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 #define INTC_INT_GLOBAL         BIT(31)
  24
  25 #define RALINK_CPU_IRQ_INTC     (MIPS_CPU_IRQ_BASE + 2)
  26 #define RALINK_CPU_IRQ_PCI      (MIPS_CPU_IRQ_BASE + 4)
  27 #define RALINK_CPU_IRQ_FE       (MIPS_CPU_IRQ_BASE + 5)
  28 #define RALINK_CPU_IRQ_WIFI     (MIPS_CPU_IRQ_BASE + 6)
  29 #define RALINK_CPU_IRQ_COUNTER  (MIPS_CPU_IRQ_BASE + 7)
  30
  31 /* we have a cascade of 8 irqs */
  32 #define RALINK_INTC_IRQ_BASE    8
  33
  34 /* we have 32 SoC irqs */
  35 #define RALINK_INTC_IRQ_COUNT   32
  36
  37 #define RALINK_INTC_IRQ_PERFC   (RALINK_INTC_IRQ_BASE + 9)
  38
  39 enum rt_intc_regs_enum {
  40         INTC_REG_STATUS0 = 0,
  41         INTC_REG_STATUS1,
  42         INTC_REG_TYPE,
  43         INTC_REG_RAW_STATUS,
  44         INTC_REG_ENABLE,
  45         INTC_REG_DISABLE,
  46 };
  47
  48 static u32 rt_intc_regs[] = {
  49         [INTC_REG_STATUS0] = 0x00,
  50         [INTC_REG_STATUS1] = 0x04,
  51         [INTC_REG_TYPE] = 0x20,
  52         [INTC_REG_RAW_STATUS] = 0x30,
  53         [INTC_REG_ENABLE] = 0x34,
  54         [INTC_REG_DISABLE] = 0x38,
  55 };
  56
  57 static void __iomem *rt_intc_membase;
  58
  59 static int rt_perfcount_irq;
  60
  61 static inline void rt_intc_w32(u32 val, unsigned reg)
  62 {
  63         __raw_writel(val, rt_intc_membase + rt_intc_regs[reg]);
  64 }
  65
  66 static inline u32 rt_intc_r32(unsigned reg)
  67 {
  68         return __raw_readl(rt_intc_membase + rt_intc_regs[reg]);
  69 }
  70
  71 static void ralink_intc_irq_unmask(struct irq_data *d)
  72 {
  73         rt_intc_w32(BIT(d->hwirq), INTC_REG_ENABLE);
  74 }
  75
  76 static void ralink_intc_irq_mask(struct irq_data *d)
  77 {
  78         rt_intc_w32(BIT(d->hwirq), INTC_REG_DISABLE);
  79 }
  80
  81 static struct irq_chip ralink_intc_irq_chip = {
  82         .name           = "INTC",
  83         .irq_unmask     = ralink_intc_irq_unmask,
  84         .irq_mask       = ralink_intc_irq_mask,
  85         .irq_mask_ack   = ralink_intc_irq_mask,
  86 };
  87
  88 int get_c0_perfcount_int(void)
  89 {
  90         return rt_perfcount_irq;
  91 }
  92
  93 unsigned int get_c0_compare_int(void)
  94 {
  95         return CP0_LEGACY_COMPARE_IRQ;
  96 }
  97
  98 static void ralink_intc_irq_handler(unsigned int irq, struct irq_desc *desc)
  99 {
 100         u32 pending = rt_intc_r32(INTC_REG_STATUS0);
 101
 102         if (pending) {
 103                 struct irq_domain *domain = irq_desc_get_handler_data(desc);
 104                 generic_handle_irq(irq_find_mapping(domain, __ffs(pending)));
 105         } else {
 106                 spurious_interrupt();
 107         }
 108 }
 109
 110 asmlinkage void plat_irq_dispatch(void)
 111 {
 112         unsigned long pending;
 113
 114         pending = read_c0_status() & read_c0_cause() & ST0_IM;
 115
 116         if (pending & STATUSF_IP7)
 117                 do_IRQ(RALINK_CPU_IRQ_COUNTER);
 118
 119         else if (pending & STATUSF_IP5)
 120                 do_IRQ(RALINK_CPU_IRQ_FE);
 121
 122         else if (pending & STATUSF_IP6)
 123                 do_IRQ(RALINK_CPU_IRQ_WIFI);
 124
 125         else if (pending & STATUSF_IP4)
 126                 do_IRQ(RALINK_CPU_IRQ_PCI);
 127
 128         else if (pending & STATUSF_IP2)
 129                 do_IRQ(RALINK_CPU_IRQ_INTC);
 130
 131         else
 132                 spurious_interrupt();
 133 }
 134
 135 static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
 136 {
 137         irq_set_chip_and_handler(irq, &ralink_intc_irq_chip, handle_level_irq);
 138
 139         return 0;
 140 }
 141
 142 static const struct irq_domain_ops irq_domain_ops = {
 143         .xlate = irq_domain_xlate_onecell,
 144         .map = intc_map,
 145 };
 146
 147 static int __init intc_of_init(struct device_node *node,
 148                                struct device_node *parent)
 149 {
 150         struct resource res;
 151         struct irq_domain *domain;
 152         int irq;
 153
 154         if (!of_property_read_u32_array(node, "ralink,intc-registers",
 155                                         rt_intc_regs, 6))
 156                 pr_info("intc: using register map from devicetree\n");
 157
 158         irq = irq_of_parse_and_map(node, 0);
 159         if (!irq)
 160                 panic("Failed to get INTC IRQ");
 161
 162         if (of_address_to_resource(node, 0, &res))
 163                 panic("Failed to get intc memory range");
 164
 165         if (request_mem_region(res.start, resource_size(&res),
 166                                 res.name) < 0)
 167                 pr_err("Failed to request intc memory");
 168
 169         rt_intc_membase = ioremap_nocache(res.start,
 170                                         resource_size(&res));
 171         if (!rt_intc_membase)
 172                 panic("Failed to remap intc memory");
 173
 174         /* disable all interrupts */
 175         rt_intc_w32(~0, INTC_REG_DISABLE);
 176
 177         /* route all INTC interrupts to MIPS HW0 interrupt */
 178         rt_intc_w32(0, INTC_REG_TYPE);
 179
 180         domain = irq_domain_add_legacy(node, RALINK_INTC_IRQ_COUNT,
 181                         RALINK_INTC_IRQ_BASE, 0, &irq_domain_ops, NULL);
 182         if (!domain)
 183                 panic("Failed to add irqdomain");
 184
 185         rt_intc_w32(INTC_INT_GLOBAL, INTC_REG_ENABLE);
 186
 187         irq_set_chained_handler_and_data(irq, ralink_intc_irq_handler, domain);
 188
 189         /* tell the kernel which irq is used for performance monitoring */
 190         rt_perfcount_irq = irq_create_mapping(domain, 9);
 191
 192         return 0;
 193 }
 194
 195 static struct of_device_id __initdata of_irq_ids[] = {
 196         { .compatible = "mti,cpu-interrupt-controller", .data = mips_cpu_irq_of_init },
 197         { .compatible = "ralink,rt2880-intc", .data = intc_of_init },
 198         {},
 199 };
 200
 201 void __init arch_init_irq(void)
 202 {
 203         of_irq_init(of_irq_ids);
 204 }
 205