1/* 2 * linux/arch/arm/mach-omap2/timer-gp.c 3 * 4 * OMAP2 GP timer support. 5 * 6 * Copyright (C) 2005 Nokia Corporation 7 * Author: Paul Mundt <paul.mundt@nokia.com> 8 * Juha Yrj�l� <juha.yrjola@nokia.com> 9 * OMAP Dual-mode timer framework support by Timo Teras 10 * 11 * Some parts based off of TI's 24xx code: 12 * 13 * Copyright (C) 2004 Texas Instruments, Inc. 14 * 15 * Roughly modelled after the OMAP1 MPU timer code. 16 * 17 * This file is subject to the terms and conditions of the GNU General Public 18 * License. See the file "COPYING" in the main directory of this archive 19 * for more details. 20 */ 21#include <linux/init.h> 22#include <linux/time.h> 23#include <linux/interrupt.h> 24#include <linux/err.h> 25#include <linux/clk.h> 26#include <linux/delay.h> 27#include <linux/irq.h> 28 29#include <asm/mach/time.h> 30#include <asm/arch/dmtimer.h> 31 32static struct omap_dm_timer *gptimer; 33 34static inline void omap2_gp_timer_start(unsigned long load_val) 35{ 36 omap_dm_timer_set_load(gptimer, 1, 0xffffffff - load_val); 37 omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW); 38 omap_dm_timer_start(gptimer); 39} 40 41static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id) 42{ 43 write_seqlock(&xtime_lock); 44 45 omap_dm_timer_write_status(gptimer, OMAP_TIMER_INT_OVERFLOW); 46 timer_tick(); 47 48 write_sequnlock(&xtime_lock); 49 50 return IRQ_HANDLED; 51} 52 53static struct irqaction omap2_gp_timer_irq = { 54 .name = "gp timer", 55 .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, 56 .handler = omap2_gp_timer_interrupt, 57}; 58 59static void __init omap2_gp_timer_init(void) 60{ 61 u32 tick_period; 62 63 omap_dm_timer_init(); 64 gptimer = omap_dm_timer_request_specific(1); 65 BUG_ON(gptimer == NULL); 66 67 omap_dm_timer_set_source(gptimer, OMAP_TIMER_SRC_SYS_CLK); 68 tick_period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / HZ; 69 tick_period -= 1; 70 71 setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq); 72 omap2_gp_timer_start(tick_period); 73} 74 75struct sys_timer omap_timer = { 76 .init = omap2_gp_timer_init, 77}; 78