| Mark.Zhan | a240a46 | 2006-05-06 17:04:20 +0800 | [diff] [blame^] | 1 | /* |
| 2 | * time.c: MIPS CPU Count/Compare timer hookup |
| 3 | * |
| 4 | * Author: Mark.Zhan, <rongkai.zhan@windriver.com> |
| 5 | * |
| 6 | * This file is subject to the terms and conditions of the GNU General Public |
| 7 | * License. See the file "COPYING" in the main directory of this archive |
| 8 | * for more details. |
| 9 | * |
| 10 | * Copyright (C) 1996, 1997, 2004 by Ralf Baechle (ralf@linux-mips.org) |
| 11 | * Copyright (C) 2006, Wind River System Inc. |
| 12 | */ |
| 13 | #include <linux/config.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/string.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/param.h> /* for HZ */ |
| 18 | #include <linux/irq.h> |
| 19 | #include <linux/timex.h> |
| 20 | #include <linux/interrupt.h> |
| 21 | |
| 22 | #include <asm/reboot.h> |
| 23 | #include <asm/time.h> |
| 24 | #include <asm/io.h> |
| 25 | #include <asm/bootinfo.h> |
| 26 | #include <asm/gt64120.h> |
| 27 | |
| 28 | #define WRPPMC_CPU_CLK_FREQ 40000000 /* 40MHZ */ |
| 29 | |
| 30 | void __init wrppmc_timer_setup(struct irqaction *irq) |
| 31 | { |
| 32 | /* Install ISR for timer interrupt */ |
| 33 | setup_irq(WRPPMC_MIPS_TIMER_IRQ, irq); |
| 34 | |
| 35 | /* to generate the first timer interrupt */ |
| 36 | write_c0_compare(mips_hpt_frequency/HZ); |
| 37 | write_c0_count(0); |
| 38 | } |
| 39 | |
| 40 | /* |
| 41 | * Estimate CPU frequency. Sets mips_hpt_frequency as a side-effect |
| 42 | * |
| 43 | * NOTE: We disable all GT64120 timers, and use MIPS processor internal |
| 44 | * timer as the source of kernel clock tick. |
| 45 | */ |
| 46 | void __init wrppmc_time_init(void) |
| 47 | { |
| 48 | /* Disable GT64120 timers */ |
| 49 | GT_WRITE(GT_TC_CONTROL_OFS, 0x00); |
| 50 | GT_WRITE(GT_TC0_OFS, 0x00); |
| 51 | GT_WRITE(GT_TC1_OFS, 0x00); |
| 52 | GT_WRITE(GT_TC2_OFS, 0x00); |
| 53 | GT_WRITE(GT_TC3_OFS, 0x00); |
| 54 | |
| 55 | /* Use MIPS compare/count internal timer */ |
| 56 | mips_hpt_frequency = WRPPMC_CPU_CLK_FREQ; |
| 57 | } |