1 /* 2 * Copyright 2010 Broadcom 3 * Copyright 2012 Simon Arlott, Chris Boot, Stephen Warren 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * Quirk 1: Shortcut interrupts don't set the bank 1/2 register pending bits 16 * 17 * If an interrupt fires on bank 1 that isn't in the shortcuts list, bit 8 18 * on bank 0 is set to signify that an interrupt in bank 1 has fired, and 19 * to look in the bank 1 status register for more information. 20 * 21 * If an interrupt fires on bank 1 that _is_ in the shortcuts list, its 22 * shortcut bit in bank 0 is set as well as its interrupt bit in the bank 1 23 * status register, but bank 0 bit 8 is _not_ set. 24 * 25 * Quirk 2: You can't mask the register 1/2 pending interrupts 26 * 27 * In a proper cascaded interrupt controller, the interrupt lines with 28 * cascaded interrupt controllers on them are just normal interrupt lines. 29 * You can mask the interrupts and get on with things. With this controller 30 * you can't do that. 31 * 32 * Quirk 3: The shortcut interrupts can't be (un)masked in bank 0 33 * 34 * Those interrupts that have shortcuts can only be masked/unmasked in 35 * their respective banks' enable/disable registers. Doing so in the bank 0 36 * enable/disable registers has no effect. 37 * 38 * The FIQ control register: 39 * Bits 0-6: IRQ (index in order of interrupts from banks 1, 2, then 0) 40 * Bit 7: Enable FIQ generation 41 * Bits 8+: Unused 42 * 43 * An interrupt must be disabled before configuring it for FIQ generation 44 * otherwise both handlers will fire at the same time! 45 */ 46 47 #include <linux/io.h> 48 #include <linux/slab.h> 49 #include <linux/of_address.h> 50 #include <linux/of_irq.h> 51 #include <linux/irqdomain.h> 52 53 #include <asm/exception.h> 54 #include <asm/mach/irq.h> 55 56 #include "irqchip.h" 57 58 /* Put the bank and irq (32 bits) into the hwirq */ 59 #define MAKE_HWIRQ(b, n) ((b << 5) | (n)) 60 #define HWIRQ_BANK(i) (i >> 5) 61 #define HWIRQ_BIT(i) BIT(i & 0x1f) 62 63 #define NR_IRQS_BANK0 8 64 #define BANK0_HWIRQ_MASK 0xff 65 /* Shortcuts can't be disabled so any unknown new ones need to be masked */ 66 #define SHORTCUT1_MASK 0x00007c00 67 #define SHORTCUT2_MASK 0x001f8000 68 #define SHORTCUT_SHIFT 10 69 #define BANK1_HWIRQ BIT(8) 70 #define BANK2_HWIRQ BIT(9) 71 #define BANK0_VALID_MASK (BANK0_HWIRQ_MASK | BANK1_HWIRQ | BANK2_HWIRQ \ 72 | SHORTCUT1_MASK | SHORTCUT2_MASK) 73 74 #define REG_FIQ_CONTROL 0x0c 75 76 #define NR_BANKS 3 77 #define IRQS_PER_BANK 32 78 79 static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 }; 80 static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 }; 81 static int reg_disable[] __initconst = { 0x24, 0x1c, 0x20 }; 82 static int bank_irqs[] __initconst = { 8, 32, 32 }; 83 84 static const int shortcuts[] = { 85 7, 9, 10, 18, 19, /* Bank 1 */ 86 21, 22, 23, 24, 25, 30 /* Bank 2 */ 87 }; 88 89 struct armctrl_ic { 90 void __iomem *base; 91 void __iomem *pending[NR_BANKS]; 92 void __iomem *enable[NR_BANKS]; 93 void __iomem *disable[NR_BANKS]; 94 struct irq_domain *domain; 95 }; 96 97 static struct armctrl_ic intc __read_mostly; 98 static void __exception_irq_entry bcm2835_handle_irq( 99 struct pt_regs *regs); 100 101 static void armctrl_mask_irq(struct irq_data *d) 102 { 103 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]); 104 } 105 106 static void armctrl_unmask_irq(struct irq_data *d) 107 { 108 writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]); 109 } 110 111 static struct irq_chip armctrl_chip = { 112 .name = "ARMCTRL-level", 113 .irq_mask = armctrl_mask_irq, 114 .irq_unmask = armctrl_unmask_irq 115 }; 116 117 static int armctrl_xlate(struct irq_domain *d, struct device_node *ctrlr, 118 const u32 *intspec, unsigned int intsize, 119 unsigned long *out_hwirq, unsigned int *out_type) 120 { 121 if (WARN_ON(intsize != 2)) 122 return -EINVAL; 123 124 if (WARN_ON(intspec[0] >= NR_BANKS)) 125 return -EINVAL; 126 127 if (WARN_ON(intspec[1] >= IRQS_PER_BANK)) 128 return -EINVAL; 129 130 if (WARN_ON(intspec[0] == 0 && intspec[1] >= NR_IRQS_BANK0)) 131 return -EINVAL; 132 133 *out_hwirq = MAKE_HWIRQ(intspec[0], intspec[1]); 134 *out_type = IRQ_TYPE_NONE; 135 return 0; 136 } 137 138 static struct irq_domain_ops armctrl_ops = { 139 .xlate = armctrl_xlate 140 }; 141 142 static int __init armctrl_of_init(struct device_node *node, 143 struct device_node *parent) 144 { 145 void __iomem *base; 146 int irq, b, i; 147 148 base = of_iomap(node, 0); 149 if (!base) 150 panic("%s: unable to map IC registers\n", 151 node->full_name); 152 153 intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0), 154 &armctrl_ops, NULL); 155 if (!intc.domain) 156 panic("%s: unable to create IRQ domain\n", node->full_name); 157 158 for (b = 0; b < NR_BANKS; b++) { 159 intc.pending[b] = base + reg_pending[b]; 160 intc.enable[b] = base + reg_enable[b]; 161 intc.disable[b] = base + reg_disable[b]; 162 163 for (i = 0; i < bank_irqs[b]; i++) { 164 irq = irq_create_mapping(intc.domain, MAKE_HWIRQ(b, i)); 165 BUG_ON(irq <= 0); 166 irq_set_chip_and_handler(irq, &armctrl_chip, 167 handle_level_irq); 168 set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); 169 } 170 } 171 172 set_handle_irq(bcm2835_handle_irq); 173 return 0; 174 } 175 176 /* 177 * Handle each interrupt across the entire interrupt controller. This reads the 178 * status register before handling each interrupt, which is necessary given that 179 * handle_IRQ may briefly re-enable interrupts for soft IRQ handling. 180 */ 181 182 static void armctrl_handle_bank(int bank, struct pt_regs *regs) 183 { 184 u32 stat, irq; 185 186 while ((stat = readl_relaxed(intc.pending[bank]))) { 187 irq = MAKE_HWIRQ(bank, ffs(stat) - 1); 188 handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); 189 } 190 } 191 192 static void armctrl_handle_shortcut(int bank, struct pt_regs *regs, 193 u32 stat) 194 { 195 u32 irq = MAKE_HWIRQ(bank, shortcuts[ffs(stat >> SHORTCUT_SHIFT) - 1]); 196 handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); 197 } 198 199 static void __exception_irq_entry bcm2835_handle_irq( 200 struct pt_regs *regs) 201 { 202 u32 stat, irq; 203 204 while ((stat = readl_relaxed(intc.pending[0]) & BANK0_VALID_MASK)) { 205 if (stat & BANK0_HWIRQ_MASK) { 206 irq = MAKE_HWIRQ(0, ffs(stat & BANK0_HWIRQ_MASK) - 1); 207 handle_IRQ(irq_linear_revmap(intc.domain, irq), regs); 208 } else if (stat & SHORTCUT1_MASK) { 209 armctrl_handle_shortcut(1, regs, stat & SHORTCUT1_MASK); 210 } else if (stat & SHORTCUT2_MASK) { 211 armctrl_handle_shortcut(2, regs, stat & SHORTCUT2_MASK); 212 } else if (stat & BANK1_HWIRQ) { 213 armctrl_handle_bank(1, regs); 214 } else if (stat & BANK2_HWIRQ) { 215 armctrl_handle_bank(2, regs); 216 } else { 217 BUG(); 218 } 219 } 220 } 221 222 IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic", armctrl_of_init); 223