From: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@xxxxxxxxx>
Add generic clocksource and clockevent driver for the timer IP
used in Intel Keem Bay SoC.
One free running Counter used as a clocksource device and one Timer
used as a clockevent device. Both are enabled through TIM_GEN_CONFIG
register. This register is in the DT resource index 1.
Timer/Counter base register is in the DT resource index 0
and it's map/unmap handled by TIMER OF api.
Signed-off-by: Vijayakannan Ayyathurai <vijayakannan.ayyathurai@xxxxxxxxx>
Acked-by: Mark Gross <mgross@xxxxxxxxxxxxxxx>
Acked-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---
drivers/clocksource/Kconfig | 10 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-keembay.c | 221 ++++++++++++++++++++++++++++
3 files changed, 232 insertions(+)
create mode 100644 drivers/clocksource/timer-keembay.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 68b087bff59c..b1f29e12c571 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -738,4 +738,14 @@ config MICROCHIP_PIT64B
modes and high resolution. It is used as a clocksource
and a clockevent.
+config KEEMBAY_TIMER
+ bool "Intel Keem Bay timer driver"
+ depends on ARCH_KEEMBAY || (ARM64 && COMPILE_TEST)
+ select TIMER_OF
+ help
+ This option enables the support for the Intel Keem Bay general
+ purpose timer and free running counter driver. Each timer can
+ generate an individual interrupt and the 64 bit counter can also
+ be used as one of the clock source.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 1c444cc3bb44..f6cfc362b406 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -94,3 +94,4 @@ 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_KEEMBAY_TIMER) += timer-keembay.o
diff --git a/drivers/clocksource/timer-keembay.c b/drivers/clocksource/timer-keembay.c
new file mode 100644
index 000000000000..41b9bbb3382d
--- /dev/null
+++ b/drivers/clocksource/timer-keembay.c
@@ -0,0 +1,221 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Keem Bay Timer driver
+ *
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/bits.h>
+#include <linux/interrupt.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/sizes.h>
+
+#include "timer-of.h"
+
+/* Registers offset */
+#define TIM_CNT_VAL_OFFSET 0
+#define TIM_RELOAD_VAL_OFFSET SZ_4
+#define TIM_CONFIG_OFFSET SZ_8
+
+/* Bit fields of TIM_GEN_CONFIG register */
+#define TIM_CONFIG_PRESCALER_ENABLE BIT(2)
+
+/* Bit fields of TIM_CONFIG registers */
+#define TIM_CONFIG_INTERRUPT_PENDING BIT(4)
+#define TIM_CONFIG_INTERRUPT_ENABLE BIT(2)
+#define TIM_CONFIG_RESTART BIT(1)
+#define TIM_CONFIG_ENABLE BIT(0)
+
+#define TIM_RATING 200
+#define TIM_CLKSRC_BITS SZ_64
+
+struct keembay_init_data {
+ struct timer_of *cfg;
+ void __iomem *base;
+ u32 mask;
+};
+
+static inline void keembay_timer_disable(void __iomem *base)
+{
+ writel(0, base + TIM_CONFIG_OFFSET);
+}
+
+static inline void keembay_timer_enable(void __iomem *base, u32 flags)
+{
+ writel(TIM_CONFIG_ENABLE | flags, base + TIM_CONFIG_OFFSET);
+}
+
+static inline void keembay_timer_update_counter(void __iomem *base, u32 val)
+{
+ writel(val, base + TIM_CNT_VAL_OFFSET);
+ writel(val, base + TIM_RELOAD_VAL_OFFSET);
+}
+
+static int keembay_timer_set_next_event(unsigned long evt,
+ struct clock_event_device *ce)
+{
+ u32 flags = TIM_CONFIG_INTERRUPT_ENABLE;
+ struct timer_of *to = to_timer_of(ce);
+
+ /* setup and enable oneshot timer */
+ keembay_timer_disable(timer_of_base(to));
+ keembay_timer_update_counter(timer_of_base(to), evt);
+ keembay_timer_enable(timer_of_base(to), flags);
+
+ return 0;
+}
+
+static int keembay_timer_periodic(struct clock_event_device *ce)
+{
+ u32 flags = TIM_CONFIG_INTERRUPT_ENABLE | TIM_CONFIG_RESTART;
+ struct timer_of *to = to_timer_of(ce);
+
+ /* setup and enable periodic timer */
+ keembay_timer_disable(timer_of_base(to));
+ keembay_timer_update_counter(timer_of_base(to), timer_of_period(to));
+ keembay_timer_enable(timer_of_base(to), flags);
+
+ return 0;
+}
+
+static int keembay_timer_shutdown(struct clock_event_device *ce)
+{
+ struct timer_of *to = to_timer_of(ce);
+
+ keembay_timer_disable(timer_of_base(to));
+
+ return 0;
+}
+
+static irqreturn_t keembay_timer_isr(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+ struct timer_of *to = to_timer_of(evt);
+ u32 val;
+
+ val = readl(timer_of_base(to) + TIM_CONFIG_OFFSET);
+ val &= ~TIM_CONFIG_INTERRUPT_PENDING;
+ writel(val, timer_of_base(to) + TIM_CONFIG_OFFSET);
+
+ if (clockevent_state_oneshot(evt))
+ keembay_timer_disable(timer_of_base(to));
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int __init keembay_init_pre(struct device_node *np,
+ struct keembay_init_data *data)
+{
+ struct timer_of *to = data->cfg;
+ u32 val;
+ int ret;
+
+ data->base = of_iomap(np, 1);
+ if (!data->base)
+ return -ENXIO;
+
+ val = readl(data->base + TIM_CONFIG_OFFSET);
+ if (!(val & data->mask)) {
+ iounmap(data->base);
+ return -ENODEV;
+ }
+
+ ret = timer_of_init(np, to);
+ if (ret)
+ iounmap(data->base);
+
+ return ret;
+}
+
+static void keembay_init_post(struct device_node *np,
+ struct keembay_init_data *data)
+{
+ iounmap(data->base);
+}
+
+static struct timer_of keembay_ce_to = {
+ .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
+ .clkevt = {
+ .name = "keembay_timer",
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .rating = TIM_RATING,
+ .set_next_event = keembay_timer_set_next_event,
+ .set_state_periodic = keembay_timer_periodic,
+ .set_state_shutdown = keembay_timer_shutdown,
+ },
+ .of_irq = {
+ .handler = keembay_timer_isr,
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ },
+};
+
+static int __init keembay_timer_init(struct device_node *np)
+{
+ struct keembay_init_data data;
+ u32 val;
+ int ret;
+
+ data.mask = TIM_CONFIG_PRESCALER_ENABLE;
+ data.cfg = &keembay_ce_to;
+ ret = keembay_init_pre(np, &data);
+ if (ret)
+ return ret;
+
+ val = readl(data.base + TIM_RELOAD_VAL_OFFSET);
+
+ keembay_ce_to.clkevt.cpumask = cpumask_of(0);
+ keembay_ce_to.of_clk.rate = keembay_ce_to.of_clk.rate / (val + 1);
+
+ keembay_timer_disable(timer_of_base(&keembay_ce_to));
+
+ keembay_init_post(np, &data);
+
+ clockevents_config_and_register(&keembay_ce_to.clkevt,
+ timer_of_rate(&keembay_ce_to), 1,
+ U32_MAX);
+ return 0;
+}
+
+static struct timer_of keembay_cs_to = {
+ .flags = TIMER_OF_BASE | TIMER_OF_CLOCK,
+};
+
+static u64 notrace keembay_clocksource_read(struct clocksource *cs)
+{
+ return lo_hi_readq(timer_of_base(&keembay_cs_to));
+}
+
+static struct clocksource keembay_counter = {
+ .name = "keembay_sys_counter",
+ .rating = TIM_RATING,
+ .read = keembay_clocksource_read,
+ .mask = CLOCKSOURCE_MASK(TIM_CLKSRC_BITS),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_SUSPEND_NONSTOP,
+};
+
+static int __init keembay_counter_init(struct device_node *np)
+{
+ struct keembay_init_data data;
+ int ret;
+
+ data.mask = TIM_CONFIG_ENABLE;
+ data.cfg = &keembay_cs_to;
+ ret = keembay_init_pre(np, &data);
+ if (ret)
+ return ret;
+
+ keembay_init_post(np, &data);
+
+ return clocksource_register_hz(&keembay_counter,
+ timer_of_rate(&keembay_cs_to));
+}
+
+TIMER_OF_DECLARE(keembay_timer, "intel,keembay-timer", keembay_timer_init);
+TIMER_OF_DECLARE(keembay_sys_counter, "intel,keembay-counter",
+ keembay_counter_init);
--
2.17.1
