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/arch/mips/sibyte/sb1250/time.c

https://bitbucket.org/evzijst/gittest
C | 136 lines | 63 code | 20 blank | 53 comment | 4 complexity | c6c8a0ce02b56ea1f4a06bc5f8faac4b MD5 | raw file
  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
 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	bus_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	bus_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
 77#ifdef CONFIG_SIMULATION
 78	bus_writeq(50000 / HZ,
 79		   IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
 80#else
 81	bus_writeq(1000000/HZ,
 82		   IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT)));
 83#endif
 84
 85	/* Set the timer running */
 86	bus_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
101void 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	__bus_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 */
130unsigned long sb1250_gettimeoffset(void)
131{
132	unsigned long count =
133		bus_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
134
135	return 1000000/HZ - count;
136 }