1// SPDX-License-Identifier: GPL-2.0 2/* 3 * linux/arch/m68k/hp300/time.c 4 * 5 * Copyright (C) 1998 Philip Blundell <philb@gnu.org> 6 * 7 * This file contains the HP300-specific time handling code. 8 */ 9 10#include <asm/ptrace.h> 11#include <linux/clocksource.h> 12#include <linux/types.h> 13#include <linux/init.h> 14#include <linux/sched.h> 15#include <linux/kernel_stat.h> 16#include <linux/interrupt.h> 17#include <asm/machdep.h> 18#include <asm/irq.h> 19#include <asm/io.h> 20#include <asm/traps.h> 21#include <asm/blinken.h> 22 23static u64 hp300_read_clk(struct clocksource *cs); 24 25static struct clocksource hp300_clk = { 26 .name = "timer", 27 .rating = 250, 28 .read = hp300_read_clk, 29 .mask = CLOCKSOURCE_MASK(32), 30 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 31}; 32 33static u32 clk_total, clk_offset; 34 35/* Clock hardware definitions */ 36 37#define CLOCKBASE 0xf05f8000 38 39#define CLKCR1 0x1 40#define CLKCR2 0x3 41#define CLKCR3 CLKCR1 42#define CLKSR CLKCR2 43#define CLKMSB1 0x5 44#define CLKLSB1 0x7 45#define CLKMSB2 0x9 46#define CLKMSB3 0xD 47 48#define CLKSR_INT1 BIT(0) 49 50/* This is for machines which generate the exact clock. */ 51 52#define HP300_TIMER_CLOCK_FREQ 250000 53#define HP300_TIMER_CYCLES (HP300_TIMER_CLOCK_FREQ / HZ) 54#define INTVAL (HP300_TIMER_CYCLES - 1) 55 56static irqreturn_t hp300_tick(int irq, void *dev_id) 57{ 58 unsigned long flags; 59 unsigned long tmp; 60 61 local_irq_save(flags); 62 in_8(CLOCKBASE + CLKSR); 63 asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE)); 64 clk_total += INTVAL; 65 clk_offset = 0; 66 legacy_timer_tick(1); 67 timer_heartbeat(); 68 local_irq_restore(flags); 69 70 /* Turn off the network and SCSI leds */ 71 blinken_leds(0, 0xe0); 72 return IRQ_HANDLED; 73} 74 75static u64 hp300_read_clk(struct clocksource *cs) 76{ 77 unsigned long flags; 78 unsigned char lsb, msb, msb_new; 79 u32 ticks; 80 81 local_irq_save(flags); 82 /* Read current timer 1 value */ 83 msb = in_8(CLOCKBASE + CLKMSB1); 84again: 85 if ((in_8(CLOCKBASE + CLKSR) & CLKSR_INT1) && msb > 0) 86 clk_offset = INTVAL; 87 lsb = in_8(CLOCKBASE + CLKLSB1); 88 msb_new = in_8(CLOCKBASE + CLKMSB1); 89 if (msb_new != msb) { 90 msb = msb_new; 91 goto again; 92 } 93 94 ticks = INTVAL - ((msb << 8) | lsb); 95 ticks += clk_offset + clk_total; 96 local_irq_restore(flags); 97 98 return ticks; 99} 100 101void __init hp300_sched_init(void) 102{ 103 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */ 104 out_8(CLOCKBASE + CLKCR1, 0x1); /* reset */ 105 106 asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE)); 107 108 if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", NULL)) 109 pr_err("Couldn't register timer interrupt\n"); 110 111 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */ 112 out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */ 113 114 clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ); 115} 116