1/* 2 * Copyright (C) 2000, 2001 Broadcom Corporation 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 17 */ 18 19/* 20 * These are routines to set up and handle interrupts from the 21 * sb1250 general purpose timer 0. We're using the timer as a 22 * system clock, so we set it up to run at 100 Hz. On every 23 * interrupt, we update our idea of what the time of day is, 24 * then call do_timer() in the architecture-independent kernel 25 * code to do general bookkeeping (e.g. update jiffies, run 26 * bottom halves, etc.) 27 */ 28#include <linux/config.h> 29#include <linux/interrupt.h> 30#include <linux/sched.h> 31#include <linux/spinlock.h> 32#include <linux/kernel_stat.h> 33 34#include <asm/irq.h> 35#include <asm/ptrace.h> 36#include <asm/addrspace.h> 37#include <asm/time.h> 38 39#include <asm/sibyte/sb1250.h> 40#include <asm/sibyte/sb1250_regs.h> 41#include <asm/sibyte/sb1250_int.h> 42#include <asm/sibyte/sb1250_scd.h> 43#include <asm/sibyte/64bit.h> 44 45 46#define IMR_IP2_VAL K_INT_MAP_I0 47#define IMR_IP3_VAL K_INT_MAP_I1 48#define IMR_IP4_VAL K_INT_MAP_I2 49 50extern int sb1250_steal_irq(int irq); 51 52void sb1250_time_init(void) 53{ 54 int cpu = smp_processor_id(); 55 int irq = K_INT_TIMER_0+cpu; 56 57 /* Only have 4 general purpose timers */ 58 if (cpu > 3) { 59 BUG(); 60 } 61 62 if (!cpu) { 63 /* Use our own gettimeoffset() routine */ 64 do_gettimeoffset = sb1250_gettimeoffset; 65 } 66 67 sb1250_mask_irq(cpu, irq); 68 69 /* Map the timer interrupt to ip[4] of this cpu */ 70 out64(IMR_IP4_VAL, KSEG1 + A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) 71 + (irq<<3)); 72 73 /* the general purpose timer ticks at 1 Mhz independent if the rest of the system */ 74 /* Disable the timer and set up the count */ 75 out64(0, KSEG1 + A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)); 76 out64( 77#ifndef CONFIG_SIMULATION 78 1000000/HZ 79#else 80 50000/HZ 81#endif 82 , KSEG1 + A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)); 83 84 /* Set the timer running */ 85 out64(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS, 86 KSEG1 + A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)); 87 88 sb1250_unmask_irq(cpu, irq); 89 sb1250_steal_irq(irq); 90 /* 91 * This interrupt is "special" in that it doesn't use the request_irq 92 * way to hook the irq line. The timer interrupt is initialized early 93 * enough to make this a major pain, and it's also firing enough to 94 * warrant a bit of special case code. sb1250_timer_interrupt is 95 * called directly from irq_handler.S when IP[4] is set during an 96 * interrupt 97 */ 98} 99 100void sb1250_timer_interrupt(struct pt_regs *regs) 101{ 102 int cpu = smp_processor_id(); 103 int irq = K_INT_TIMER_0+cpu; 104 105 kstat.irqs[cpu][irq]++; 106 /* Reset the timer */ 107 out64(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS, 108 KSEG1 + A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)); 109 110 /* 111 * CPU 0 handles the global timer interrupt job 112 */ 113 if (cpu == 0) { 114 ll_timer_interrupt(irq, regs); 115 } 116 117 /* 118 * every CPU should do profiling and process accouting 119 */ 120 ll_local_timer_interrupt(irq, regs); 121} 122 123/* 124 * We use our own do_gettimeoffset() instead of the generic one, 125 * because the generic one does not work for SMP case. 126 * In addition, since we use general timer 0 for system time, 127 * we can get accurate intra-jiffy offset without calibration. 128 */ 129unsigned long sb1250_gettimeoffset(void) 130{ 131 unsigned long count = 132 in64(KSEG1 + A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)); 133 134 return 1000000/HZ - count; 135 } 136