arch/mips/ralink/irq.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify it
   3  * under the terms of the GNU General Public License version 2 as published
   4  * by the Free Software Foundation.
   5  *
   6  * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   7  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
   8  */
   9
  10 #include <linux/io.h>
  11 #include <linux/bitops.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/irqdomain.h>
  16 #include <linux/interrupt.h>
  17
  18 #include <asm/irq_cpu.h>
  19 #include <asm/mipsregs.h>
  20
  21 #include "common.h"
  22
  23 /* INTC register offsets */
  24 #define INTC_REG_STATUS0        0x00
  25 #define INTC_REG_STATUS1        0x04
  26 #define INTC_REG_TYPE           0x20
  27 #define INTC_REG_RAW_STATUS     0x30
  28 #define INTC_REG_ENABLE         0x34
  29 #define INTC_REG_DISABLE        0x38
  30
  31 #define INTC_INT_GLOBAL         BIT(31)
  32
  33 #define RALINK_CPU_IRQ_INTC     (MIPS_CPU_IRQ_BASE + 2)
  34 #define RALINK_CPU_IRQ_PCI      (MIPS_CPU_IRQ_BASE + 4)
  35 #define RALINK_CPU_IRQ_FE       (MIPS_CPU_IRQ_BASE + 5)
  36 #define RALINK_CPU_IRQ_WIFI     (MIPS_CPU_IRQ_BASE + 6)
  37 #define RALINK_CPU_IRQ_COUNTER  (MIPS_CPU_IRQ_BASE + 7)
  38
  39 /* we have a cascade of 8 irqs */
  40 #define RALINK_INTC_IRQ_BASE    8
  41
  42 /* we have 32 SoC irqs */
  43 #define RALINK_INTC_IRQ_COUNT   32
  44
  45 #define RALINK_INTC_IRQ_PERFC   (RALINK_INTC_IRQ_BASE + 9)
  46
  47 static void __iomem *rt_intc_membase;
  48
  49 static inline void rt_intc_w32(u32 val, unsigned reg)
  50 {
  51         __raw_writel(val, rt_intc_membase + reg);
  52 }
  53
  54 static inline u32 rt_intc_r32(unsigned reg)
  55 {
  56         return __raw_readl(rt_intc_membase + reg);
  57 }
  58
  59 static void ralink_intc_irq_unmask(struct irq_data *d)
  60 {
  61         rt_intc_w32(BIT(d->hwirq), INTC_REG_ENABLE);
  62 }
  63
  64 static void ralink_intc_irq_mask(struct irq_data *d)
  65 {
  66         rt_intc_w32(BIT(d->hwirq), INTC_REG_DISABLE);
  67 }
  68
  69 static struct irq_chip ralink_intc_irq_chip = {
  70         .name           = "INTC",
  71         .irq_unmask     = ralink_intc_irq_unmask,
  72         .irq_mask       = ralink_intc_irq_mask,
  73         .irq_mask_ack   = ralink_intc_irq_mask,
  74 };
  75
  76 unsigned int __cpuinit get_c0_compare_int(void)
  77 {
  78         return CP0_LEGACY_COMPARE_IRQ;
  79 }
  80
  81 static void ralink_intc_irq_handler(unsigned int irq, struct irq_desc *desc)
  82 {
  83         u32 pending = rt_intc_r32(INTC_REG_STATUS0);
  84
  85         if (pending) {
  86                 struct irq_domain *domain = irq_get_handler_data(irq);
  87                 generic_handle_irq(irq_find_mapping(domain, __ffs(pending)));
  88         } else {
  89                 spurious_interrupt();
  90         }
  91 }
  92
  93 asmlinkage void plat_irq_dispatch(void)
  94 {
  95         unsigned long pending;
  96
  97         pending = read_c0_status() & read_c0_cause() & ST0_IM;
  98
  99         if (pending & STATUSF_IP7)
 100                 do_IRQ(RALINK_CPU_IRQ_COUNTER);
 101
 102         else if (pending & STATUSF_IP5)
 103                 do_IRQ(RALINK_CPU_IRQ_FE);
 104
 105         else if (pending & STATUSF_IP6)
 106                 do_IRQ(RALINK_CPU_IRQ_WIFI);
 107
 108         else if (pending & STATUSF_IP4)
 109                 do_IRQ(RALINK_CPU_IRQ_PCI);
 110
 111         else if (pending & STATUSF_IP2)
 112                 do_IRQ(RALINK_CPU_IRQ_INTC);
 113
 114         else
 115                 spurious_interrupt();
 116 }
 117
 118 static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
 119 {
 120         irq_set_chip_and_handler(irq, &ralink_intc_irq_chip, handle_level_irq);
 121
 122         return 0;
 123 }
 124
 125 static const struct irq_domain_ops irq_domain_ops = {
 126         .xlate = irq_domain_xlate_onecell,
 127         .map = intc_map,
 128 };
 129
 130 static int __init intc_of_init(struct device_node *node,
 131                                struct device_node *parent)
 132 {
 133         struct resource res;
 134         struct irq_domain *domain;
 135         int irq;
 136
 137         irq = irq_of_parse_and_map(node, 0);
 138         if (!irq)
 139                 panic("Failed to get INTC IRQ");
 140
 141         if (of_address_to_resource(node, 0, &res))
 142                 panic("Failed to get intc memory range");
 143
 144         if (request_mem_region(res.start, resource_size(&res),
 145                                 res.name) < 0)
 146                 pr_err("Failed to request intc memory");
 147
 148         rt_intc_membase = ioremap_nocache(res.start,
 149                                         resource_size(&res));
 150         if (!rt_intc_membase)
 151                 panic("Failed to remap intc memory");
 152
 153         /* disable all interrupts */
 154         rt_intc_w32(~0, INTC_REG_DISABLE);
 155
 156         /* route all INTC interrupts to MIPS HW0 interrupt */
 157         rt_intc_w32(0, INTC_REG_TYPE);
 158
 159         domain = irq_domain_add_legacy(node, RALINK_INTC_IRQ_COUNT,
 160                         RALINK_INTC_IRQ_BASE, 0, &irq_domain_ops, NULL);
 161         if (!domain)
 162                 panic("Failed to add irqdomain");
 163
 164         rt_intc_w32(INTC_INT_GLOBAL, INTC_REG_ENABLE);
 165
 166         irq_set_chained_handler(irq, ralink_intc_irq_handler);
 167         irq_set_handler_data(irq, domain);
 168
 169         /* tell the kernel which irq is used for performance monitoring */
 170         cp0_perfcount_irq = irq_create_mapping(domain, 9);
 171
 172         return 0;
 173 }
 174
 175 static struct of_device_id __initdata of_irq_ids[] = {
 176         { .compatible = "mti,cpu-interrupt-controller", .data = mips_cpu_intc_init },
 177         { .compatible = "ralink,rt2880-intc", .data = intc_of_init },
 178         {},
 179 };
 180
 181 void __init arch_init_irq(void)
 182 {
 183         of_irq_init(of_irq_ids);
 184 }
 185