cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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opal-rtc.c (1957B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * PowerNV Real Time Clock.
      4 *
      5 * Copyright 2011 IBM Corp.
      6 */
      7
      8
      9#include <linux/kernel.h>
     10#include <linux/time.h>
     11#include <linux/bcd.h>
     12#include <linux/rtc.h>
     13#include <linux/delay.h>
     14#include <linux/platform_device.h>
     15#include <linux/of_platform.h>
     16
     17#include <asm/opal.h>
     18#include <asm/firmware.h>
     19#include <asm/machdep.h>
     20
     21static void __init opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
     22{
     23	tm->tm_year	= ((bcd2bin(y_m_d >> 24) * 100) +
     24			   bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
     25	tm->tm_mon	= bcd2bin((y_m_d >> 8) & 0xff) - 1;
     26	tm->tm_mday	= bcd2bin(y_m_d & 0xff);
     27	tm->tm_hour	= bcd2bin((h_m_s_ms >> 56) & 0xff);
     28	tm->tm_min	= bcd2bin((h_m_s_ms >> 48) & 0xff);
     29	tm->tm_sec	= bcd2bin((h_m_s_ms >> 40) & 0xff);
     30	tm->tm_wday     = -1;
     31}
     32
     33time64_t __init opal_get_boot_time(void)
     34{
     35	struct rtc_time tm;
     36	u32 y_m_d;
     37	u64 h_m_s_ms;
     38	__be32 __y_m_d;
     39	__be64 __h_m_s_ms;
     40	long rc = OPAL_BUSY;
     41
     42	if (!opal_check_token(OPAL_RTC_READ))
     43		return 0;
     44
     45	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
     46		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
     47		if (rc == OPAL_BUSY_EVENT) {
     48			mdelay(OPAL_BUSY_DELAY_MS);
     49			opal_poll_events(NULL);
     50		} else if (rc == OPAL_BUSY) {
     51			mdelay(OPAL_BUSY_DELAY_MS);
     52		}
     53	}
     54	if (rc != OPAL_SUCCESS)
     55		return 0;
     56
     57	y_m_d = be32_to_cpu(__y_m_d);
     58	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
     59	opal_to_tm(y_m_d, h_m_s_ms, &tm);
     60	return rtc_tm_to_time64(&tm);
     61}
     62
     63static __init int opal_time_init(void)
     64{
     65	struct platform_device *pdev;
     66	struct device_node *rtc;
     67
     68	rtc = of_find_node_by_path("/ibm,opal/rtc");
     69	if (rtc) {
     70		pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
     71		of_node_put(rtc);
     72	} else {
     73		if (opal_check_token(OPAL_RTC_READ) ||
     74		    opal_check_token(OPAL_READ_TPO))
     75			pdev = platform_device_register_simple("opal-rtc", -1,
     76							       NULL, 0);
     77		else
     78			return -ENODEV;
     79	}
     80
     81	return PTR_ERR_OR_ZERO(pdev);
     82}
     83machine_subsys_initcall(powernv, opal_time_init);