1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C) 2007 Lemote Inc. 4 * Author: Fuxin Zhang, zhangfx@lemote.com 5 */ 6 7 #include <linux/export.h> 8 #include <linux/init.h> 9 #include <linux/interrupt.h> 10 11 #include <asm/irq_cpu.h> 12 #include <asm/i8259.h> 13 #include <asm/mipsregs.h> 14 15 #include <loongson.h> 16 #include <machine.h> 17 18 #define LOONGSON_TIMER_IRQ (MIPS_CPU_IRQ_BASE + 7) /* cpu timer */ 19 #define LOONGSON_NORTH_BRIDGE_IRQ (MIPS_CPU_IRQ_BASE + 6) /* bonito */ 20 #define LOONGSON_UART_IRQ (MIPS_CPU_IRQ_BASE + 3) /* cpu serial port */ 21 #define LOONGSON_SOUTH_BRIDGE_IRQ (MIPS_CPU_IRQ_BASE + 2) /* i8259 */ 22 23 #define LOONGSON_INT_BIT_INT0 (1 << 11) 24 #define LOONGSON_INT_BIT_INT1 (1 << 12) 25 26 /* 27 * The generic i8259_irq() make the kernel hang on booting. Since we cannot 28 * get the irq via the IRR directly, we access the ISR instead. 29 */ 30 int mach_i8259_irq(void) 31 { 32 int irq, isr; 33 34 irq = -1; 35 36 if ((LOONGSON_INTISR & LOONGSON_INTEN) & LOONGSON_INT_BIT_INT0) { 37 raw_spin_lock(&i8259A_lock); 38 isr = inb(PIC_MASTER_CMD) & 39 ~inb(PIC_MASTER_IMR) & ~(1 << PIC_CASCADE_IR); 40 if (!isr) 41 isr = (inb(PIC_SLAVE_CMD) & ~inb(PIC_SLAVE_IMR)) << 8; 42 irq = ffs(isr) - 1; 43 if (unlikely(irq == 7)) { 44 /* 45 * This may be a spurious interrupt. 46 * 47 * Read the interrupt status register (ISR). If the most 48 * significant bit is not set then there is no valid 49 * interrupt. 50 */ 51 outb(0x0B, PIC_MASTER_ISR); /* ISR register */ 52 if (~inb(PIC_MASTER_ISR) & 0x80) 53 irq = -1; 54 } 55 raw_spin_unlock(&i8259A_lock); 56 } 57 58 return irq; 59 } 60 EXPORT_SYMBOL(mach_i8259_irq); 61 62 static void i8259_irqdispatch(void) 63 { 64 int irq; 65 66 irq = mach_i8259_irq(); 67 if (irq >= 0) 68 do_IRQ(irq); 69 else 70 spurious_interrupt(); 71 } 72 73 void mach_irq_dispatch(unsigned int pending) 74 { 75 if (pending & CAUSEF_IP7) 76 do_IRQ(LOONGSON_TIMER_IRQ); 77 else if (pending & CAUSEF_IP6) { /* North Bridge, Perf counter */ 78 bonito_irqdispatch(); 79 } else if (pending & CAUSEF_IP3) /* CPU UART */ 80 do_IRQ(LOONGSON_UART_IRQ); 81 else if (pending & CAUSEF_IP2) /* South Bridge */ 82 i8259_irqdispatch(); 83 else 84 spurious_interrupt(); 85 } 86 87 static irqreturn_t ip6_action(int cpl, void *dev_id) 88 { 89 return IRQ_HANDLED; 90 } 91 92 void __init mach_init_irq(void) 93 { 94 /* init all controller 95 * 0-15 ------> i8259 interrupt 96 * 16-23 ------> mips cpu interrupt 97 * 32-63 ------> bonito irq 98 */ 99 100 /* setup cs5536 as high level trigger */ 101 LOONGSON_INTPOL = LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1; 102 LOONGSON_INTEDGE &= ~(LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1); 103 104 /* Sets the first-level interrupt dispatcher. */ 105 mips_cpu_irq_init(); 106 init_i8259_irqs(); 107 bonito_irq_init(); 108 109 /* setup north bridge irq (bonito) */ 110 if (request_irq(LOONGSON_NORTH_BRIDGE_IRQ, ip6_action, 111 IRQF_SHARED | IRQF_NO_THREAD, "cascade", ip6_action)) 112 pr_err("Failed to register north bridge cascade interrupt\n"); 113 /* setup source bridge irq (i8259) */ 114 if (request_irq(LOONGSON_SOUTH_BRIDGE_IRQ, no_action, 115 IRQF_NO_THREAD | IRQF_NO_SUSPEND, "cascade", NULL)) 116 pr_err("Failed to register south bridge cascade interrupt\n"); 117 } 118