm2836_arm_irqchip_gpu);
 315         bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_PMU_FAST,
 316                                          &bcm2836_arm_irqchip_pmu);
 317
 318         bcm2836_arm_irqchip_smp_init();
 319
 320         set_handle_irq(bcm2836_arm_irqchip_handle_irq);
 321         return 0;
 322 }
 323
 324 IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
 325                 bcm2836_arm_irqchip_l1_intc_of_init);