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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/powerpc/platforms/powernv/opal-rtc.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 * PowerNV Real Time Clock.

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 *

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 * Copyright 2011 IBM Corp.

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 */

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#include <linux/kernel.h>

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#include <linux/time.h>

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#include <linux/bcd.h>

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#include <linux/rtc.h>

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#include <linux/delay.h>

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#include <linux/of.h>

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#include <linux/of_platform.h>

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#include <linux/platform_device.h>

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#include <asm/opal.h>

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#include <asm/firmware.h>

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#include <asm/machdep.h>

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static void __init opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)

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{

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	tm->tm_year	= ((bcd2bin(y_m_d >> 24) * 100) +

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			   bcd2bin((y_m_d >> 16) & 0xff)) - 1900;

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	tm->tm_mon	= bcd2bin((y_m_d >> 8) & 0xff) - 1;

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	tm->tm_mday	= bcd2bin(y_m_d & 0xff);

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	tm->tm_hour	= bcd2bin((h_m_s_ms >> 56) & 0xff);

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	tm->tm_min	= bcd2bin((h_m_s_ms >> 48) & 0xff);

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	tm->tm_sec	= bcd2bin((h_m_s_ms >> 40) & 0xff);

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	tm->tm_wday     = -1;

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}

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time64_t __init opal_get_boot_time(void)

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{

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	struct rtc_time tm;

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	u32 y_m_d;

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	u64 h_m_s_ms;

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	__be32 __y_m_d;

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	__be64 __h_m_s_ms;

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	long rc = OPAL_BUSY;

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	if (!opal_check_token(OPAL_RTC_READ))

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		return 0;

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	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {

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		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);

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		if (rc == OPAL_BUSY_EVENT) {

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			mdelay(OPAL_BUSY_DELAY_MS);

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			opal_poll_events(NULL);

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		} else if (rc == OPAL_BUSY) {

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			mdelay(OPAL_BUSY_DELAY_MS);

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		}

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	}

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	if (rc != OPAL_SUCCESS)

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		return 0;

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	y_m_d = be32_to_cpu(__y_m_d);

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	h_m_s_ms = be64_to_cpu(__h_m_s_ms);

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	opal_to_tm(y_m_d, h_m_s_ms, &tm);

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	return rtc_tm_to_time64(&tm);

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}

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static __init int opal_time_init(void)

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{

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	struct platform_device *pdev;

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	struct device_node *rtc;

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	rtc = of_find_node_by_path("/ibm,opal/rtc");

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	if (rtc) {

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		pdev = of_platform_device_create(rtc, "opal-rtc", NULL);

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		of_node_put(rtc);

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	} else {

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		if (opal_check_token(OPAL_RTC_READ) ||

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		    opal_check_token(OPAL_READ_TPO))

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			pdev = platform_device_register_simple("opal-rtc", -1,

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							       NULL, 0);

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		else

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			return -ENODEV;

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	}

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	return PTR_ERR_OR_ZERO(pdev);

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}

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machine_subsys_initcall(powernv, opal_time_init);

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