timers.c (5323B)
1// SPDX-License-Identifier: GPL-2.0 2/***************************************************************************/ 3 4/* 5 * timers.c -- generic ColdFire hardware timer support. 6 * 7 * Copyright (C) 1999-2008, Greg Ungerer <gerg@snapgear.com> 8 */ 9 10/***************************************************************************/ 11 12#include <linux/kernel.h> 13#include <linux/init.h> 14#include <linux/sched.h> 15#include <linux/interrupt.h> 16#include <linux/irq.h> 17#include <linux/profile.h> 18#include <linux/clocksource.h> 19#include <asm/io.h> 20#include <asm/traps.h> 21#include <asm/machdep.h> 22#include <asm/coldfire.h> 23#include <asm/mcftimer.h> 24#include <asm/mcfsim.h> 25 26/***************************************************************************/ 27 28/* 29 * By default use timer1 as the system clock timer. 30 */ 31#define FREQ (MCF_BUSCLK / 16) 32#define TA(a) (MCFTIMER_BASE1 + (a)) 33 34/* 35 * These provide the underlying interrupt vector support. 36 * Unfortunately it is a little different on each ColdFire. 37 */ 38void coldfire_profile_init(void); 39 40#if defined(CONFIG_M53xx) || defined(CONFIG_M5441x) 41#define __raw_readtrr __raw_readl 42#define __raw_writetrr __raw_writel 43#else 44#define __raw_readtrr __raw_readw 45#define __raw_writetrr __raw_writew 46#endif 47 48static u32 mcftmr_cycles_per_jiffy; 49static u32 mcftmr_cnt; 50 51/***************************************************************************/ 52 53static void init_timer_irq(void) 54{ 55#ifdef MCFSIM_ICR_AUTOVEC 56 /* Timer1 is always used as system timer */ 57 writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL6 | MCFSIM_ICR_PRI3, 58 MCFSIM_TIMER1ICR); 59 mcf_mapirq2imr(MCF_IRQ_TIMER, MCFINTC_TIMER1); 60 61#ifdef CONFIG_HIGHPROFILE 62 /* Timer2 is to be used as a high speed profile timer */ 63 writeb(MCFSIM_ICR_AUTOVEC | MCFSIM_ICR_LEVEL7 | MCFSIM_ICR_PRI3, 64 MCFSIM_TIMER2ICR); 65 mcf_mapirq2imr(MCF_IRQ_PROFILER, MCFINTC_TIMER2); 66#endif 67#endif /* MCFSIM_ICR_AUTOVEC */ 68} 69 70/***************************************************************************/ 71 72static irqreturn_t mcftmr_tick(int irq, void *dummy) 73{ 74 /* Reset the ColdFire timer */ 75 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, TA(MCFTIMER_TER)); 76 77 mcftmr_cnt += mcftmr_cycles_per_jiffy; 78 legacy_timer_tick(1); 79 return IRQ_HANDLED; 80} 81 82/***************************************************************************/ 83 84static u64 mcftmr_read_clk(struct clocksource *cs) 85{ 86 unsigned long flags; 87 u32 cycles; 88 u16 tcn; 89 90 local_irq_save(flags); 91 tcn = __raw_readw(TA(MCFTIMER_TCN)); 92 cycles = mcftmr_cnt; 93 local_irq_restore(flags); 94 95 return cycles + tcn; 96} 97 98/***************************************************************************/ 99 100static struct clocksource mcftmr_clk = { 101 .name = "tmr", 102 .rating = 250, 103 .read = mcftmr_read_clk, 104 .mask = CLOCKSOURCE_MASK(32), 105 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 106}; 107 108/***************************************************************************/ 109 110void hw_timer_init(void) 111{ 112 int r; 113 114 __raw_writew(MCFTIMER_TMR_DISABLE, TA(MCFTIMER_TMR)); 115 mcftmr_cycles_per_jiffy = FREQ / HZ; 116 /* 117 * The coldfire timer runs from 0 to TRR included, then 0 118 * again and so on. It counts thus actually TRR + 1 steps 119 * for 1 tick, not TRR. So if you want n cycles, 120 * initialize TRR with n - 1. 121 */ 122 __raw_writetrr(mcftmr_cycles_per_jiffy - 1, TA(MCFTIMER_TRR)); 123 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 | 124 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, TA(MCFTIMER_TMR)); 125 126 clocksource_register_hz(&mcftmr_clk, FREQ); 127 128 init_timer_irq(); 129 r = request_irq(MCF_IRQ_TIMER, mcftmr_tick, IRQF_TIMER, "timer", NULL); 130 if (r) { 131 pr_err("Failed to request irq %d (timer): %pe\n", MCF_IRQ_TIMER, 132 ERR_PTR(r)); 133 } 134 135#ifdef CONFIG_HIGHPROFILE 136 coldfire_profile_init(); 137#endif 138} 139 140/***************************************************************************/ 141#ifdef CONFIG_HIGHPROFILE 142/***************************************************************************/ 143 144/* 145 * By default use timer2 as the profiler clock timer. 146 */ 147#define PA(a) (MCFTIMER_BASE2 + (a)) 148 149/* 150 * Choose a reasonably fast profile timer. Make it an odd value to 151 * try and get good coverage of kernel operations. 152 */ 153#define PROFILEHZ 1013 154 155/* 156 * Use the other timer to provide high accuracy profiling info. 157 */ 158irqreturn_t coldfire_profile_tick(int irq, void *dummy) 159{ 160 /* Reset ColdFire timer2 */ 161 __raw_writeb(MCFTIMER_TER_CAP | MCFTIMER_TER_REF, PA(MCFTIMER_TER)); 162 if (current->pid) 163 profile_tick(CPU_PROFILING); 164 return IRQ_HANDLED; 165} 166 167/***************************************************************************/ 168 169void coldfire_profile_init(void) 170{ 171 int ret; 172 173 printk(KERN_INFO "PROFILE: lodging TIMER2 @ %dHz as profile timer\n", 174 PROFILEHZ); 175 176 /* Set up TIMER 2 as high speed profile clock */ 177 __raw_writew(MCFTIMER_TMR_DISABLE, PA(MCFTIMER_TMR)); 178 179 __raw_writetrr(((MCF_BUSCLK / 16) / PROFILEHZ), PA(MCFTIMER_TRR)); 180 __raw_writew(MCFTIMER_TMR_ENORI | MCFTIMER_TMR_CLK16 | 181 MCFTIMER_TMR_RESTART | MCFTIMER_TMR_ENABLE, PA(MCFTIMER_TMR)); 182 183 ret = request_irq(MCF_IRQ_PROFILER, coldfire_profile_tick, IRQF_TIMER, 184 "profile timer", NULL); 185 if (ret) { 186 pr_err("Failed to request irq %d (profile timer): %pe\n", 187 MCF_IRQ_PROFILER, ERR_PTR(ret)); 188 } 189} 190 191/***************************************************************************/ 192#endif /* CONFIG_HIGHPROFILE */ 193/***************************************************************************/