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 #include <asm/io.h> 39 40 #include <asm/sibyte/sb1250.h> 41 #include <asm/sibyte/sb1250_regs.h> 42 #include <asm/sibyte/sb1250_int.h> 43 #include <asm/sibyte/sb1250_scd.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 50 extern int sb1250_steal_irq(int irq); 51 52 void 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 __raw_writeq(IMR_IP4_VAL, 71 IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) + 72 (irq << 3))); 73 74 /* the general purpose timer ticks at 1 Mhz independent if the rest of the system */ 75 /* Disable the timer and set up the count */ 76 __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 77 #ifdef CONFIG_SIMULATION 78 __raw_writeq(50000 / HZ, 79 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT))); 80 #else 81 __raw_writeq(1000000 / HZ, 82 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT))); 83 #endif 84 85 /* Set the timer running */ 86 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, 87 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 88 89 sb1250_unmask_irq(cpu, irq); 90 sb1250_steal_irq(irq); 91 /* 92 * This interrupt is "special" in that it doesn't use the request_irq 93 * way to hook the irq line. The timer interrupt is initialized early 94 * enough to make this a major pain, and it's also firing enough to 95 * warrant a bit of special case code. sb1250_timer_interrupt is 96 * called directly from irq_handler.S when IP[4] is set during an 97 * interrupt 98 */ 99 } 100 101 void sb1250_timer_interrupt(struct pt_regs *regs) 102 { 103 extern asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs); 104 int cpu = smp_processor_id(); 105 int irq = K_INT_TIMER_0 + cpu; 106 107 /* Reset the timer */ 108 ____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS, 109 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 110 111 /* 112 * CPU 0 handles the global timer interrupt job 113 */ 114 if (cpu == 0) { 115 ll_timer_interrupt(irq, regs); 116 } 117 118 /* 119 * every CPU should do profiling and process accouting 120 */ 121 ll_local_timer_interrupt(irq, regs); 122 } 123 124 /* 125 * We use our own do_gettimeoffset() instead of the generic one, 126 * because the generic one does not work for SMP case. 127 * In addition, since we use general timer 0 for system time, 128 * we can get accurate intra-jiffy offset without calibration. 129 */ 130 unsigned long sb1250_gettimeoffset(void) 131 { 132 unsigned long count = 133 __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT))); 134 135 return 1000000/HZ - count; 136 } 137