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Subject[PATCH v4 2/8] rtc: goldfish: Add RTC driver for Android emulator
Date
From: Miodrag Dinic <miodrag.dinic@imgtec.com>

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>
---
MAINTAINERS | 1 +
drivers/rtc/Kconfig | 8 ++
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-goldfish.c | 237 +++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 247 insertions(+)
create mode 100644 drivers/rtc/rtc-goldfish.c

diff --git a/MAINTAINERS b/MAINTAINERS
index f64c81b..3d105be 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -844,6 +844,7 @@ 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>
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 72419ac..0101dba 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -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
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index acd366b..d995d49 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -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
diff --git a/drivers/rtc/rtc-goldfish.c b/drivers/rtc/rtc-goldfish.c
new file mode 100644
index 0000000..d677692
--- /dev/null
+++ b/drivers/rtc/rtc-goldfish.c
@@ -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);
--
2.7.4
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