[U-Boot] [PATCH v5 2/2] timer: Add High Precision Event Timers (HPET) support

[Simon Glass]

Hi,

On 8 April 2018 at 19:22, Bin Meng <bmeng.cn at gmail.com> wrote:
> Hi Ivan,
>
> On Sat, Apr 7, 2018 at 3:18 AM, Ivan Gorinov <ivan.gorinov at intel.com> wrote:
>> Add HPET driver as an alternative timer for x86 (default is TSC).
>> HPET counter has constant frequency and does not need calibration.
>> This change also makes TSC timer driver optional on x86.
>> New HPET driver can also be selected as the early timer on x86.
>>
>> HPET can be selected as the tick timer in the Device Tree "chosen" node:
>>
>>     /include/ "hpet.dtsi"
>>
>> ...
>>
>>     chosen {
>>         tick-timer = "/hpet";
>>     };
>>
>> Signed-off-by: Ivan Gorinov <ivan.gorinov at intel.com>
>> ---
>>  arch/Kconfig               |   2 +-
>>  arch/x86/Kconfig           |  21 ++++++
>>  arch/x86/dts/hpet.dtsi     |   7 ++
>>  drivers/timer/Kconfig      |   9 +++
>>  drivers/timer/Makefile     |   1 +
>>  drivers/timer/hpet_timer.c | 179 +++++++++++++++++++++++++++++++++++++++++++++
>>  drivers/timer/tsc_timer.c  |   8 ++
>>  7 files changed, 226 insertions(+), 1 deletion(-)
>>  create mode 100644 arch/x86/dts/hpet.dtsi
>>  create mode 100644 drivers/timer/hpet_timer.c
>>

[..]
>> diff --git a/drivers/timer/tsc_timer.c b/drivers/timer/tsc_timer.c
>> index 9296de6..bd0e75c 100644
>> --- a/drivers/timer/tsc_timer.c
>> +++ b/drivers/timer/tsc_timer.c
>> @@ -277,6 +277,8 @@ success:
>>         return delta / 1000;
>>  }
>>
>> +#ifdef CONFIG_X86_EARLY_TIMER_TSC
>
> Why do we surround the following APIs with CONFIG_X86_EARLY_TIMER_TSC?
> These APIs are generic U-Boot timer APIs. If we select
> CONFIG_X86_EARLY_TIMER_HPET, these APIs are not available and will
> cause build error.
>
> Simon, do you think we should fix such in the timer uclass driver?

We should not have arch-specific code in the uclass, or in any generic driver.

Regards,
Simon