From: Shruthi Sanil <shruthi.sanil@xxxxxxxxx>
The Intel Keem Bay timer driver supports clocksource and clockevent
features for the timer IP used in Intel Keem Bay SoC.
The timer block supports 1 free running counter and 8 timers.
The free running counter can be used as a clocksource and
the timers can be used as clockevent. Each timer is capable of
generating individual interrupt.
Both the features are enabled through the timer general config register.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Signed-off-by: Shruthi Sanil <shruthi.sanil@xxxxxxxxx>
---
MAINTAINERS | 5 +
drivers/clocksource/Kconfig | 11 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-keembay.c | 255 ++++++++++++++++++++++++++++
4 files changed, 272 insertions(+)
create mode 100644 drivers/clocksource/timer-keembay.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 19135a9d778e..a1ad37cd5350 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9436,6 +9436,11 @@ F: drivers/crypto/keembay/keembay-ocs-hcu-core.c
F: drivers/crypto/keembay/ocs-hcu.c
F: drivers/crypto/keembay/ocs-hcu.h
+INTEL KEEM BAY TIMER SUPPORT
+M: Shruthi Sanil <shruthi.sanil@xxxxxxxxx>
+S: Maintained
+F: drivers/clocksource/timer-keembay.c
+
INTEL MANAGEMENT ENGINE (mei)
M: Tomas Winkler <tomas.winkler@xxxxxxxxx>
L: linux-kernel@xxxxxxxxxxxxxxx
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index eb661b539a3e..4878784dba94 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -707,4 +707,15 @@ config MICROCHIP_PIT64B
modes and high resolution. It is used as a clocksource
and a clockevent.
+config KEEMBAY_TIMER
+ bool "Intel Keem Bay timer"
+ depends on ARCH_KEEMBAY || 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
+ supports oneshot and periodic modes.
+ The 64-bit counter can be used as a clock source.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index c17ee32a7151..ea319063ba47 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_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..e62187eeb4f6
--- /dev/null
+++ b/drivers/clocksource/timer-keembay.c
@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Keem Bay Timer driver
+ *
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/bitops.h>
+#include <linux/idr.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 <linux/slab.h>
+
+#include "timer-of.h"
+
+/* Timer register offset */
+#define TIM_CNT_VAL_OFFSET 0x0
+#define TIM_RELOAD_VAL_OFFSET 0x4
+#define TIM_CONFIG_OFFSET 0x8
+
+/* Bit fields of timer general config register */
+#define TIM_CONFIG_PRESCALER_ENABLE BIT(2)
+#define TIM_CONFIG_COUNTER_ENABLE BIT(0)
+
+/* Bit fields of timer config register */
+#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_GEN_MASK GENMASK(31, 12)
+#define TIM_RATING 200
+#define TIM_CLKSRC_MASK_BITS 64
+
+#define TIMER_NAME_SIZE 25
+
+/* Provides a unique ID for each timer */
+static DEFINE_IDA(keembay_timer_ida);
+
+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_disable(void __iomem *base)
+{
+ writel(0x0, 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 inline void keembay_timer_clear_pending_int(void __iomem *base)
+{
+ u32 val;
+
+ val = readl(base + TIM_CONFIG_OFFSET);
+ val &= ~TIM_CONFIG_INTERRUPT_PENDING;
+ writel(val, base + TIM_CONFIG_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);
+ void __iomem *tim_base = timer_of_base(to);
+
+ keembay_timer_disable(tim_base);
+ keembay_timer_update_counter(tim_base, evt);
+ keembay_timer_enable(tim_base, 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);
+ void __iomem *tim_base = timer_of_base(to);
+
+ keembay_timer_disable(tim_base);
+ keembay_timer_update_counter(tim_base, timer_of_period(to));
+ keembay_timer_enable(tim_base, 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);
+ void __iomem *tim_base = timer_of_base(to);
+ u32 val;
+
+ val = readl(tim_base + TIM_CONFIG_OFFSET);
+
+ if (val & TIM_CONFIG_RESTART) {
+ /* Clear interrupt for periodic timer*/
+ keembay_timer_clear_pending_int(tim_base);
+ } else {
+ /* Disable the timer for one shot timer */
+ keembay_timer_disable(tim_base);
+ }
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static int __init keembay_clockevent_init(struct device_node *np)
+{
+ struct device_node *gpt_node = np->parent;
+ struct timer_of *keembay_ce_to;
+ void __iomem *gpt_base;
+ char *timer_name;
+ int timer_id;
+ int ret;
+ u32 val;
+
+ gpt_base = of_iomap(gpt_node, 0);
+ if (!gpt_base) {
+ pr_err("%pOF: Failed to get general config base address\n", np);
+ return -ENXIO;
+ }
+
+ /* Prescaler must be enabled for the timer to operate */
+ val = readl(gpt_base + TIM_CONFIG_OFFSET);
+ if (!(val & TIM_CONFIG_PRESCALER_ENABLE)) {
+ pr_err("%pOF: Prescaler is not enabled\n", np);
+ ret = -ENODEV;
+ goto err_iounmap;
+ }
+
+ keembay_ce_to = kzalloc(sizeof(*keembay_ce_to), GFP_KERNEL);
+ if (!keembay_ce_to) {
+ ret = -ENOMEM;
+ goto err_iounmap;
+ }
+
+ timer_id = ida_alloc(&keembay_timer_ida, GFP_KERNEL);
+ if (timer_id < 0) {
+ ret = timer_id;
+ goto err_keembay_ce_to_free;
+ }
+
+ timer_name = kasprintf(GFP_KERNEL, "keembay_timer%d", timer_id);
+ if (!timer_name) {
+ ret = -ENOMEM;
+ goto err_free_ida;
+ }
+
+ keembay_ce_to->flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK;
+ keembay_ce_to->clkevt.name = timer_name;
+ keembay_ce_to->clkevt.cpumask = cpumask_of(0);
+ keembay_ce_to->clkevt.features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT |
+ CLOCK_EVT_FEAT_DYNIRQ;
+ keembay_ce_to->clkevt.rating = TIM_RATING;
+ keembay_ce_to->clkevt.set_next_event = keembay_timer_set_next_event;
+ keembay_ce_to->clkevt.set_state_periodic = keembay_timer_periodic;
+ keembay_ce_to->clkevt.set_state_shutdown = keembay_timer_shutdown;
+ keembay_ce_to->of_irq.handler = keembay_timer_isr;
+ keembay_ce_to->of_irq.flags = IRQF_TIMER;
+
+ ret = timer_of_init(np, keembay_ce_to);
+ if (ret)
+ goto err_timer_name_free;
+
+ val = readl(gpt_base + TIM_RELOAD_VAL_OFFSET);
+ iounmap(gpt_base);
+
+ keembay_ce_to->of_clk.rate = keembay_ce_to->of_clk.rate / (val + 1);
+
+ clockevents_config_and_register(&keembay_ce_to->clkevt,
+ timer_of_rate(keembay_ce_to),
+ 1,
+ U32_MAX);
+
+ return 0;
+
+err_timer_name_free:
+ kfree(timer_name);
+err_free_ida:
+ ida_free(&keembay_timer_ida, timer_id);
+err_keembay_ce_to_free:
+ kfree(keembay_ce_to);
+err_iounmap:
+ iounmap(gpt_base);
+
+ return ret;
+}
+
+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_MASK_BITS),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_SUSPEND_NONSTOP,
+};
+
+static int __init keembay_clocksource_init(struct device_node *np)
+{
+ struct device_node *gpt_node = np->parent;
+ void __iomem *gpt_base;
+ u32 val;
+ int ret;
+
+ gpt_base = of_iomap(gpt_node, 0);
+ if (!gpt_base) {
+ pr_err("%pOF: Failed to get general config base address\n", np);
+ return -ENXIO;
+ }
+
+ /* Free Running Counter must be enabled */
+ val = readl(gpt_base + TIM_CONFIG_OFFSET);
+ iounmap(gpt_base);
+ if (!(val & TIM_CONFIG_COUNTER_ENABLE)) {
+ pr_err("%pOF: free running counter is not enabled\n", np);
+ return -ENODEV;
+ }
+
+ ret = timer_of_init(np, &keembay_cs_to);
+ if (ret)
+ return ret;
+
+ return clocksource_register_hz(&keembay_counter, timer_of_rate(&keembay_cs_to));
+}
+
+TIMER_OF_DECLARE(keembay_clockevent, "intel,keembay-timer", keembay_clockevent_init);
+TIMER_OF_DECLARE(keembay_clocksource, "intel,keembay-counter", keembay_clocksource_init);
--
2.17.1
