[PATCH V5 30/30] clocksource: add gx6605s SOC system timer

Guo Ren
2018-09-24T23:44:20Z

Changelog:
- Add COMPILE_TEST in Kconfig
- Add License and Copyright
- Use timer-of framework
- Change name with upstream feedback
- Use clksource_mmio framework

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
---
drivers/clocksource/Kconfig | 8 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-gx6605s.c | 150 ++++++++++++++++++++++++++++++++++++
3 files changed, 159 insertions(+)
create mode 100644 drivers/clocksource/timer-gx6605s.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index a28043f..3dc24ca 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -628,4 +628,12 @@ config CSKY_MPTIMER
Say yes here to enable C-SKY SMP timer driver used for C-SKY SMP
system.

+config GX6605S_TIMER
+ bool "Gx6605s SOC system timer driver" if COMPILE_TEST
+ depends on CSKY
+ select CLKSRC_MMIO
+ select TIMER_OF
+ help
+ This option enables support for gx6605s SOC's timer.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 848c676..7a1b0f4 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -80,3 +80,4 @@ obj-$(CONFIG_X86_NUMACHIP) += numachip.o
obj-$(CONFIG_ATCPIT100_TIMER) += timer-atcpit100.o
obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o
obj-$(CONFIG_CSKY_MPTIMER) += csky_mptimer.o
+obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
diff --git a/drivers/clocksource/timer-gx6605s.c b/drivers/clocksource/timer-gx6605s.c
new file mode 100644
index 0000000..3974ede
--- /dev/null
+++ b/drivers/clocksource/timer-gx6605s.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched_clock.h>
+
+#include "timer-of.h"
+
+#define CLKSRC_OFFSET 0x40
+
+#define TIMER_STATUS 0x00
+#define TIMER_VALUE 0x04
+#define TIMER_CONTRL 0x10
+#define TIMER_CONFIG 0x20
+#define TIMER_DIV 0x24
+#define TIMER_INI 0x28
+
+#define GX6605S_STATUS_CLR BIT(0)
+#define GX6605S_CONTRL_RST BIT(0)
+#define GX6605S_CONTRL_START BIT(1)
+#define GX6605S_CONFIG_EN BIT(0)
+#define GX6605S_CONFIG_IRQ_EN BIT(1)
+
+static irqreturn_t gx6605s_timer_interrupt(int irq, void *dev)
+{
+ struct clock_event_device *ce = dev;
+ void __iomem *base = timer_of_base(to_timer_of(ce));
+
+ writel_relaxed(GX6605S_STATUS_CLR, base + TIMER_STATUS);
+
+ ce->event_handler(ce);
+
+ return IRQ_HANDLED;
+}
+
+static int gx6605s_timer_set_oneshot(struct clock_event_device *ce)
+{
+ void __iomem *base = timer_of_base(to_timer_of(ce));
+
+ /* reset and stop counter */
+ writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
+
+ /* enable with irq and start */
+ writel_relaxed(GX6605S_CONFIG_EN | GX6605S_CONFIG_IRQ_EN, base + TIMER_CONFIG);
+
+ return 0;
+}
+
+static int gx6605s_timer_set_next_event(unsigned long delta, struct clock_event_device *ce)
+{
+ void __iomem *base = timer_of_base(to_timer_of(ce));
+
+ /* use reset to pause timer */
+ writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
+
+ /* config next timeout value */
+ writel_relaxed(ULONG_MAX - delta, base + TIMER_INI);
+ writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL);
+
+ return 0;
+}
+
+static int gx6605s_timer_shutdown(struct clock_event_device *ce)
+{
+ void __iomem *base = timer_of_base(to_timer_of(ce));
+
+ writel_relaxed(0, base + TIMER_CONTRL);
+ writel_relaxed(0, base + TIMER_CONFIG);
+
+ return 0;
+}
+
+static struct timer_of to = {
+ .flags = TIMER_OF_IRQ | TIMER_OF_BASE | TIMER_OF_CLOCK,
+ .clkevt = {
+ .rating = 300,
+ .features = CLOCK_EVT_FEAT_DYNIRQ |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = gx6605s_timer_shutdown,
+ .set_state_oneshot = gx6605s_timer_set_oneshot,
+ .set_next_event = gx6605s_timer_set_next_event,
+ .cpumask = cpu_possible_mask,
+ },
+ .of_irq = {
+ .handler = gx6605s_timer_interrupt,
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ },
+};
+
+static u64 notrace gx6605s_sched_clock_read(void)
+{
+ void __iomem *base;
+
+ base = timer_of_base(&to) + CLKSRC_OFFSET;
+
+ return (u64)readl_relaxed(base + TIMER_VALUE);
+}
+
+static void gx6605s_clkevt_init(void __iomem *base)
+{
+ writel_relaxed(0, base + TIMER_DIV);
+ writel_relaxed(0, base + TIMER_CONFIG);
+
+ clockevents_config_and_register(&to.clkevt, timer_of_rate(&to), 2, ULONG_MAX);
+}
+
+static int gx6605s_clksrc_init(void __iomem *base)
+{
+ writel_relaxed(0, base + TIMER_DIV);
+ writel_relaxed(0, base + TIMER_INI);
+
+ writel_relaxed(GX6605S_CONTRL_RST, base + TIMER_CONTRL);
+
+ writel_relaxed(GX6605S_CONFIG_EN, base + TIMER_CONFIG);
+
+ writel_relaxed(GX6605S_CONTRL_START, base + TIMER_CONTRL);
+
+ sched_clock_register(gx6605s_sched_clock_read, 32, timer_of_rate(&to));
+
+ return clocksource_mmio_init(base + TIMER_VALUE, "gx6605s", timer_of_rate(&to),
+ 200, 32, clocksource_mmio_readl_up);
+}
+
+static int __init gx6605s_timer_init(struct device_node *np)
+{
+ int ret;
+
+ /*
+ * The timer driver is for nationalchip gx6605s SOC and there are two same timer
+ * in gx6605s. We use one for clkevt and another for clksrc.
+ *
+ * The timer is mmio map to access, so we need give mmio addres in dts.
+ *
+ * It provides a 32bit countup timer and interrupt will be caused by count-overflow.
+ * So we need set-next-event by ULONG_MAX - delta in TIMER_INI reg.
+ *
+ * The counter at 0x0 offset is clock event.
+ * The counter at 0x40 offset is clock source.
+ * They are the same in hardware, just different used by driver.
+ */
+ ret = timer_of_init(np, &to);
+ if (ret)
+ return ret;
+
+ gx6605s_clkevt_init(timer_of_base(&to));
+
+ return gx6605s_clksrc_init(timer_of_base(&to) + CLKSRC_OFFSET);
+}
+TIMER_OF_DECLARE(csky_gx6605s_timer, "csky,gx6605s-timer", gx6605s_timer_init);
--
2.7.4