arch/powerpc/platforms/chrp/time.c

Source file repositories/reference/linux-study-clean/arch/powerpc/platforms/chrp/time.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/platforms/chrp/time.c
Extension
.c
Size
4115 bytes
Lines
160
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
 *
 * Adapted for PowerPC (PReP) by Gary Thomas
 * Modified by Cort Dougan (cort@cs.nmt.edu).
 * Copied and modified from arch/i386/kernel/time.c
 *
 */
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/kernel_stat.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bcd.h>
#include <linux/ioport.h>
#include <linux/of_address.h>

#include <asm/io.h>
#include <asm/nvram.h>
#include <asm/sections.h>
#include <asm/time.h>

#include <platforms/chrp/chrp.h>

#define NVRAM_AS0  0x74
#define NVRAM_AS1  0x75
#define NVRAM_DATA 0x77

static int nvram_as1 = NVRAM_AS1;
static int nvram_as0 = NVRAM_AS0;
static int nvram_data = NVRAM_DATA;

long __init chrp_time_init(void)
{
	struct device_node *rtcs;
	struct resource r;
	int base;

	rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
	if (rtcs == NULL)
		rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
	if (rtcs == NULL)
		return 0;
	if (of_address_to_resource(rtcs, 0, &r)) {
		of_node_put(rtcs);
		return 0;
	}
	of_node_put(rtcs);

	base = r.start;
	nvram_as1 = 0;
	nvram_as0 = base;
	nvram_data = base + 1;

	return 0;
}

static int chrp_cmos_clock_read(int addr)
{
	if (nvram_as1 != 0)
		outb(addr>>8, nvram_as1);
	outb(addr, nvram_as0);
	return (inb(nvram_data));
}

static void chrp_cmos_clock_write(unsigned long val, int addr)
{
	if (nvram_as1 != 0)
		outb(addr>>8, nvram_as1);
	outb(addr, nvram_as0);
	outb(val, nvram_data);
	return;
}

/*
 * Set the hardware clock. -- Cort
 */
int chrp_set_rtc_time(struct rtc_time *tmarg)
{
	unsigned char save_control, save_freq_select;
	struct rtc_time tm = *tmarg;

Annotation

Implementation Notes