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/* Copyright 2013-2014 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <skiboot.h>
#include <opal.h>
#include <mem_region.h>
#include <device.h>
#include <timebase.h>
#include <time-utils.h>
#include <lock.h>
/* timebase when tm_offset was assigned */
static unsigned long tb_synctime;
/*
* Absolute time that was last assigned.
* Current rtc value is calculated from this.
*/
static struct tm tm_offset;
/* protects tm_offset & tb_synctime */
static struct lock emulation_lock;
static int64_t fake_rtc_write(uint32_t ymd, uint64_t hmsm)
{
lock(&emulation_lock);
datetime_to_tm(ymd, hmsm, &tm_offset);
tb_synctime = mftb();
unlock(&emulation_lock);
return OPAL_SUCCESS;
}
static int64_t fake_rtc_read(uint32_t *ymd, uint64_t *hmsm)
{
time_t sec;
struct tm tm_calculated;
if (!ymd || !hmsm)
return OPAL_PARAMETER;
/* Compute the emulated clock value */
lock(&emulation_lock);
sec = tb_to_secs(mftb() - tb_synctime) + mktime(&tm_offset);
gmtime_r(&sec, &tm_calculated);
tm_to_datetime(&tm_calculated, ymd, hmsm);
unlock(&emulation_lock);
return OPAL_SUCCESS;
}
void fake_rtc_init(void)
{
struct mem_region *rtc_region = NULL;
uint32_t *rtc = NULL, *fake_ymd;
uint64_t *fake_hmsm;
struct dt_node *np;
/* Read initial values from reserved memory */
rtc_region = find_mem_region("ibm,fake-rtc");
/* Should we register anyway? */
if (!rtc_region) {
prlog(PR_TRACE, "No initial RTC value found\n");
return;
}
init_lock(&emulation_lock);
/* Fetch the initial rtc values */
rtc = (uint32_t *) rtc_region->start;
fake_ymd = rtc;
fake_hmsm = ((uint64_t *) &rtc[1]);
fake_rtc_write(*fake_ymd, *fake_hmsm);
/* Register opal calls */
opal_register(OPAL_RTC_READ, fake_rtc_read, 2);
opal_register(OPAL_RTC_WRITE, fake_rtc_write, 2);
/* add the fake rtc dt node */
np = dt_new(opal_node, "rtc");
dt_add_property_strings(np, "compatible", "ibm,opal-rtc");
prlog(PR_TRACE, "Init fake RTC to Date:%d-%d-%d Time:%d-%d-%d\n",
tm_offset.tm_mon, tm_offset.tm_mday, tm_offset.tm_year,
tm_offset.tm_hour, tm_offset.tm_min, tm_offset.tm_sec);
}
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