Re: [PATCH v6 2/3] clocksource: Add JH7110 timer driver
From: Emil Renner Berthing
Date: Mon Oct 16 2023 - 05:24:02 EST
Xingyu Wu wrote:
> On 2023/10/13 19:34, Emil Renner Berthing wrote:
> > Xingyu Wu wrote:
> >> Add timer driver for the StarFive JH7110 SoC.
> >>
> >> Signed-off-by: Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
> >> ---
> >> MAINTAINERS | 7 +
> >> drivers/clocksource/Kconfig | 11 +
> >> drivers/clocksource/Makefile | 1 +
> >> drivers/clocksource/timer-jh7110.c | 387 +++++++++++++++++++++++++++++
> >> 4 files changed, 406 insertions(+)
> >> create mode 100644 drivers/clocksource/timer-jh7110.c
> >>
> >> diff --git a/MAINTAINERS b/MAINTAINERS
> >> index 6c4cce45a09d..1525f031d4a2 100644
> >> --- a/MAINTAINERS
> >> +++ b/MAINTAINERS
> >> @@ -20472,6 +20472,13 @@ S: Maintained
> >> F: Documentation/devicetree/bindings/sound/starfive,jh7110-tdm.yaml
> >> F: sound/soc/starfive/jh7110_tdm.c
> >>
> >> +STARFIVE JH7110 TIMER DRIVER
> >> +M: Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
> >> +M: Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
> >> +S: Supported
> >> +F: Documentation/devicetree/bindings/timer/starfive,jh7110-timer.yaml
> >> +F: drivers/clocksource/timer-jh7110.c
> >> +
> >> STARFIVE JH71X0 CLOCK DRIVERS
> >> M: Emil Renner Berthing <kernel@xxxxxxxx>
> >> M: Hal Feng <hal.feng@xxxxxxxxxxxxxxxx>
> >> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> >> index 0ba0dc4ecf06..821abcc1e517 100644
> >> --- a/drivers/clocksource/Kconfig
> >> +++ b/drivers/clocksource/Kconfig
> >> @@ -641,6 +641,17 @@ config RISCV_TIMER
> >> is accessed via both the SBI and the rdcycle instruction. This is
> >> required for all RISC-V systems.
> >>
> >> +config STARFIVE_JH7110_TIMER
> >> + bool "Timer for the STARFIVE JH7110 SoC"
> >> + depends on ARCH_STARFIVE || COMPILE_TEST
> >> + select TIMER_OF
> >> + select CLKSRC_MMIO
> >> + default ARCH_STARFIVE
> >> + help
> >> + This enables the timer for StarFive JH7110 SoC. On RISC-V platform,
> >> + the system has started RISCV_TIMER, but you can also use this timer
> >> + which can provide four channels to do a lot more things on JH7110 SoC.
> >> +
> >> config CLINT_TIMER
> >> bool "CLINT Timer for the RISC-V platform" if COMPILE_TEST
> >> depends on GENERIC_SCHED_CLOCK && RISCV
> >> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> >> index 368c3461dab8..b66ac05ec086 100644
> >> --- a/drivers/clocksource/Makefile
> >> +++ b/drivers/clocksource/Makefile
> >> @@ -80,6 +80,7 @@ obj-$(CONFIG_INGENIC_TIMER) += ingenic-timer.o
> >> obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o
> >> obj-$(CONFIG_X86_NUMACHIP) += numachip.o
> >> obj-$(CONFIG_RISCV_TIMER) += timer-riscv.o
> >> +obj-$(CONFIG_STARFIVE_JH7110_TIMER) += timer-jh7110.o
> >> obj-$(CONFIG_CLINT_TIMER) += timer-clint.o
> >> obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o
> >> obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o
> >> diff --git a/drivers/clocksource/timer-jh7110.c b/drivers/clocksource/timer-jh7110.c
> >> new file mode 100644
> >> index 000000000000..914424368290
> >> --- /dev/null
> >> +++ b/drivers/clocksource/timer-jh7110.c
> >> @@ -0,0 +1,387 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Starfive JH7110 Timer driver
> >> + *
> >> + * Copyright (C) 2022-2023 StarFive Technology Co., Ltd.
> >> + *
> >> + * Author:
> >> + * Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>
> >> + * Samin Guo <samin.guo@xxxxxxxxxxxxxxxx>
> >> + */
> >> +
> >> +#include <linux/clk.h>
> >> +#include <linux/clockchips.h>
> >> +#include <linux/clocksource.h>
> >> +#include <linux/err.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/io.h>
> >> +#include <linux/iopoll.h>
> >> +#include <linux/irq.h>
> >> +#include <linux/kernel.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/reset.h>
> >> +#include <linux/sched_clock.h>
> >> +
> >> +/* Bias: Ch0-0x0, Ch1-0x40, Ch2-0x80, and so on. */
> >> +#define JH7110_TIMER_CH_LEN 0x40
> >> +#define JH7110_TIMER_CH_BASE(x) ((x) * JH7110_TIMER_CH_LEN)
> >> +#define JH7110_TIMER_CH_MAX 4
> >> +
> >> +#define JH7110_CLOCK_SOURCE_RATING 200
> >> +#define JH7110_VALID_BITS 32
> >> +#define JH7110_DELAY_US 0
> >> +#define JH7110_TIMEOUT_US 10000
> >> +#define JH7110_CLOCKEVENT_RATING 300
> >> +#define JH7110_TIMER_MAX_TICKS 0xffffffff
> >> +#define JH7110_TIMER_MIN_TICKS 0xf
> >> +#define JH7110_TIMER_NAME_NUM 19
> >> +
> >> +#define JH7110_TIMER_INT_STATUS 0x00 /* RO[0:4]: Interrupt Status for channel0~4 */
> >> +#define JH7110_TIMER_CTL 0x04 /* RW[0]: 0-continuous run, 1-single run */
> >> +#define JH7110_TIMER_LOAD 0x08 /* RW: load value to counter */
> >> +#define JH7110_TIMER_ENABLE 0x10 /* RW[0]: timer enable register */
> >> +#define JH7110_TIMER_RELOAD 0x14 /* RW: write 1 or 0 both reload counter */
> >> +#define JH7110_TIMER_VALUE 0x18 /* RO: timer value register */
> >> +#define JH7110_TIMER_INT_CLR 0x20 /* RW: timer interrupt clear register */
> >> +#define JH7110_TIMER_INT_MASK 0x24 /* RW[0]: timer interrupt mask register */
> >> +#define JH7110_TIMER_INT_CLR_AVA_MASK BIT(1)
> >> +
> >> +struct jh7110_clkevt {
> >> + struct clock_event_device evt;
> >> + struct clocksource cs;
> >> + struct clk *clk;
> >> + char name[JH7110_TIMER_NAME_NUM];
> >
> > Instead of this define maybe just use something like
> >
> > char name[sizeof("jh7110-timer.chX")];
> >
>
> Will fix.
>
> >> + int irq;
> >
> > You wrote that you "dropped the extra copy of irq", but here you didn't.
>
> What I mean is to drop the local variable of irq in the probe. Do you mean to use a local variable instead this in the probe?
No, what I mean is that this field is no longer used, so you can delete it.
>
> >
> >> + u32 rate;
> >> + u32 reload_val;
> >> + void __iomem *base;
> >> +};
> >> +
> >> +static inline struct jh7110_clkevt *to_jh7110_clkevt(struct clock_event_device *evt)
> >> +{
> >> + return container_of(evt, struct jh7110_clkevt, evt);
> >> +}
> >> +
> >> +/* 0:continuous-run mode, 1:single-run mode */
> >> +static inline void jh7110_timer_set_continuous_mod(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(0, clkevt->base + JH7110_TIMER_CTL);
> >> +}
> >> +
> >> +static inline void jh7110_timer_set_single_mod(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(1, clkevt->base + JH7110_TIMER_CTL);
> >> +}
> >> +
> >> +/* Interrupt Mask Register, 0:Unmask, 1:Mask */
> >> +static inline void jh7110_timer_int_enable(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(0, clkevt->base + JH7110_TIMER_INT_MASK);
> >> +}
> >> +
> >> +static inline void jh7110_timer_int_disable(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(1, clkevt->base + JH7110_TIMER_INT_MASK);
> >> +}
> >
> > I really don't think all these wrappers make the code any clearer. Please just
> > inline the writel() calls. What you can do to make it a bit clearer is
> > something like
> >
> > enum {
> > JH7110_TIMER_MODE_CONTINUOUS,
> > JH7110_TIMER_MODE_SINGLE,
> > };
> >
> > so you can write
> >
> > writel(JH7110_TIMER_MODE_CONTINUOUS, clkevt->base + JH7110_TIMER_CTL);
> >
>
> Will fix.
>
> >> +
> >> +/*
> >> + * BIT(0): Read value represent channel intr status.
> >> + * Write 1 to this bit to clear interrupt. Write 0 has no effects.
> >> + * BIT(1): "1" means that it is clearing interrupt. BIT(0) can not be written.
> >> + */
> >> +static inline int jh7110_timer_int_clear(struct jh7110_clkevt *clkevt)
> >> +{
> >> + u32 value;
> >> + int ret;
> >> +
> >> + /* waiting interrupt can be to clearing */
> >> + ret = readl_poll_timeout_atomic(clkevt->base + JH7110_TIMER_INT_CLR, value,
> >> + !(value & JH7110_TIMER_INT_CLR_AVA_MASK),
> >> + JH7110_DELAY_US, JH7110_TIMEOUT_US);
> >> + if (!ret)
> >> + writel(0x1, clkevt->base + JH7110_TIMER_INT_CLR);
> >> +
> >> + return ret;
> >> +}
> >> +
> >> +/*
> >> + * The initial value to be loaded into the
> >> + * counter and is also used as the reload value.
> >> + * val = clock rate --> 1s
> >> + */
> >> +static inline void jh7110_timer_set_load(struct jh7110_clkevt *clkevt, u32 val)
> >> +{
> >> + writel(val, clkevt->base + JH7110_TIMER_LOAD);
> >> +}
> >> +
> >> +static inline u32 jh7110_timer_get_val(struct jh7110_clkevt *clkevt)
> >> +{
> >> + return readl(clkevt->base + JH7110_TIMER_VALUE);
> >> +}
> >> +
> >> +/*
> >> + * Write RELOAD register to reload preset value to counter.
> >> + * Write 0 and write 1 are both ok.
> >> + */
> >> +static inline void jh7110_timer_set_reload(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(0, clkevt->base + JH7110_TIMER_RELOAD);
> >> +}
> >> +
> >> +static inline void jh7110_timer_enable(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(1, clkevt->base + JH7110_TIMER_ENABLE);
> >> +}
> >> +
> >> +static inline void jh7110_timer_disable(struct jh7110_clkevt *clkevt)
> >> +{
> >> + writel(0, clkevt->base + JH7110_TIMER_ENABLE);
> >> +}
> >
> > The same thing goes for all these wrappers. If you do insist on having these
> > wrappers then at least group them all together so you can quickly scroll past
> > them to get to the "real" code.
>
> Will fix.
>
> >
> >> +
> >> +static int jh7110_timer_int_init_enable(struct jh7110_clkevt *clkevt)
> >> +{
> >> + int ret;
> >> +
> >> + jh7110_timer_int_disable(clkevt);
> >> + ret = jh7110_timer_int_clear(clkevt);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + jh7110_timer_int_enable(clkevt);
> >> + jh7110_timer_enable(clkevt);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static int jh7110_timer_shutdown(struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + jh7110_timer_disable(clkevt);
> >> + return jh7110_timer_int_clear(clkevt);
> >> +}
> >> +
> >> +static void jh7110_timer_suspend(struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + clkevt->reload_val = jh7110_timer_get_val(clkevt);
> >> + jh7110_timer_shutdown(evt);
> >> +}
> >> +
> >> +static void jh7110_timer_resume(struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + jh7110_timer_set_load(clkevt, clkevt->reload_val);
> >> + jh7110_timer_set_reload(clkevt);
> >> + jh7110_timer_int_enable(clkevt);
> >> + jh7110_timer_enable(clkevt);
> >> +}
> >> +
> >> +static int jh7110_timer_tick_resume(struct clock_event_device *evt)
> >> +{
> >> + jh7110_timer_resume(evt);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +/* IRQ handler for the timer */
> >> +static irqreturn_t jh7110_timer_interrupt(int irq, void *priv)
> >> +{
> >> + struct clock_event_device *evt = (struct clock_event_device *)priv;
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + if (jh7110_timer_int_clear(clkevt))
> >> + return IRQ_NONE;
> >> +
> >> + if (evt->event_handler)
> >> + evt->event_handler(evt);
> >> +
> >> + return IRQ_HANDLED;
> >> +}
> >> +
> >> +static int jh7110_timer_set_periodic(struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> + u32 periodic = DIV_ROUND_CLOSEST(clkevt->rate, HZ);
> >> +
> >> + jh7110_timer_disable(clkevt);
> >> + jh7110_timer_set_continuous_mod(clkevt);
> >> + jh7110_timer_set_load(clkevt, periodic);
> >> +
> >> + return jh7110_timer_int_init_enable(clkevt);
> >> +}
> >> +
> >> +static int jh7110_timer_set_oneshot(struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + jh7110_timer_disable(clkevt);
> >> + jh7110_timer_set_single_mod(clkevt);
> >> + jh7110_timer_set_load(clkevt, JH7110_TIMER_MAX_TICKS);
> >> +
> >> + return jh7110_timer_int_init_enable(clkevt);
> >> +}
> >> +
> >> +static int jh7110_timer_set_next_event(unsigned long next,
> >> + struct clock_event_device *evt)
> >> +{
> >> + struct jh7110_clkevt *clkevt = to_jh7110_clkevt(evt);
> >> +
> >> + jh7110_timer_disable(clkevt);
> >> + jh7110_timer_set_single_mod(clkevt);
> >> + jh7110_timer_set_load(clkevt, next);
> >> + jh7110_timer_enable(clkevt);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static void jh7110_set_clockevent(struct clock_event_device *evt)
> >> +{
> >> + evt->features = CLOCK_EVT_FEAT_PERIODIC |
> >> + CLOCK_EVT_FEAT_ONESHOT |
> >> + CLOCK_EVT_FEAT_DYNIRQ;
> >> + evt->set_state_shutdown = jh7110_timer_shutdown;
> >> + evt->set_state_periodic = jh7110_timer_set_periodic;
> >> + evt->set_state_oneshot = jh7110_timer_set_oneshot;
> >> + evt->set_state_oneshot_stopped = jh7110_timer_shutdown;
> >> + evt->tick_resume = jh7110_timer_tick_resume;
> >> + evt->set_next_event = jh7110_timer_set_next_event;
> >> + evt->suspend = jh7110_timer_suspend;
> >> + evt->resume = jh7110_timer_resume;
> >> + evt->rating = JH7110_CLOCKEVENT_RATING;
> >> +}
> >> +
> >> +static u64 jh7110_timer_clocksource_read(struct clocksource *cs)
> >> +{
> >> + struct jh7110_clkevt *clkevt = container_of(cs, struct jh7110_clkevt, cs);
> >> +
> >> + return (u64)jh7110_timer_get_val(clkevt);
> >> +}
> >> +
> >> +static int jh7110_clocksource_init(struct jh7110_clkevt *clkevt)
> >> +{
> >> + int ret;
> >> +
> >> + jh7110_timer_set_continuous_mod(clkevt);
> >> + jh7110_timer_set_load(clkevt, JH7110_TIMER_MAX_TICKS);
> >> +
> >> + ret = jh7110_timer_int_init_enable(clkevt);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + clkevt->cs.name = clkevt->name;
> >> + clkevt->cs.rating = JH7110_CLOCK_SOURCE_RATING;
> >> + clkevt->cs.read = jh7110_timer_clocksource_read;
> >> + clkevt->cs.mask = CLOCKSOURCE_MASK(JH7110_VALID_BITS);
> >> + clkevt->cs.flags = CLOCK_SOURCE_IS_CONTINUOUS;
> >> +
> >> + return clocksource_register_hz(&clkevt->cs, clkevt->rate);
> >> +}
> >> +
> >> +static void jh7110_clockevents_register(struct jh7110_clkevt *clkevt)
> >> +{
> >> + clkevt->rate = clk_get_rate(clkevt->clk);
> >> +
> >> + jh7110_set_clockevent(&clkevt->evt);
> >> + clkevt->evt.name = clkevt->name;
> >> + clkevt->evt.cpumask = cpu_possible_mask;
> >> +
> >> + clockevents_config_and_register(&clkevt->evt, clkevt->rate,
> >> + JH7110_TIMER_MIN_TICKS, JH7110_TIMER_MAX_TICKS);
> >> +}
> >> +
> >> +static int jh7110_timer_probe(struct platform_device *pdev)
> >> +{
> >> + struct jh7110_clkevt *clkevt[JH7110_TIMER_CH_MAX];
> >> + char name[4];
> >> + struct clk *pclk;
> >> + struct reset_control *rst;
> >> + int ch;
> >> + int ret;
> >> + void __iomem *base;
> >> +
> >> + base = devm_platform_ioremap_resource(pdev, 0);
> >> + if (IS_ERR(base))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(base),
> >> + "failed to map registers\n");
> >> +
> >> + rst = devm_reset_control_get_exclusive(&pdev->dev, "apb");
> >> + if (IS_ERR(rst))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(rst), "failed to get apb reset\n");
> >> +
> >> + pclk = devm_clk_get_enabled(&pdev->dev, "apb");
> >> + if (IS_ERR(pclk))
> >> + return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
> >> + "failed to get & enable apb clock\n");
> >> +
> >> + ret = reset_control_deassert(rst);
> >> + if (ret)
> >> + return dev_err_probe(&pdev->dev, ret, "failed to deassert apb reset\n");
> >> +
> >> + for (ch = 0; ch < JH7110_TIMER_CH_MAX; ch++) {
> >> + clkevt[ch] = devm_kzalloc(&pdev->dev, sizeof(*clkevt[ch]), GFP_KERNEL);
> >> + if (!clkevt[ch])
> >> + return -ENOMEM;
> >> +
> >> + snprintf(name, sizeof(name), "ch%d", ch);
> >> +
> >> + clkevt[ch]->base = base + JH7110_TIMER_CH_BASE(ch);
> >> + /* Ensure timer is disabled */
> >> + jh7110_timer_disable(clkevt[ch]);
> >> +
> >> + rst = devm_reset_control_get_exclusive(&pdev->dev, name);
> >> + if (IS_ERR(rst))
> >> + return PTR_ERR(rst);
> >> +
> >> + clkevt[ch]->clk = devm_clk_get_enabled(&pdev->dev, name);
> >> + if (IS_ERR(clkevt[ch]->clk))
> >> + return PTR_ERR(clkevt[ch]->clk);
> >> +
> >> + ret = reset_control_deassert(rst);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + clkevt[ch]->evt.irq = platform_get_irq(pdev, ch);
> >> + if (clkevt[ch]->evt.irq < 0)
> >> + return clkevt[ch]->evt.irq;
> >> +
> >> + snprintf(clkevt[ch]->name, sizeof(clkevt[ch]->name), "%s.ch%d", pdev->name, ch);
> >> + jh7110_clockevents_register(clkevt[ch]);
> >> +
> >> + ret = devm_request_irq(&pdev->dev, clkevt[ch]->evt.irq, jh7110_timer_interrupt,
> >> + IRQF_TIMER | IRQF_IRQPOLL,
> >> + clkevt[ch]->name, &clkevt[ch]->evt);
> >> + if (ret)
> >> + return ret;
> >> +
> >> + ret = jh7110_clocksource_init(clkevt[ch]);
> >> + if (ret)
> >> + return ret;
> >> + }
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +static const struct of_device_id jh7110_timer_match[] = {
> >> + { .compatible = "starfive,jh7110-timer", },
> >> + { /* sentinel */ }
> >> +};
> >> +MODULE_DEVICE_TABLE(of, jh7110_timer_match);
> >> +
> >> +static struct platform_driver jh7110_timer_driver = {
> >> + .probe = jh7110_timer_probe,
> >> + .driver = {
> >> + .name = "jh7110-timer",
> >> + .of_match_table = jh7110_timer_match,
> >> + },
> >> +};
> >> +module_platform_driver(jh7110_timer_driver);
> >> +
> >> +MODULE_AUTHOR("Xingyu Wu <xingyu.wu@xxxxxxxxxxxxxxxx>");
> >> +MODULE_DESCRIPTION("StarFive JH7110 timer driver");
> >> +MODULE_LICENSE("GPL");
> >> --
> >> 2.25.1