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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 15:35:06 +07:00
682e6b4da5
The OPAL RTC driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware, which causes large scheduling
latencies, up to 50 seconds have been observed here when RTC stops
responding (BMC reboot can do it).
Fix this by converting it to the standard form OPAL_BUSY loop that
sleeps.
Fixes: 628daa8d5a ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks")
Cc: stable@vger.kernel.org # v3.2+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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/platform_device.h>
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#include <linux/of_platform.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 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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unsigned long __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 mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
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tm.tm_hour, tm.tm_min, tm.tm_sec);
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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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