1 /* 2 * Allwinner A1X SoCs IRQ chip driver. 3 * 4 * Copyright (C) 2012 Maxime Ripard 5 * 6 * Maxime Ripard <maxime.ripard@free-electrons.com> 7 * 8 * Based on code from 9 * Allwinner Technology Co., Ltd. <www.allwinnertech.com> 10 * Benn Huang <benn@allwinnertech.com> 11 * 12 * This file is licensed under the terms of the GNU General Public 13 * License version 2. This program is licensed "as is" without any 14 * warranty of any kind, whether express or implied. 15 */ 16 17 #include <linux/io.h> 18 #include <linux/irq.h> 19 #include <linux/irqchip.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_irq.h> 23 24 #include <asm/exception.h> 25 26 #define SUN4I_IRQ_VECTOR_REG 0x00 27 #define SUN4I_IRQ_PROTECTION_REG 0x08 28 #define SUN4I_IRQ_NMI_CTRL_REG 0x0c 29 #define SUN4I_IRQ_PENDING_REG(x) (0x10 + 0x4 * x) 30 #define SUN4I_IRQ_FIQ_PENDING_REG(x) (0x20 + 0x4 * x) 31 #define SUN4I_IRQ_ENABLE_REG(x) (0x40 + 0x4 * x) 32 #define SUN4I_IRQ_MASK_REG(x) (0x50 + 0x4 * x) 33 34 static void __iomem *sun4i_irq_base; 35 static struct irq_domain *sun4i_irq_domain; 36 37 static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs); 38 39 static void sun4i_irq_ack(struct irq_data *irqd) 40 { 41 unsigned int irq = irqd_to_hwirq(irqd); 42 43 if (irq != 0) 44 return; /* Only IRQ 0 / the ENMI needs to be acked */ 45 46 writel(BIT(0), sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)); 47 } 48 49 static void sun4i_irq_mask(struct irq_data *irqd) 50 { 51 unsigned int irq = irqd_to_hwirq(irqd); 52 unsigned int irq_off = irq % 32; 53 int reg = irq / 32; 54 u32 val; 55 56 val = readl(sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg)); 57 writel(val & ~(1 << irq_off), 58 sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg)); 59 } 60 61 static void sun4i_irq_unmask(struct irq_data *irqd) 62 { 63 unsigned int irq = irqd_to_hwirq(irqd); 64 unsigned int irq_off = irq % 32; 65 int reg = irq / 32; 66 u32 val; 67 68 val = readl(sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg)); 69 writel(val | (1 << irq_off), 70 sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(reg)); 71 } 72 73 static struct irq_chip sun4i_irq_chip = { 74 .name = "sun4i_irq", 75 .irq_eoi = sun4i_irq_ack, 76 .irq_mask = sun4i_irq_mask, 77 .irq_unmask = sun4i_irq_unmask, 78 .flags = IRQCHIP_EOI_THREADED | IRQCHIP_EOI_IF_HANDLED, 79 }; 80 81 static int sun4i_irq_map(struct irq_domain *d, unsigned int virq, 82 irq_hw_number_t hw) 83 { 84 irq_set_chip_and_handler(virq, &sun4i_irq_chip, handle_fasteoi_irq); 85 irq_set_probe(virq); 86 87 return 0; 88 } 89 90 static const struct irq_domain_ops sun4i_irq_ops = { 91 .map = sun4i_irq_map, 92 .xlate = irq_domain_xlate_onecell, 93 }; 94 95 static int __init sun4i_of_init(struct device_node *node, 96 struct device_node *parent) 97 { 98 sun4i_irq_base = of_iomap(node, 0); 99 if (!sun4i_irq_base) 100 panic("%pOF: unable to map IC registers\n", 101 node); 102 103 /* Disable all interrupts */ 104 writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(0)); 105 writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(1)); 106 writel(0, sun4i_irq_base + SUN4I_IRQ_ENABLE_REG(2)); 107 108 /* Unmask all the interrupts, ENABLE_REG(x) is used for masking */ 109 writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(0)); 110 writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(1)); 111 writel(0, sun4i_irq_base + SUN4I_IRQ_MASK_REG(2)); 112 113 /* Clear all the pending interrupts */ 114 writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)); 115 writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(1)); 116 writel(0xffffffff, sun4i_irq_base + SUN4I_IRQ_PENDING_REG(2)); 117 118 /* Enable protection mode */ 119 writel(0x01, sun4i_irq_base + SUN4I_IRQ_PROTECTION_REG); 120 121 /* Configure the external interrupt source type */ 122 writel(0x00, sun4i_irq_base + SUN4I_IRQ_NMI_CTRL_REG); 123 124 sun4i_irq_domain = irq_domain_add_linear(node, 3 * 32, 125 &sun4i_irq_ops, NULL); 126 if (!sun4i_irq_domain) 127 panic("%pOF: unable to create IRQ domain\n", node); 128 129 set_handle_irq(sun4i_handle_irq); 130 131 return 0; 132 } 133 IRQCHIP_DECLARE(allwinner_sun4i_ic, "allwinner,sun4i-a10-ic", sun4i_of_init); 134 135 static void __exception_irq_entry sun4i_handle_irq(struct pt_regs *regs) 136 { 137 u32 hwirq; 138 139 /* 140 * hwirq == 0 can mean one of 3 things: 141 * 1) no more irqs pending 142 * 2) irq 0 pending 143 * 3) spurious irq 144 * So if we immediately get a reading of 0, check the irq-pending reg 145 * to differentiate between 2 and 3. We only do this once to avoid 146 * the extra check in the common case of 1 hapening after having 147 * read the vector-reg once. 148 */ 149 hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2; 150 if (hwirq == 0 && 151 !(readl(sun4i_irq_base + SUN4I_IRQ_PENDING_REG(0)) & BIT(0))) 152 return; 153 154 do { 155 handle_domain_irq(sun4i_irq_domain, hwirq, regs); 156 hwirq = readl(sun4i_irq_base + SUN4I_IRQ_VECTOR_REG) >> 2; 157 } while (hwirq != 0); 158 } 159