Re: [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers

From: Daniel Lezcano
Date: Wed Jul 04 2018 - 13:05:14 EST

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In reply to: Guo Ren: "Re: [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers"
Next in thread: Guo Ren: "Re: [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers"
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Hi Guo,

as you are introducing a new drivers, add a detailed changelog
describing in details the timers.

On 01/07/2018 19:34, Guo Ren wrote:
> Signed-off-by: Guo Ren <ren_guo@xxxxxxxxx>
> ---
> drivers/clocksource/Makefile | 1 +
> drivers/clocksource/timer-csky-v1.c | 169 +++++++++++++++++++++++++++++++
> drivers/clocksource/timer-nationalchip.c | 165 ++++++++++++++++++++++++++++++
> 3 files changed, 335 insertions(+)
> create mode 100644 drivers/clocksource/timer-csky-v1.c
> create mode 100644 drivers/clocksource/timer-nationalchip.c

Provide two separates patches, one for each timer.

> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index d6dec44..bbc567b 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -76,3 +76,4 @@ obj-$(CONFIG_H8300_TMR16) += h8300_timer16.o
> obj-$(CONFIG_H8300_TPU) += h8300_tpu.o
> obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o
> obj-$(CONFIG_X86_NUMACHIP) += numachip.o
> +obj-$(CONFIG_CSKY) += timer-csky-v1.o timer-nationalchip.o

Split this in two.

CONFIG_TIMER_CSKY += timer-csky.o

Note, no v1.

CONFIG_TIMER_NATCHIP += timer-natchip.o

And in the Kconfig add the silent timer option.

config TIMER_CSKY
bool

config TIMER_NATCHIP
bool

(If you want to keep the nationalchip name, I'm fine with that).

> diff --git a/drivers/clocksource/timer-csky-v1.c b/drivers/clocksource/timer-csky-v1.c
> new file mode 100644
> index 0000000..f3a822a
> --- /dev/null
> +++ b/drivers/clocksource/timer-csky-v1.c
> @@ -0,0 +1,169 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2018 Hangzhou NationalChip Science & Technology Co.,Ltd.
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/sched_clock.h>
> +#include <linux/cpu.h>
> +#include <asm/reg_ops.h>
> +
> +#include "timer-of.h"
> +
> +#define PTIM_CTLR "cr<0, 14>"
> +#define PTIM_TSR "cr<1, 14>"
> +#define PTIM_CCVR_HI "cr<2, 14>"
> +#define PTIM_CCVR_LO "cr<3, 14>"
> +#define PTIM_LVR "cr<6, 14>"
> +
> +#define BITS_CSKY_TIMER 56
> +
> +DECLARE_PER_CPU(struct timer_of, csky_to);
> +
> +static int csky_timer_irq;
> +static int csky_timer_rate;

You can get the value from the timer-of in all the places it is needed.

> +static inline u64 get_ccvr(void)
> +{
> + u32 lo, hi, t;
> +
> + do {
> + hi = mfcr(PTIM_CCVR_HI);
> + lo = mfcr(PTIM_CCVR_LO);
> + t = mfcr(PTIM_CCVR_HI);
> + } while(t != hi);
> +
> + return ((u64)hi << 32) | lo;
> +}
> +
> +static irqreturn_t timer_interrupt(int irq, void *dev)
> +{
> + struct timer_of *to = this_cpu_ptr(&csky_to);
> +
> + mtcr(PTIM_TSR, 0);
> +
> + to->clkevt.event_handler(&to->clkevt);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int csky_timer_set_next_event(unsigned long delta, struct clock_event_device *ce)
> +{
> + mtcr(PTIM_LVR, delta);
> +
> + return 0;
> +}
> +
> +static int csky_timer_shutdown(struct clock_event_device *ce)
> +{
> + mtcr(PTIM_CTLR, 0);
> +
> + return 0;
> +}
> +
> +static int csky_timer_oneshot(struct clock_event_device *ce)
> +{
> + mtcr(PTIM_CTLR, 1);
> +
> + return 0;
> +}
> +
> +static int csky_timer_oneshot_stopped(struct clock_event_device *ce)
> +{
> + mtcr(PTIM_CTLR, 0);
> +
> + return 0;
> +}
> +
> +DEFINE_PER_CPU(struct timer_of, csky_to) = {
> + .flags = TIMER_OF_CLOCK | TIMER_OF_IRQ,
> +
> + .clkevt = {
> + .name = "C-SKY SMP Timer V1",

If the node name is nice enough, you can discard this. See below
TIMER_OF_DECLARE comment.

> + .rating = 300,
> + .features = CLOCK_EVT_FEAT_PERCPU | CLOCK_EVT_FEAT_ONESHOT,
> + .set_state_shutdown = csky_timer_shutdown,
> + .set_state_oneshot = csky_timer_oneshot,
> + .set_state_oneshot_stopped = csky_timer_oneshot_stopped,
> + .set_next_event = csky_timer_set_next_event,
> + },
> +
> + .of_irq = {
> + .handler = timer_interrupt,
> + .flags = IRQF_TIMER> + .percpu = 1,> + },
> +};
> +
> +/*** clock event for percpu ***/
> +static int csky_timer_starting_cpu(unsigned int cpu)
> +{
> + struct timer_of *to = this_cpu_ptr(&csky_to);

per_cpu_ptr(&csky_to, cpu);

> + to->clkevt.cpumask = cpumask_of(smp_processor_id());

cpumask_of(cpu); ?

> +
> + clockevents_config_and_register(&to->clkevt, csky_timer_rate, 0, ULONG_MAX);

I suggest to choose something different than zero for the min_delta.

> + enable_percpu_irq(csky_timer_irq, 0);
> +
> + return 0;
> +}
> +
> +static int csky_timer_dying_cpu(unsigned int cpu)
> +{
> + disable_percpu_irq(csky_timer_irq);
> +
> + return 0;
> +}
> +
> +/*** clock source ***/
> +static u64 sched_clock_read(void)
> +{
> + return get_ccvr();
> +}
> +
> +static u64 clksrc_read(struct clocksource *c)
> +{
> + return get_ccvr();
> +}
> +
> +struct clocksource csky_clocksource = {
> + .name = "csky_timer_v1_clksrc",

"csky"

> + .rating = 400,
> + .mask = CLOCKSOURCE_MASK(BITS_CSKY_TIMER),
> + .flags = CLOCK_SOURCE_IS_CONTINUOUS,
> + .read = clksrc_read,
> +};
> +
> +static void csky_clksrc_init(void)
> +{
> + clocksource_register_hz(&csky_clocksource, csky_timer_rate);
> +
> + sched_clock_register(sched_clock_read, BITS_CSKY_TIMER, csky_timer_rate);
> +}
> +
> +static int __init csky_timer_v1_init(struct device_node *np)
> +{
> + int ret;
> + struct timer_of *to = this_cpu_ptr(&csky_to);
> +
> + ret = timer_of_init(np, to);
> + if (ret)
> + return ret;
> +
> + csky_timer_irq = to->of_irq.irq;
> + csky_timer_rate = timer_of_rate(to);
> +
> + ret = cpuhp_setup_state(CPUHP_AP_DUMMY_TIMER_STARTING,
> + "clockevents/csky/timer:starting",
> + csky_timer_starting_cpu,
> + csky_timer_dying_cpu);
> + if (ret) {
> + pr_err("%s: Failed to cpuhp_setup_state.\n", __func__);
> + return ret;
> + }
> +
> + csky_clksrc_init();

inline the function here. It is not worth to add a function for a couple
of lines which is called one time.

> +
> + return ret;

return 0;

> +}
> +TIMER_OF_DECLARE(csky_timer_v1, "csky,timer-v1", csky_timer_v1_init);

Stick to the hardware name.

eg.

TIMER_OF_DECLARE(csky_610, "csky,ck610-timer", csky_timer_init);
TIMER_OF_DECLARE(csky_807, "csky,ck807-timer", csky_timer_init);

(Beside /proc/interrupts will show the node name which states clearly
what timer it is).

...

v1, v2, etc ... has no sense here.

> +
> diff --git a/drivers/clocksource/timer-nationalchip.c b/drivers/clocksource/timer-nationalchip.c
> new file mode 100644
> index 0000000..8f4e1e5
> --- /dev/null
> +++ b/drivers/clocksource/timer-nationalchip.c
> @@ -0,0 +1,165 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (C) 2018 Hangzhou NationalChip Science & Technology Co.,Ltd.
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/sched_clock.h>
> +
> +#include "timer-of.h"
> +
> +#define TIMER_NAME "nc_timer"
> +#define TIMER_FREQ 1000000
> +#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 STATUS_clr BIT(0)
> +
> +#define CONTRL_rst BIT(0)
> +#define CONTRL_start BIT(1)
> +
> +#define CONFIG_en BIT(0)
> +#define CONFIG_irq_en BIT(1)

Prefix the macros with a shortened timer name and don't mix lower case
and uppercase.

NC_ is too short, something like NATCHIP may be better.

> +
> +static irqreturn_t timer_interrupt(int irq, void *dev)

Fix the function name.

> +{
> + struct clock_event_device *ce = (struct clock_event_device *) dev;
> + void __iomem *base = timer_of_base(to_timer_of(ce));
> +
> + writel_relaxed(STATUS_clr, base + TIMER_STATUS);
> +
> + ce->event_handler(ce);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int nc_timer_set_periodic(struct clock_event_device *ce)
> +{
> + void __iomem *base = timer_of_base(to_timer_of(ce));
> +
> + /* reset */
> + writel_relaxed(CONTRL_rst, base + TIMER_CONTRL);
> +
> + /* config the timeout value */
> + writel_relaxed(ULONG_MAX - timer_of_period(to_timer_of(ce)),
> + base + TIMER_INI);
> +
> + /* enable with irq and start */
> + writel_relaxed(CONFIG_en|CONFIG_irq_en, base + TIMER_CONFIG);
> + writel_relaxed(CONTRL_start, base + TIMER_CONTRL);
> +
> + return 0;
> +}
> +
> +static int nc_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(CONTRL_rst, base + TIMER_CONTRL);
> +
> + /* config next timeout value */
> + writel_relaxed(ULONG_MAX - delta, base + TIMER_INI);
> + writel_relaxed(CONTRL_start, base + TIMER_CONTRL);
> +
> + return 0;
> +}
> +
> +static int nc_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 = {
> + .name = TIMER_NAME,

Let the node name.

> + .rating = 300,
> + .features = CLOCK_EVT_FEAT_DYNIRQ | CLOCK_EVT_FEAT_PERIODIC |
> + CLOCK_EVT_FEAT_ONESHOT,
> + .set_state_shutdown = nc_timer_shutdown,
> + .set_state_periodic = nc_timer_set_periodic,
> + .set_next_event = nc_timer_set_next_event,

set_oneshot ?

> + .cpumask = cpu_possible_mask,
> + },
> +
> + .of_irq = {
> + .handler = timer_interrupt,
> + .flags = IRQF_TIMER | IRQF_IRQPOLL,
> + },
> +};
> +
> +static u64 notrace nc_sched_clock_read(void)
> +{
> + void __iomem *base;
> +
> + base = timer_of_base(&to) + CLKSRC_OFFSET;
> +
> + return (u64) readl_relaxed(base + TIMER_VALUE);
> +}
> +
> +static void nc_timer_set_div(void __iomem *base)
> +{
> + unsigned int div;
> +
> + div = timer_of_rate(&to)/TIMER_FREQ - 1;

space ' / '

Is it
(timer_of_rate(&to) / TIMER_FREQ) - 1
or
timer_of_rate(&to) / (TIMER_FREQ - 1)

?

> +
> + writel_relaxed(div, base + TIMER_DIV);
> +}
> +
> +static void nc_clkevt_init(void __iomem *base)
> +{
> + /* reset */
> + writel_relaxed(CONTRL_rst, base + TIMER_CONTRL);
> +
> + /* reset config */
> + writel_relaxed(0, base + TIMER_CONFIG);
> +
> + nc_timer_set_div(base);
> +
> + clockevents_config_and_register(&to.clkevt, TIMER_FREQ, 1, ULONG_MAX);
> +}
> +
> +static void nc_clksrc_init(void __iomem *base)
> +{
> + writel_relaxed(CONTRL_rst, base + TIMER_CONTRL);
> +
> + writel_relaxed(CONFIG_en, base + TIMER_CONFIG);
> +
> + nc_timer_set_div(base);
> +
> + writel_relaxed(0, base + TIMER_INI);
> + writel_relaxed(CONTRL_start, base + TIMER_CONTRL);
> +
> + clocksource_mmio_init(base + TIMER_VALUE, "nationalchip", TIMER_FREQ, 200, 32,
> + clocksource_mmio_readl_up);

return code check ?

> + sched_clock_register(nc_sched_clock_read, 32, TIMER_FREQ);
> +}
> +
> +static int __init nc_timer_init(struct device_node *np)
> +{
> + int ret;
> +
> + ret = timer_of_init(np, &to);
> + if (ret)
> + return ret;
> +
> + nc_clkevt_init(timer_of_base(&to));
> +
> + nc_clksrc_init(timer_of_base(&to) + CLKSRC_OFFSET);
> +
> + return 0;
> +}
> +TIMER_OF_DECLARE(nc_timer, "nationalchip,timer-v1", nc_timer_init);

same comment than cksy timer.

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Next message: Will Deacon: "Re: [PATCH v2 3/4] efi/arm: map UEFI memory map earlier on boot"
Previous message: kbuild test robot: "Re: [PATCHv3 2/4] drivers/base: utilize device tree info to shutdown devices"
In reply to: Guo Ren: "Re: [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers"
Next in thread: Guo Ren: "Re: [PATCH V2 18/19] clocksource: add C-SKY clocksource drivers"
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