[PATCH v3 2/3] clocksource: Add JH7110 timer driver
Emil Renner Berthing
emil.renner.berthing at canonical.com
Thu Aug 3 04:30:56 PDT 2023
On Tue, 27 Jun 2023 at 07:55, Xingyu Wu <xingyu.wu at starfivetech.com> wrote:
>
> Add timer driver for the StarFive JH7110 SoC.
>
> Signed-off-by: Xingyu Wu <xingyu.wu at starfivetech.com>
> ---
> MAINTAINERS | 7 +
> drivers/clocksource/Kconfig | 11 +
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-jh7110.c | 485 +++++++++++++++++++++++++++++
> 4 files changed, 504 insertions(+)
> create mode 100644 drivers/clocksource/timer-jh7110.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 6992b7cc7095..4e8e39ae685c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20125,6 +20125,13 @@ S: Supported
> F: Documentation/devicetree/bindings/mmc/starfive*
> F: drivers/mmc/host/dw_mmc-starfive.c
>
> +STARFIVE JH7110 TIMER DRIVER
> +M: Samin Guo <samin.guo at starfivetech.com>
> +M: Xingyu Wu <xingyu.wu at starfivetech.com>
> +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 at esmil.dk>
> M: Hal Feng <hal.feng at starfivetech.com>
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index 526382dc7482..a1393ec074c0 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -639,6 +639,17 @@ 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 SoCs. On RISC-V platform,
> + the system has started RISCV_TIMER. But you can also use this timer
> + which can provides four channels to do a lot more 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 f12d3987a960..791fb3379f50 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -81,6 +81,7 @@ 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..b88334a916fb
> --- /dev/null
> +++ b/drivers/clocksource/timer-jh7110.c
> @@ -0,0 +1,485 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Starfive JH7110 Timer driver
> + *
> + * Copyright (C) 2022 StarFive Technology Co., Ltd.
> + *
> + * Author:
> + * Xingyu Wu <xingyu.wu at starfivetech.com>
> + * Samin Guo <samin.guo at starfivetech.com>
> + */
> +
> +#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_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 20
> +
> +#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)
> +
> +enum JH7110_TIMER_CH {
> + JH7110_TIMER_CH_0 = 0,
> + JH7110_TIMER_CH_1,
> + JH7110_TIMER_CH_2,
> + JH7110_TIMER_CH_3,
> + JH7110_TIMER_CH_MAX
> +};
Usually enum names are not uppercase in kenel code. Also these names
for 0, 1, 2, 3 doesn't really add any value.
> +enum JH7110_TIMER_INTMASK {
> + JH7110_TIMER_INTMASK_DIS = 0,
> + JH7110_TIMER_INTMASK_ENA = 1
> +};
> +
> +enum JH7110_TIMER_MOD {
> + JH7110_TIMER_MOD_CONTIN = 0,
> + JH7110_TIMER_MOD_SINGLE = 1
> +};
> +
> +enum JH7110_TIMER_CTL_EN {
> + JH7110_TIMER_DIS = 0,
> + JH7110_TIMER_ENA = 1
> +};
> +
> +struct jh7110_timer_info {
> + /* Resgister */
> + unsigned int ctrl;
> + unsigned int load;
> + unsigned int enable;
> + unsigned int reload;
> + unsigned int value;
> + unsigned int intclr;
> + unsigned int intmask;
> + unsigned int channel_base[JH7110_TIMER_CH_MAX];
> +};
> +
> +struct jh7110_clkevt {
> + struct clock_event_device evt;
> + struct clocksource cs;
> + struct clk *clk;
> + char name[JH7110_TIMER_NAME_NUM];
> + int irq;
> + u32 periodic;
> + u32 rate;
> + u32 reload_val;
> + void __iomem *base;
> + void __iomem *ctrl;
> + void __iomem *load;
> + void __iomem *enable;
> + void __iomem *reload;
> + void __iomem *value;
> + void __iomem *intclr;
> + void __iomem *intmask;
> +};
> +
> +struct jh7110_timer_priv {
> + struct device *dev;
> + void __iomem *base;
> + struct jh7110_clkevt clkevt[JH7110_TIMER_CH_MAX];
> +};
> +
> +static const struct jh7110_timer_info jh7110_timer_data = {
> + .ctrl = JH7110_TIMER_CTL,
> + .load = JH7110_TIMER_LOAD,
> + .enable = JH7110_TIMER_ENABLE,
> + .reload = JH7110_TIMER_RELOAD,
> + .value = JH7110_TIMER_VALUE,
> + .intclr = JH7110_TIMER_INT_CLR,
> + .intmask = JH7110_TIMER_INT_MASK,
> + .channel_base = {JH7110_TIMER_CH_BASE(JH7110_TIMER_CH_0),
> + JH7110_TIMER_CH_BASE(JH7110_TIMER_CH_1),
> + JH7110_TIMER_CH_BASE(JH7110_TIMER_CH_2),
> + JH7110_TIMER_CH_BASE(JH7110_TIMER_CH_3)},
> +};
This driver is specific to the JH7110, so why do you need this level
of abstraction? Can't you just use the register offsets directly?
> +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_mod(struct jh7110_clkevt *clkevt, int mod)
> +{
> + writel(mod, clkevt->ctrl);
> +}
You have an enum these two choices. Why not use that instead of the
non-specific int type?
> +/* Interrupt Mask Register, 0:Unmask, 1:Mask */
> +static inline void jh7110_timer_int_enable(struct jh7110_clkevt *clkevt)
> +{
> + writel(JH7110_TIMER_INTMASK_DIS, clkevt->intmask);
> +}
> +
> +static inline void jh7110_timer_int_disable(struct jh7110_clkevt *clkevt)
> +{
> + writel(JH7110_TIMER_INTMASK_ENA, clkevt->intmask);
> +}
> +
> +/*
> + * 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->intclr, value,
> + !(value & JH7110_TIMER_INT_CLR_AVA_MASK),
> + JH7110_DELAY_US, JH7110_TIMEOUT_US);
> + if (!ret)
> + writel(0x1, clkevt->intclr);
> +
> + 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->load);
> +}
> +
> +static inline u32 jh7110_timer_get_val(struct jh7110_clkevt *clkevt)
> +{
> + return readl(clkevt->value);
> +}
Do these wrappers really add any value? To me this is just as clear:
writel(clkevt->base + JH7110_TIMER_LOAD, val);
Same goes for the wrappers below.
> +/*
> + * 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->reload);
> +}
> +
> +static inline void jh7110_timer_enable(struct jh7110_clkevt *clkevt)
> +{
> + writel(JH7110_TIMER_ENA, clkevt->enable);
> +}
> +
> +static inline void jh7110_timer_disable(struct jh7110_clkevt *clkevt)
> +{
> + writel(JH7110_TIMER_DIS, clkevt->enable);
> +}
> +
> +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;
> +}
> +
> +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_mod(clkevt, JH7110_TIMER_MOD_CONTIN);
> + 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);
> +}
> +
> +/* 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);
> +
> + clkevt->periodic = DIV_ROUND_CLOSEST(clkevt->rate, HZ);
> + jh7110_timer_disable(clkevt);
> + jh7110_timer_set_mod(clkevt, JH7110_TIMER_MOD_CONTIN);
> + jh7110_timer_set_load(clkevt, 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_mod(clkevt, JH7110_TIMER_MOD_SINGLE);
> + 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_mod(clkevt, JH7110_TIMER_MOD_SINGLE);
> + 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 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.irq = clkevt->irq;
> + clkevt->evt.cpumask = cpu_possible_mask;
> +
> + clockevents_config_and_register(&clkevt->evt, clkevt->rate,
> + JH7110_TIMER_MIN_TICKS, JH7110_TIMER_MAX_TICKS);
> +}
> +
> +static void jh7110_clkevt_base_init(const struct jh7110_timer_info *data,
> + struct jh7110_clkevt *clkevt,
> + void __iomem *base, int ch)
> +{
> + void __iomem *channel_base;
> +
> + channel_base = base + data->channel_base[ch];
> + clkevt->base = channel_base;
> + clkevt->ctrl = channel_base + data->ctrl;
> + clkevt->load = channel_base + data->load;
> + clkevt->enable = channel_base + data->enable;
> + clkevt->reload = channel_base + data->reload;
> + clkevt->value = channel_base + data->value;
> + clkevt->intclr = channel_base + data->intclr;
> + clkevt->intmask = channel_base + data->intmask;
> +}
> +
> +static int jh7110_timer_probe(struct platform_device *pdev)
> +{
> + const struct jh7110_timer_info *data = of_device_get_match_data(&pdev->dev);
> + char name[JH7110_TIMER_NAME_NUM];
> + struct jh7110_timer_priv *priv;
> + struct jh7110_clkevt *clkevt;
> + struct clk *pclk;
> + struct reset_control *rst;
> + int ch;
> + int ret;
> +
> + if (!data)
> + return -ENOENT;
> +
> + priv = devm_kzalloc(&pdev->dev, struct_size(priv, clkevt, JH7110_TIMER_CH_MAX),
> + GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(priv->base))
> + return dev_err_probe(&pdev->dev, PTR_ERR(priv->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)
> + goto err;
You get and enable the clocks with devm_clk_get_enabled(), so they
will be automatically disabled and put when the driver is unloaded, so
why do you need the explicit call to clk_disable_unprepare() below?
> +
> + priv->dev = &pdev->dev;
> + platform_set_drvdata(pdev, priv);
> +
> + for (ch = 0; ch < JH7110_TIMER_CH_MAX; ch++) {
> + clkevt = &priv->clkevt[ch];
> + snprintf(name, sizeof(name), "ch%d", ch);
> +
> + jh7110_clkevt_base_init(data, clkevt, priv->base, ch);
> + /* Ensure timers are disabled */
> + jh7110_timer_disable(clkevt);
> +
> + rst = devm_reset_control_get_exclusive(&pdev->dev, name);
> + if (IS_ERR(rst)) {
> + ret = PTR_ERR(rst);
> + goto err;
> + }
> +
> + clkevt->clk = devm_clk_get_enabled(&pdev->dev, name);
> + if (IS_ERR(clkevt->clk)) {
> + ret = PTR_ERR(clkevt->clk);
> + goto err;
> + }
> +
> + ret = reset_control_deassert(rst);
> + if (ret)
> + goto ch_err;
> +
> + clkevt->irq = platform_get_irq(pdev, ch);
> + if (clkevt->irq < 0) {
> + ret = clkevt->irq;
> + goto ch_err;
> + }
> +
> + snprintf(clkevt->name, sizeof(clkevt->name), "%s.ch%d", pdev->name, ch);
> + jh7110_clockevents_register(clkevt);
> +
> + ret = devm_request_irq(&pdev->dev, clkevt->irq, jh7110_timer_interrupt,
> + IRQF_TIMER | IRQF_IRQPOLL,
> + clkevt->name, &clkevt->evt);
> + if (ret)
> + goto ch_err;
> +
> + ret = jh7110_clocksource_init(clkevt);
> + if (ret)
> + goto ch_err;
> + }
> +
> + return 0;
> +
> +ch_err:
> + for (; ch < 0; ch--)
> + clk_disable_unprepare(priv->clkevt[ch].clk);
> +err:
> + clk_disable_unprepare(pclk);
> +
> + return ret;
> +}
> +
> +static const struct of_device_id jh7110_timer_match[] = {
> + { .compatible = "starfive,jh7110-timer", .data = &jh7110_timer_data },
This driver only works on the JH7110, so why do you need this match data?
> + { /* 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 at starfivetech.com>");
> +MODULE_DESCRIPTION("StarFive JH7110 timer driver");
> +MODULE_LICENSE("GPL");
> --
> 2.17.1
>
>
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