1 // SPDX-License-Identifier: GPL-2.0
3 * linux/arch/m68k/hp300/time.c
5 * Copyright (C) 1998 Philip Blundell <philb@gnu.org>
7 * This file contains the HP300-specific time handling code.
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>
20 #include <asm/traps.h>
21 #include <asm/blinken.h>
23 static u64 hp300_read_clk(struct clocksource *cs);
25 static struct clocksource hp300_clk = {
28 .read = hp300_read_clk,
29 .mask = CLOCKSOURCE_MASK(32),
30 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
33 static u32 clk_total, clk_offset;
35 /* Clock hardware definitions */
37 #define CLOCKBASE 0xf05f8000
48 #define CLKSR_INT1 BIT(0)
50 /* This is for machines which generate the exact clock. */
52 #define HP300_TIMER_CLOCK_FREQ 250000
53 #define HP300_TIMER_CYCLES (HP300_TIMER_CLOCK_FREQ / HZ)
54 #define INTVAL (HP300_TIMER_CYCLES - 1)
56 static irqreturn_t hp300_tick(int irq, void *dev_id)
61 local_irq_save(flags);
62 in_8(CLOCKBASE + CLKSR);
63 asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
68 local_irq_restore(flags);
70 /* Turn off the network and SCSI leds */
71 blinken_leds(0, 0xe0);
75 static u64 hp300_read_clk(struct clocksource *cs)
78 unsigned char lsb, msb, msb_new;
81 local_irq_save(flags);
82 /* Read current timer 1 value */
83 msb = in_8(CLOCKBASE + CLKMSB1);
85 if ((in_8(CLOCKBASE + CLKSR) & CLKSR_INT1) && msb > 0)
87 lsb = in_8(CLOCKBASE + CLKLSB1);
88 msb_new = in_8(CLOCKBASE + CLKMSB1);
94 ticks = INTVAL - ((msb << 8) | lsb);
95 ticks += clk_offset + clk_total;
96 local_irq_restore(flags);
101 void __init hp300_sched_init(void)
103 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
104 out_8(CLOCKBASE + CLKCR1, 0x1); /* reset */
106 asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
108 if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", NULL))
109 pr_err("Couldn't register timer interrupt\n");
111 out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
112 out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
114 clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);