Hi, Daniel:
2017-12-12 18:05 GMT+08:00 Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>:
> On 12/12/2017 06:46, Rick Chen wrote:
>> ATCPIT100 is often used on the Andes architecture,
>> This timer provide 4 PIT channels. Each PIT channel is a
>> multi-function timer, can be configured as 32,16,8 bit timers
>> or PWM as well.
>>
>> For system timer it will set channel 1 32-bit timer0 as clock
>> source and count downwards until underflow and restart again.
>
> [ ... ]
>
>> +config CLKSRC_ATCPIT100
>> + bool "Clocksource for AE3XX platform"
>> + depends on NDS32 || COMPILE_TEST
>> + depends on HAS_IOMEM
>> + help
>> + This option enables support for the Andestech AE3XX platform timers.
>
> Hi Rick,
>
> the general rule for the Kconfig is:
>
> bool "Clocksource for AE3XX platform" if COMPILE_TEST
>
> and no deps on the platform.
>
> It is up to the platform Kconfig to select the option.
>
> We want here a silent option but make it selectable in case of
> compilation test coverage.
The way we like to use it is because
1. This timer is a basic component to boot an nds32 CPU and it should
be able to select without COMPILE_TEST for nds32 architecture.
2. It seems conflict with debug info. I am not sure if there is
another way to debug kernel(with debug info) with COMPILE_TEST and
DEBUG_INFO because we need this driver for nds32 architecture.
Symbol: DEBUG_INFO [=n]
Type : boolean
Prompt: Compile the kernel with debug info
Location:
-> Kernel hacking
-> Compile-time checks and compiler options
Defined at lib/Kconfig.debug:140
Depends on: DEBUG_KERNEL [=y] && !COMPILE_TEST [=n]
> Also, this driver is not a CLKSRC but a TIMER. Rename CLKSRC_ATCPIT100
> to TIMER_ATCPIT100.
Thanks. We will rename it in the next version patch.
>> +
>> endmenu
>> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
>> index 72711f1..7d072f5 100644
>> --- a/drivers/clocksource/Makefile
>> +++ b/drivers/clocksource/Makefile
>> @@ -75,3 +75,4 @@ 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_CLKSRC_ATCPIT100) += timer-atcpit100.o
>
> [ ... ]
>
>> +static struct timer_of to = {
>> + .flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE,
>> +
>> + .clkevt = {
>> + .name = "atcpit100_tick",
>> + .rating = 300,
>> + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
>> + .set_state_shutdown = atcpit100_clkevt_shutdown,
>> + .set_state_periodic = atcpit100_clkevt_set_periodic,
>> + .set_state_oneshot = atcpit100_clkevt_set_oneshot,
>> + .tick_resume = atcpit100_clkevt_shutdown,
>> + .set_next_event = atcpit100_clkevt_next_event,
>> + .cpumask = cpu_all_mask,
>
> You may consider CLOCK_EVT_DYN_IRQ
> https://lwn.net/Articles/540160/
Thanks.
We will consider to implement this feature once we support SMP or our
CPU has local timer.
>> + },
>> +
>> + .of_irq = {
>> + .handler = atcpit100_timer_interrupt,
>> + .flags = IRQF_TIMER | IRQF_IRQPOLL,
>> + },
>> +
>> + /*
>> + * FIXME: we currently only support clocking using PCLK
>> + * and using EXTCLK is not supported in the driver.
>> + */
>> + .of_clk = {
>> + .name = "PCLK",
>> + }
>
> What do you mean ? We can't specify several clock names with timer-of?
It means we currently support PCLK only.
https://lkml.org/lkml/2017/12/1/316
Thanks.
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