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rtc: goldfish: Add RTC driver for Android emulator

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Add device driver for a virtual RTC device in Android emulator.

The compatible string used by OS for binding the driver is defined
as "google,goldfish-rtc".

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Miodrag Dinic 2017-08-18 15:08:54 +02:00 committed by Alexandre Belloni
parent 7a08de1d8f
commit f22d9cdcb5
4 changed files with 247 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
MAINTAINERS
View file

@ -845,6 +845,7 @@ ANDROID GOLDFISH RTC DRIVER
M: Miodrag Dinic <miodrag.dinic@imgtec.com>
S: Supported
F: Documentation/devicetree/bindings/rtc/google,goldfish-rtc.txt
F: drivers/rtc/rtc-goldfish.c
ANDROID ION DRIVER
M: Laura Abbott <labbott@redhat.com>

8
drivers/rtc/Kconfig
View file

@ -1780,5 +1780,13 @@ config RTC_DRV_HID_SENSOR_TIME
If this driver is compiled as a module, it will be named
rtc-hid-sensor-time.
config RTC_DRV_GOLDFISH
tristate "Goldfish Real Time Clock"
depends on MIPS && (GOLDFISH || COMPILE_TEST)
help
Say yes to enable RTC driver for the Goldfish based virtual platform.
Goldfish is a code name for the virtual platform developed by Google
for Android emulation.
endif # RTC_CLASS

1
drivers/rtc/Makefile
View file

@ -170,3 +170,4 @@ obj-$(CONFIG_RTC_DRV_WM8350) += rtc-wm8350.o
obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o
obj-$(CONFIG_RTC_DRV_XGENE) += rtc-xgene.o
obj-$(CONFIG_RTC_DRV_ZYNQMP) += rtc-zynqmp.o
obj-$(CONFIG_RTC_DRV_GOLDFISH) += rtc-goldfish.o

237
drivers/rtc/rtc-goldfish.c Normal file
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@ -0,0 +1,237 @@
/* drivers/rtc/rtc-goldfish.c
*
* Copyright (C) 2007 Google, Inc.
* Copyright (C) 2017 Imagination Technologies Ltd.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/rtc.h>
#include <linux/io.h>
#define TIMER_TIME_LOW 0x00 /* get low bits of current time */
/* and update TIMER_TIME_HIGH */
#define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */
/* TIMER_TIME_LOW read */
#define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */
/* activate it */
#define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */
#define TIMER_IRQ_ENABLED 0x10
#define TIMER_CLEAR_ALARM 0x14
#define TIMER_ALARM_STATUS 0x18
#define TIMER_CLEAR_INTERRUPT 0x1c
struct goldfish_rtc {
void __iomem *base;
int irq;
struct rtc_device *rtc;
};
static int goldfish_rtc_read_alarm(struct device *dev,
struct rtc_wkalrm *alrm)
{
u64 rtc_alarm;
u64 rtc_alarm_low;
u64 rtc_alarm_high;
void __iomem *base;
struct goldfish_rtc *rtcdrv;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
rtc_alarm_low = readl(base + TIMER_ALARM_LOW);
rtc_alarm_high = readl(base + TIMER_ALARM_HIGH);
rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low;
do_div(rtc_alarm, NSEC_PER_SEC);
memset(alrm, 0, sizeof(struct rtc_wkalrm));
rtc_time_to_tm(rtc_alarm, &alrm->time);
if (readl(base + TIMER_ALARM_STATUS))
alrm->enabled = 1;
else
alrm->enabled = 0;
return 0;
}
static int goldfish_rtc_set_alarm(struct device *dev,
struct rtc_wkalrm *alrm)
{
struct goldfish_rtc *rtcdrv;
unsigned long rtc_alarm;
u64 rtc_alarm64;
u64 rtc_status_reg;
void __iomem *base;
int ret = 0;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
if (alrm->enabled) {
ret = rtc_tm_to_time(&alrm->time, &rtc_alarm);
if (ret != 0)
return ret;
rtc_alarm64 = rtc_alarm * NSEC_PER_SEC;
writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH);
writel(rtc_alarm64, base + TIMER_ALARM_LOW);
} else {
/*
* if this function was called with enabled=0
* then it could mean that the application is
* trying to cancel an ongoing alarm
*/
rtc_status_reg = readl(base + TIMER_ALARM_STATUS);
if (rtc_status_reg)
writel(1, base + TIMER_CLEAR_ALARM);
}
return ret;
}
static int goldfish_rtc_alarm_irq_enable(struct device *dev,
unsigned int enabled)
{
void __iomem *base;
struct goldfish_rtc *rtcdrv;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
if (enabled)
writel(1, base + TIMER_IRQ_ENABLED);
else
writel(0, base + TIMER_IRQ_ENABLED);
return 0;
}
static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id)
{
struct goldfish_rtc *rtcdrv = dev_id;
void __iomem *base = rtcdrv->base;
writel(1, base + TIMER_CLEAR_INTERRUPT);
rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF);
return IRQ_HANDLED;
}
static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct goldfish_rtc *rtcdrv;
void __iomem *base;
u64 time_high;
u64 time_low;
u64 time;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
time_low = readl(base + TIMER_TIME_LOW);
time_high = readl(base + TIMER_TIME_HIGH);
time = (time_high << 32) | time_low;
do_div(time, NSEC_PER_SEC);
rtc_time_to_tm(time, tm);
return 0;
}
static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct goldfish_rtc *rtcdrv;
void __iomem *base;
unsigned long now;
u64 now64;
int ret;
rtcdrv = dev_get_drvdata(dev);
base = rtcdrv->base;
ret = rtc_tm_to_time(tm, &now);
if (ret == 0) {
now64 = now * NSEC_PER_SEC;
writel((now64 >> 32), base + TIMER_TIME_HIGH);
writel(now64, base + TIMER_TIME_LOW);
}
return ret;
}
static const struct rtc_class_ops goldfish_rtc_ops = {
.read_time = goldfish_rtc_read_time,
.set_time = goldfish_rtc_set_time,
.read_alarm = goldfish_rtc_read_alarm,
.set_alarm = goldfish_rtc_set_alarm,
.alarm_irq_enable = goldfish_rtc_alarm_irq_enable
};
static int goldfish_rtc_probe(struct platform_device *pdev)
{
struct goldfish_rtc *rtcdrv;
struct resource *r;
int err;
rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL);
if (!rtcdrv)
return -ENOMEM;
platform_set_drvdata(pdev, rtcdrv);
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r)
return -ENODEV;
rtcdrv->base = devm_ioremap_resource(&pdev->dev, r);
if (IS_ERR(rtcdrv->base))
return -ENODEV;
rtcdrv->irq = platform_get_irq(pdev, 0);
if (rtcdrv->irq < 0)
return -ENODEV;
rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
&goldfish_rtc_ops,
THIS_MODULE);
if (IS_ERR(rtcdrv->rtc))
return PTR_ERR(rtcdrv->rtc);
err = devm_request_irq(&pdev->dev, rtcdrv->irq,
goldfish_rtc_interrupt,
0, pdev->name, rtcdrv);
if (err)
return err;
return 0;
}
static const struct of_device_id goldfish_rtc_of_match[] = {
{ .compatible = "google,goldfish-rtc", },
{},
};
MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match);
static struct platform_driver goldfish_rtc = {
.probe = goldfish_rtc_probe,
.driver = {
.name = "goldfish_rtc",
.of_match_table = goldfish_rtc_of_match,
}
};
module_platform_driver(goldfish_rtc);