1 /* 2 * Copyright (C) 2000,2001,2004 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 * bcm1480 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/bcm1480_regs.h> 41 #include <asm/sibyte/sb1250_regs.h> 42 #include <asm/sibyte/bcm1480_int.h> 43 #include <asm/sibyte/bcm1480_scd.h> 44 45 #include <asm/sibyte/sb1250.h> 46 47 48 #define IMR_IP2_VAL K_BCM1480_INT_MAP_I0 49 #define IMR_IP3_VAL K_BCM1480_INT_MAP_I1 50 #define IMR_IP4_VAL K_BCM1480_INT_MAP_I2 51 52 extern int bcm1480_steal_irq(int irq); 53 54 void bcm1480_time_init(void) 55 { 56 int cpu = smp_processor_id(); 57 int irq = K_BCM1480_INT_TIMER_0+cpu; 58 59 /* Only have 4 general purpose timers */ 60 if (cpu > 3) { 61 BUG(); 62 } 63 64 if (!cpu) { 65 /* Use our own gettimeoffset() routine */ 66 do_gettimeoffset = bcm1480_gettimeoffset; 67 } 68 69 bcm1480_mask_irq(cpu, irq); 70 71 /* Map the timer interrupt to ip[4] of this cpu */ 72 __raw_writeq(IMR_IP4_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) 73 + (irq<<3))); 74 75 /* the general purpose timer ticks at 1 Mhz independent of the rest of the system */ 76 /* Disable the timer and set up the count */ 77 __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 78 __raw_writeq( 79 #ifndef CONFIG_SIMULATION 80 1000000/HZ 81 #else 82 50000/HZ 83 #endif 84 , IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT))); 85 86 /* Set the timer running */ 87 __raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS, 88 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 89 90 bcm1480_unmask_irq(cpu, irq); 91 bcm1480_steal_irq(irq); 92 /* 93 * This interrupt is "special" in that it doesn't use the request_irq 94 * way to hook the irq line. The timer interrupt is initialized early 95 * enough to make this a major pain, and it's also firing enough to 96 * warrant a bit of special case code. bcm1480_timer_interrupt is 97 * called directly from irq_handler.S when IP[4] is set during an 98 * interrupt 99 */ 100 } 101 102 #include <asm/sibyte/sb1250.h> 103 104 void bcm1480_timer_interrupt(struct pt_regs *regs) 105 { 106 int cpu = smp_processor_id(); 107 int irq = K_BCM1480_INT_TIMER_0+cpu; 108 109 /* Reset the timer */ 110 __raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS, 111 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 112 113 if (cpu == 0) { 114 /* 115 * CPU 0 handles the global timer interrupt job 116 */ 117 ll_timer_interrupt(irq, regs); 118 } 119 else { 120 /* 121 * other CPUs should just do profiling and process accounting 122 */ 123 ll_local_timer_interrupt(irq, regs); 124 } 125 } 126 127 /* 128 * We use our own do_gettimeoffset() instead of the generic one, 129 * because the generic one does not work for SMP case. 130 * In addition, since we use general timer 0 for system time, 131 * we can get accurate intra-jiffy offset without calibration. 132 */ 133 unsigned long bcm1480_gettimeoffset(void) 134 { 135 unsigned long count = 136 __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT))); 137 138 return 1000000/HZ - count; 139 } 140