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Message-Id: <20220113201920.3201760-4-laurent@vivier.eu>
Date: Thu, 13 Jan 2022 21:19:19 +0100
From: Laurent Vivier <laurent@...ier.eu>
To: linux-kernel@...r.kernel.org
Cc: Thomas Gleixner <tglx@...utronix.de>,
Jiaxun Yang <jiaxun.yang@...goat.com>,
Alessandro Zummo <a.zummo@...ertech.it>,
linux-m68k@...ts.linux-m68k.org,
John Stultz <john.stultz@...aro.org>,
linux-rtc@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
Stephen Boyd <sboyd@...nel.org>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Laurent Vivier <laurent@...ier.eu>
Subject: [PATCH v6 3/4] clocksource/drivers: Add a goldfish-timer clocksource
Add a clocksource based on the goldfish-rtc device.
Signed-off-by: Laurent Vivier <laurent@...ier.eu>
---
drivers/clocksource/Kconfig | 7 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-goldfish.c | 130 +++++++++++++++++++++++++++
include/clocksource/timer-goldfish.h | 12 +++
4 files changed, 150 insertions(+)
create mode 100644 drivers/clocksource/timer-goldfish.c
create mode 100644 include/clocksource/timer-goldfish.h
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index f65e31bab9ae..6ca9bb78407d 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -711,4 +711,11 @@ config MICROCHIP_PIT64B
modes and high resolution. It is used as a clocksource
and a clockevent.
+config GOLDFISH_TIMER
+ bool "Clocksource using goldfish-rtc"
+ select RTC_CLASS
+ select RTC_DRV_GOLDFISH
+ help
+ Support for the timer/counter of goldfish-rtc
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index c17ee32a7151..e624a1a27027 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -88,3 +88,4 @@ obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o
obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o
obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o
+obj-$(CONFIG_GOLDFISH_TIMER) += timer-goldfish.o
diff --git a/drivers/clocksource/timer-goldfish.c b/drivers/clocksource/timer-goldfish.c
new file mode 100644
index 000000000000..b1553c3c9456
--- /dev/null
+++ b/drivers/clocksource/timer-goldfish.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/module.h>
+#include <clocksource/timer-goldfish.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_timer {
+ struct clock_event_device ced;
+ struct resource res;
+ void __iomem *base;
+ int irq;
+};
+
+static struct goldfish_timer *ced_to_gf(struct clock_event_device *ced)
+{
+ return container_of(ced, struct goldfish_timer, ced);
+}
+
+static int goldfish_timer_set_oneshot(struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+
+ __raw_writel(0, base + TIMER_ALARM_HIGH);
+ __raw_writel(0, base + TIMER_ALARM_LOW);
+ __raw_writel(1, base + TIMER_IRQ_ENABLED);
+
+ return 0;
+}
+
+static int goldfish_timer_shutdown(struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+
+ __raw_writel(0, base + TIMER_IRQ_ENABLED);
+
+ return 0;
+}
+
+static int goldfish_timer_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ struct goldfish_timer *timerdrv = ced_to_gf(evt);
+ void __iomem *base = timerdrv->base;
+ u64 now;
+
+ __raw_writel(1, base + TIMER_CLEAR_INTERRUPT);
+
+ /*
+ * time_low: get low bits of current time and update time_high
+ * time_high: get high bits of time at last time_low read
+ */
+ now = __raw_readl(base + TIMER_TIME_LOW);
+ now += (u64)__raw_readl(base + TIMER_TIME_HIGH) << 32;
+
+ now += delta;
+
+ __raw_writel(upper_32_bits(now), base + TIMER_ALARM_HIGH);
+ __raw_writel(lower_32_bits(now), base + TIMER_ALARM_LOW);
+
+ return 0;
+}
+
+static irqreturn_t golfish_timer_tick(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+void __init goldfish_timer_init(int irq, void __iomem *base)
+{
+ struct goldfish_timer *timerdrv;
+ int ret;
+
+ timerdrv = kzalloc(sizeof(*timerdrv), GFP_KERNEL);
+ if (!timerdrv)
+ return;
+
+ timerdrv->base = base;
+ timerdrv->irq = irq;
+
+ timerdrv->ced = (struct clock_event_device){
+ .name = "goldfish_timer",
+ .features = CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = goldfish_timer_shutdown,
+ .set_state_oneshot = goldfish_timer_set_oneshot,
+ .set_next_event = goldfish_timer_next_event,
+ .shift = 32,
+ };
+ timerdrv->res = (struct resource){
+ .name = "goldfish_timer",
+ .start = (unsigned long)base,
+ .end = (unsigned long)base + 0xfff,
+ };
+
+ if (request_resource(&iomem_resource, &timerdrv->res)) {
+ pr_err("Cannot allocate goldfish-timer resource\n");
+ return;
+ }
+
+ ret = request_irq(timerdrv->irq, golfish_timer_tick, IRQF_TIMER,
+ "goldfish_timer", &timerdrv->ced);
+ if (ret) {
+ pr_err("Couldn't register goldfish-timer interrupt\n");
+ return;
+ }
+
+ clockevents_config_and_register(&timerdrv->ced, NSEC_PER_SEC,
+ 1, 0xffffffff);
+}
+EXPORT_SYMBOL_GPL(goldfish_timer_init);
diff --git a/include/clocksource/timer-goldfish.h b/include/clocksource/timer-goldfish.h
new file mode 100644
index 000000000000..12bcd08f90af
--- /dev/null
+++ b/include/clocksource/timer-goldfish.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * goldfish-timer clocksource
+ */
+
+#ifndef _CLOCKSOURCE_GOLDFISH_TIMER_H
+#define _CLOCKSOURCE_GOLDFISH_TIMER_H
+
+extern void goldfish_timer_init(int irq, void __iomem *base);
+
+#endif /* _CLOCKSOURCE_GOLDFISH_TIMER_H */
+
--
2.34.1
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