drivers/irqchip/irq-bcm2836.c

   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/chained_irq.h>
  14 #include <linux/irqchip/irq-bcm2836.h>
  15
  16 #include <asm/exception.h>
  17
  18 struct bcm2836_arm_irqchip_intc {
  19         struct irq_domain *domain;
  20         void __iomem *base;
  21 };
  22
  23 static struct bcm2836_arm_irqchip_intc intc  __read_mostly;
  24
  25 static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
  26                                                  unsigned int bit,
  27                                                  int cpu)
  28 {
  29         void __iomem *reg = intc.base + reg_offset + 4 * cpu;
  30
  31         writel(readl(reg) & ~BIT(bit), reg);
  32 }
  33
  34 static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
  35                                                    unsigned int bit,
  36                                                  int cpu)
  37 {
  38         void __iomem *reg = intc.base + reg_offset + 4 * cpu;
  39
  40         writel(readl(reg) | BIT(bit), reg);
  41 }
  42
  43 static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
  44 {
  45         bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
  46                                              d->hwirq - LOCAL_IRQ_CNTPSIRQ,
  47                                              smp_processor_id());
  48 }
  49
  50 static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
  51 {
  52         bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
  53                                                d->hwirq - LOCAL_IRQ_CNTPSIRQ,
  54                                                smp_processor_id());
  55 }
  56
  57 static struct irq_chip bcm2836_arm_irqchip_timer = {
  58         .name           = "bcm2836-timer",
  59         .irq_mask       = bcm2836_arm_irqchip_mask_timer_irq,
  60         .irq_unmask     = bcm2836_arm_irqchip_unmask_timer_irq,
  61 };
  62
  63 static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
  64 {
  65         writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
  66 }
  67
  68 static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
  69 {
  70         writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
  71 }
  72
  73 static struct irq_chip bcm2836_arm_irqchip_pmu = {
  74         .name           = "bcm2836-pmu",
  75         .irq_mask       = bcm2836_arm_irqchip_mask_pmu_irq,
  76         .irq_unmask     = bcm2836_arm_irqchip_unmask_pmu_irq,
  77 };
  78
  79 static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
  80 {
  81 }
  82
  83 static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
  84 {
  85 }
  86
  87 static struct irq_chip bcm2836_arm_irqchip_gpu = {
  88         .name           = "bcm2836-gpu",
  89         .irq_mask       = bcm2836_arm_irqchip_mask_gpu_irq,
  90         .irq_unmask     = bcm2836_arm_irqchip_unmask_gpu_irq,
  91 };
  92
  93 static void bcm2836_arm_irqchip_dummy_op(struct irq_data *d)
  94 {
  95 }
  96
  97 static struct irq_chip bcm2836_arm_irqchip_dummy = {
  98         .name           = "bcm2836-dummy",
  99         .irq_eoi        = bcm2836_arm_irqchip_dummy_op,
 100 };
 101
 102 static int bcm2836_map(struct irq_domain *d, unsigned int irq,
 103                        irq_hw_number_t hw)
 104 {
 105         struct irq_chip *chip;
 106
 107         switch (hw) {
 108         case LOCAL_IRQ_MAILBOX0:
 109                 chip = &bcm2836_arm_irqchip_dummy;
 110                 break;
 111         case LOCAL_IRQ_CNTPSIRQ:
 112         case LOCAL_IRQ_CNTPNSIRQ:
 113         case LOCAL_IRQ_CNTHPIRQ:
 114         case LOCAL_IRQ_CNTVIRQ:
 115                 chip = &bcm2836_arm_irqchip_timer;
 116                 break;
 117         case LOCAL_IRQ_GPU_FAST:
 118                 chip = &bcm2836_arm_irqchip_gpu;
 119                 break;
 120         case LOCAL_IRQ_PMU_FAST:
 121                 chip = &bcm2836_arm_irqchip_pmu;
 122                 break;
 123         default:
 124                 pr_warn_once("Unexpected hw irq: %lu\n", hw);
 125                 return -EINVAL;
 126         }
 127
 128         irq_set_percpu_devid(irq);
 129         irq_domain_set_info(d, irq, hw, chip, d->host_data,
 130                             handle_percpu_devid_irq, NULL, NULL);
 131         irq_set_status_flags(irq, IRQ_NOAUTOEN);
 132
 133         return 0;
 134 }
 135
 136 static void
 137 __exception_irq_entry bcm2836_arm_irqchip_handle_irq(struct pt_regs *regs)
 138 {
 139         int cpu = smp_processor_id();
 140         u32 stat;
 141
 142         stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
 143         if (stat) {
 144                 u32 hwirq = ffs(stat) - 1;
 145
 146                 handle_domain_irq(intc.domain, hwirq, regs);
 147         }
 148 }
 149
 150 #ifdef CONFIG_SMP
 151 static struct irq_domain *ipi_domain;
 152
 153 static void bcm2836_arm_irqchip_handle_ipi(struct irq_desc *desc)
 154 {
 155         struct irq_chip *chip = irq_desc_get_chip(desc);
 156         int cpu = smp_processor_id();
 157         u32 mbox_val;
 158
 159         chained_irq_enter(chip, desc);
 160
 161         mbox_val = readl_relaxed(intc.base + LOCAL_MAILBOX0_CLR0 + 16 * cpu);
 162         if (mbox_val) {
 163                 int hwirq = ffs(mbox_val) - 1;
 164                 generic_handle_domain_irq(ipi_domain, hwirq);
 165         }
 166
 167         chained_irq_exit(chip, desc);
 168 }
 169
 170 static void bcm2836_arm_irqchip_ipi_ack(struct irq_data *d)
 171 {
 172         int cpu = smp_processor_id();
 173
 174         writel_relaxed(BIT(d->hwirq),
 175                        intc.base + LOCAL_MAILBOX0_CLR0 + 16 * cpu);
 176 }
 177
 178 static void bcm2836_arm_irqchip_ipi_send_mask(struct irq_data *d,
 179                                               const struct cpumask *mask)
 180 {
 181         int cpu;
 182         void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;
 183
 184         /*
 185          * Ensure that stores to normal memory are visible to the
 186          * other CPUs before issuing the IPI.
 187          */
 188         smp_wmb();
 189
 190         for_each_cpu(cpu, mask)
 191                 writel_relaxed(BIT(d->hwirq), mailbox0_base + 16 * cpu);
 192 }
 193
 194 static struct irq_chip bcm2836_arm_irqchip_ipi = {
 195         .name           = "IPI",
 196         .irq_mask       = bcm2836_arm_irqchip_dummy_op,
 197         .irq_unmask     = bcm2836_arm_irqchip_dummy_op,
 198         .irq_ack        = bcm2836_arm_irqchip_ipi_ack,
 199         .ipi_send_mask  = bcm2836_arm_irqchip_ipi_send_mask,
 200 };
 201
 202 static int bcm2836_arm_irqchip_ipi_alloc(struct irq_domain *d,
 203                                          unsigned int virq,
 204                                          unsigned int nr_irqs, void *args)
 205 {
 206         int i;
 207
 208         for (i = 0; i < nr_irqs; i++) {
 209                 irq_set_percpu_devid(virq + i);
 210                 irq_domain_set_info(d, virq + i, i, &bcm2836_arm_irqchip_ipi,
 211                                     d->host_data,
 212                                     handle_percpu_devid_irq,
 213                                     NULL, NULL);
 214         }
 215
 216         return 0;
 217 }
 218
 219 static void bcm2836_arm_irqchip_ipi_free(struct irq_domain *d,
 220                                          unsigned int virq,
 221                                          unsigned int nr_irqs)
 222 {
 223         /* Not freeing IPIs */
 224 }
 225
 226 static const struct irq_domain_ops ipi_domain_ops = {
 227         .alloc  = bcm2836_arm_irqchip_ipi_alloc,
 228         .free   = bcm2836_arm_irqchip_ipi_free,
 229 };
 230
 231 static int bcm2836_cpu_starting(unsigned int cpu)
 232 {
 233         bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
 234                                                cpu);
 235         return 0;
 236 }
 237
 238 static int bcm2836_cpu_dying(unsigned int cpu)
 239 {
 240         bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
 241                                              cpu);
 242         return 0;
 243 }
 244
 245 #define BITS_PER_MBOX   32
 246
 247 static void __init bcm2836_arm_irqchip_smp_init(void)
 248 {
 249         struct irq_fwspec ipi_fwspec = {
 250                 .fwnode         = intc.domain->fwnode,
 251                 .param_count    = 1,
 252                 .param          = {
 253                         [0]     = LOCAL_IRQ_MAILBOX0,
 254                 },
 255         };
 256         int base_ipi, mux_irq;
 257
 258         mux_irq = irq_create_fwspec_mapping(&ipi_fwspec);
 259         if (WARN_ON(mux_irq <= 0))
 260                 return;
 261
 262         ipi_domain = irq_domain_create_linear(intc.domain->fwnode,
 263                                               BITS_PER_MBOX, &ipi_domain_ops,
 264                                               NULL);
 265         if (WARN_ON(!ipi_domain))
 266                 return;
 267
 268         ipi_domain->flags |= IRQ_DOMAIN_FLAG_IPI_SINGLE;
 269         irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
 270
 271         base_ipi = __irq_domain_alloc_irqs(ipi_domain, -1, BITS_PER_MBOX,
 272                                            NUMA_NO_NODE, NULL,
 273                                            false, NULL);
 274
 275         if (WARN_ON(!base_ipi))
 276                 return;
 277
 278         set_smp_ipi_range(base_ipi, BITS_PER_MBOX);
 279
 280         irq_set_chained_handler_and_data(mux_irq,
 281                                          bcm2836_arm_irqchip_handle_ipi, NULL);
 282
 283         /* Unmask IPIs to the boot CPU. */
 284         cpuhp_setup_state(CPUHP_AP_IRQ_BCM2836_STARTING,
 285                           "irqchip/bcm2836:starting", bcm2836_cpu_starting,
 286                           bcm2836_cpu_dying);
 287 }
 288 #else
 289 #define bcm2836_arm_irqchip_smp_init()  do { } while(0)
 290 #endif
 291
 292 static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
 293         .xlate = irq_domain_xlate_onetwocell,
 294         .map = bcm2836_map,
 295 };
 296
 297 /*
 298  * The LOCAL_IRQ_CNT* timer firings are based off of the external
 299  * oscillator with some scaling.  The firmware sets up CNTFRQ to
 300  * report 19.2Mhz, but doesn't set up the scaling registers.
 301  */
 302 static void bcm2835_init_local_timer_frequency(void)
 303 {
 304         /*
 305          * Set the timer to source from the 19.2Mhz crystal clock (bit
 306          * 8 unset), and only increment by 1 instead of 2 (bit 9
 307          * unset).
 308          */
 309         writel(0, intc.base + LOCAL_CONTROL);
 310
 311         /*
 312          * Set the timer prescaler to 1:1 (timer freq = input freq *
 313          * 2**31 / prescaler)
 314          */
 315         writel(0x80000000, intc.base + LOCAL_PRESCALER);
 316 }
 317
 318 static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
 319                                                       struct device_node *parent)
 320 {
 321         intc.base = of_iomap(node, 0);
 322         if (!intc.base) {
 323                 panic("%pOF: unable to map local interrupt registers\n", node);
 324         }
 325
 326         bcm2835_init_local_timer_frequency();
 327
 328         intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
 329                                             &bcm2836_arm_irqchip_intc_ops,
 330                                             NULL);
 331         if (!intc.domain)
 332                 panic("%pOF: unable to create IRQ domain\n", node);
 333
 334         irq_domain_update_bus_token(intc.domain, DOMAIN_BUS_WIRED);
 335
 336         bcm2836_arm_irqchip_smp_init();
 337
 338         set_handle_irq(bcm2836_arm_irqchip_handle_irq);
 339         return 0;
 340 }
 341
 342 IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
 343                 bcm2836_arm_irqchip_l1_intc_of_init);