linux/drivers/rtc/rtc-opal.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IBM OPAL RTC driver
* Copyright (C) 2014 IBM
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#define DRVNAME "rtc-opal"
#include <linux/module.h>
#include <linux/err.h>
#include <linux/rtc.h>
#include <linux/delay.h>
#include <linux/bcd.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <asm/opal.h>
#include <asm/firmware.h>
static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
{
tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1;
tm->tm_mday = bcd2bin(y_m_d & 0xff);
tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff);
tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff);
tm->tm_wday = -1;
}
static void tm_to_opal(struct rtc_time *tm, u32 *y_m_d, u64 *h_m_s_ms)
{
*y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
*y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
*y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
*y_m_d |= ((u32)bin2bcd(tm->tm_mday));
*h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
*h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
*h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
}
static int opal_get_rtc_time(struct device *dev, struct rtc_time *tm)
{
s64 rc = OPAL_BUSY;
int retries = 10;
u32 y_m_d;
u64 h_m_s_ms;
__be32 __y_m_d;
__be64 __h_m_s_ms;
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
if (rc == OPAL_BUSY_EVENT) {
msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
} else if (rc == OPAL_BUSY) {
msleep(OPAL_BUSY_DELAY_MS);
} else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
if (retries--) {
msleep(10); /* Wait 10ms before retry */
rc = OPAL_BUSY; /* go around again */
}
}
}
if (rc != OPAL_SUCCESS)
return -EIO;
y_m_d = be32_to_cpu(__y_m_d);
h_m_s_ms = be64_to_cpu(__h_m_s_ms);
opal_to_tm(y_m_d, h_m_s_ms, tm);
return 0;
}
static int opal_set_rtc_time(struct device *dev, struct rtc_time *tm)
{
s64 rc = OPAL_BUSY;
int retries = 10;
u32 y_m_d = 0;
u64 h_m_s_ms = 0;
tm_to_opal(tm, &y_m_d, &h_m_s_ms);
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
rc = opal_rtc_write(y_m_d, h_m_s_ms);
if (rc == OPAL_BUSY_EVENT) {
msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
} else if (rc == OPAL_BUSY) {
msleep(OPAL_BUSY_DELAY_MS);
} else if (rc == OPAL_HARDWARE || rc == OPAL_INTERNAL_ERROR) {
if (retries--) {
msleep(10); /* Wait 10ms before retry */
rc = OPAL_BUSY; /* go around again */
}
}
}
return rc == OPAL_SUCCESS ? 0 : -EIO;
}
/*
* TPO Timed Power-On
*
* TPO get/set OPAL calls care about the hour and min and to make it consistent
* with the rtc utility time conversion functions, we use the 'u64' to store
* its value and perform bit shift by 32 before use..
*/
static int opal_get_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
{
__be32 __y_m_d, __h_m;
struct opal_msg msg;
int rc, token;
u64 h_m_s_ms;
u32 y_m_d;
token = opal_async_get_token_interruptible();
if (token < 0) {
if (token != -ERESTARTSYS)
pr_err("Failed to get the async token\n");
return token;
}
rc = opal_tpo_read(token, &__y_m_d, &__h_m);
if (rc != OPAL_ASYNC_COMPLETION) {
rc = -EIO;
goto exit;
}
rc = opal_async_wait_response(token, &msg);
if (rc) {
rc = -EIO;
goto exit;
}
rc = opal_get_async_rc(msg);
if (rc != OPAL_SUCCESS) {
rc = -EIO;
goto exit;
}
y_m_d = be32_to_cpu(__y_m_d);
h_m_s_ms = ((u64)be32_to_cpu(__h_m) << 32);
/* check if no alarm is set */
if (y_m_d == 0 && h_m_s_ms == 0) {
pr_debug("No alarm is set\n");
rc = -ENOENT;
goto exit;
} else {
pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
}
opal_to_tm(y_m_d, h_m_s_ms, &alarm->time);
exit:
opal_async_release_token(token);
return rc;
}
/* Set Timed Power-On */
static int opal_set_tpo_time(struct device *dev, struct rtc_wkalrm *alarm)
{
u64 h_m_s_ms = 0;
struct opal_msg msg;
u32 y_m_d = 0;
int token, rc;
/* if alarm is enabled */
if (alarm->enabled) {
tm_to_opal(&alarm->time, &y_m_d, &h_m_s_ms);
pr_debug("Alarm set to %x %llx\n", y_m_d, h_m_s_ms);
} else {
pr_debug("Alarm getting disabled\n");
}
token = opal_async_get_token_interruptible();
if (token < 0) {
if (token != -ERESTARTSYS)
pr_err("Failed to get the async token\n");
return token;
}
/* TPO, we care about hour and minute */
rc = opal_tpo_write(token, y_m_d,
(u32)((h_m_s_ms >> 32) & 0xffff0000));
if (rc != OPAL_ASYNC_COMPLETION) {
rc = -EIO;
goto exit;
}
rc = opal_async_wait_response(token, &msg);
if (rc) {
rc = -EIO;
goto exit;
}
rc = opal_get_async_rc(msg);
if (rc != OPAL_SUCCESS)
rc = -EIO;
exit:
opal_async_release_token(token);
return rc;
}
static int opal_tpo_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct rtc_wkalrm alarm = { .enabled = 0 };
/*
* TPO is automatically enabled when opal_set_tpo_time() is called with
* non-zero rtc-time. We only handle disable case which needs to be
* explicitly told to opal.
*/
return enabled ? 0 : opal_set_tpo_time(dev, &alarm);
}
static const struct rtc_class_ops opal_rtc_ops = {
.read_time = opal_get_rtc_time,
.set_time = opal_set_rtc_time,
.read_alarm = opal_get_tpo_time,
.set_alarm = opal_set_tpo_time,
.alarm_irq_enable = opal_tpo_alarm_irq_enable,
};
static int opal_rtc_probe(struct platform_device *pdev)
{
struct rtc_device *rtc;
rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
if (pdev->dev.of_node &&
(of_property_read_bool(pdev->dev.of_node, "wakeup-source") ||
of_property_read_bool(pdev->dev.of_node, "has-tpo")/* legacy */))
device_set_wakeup_capable(&pdev->dev, true);
else
clear_bit(RTC_FEATURE_ALARM, rtc->features);
rtc->ops = &opal_rtc_ops;
rtc->range_min = RTC_TIMESTAMP_BEGIN_0000;
rtc->range_max = RTC_TIMESTAMP_END_9999;
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
return devm_rtc_register_device(rtc);
}
static const struct of_device_id opal_rtc_match[] = {
{
.compatible = "ibm,opal-rtc",
},
{ }
};
MODULE_DEVICE_TABLE(of, opal_rtc_match);
static const struct platform_device_id opal_rtc_driver_ids[] = {
{
.name = "opal-rtc",
},
{ }
};
MODULE_DEVICE_TABLE(platform, opal_rtc_driver_ids);
static struct platform_driver opal_rtc_driver = {
.probe = opal_rtc_probe,
.id_table = opal_rtc_driver_ids,
.driver = {
.name = DRVNAME,
.of_match_table = opal_rtc_match,
},
};
static int __init opal_rtc_init(void)
{
if (!firmware_has_feature(FW_FEATURE_OPAL))
return -ENODEV;
return platform_driver_register(&opal_rtc_driver);
}
static void __exit opal_rtc_exit(void)
{
platform_driver_unregister(&opal_rtc_driver);
}
MODULE_AUTHOR("Neelesh Gupta <neelegup@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("IBM OPAL RTC driver");
MODULE_LICENSE("GPL");
module_init(opal_rtc_init);
module_exit(opal_rtc_exit);