| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 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/types.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/sched.h> |
| 14 | #include <linux/kernel_stat.h> |
| 15 | #include <linux/interrupt.h> |
| 16 | #include <asm/machdep.h> |
| 17 | #include <asm/irq.h> |
| 18 | #include <asm/io.h> |
| 19 | #include <asm/traps.h> |
| 20 | #include <asm/blinken.h> |
| 21 | |
| 22 | /* Clock hardware definitions */ |
| 23 | |
| 24 | #define CLOCKBASE 0xf05f8000 |
| 25 | |
| 26 | #define CLKCR1 0x1 |
| 27 | #define CLKCR2 0x3 |
| 28 | #define CLKCR3 CLKCR1 |
| 29 | #define CLKSR CLKCR2 |
| 30 | #define CLKMSB1 0x5 |
| 31 | #define CLKMSB2 0x9 |
| 32 | #define CLKMSB3 0xD |
| 33 | |
| 34 | /* This is for machines which generate the exact clock. */ |
| 35 | #define USECS_PER_JIFFY (1000000/HZ) |
| 36 | |
| 37 | #define INTVAL ((10000 / 4) - 1) |
| 38 | |
| 39 | static irqreturn_t hp300_tick(int irq, void *dev_id) |
| 40 | { |
| 41 | irq_handler_t timer_routine = dev_id; |
| 42 | unsigned long flags; |
| 43 | unsigned long tmp; |
| 44 | |
| 45 | local_irq_save(flags); |
| 46 | in_8(CLOCKBASE + CLKSR); |
| 47 | asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE)); |
| 48 | timer_routine(0, NULL); |
| 49 | local_irq_restore(flags); |
| 50 | |
| 51 | /* Turn off the network and SCSI leds */ |
| 52 | blinken_leds(0, 0xe0); |
| 53 | return IRQ_HANDLED; |
| 54 | } |
| 55 | |
| 56 | u32 hp300_gettimeoffset(void) |
| 57 | { |
| 58 | /* Read current timer 1 value */ |
| 59 | unsigned char lsb, msb1, msb2; |
| 60 | unsigned short ticks; |
| 61 | |
| 62 | msb1 = in_8(CLOCKBASE + 5); |
| 63 | lsb = in_8(CLOCKBASE + 7); |
| 64 | msb2 = in_8(CLOCKBASE + 5); |
| 65 | if (msb1 != msb2) |
| 66 | /* A carry happened while we were reading. Read it again */ |
| 67 | lsb = in_8(CLOCKBASE + 7); |
| 68 | ticks = INTVAL - ((msb2 << 8) | lsb); |
| 69 | return ((USECS_PER_JIFFY * ticks) / INTVAL) * 1000; |
| 70 | } |
| 71 | |
| 72 | void __init hp300_sched_init(irq_handler_t vector) |
| 73 | { |
| 74 | out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */ |
| 75 | out_8(CLOCKBASE + CLKCR1, 0x1); /* reset */ |
| 76 | |
| 77 | asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE)); |
| 78 | |
| 79 | if (request_irq(IRQ_AUTO_6, hp300_tick, 0, "timer tick", vector)) |
| 80 | pr_err("Couldn't register timer interrupt\n"); |
| 81 | |
| 82 | out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */ |
| 83 | out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */ |
| 84 | } |