1 /* 2 * linux/arch/mips/dec/kn02-irq.c 3 * 4 * DECstation 5000/200 (KN02) Control and Status Register 5 * interrupts. 6 * 7 * Copyright (c) 2002, 2003, 2005 Maciej W. Rozycki 8 * 9 * This program is free software; you can redistribute it and/or 10 * modify it under the terms of the GNU General Public License 11 * as published by the Free Software Foundation; either version 12 * 2 of the License, or (at your option) any later version. 13 */ 14 15 #include <linux/init.h> 16 #include <linux/irq.h> 17 #include <linux/types.h> 18 19 #include <asm/dec/kn02.h> 20 21 22 /* 23 * Bits 7:0 of the Control Register are write-only -- the 24 * corresponding bits of the Status Register have a different 25 * meaning. Hence we use a cache. It speeds up things a bit 26 * as well. 27 * 28 * There is no default value -- it has to be initialized. 29 */ 30 u32 cached_kn02_csr; 31 32 33 static int kn02_irq_base; 34 35 36 static inline void unmask_kn02_irq(unsigned int irq) 37 { 38 volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE + 39 KN02_CSR); 40 41 cached_kn02_csr |= (1 << (irq - kn02_irq_base + 16)); 42 *csr = cached_kn02_csr; 43 } 44 45 static inline void mask_kn02_irq(unsigned int irq) 46 { 47 volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE + 48 KN02_CSR); 49 50 cached_kn02_csr &= ~(1 << (irq - kn02_irq_base + 16)); 51 *csr = cached_kn02_csr; 52 } 53 54 static void ack_kn02_irq(unsigned int irq) 55 { 56 mask_kn02_irq(irq); 57 iob(); 58 } 59 60 static struct irq_chip kn02_irq_type = { 61 .name = "KN02-CSR", 62 .ack = ack_kn02_irq, 63 .mask = mask_kn02_irq, 64 .mask_ack = ack_kn02_irq, 65 .unmask = unmask_kn02_irq, 66 }; 67 68 69 void __init init_kn02_irqs(int base) 70 { 71 volatile u32 *csr = (volatile u32 *)CKSEG1ADDR(KN02_SLOT_BASE + 72 KN02_CSR); 73 int i; 74 75 /* Mask interrupts. */ 76 cached_kn02_csr &= ~KN02_CSR_IOINTEN; 77 *csr = cached_kn02_csr; 78 iob(); 79 80 for (i = base; i < base + KN02_IRQ_LINES; i++) 81 set_irq_chip_and_handler(i, &kn02_irq_type, handle_level_irq); 82 83 kn02_irq_base = base; 84 } 85