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/interrupt.h> 29 #include <linux/sched.h> 30 #include <linux/spinlock.h> 31 #include <linux/kernel_stat.h> 32 33 #include <asm/irq.h> 34 #include <asm/ptrace.h> 35 #include <asm/addrspace.h> 36 #include <asm/time.h> 37 #include <asm/io.h> 38 39 #include <asm/sibyte/bcm1480_regs.h> 40 #include <asm/sibyte/sb1250_regs.h> 41 #include <asm/sibyte/bcm1480_int.h> 42 #include <asm/sibyte/bcm1480_scd.h> 43 44 #include <asm/sibyte/sb1250.h> 45 46 47 #define IMR_IP2_VAL K_BCM1480_INT_MAP_I0 48 #define IMR_IP3_VAL K_BCM1480_INT_MAP_I1 49 #define IMR_IP4_VAL K_BCM1480_INT_MAP_I2 50 51 extern int bcm1480_steal_irq(int irq); 52 53 void bcm1480_time_init(void) 54 { 55 int cpu = smp_processor_id(); 56 int irq = K_BCM1480_INT_TIMER_0+cpu; 57 58 /* Only have 4 general purpose timers */ 59 if (cpu > 3) { 60 BUG(); 61 } 62 63 if (!cpu) { 64 /* Use our own gettimeoffset() routine */ 65 do_gettimeoffset = bcm1480_gettimeoffset; 66 } 67 68 bcm1480_mask_irq(cpu, irq); 69 70 /* Map the timer interrupt to ip[4] of this cpu */ 71 __raw_writeq(IMR_IP4_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) 72 + (irq<<3))); 73 74 /* the general purpose timer ticks at 1 Mhz independent of 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 __raw_writeq( 78 #ifndef CONFIG_SIMULATION 79 1000000/HZ 80 #else 81 50000/HZ 82 #endif 83 , IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT))); 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 bcm1480_unmask_irq(cpu, irq); 90 bcm1480_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. bcm1480_timer_interrupt is 96 * called directly from irq_handler.S when IP[4] is set during an 97 * interrupt 98 */ 99 } 100 101 #include <asm/sibyte/sb1250.h> 102 103 void bcm1480_timer_interrupt(struct pt_regs *regs) 104 { 105 int cpu = smp_processor_id(); 106 int irq = K_BCM1480_INT_TIMER_0+cpu; 107 108 /* Reset the timer */ 109 __raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS, 110 IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG))); 111 112 if (cpu == 0) { 113 /* 114 * CPU 0 handles the global timer interrupt job 115 */ 116 ll_timer_interrupt(irq, regs); 117 } 118 else { 119 /* 120 * other CPUs should just do profiling and process accounting 121 */ 122 ll_local_timer_interrupt(irq, regs); 123 } 124 } 125 126 /* 127 * We use our own do_gettimeoffset() instead of the generic one, 128 * because the generic one does not work for SMP case. 129 * In addition, since we use general timer 0 for system time, 130 * we can get accurate intra-jiffy offset without calibration. 131 */ 132 unsigned long bcm1480_gettimeoffset(void) 133 { 134 unsigned long count = 135 __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT))); 136 137 return 1000000/HZ - count; 138 } 139