LXR linux/arch/powerpc/platforms/powernv/opal-rtc.c

   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 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);
  84