[PATCH V3 1/3] rtdm/testing: latmus: introduce latmus driver

[Jan Kiszka]

On 21.05.21 03:27, Chen, Hongzhan wrote:
> 
>>
>> -----Original Message-----
>> From: Jan Kiszka <jan.kiszka at siemens.com> 
>> Sent: Thursday, May 20, 2021 11:54 PM
>> To: Chen, Hongzhan <hongzhan.chen at intel.com>; xenomai at xenomai.org
>> Subject: Re: [PATCH V3 1/3] rtdm/testing: latmus: introduce latmus driver
>>
>> On 21.04.21 07:05, hongzha1 via Xenomai wrote:
>>> To support the latmus application for determining the best
>>> gravity values for the cobalt core clock, and measuring
>>> the response time to timer events.
>>>
>>> Signed-off-by: hongzha1 <hongzhan.chen at intel.com>
>>> ---
>>>  include/rtdm/uapi/testing.h     |   63 ++
>>>  kernel/drivers/testing/Kconfig  |   10 +
>>>  kernel/drivers/testing/Makefile |    3 +
>>>  kernel/drivers/testing/latmus.c | 1237 +++++++++++++++++++++++++++++++
>>>  4 files changed, 1313 insertions(+)
>>>  create mode 100644 kernel/drivers/testing/latmus.c
>>>
>>
>> ...
>>
>>> diff --git a/kernel/drivers/testing/latmus.c b/kernel/drivers/testing/latmus.c
>>> new file mode 100644
>>> index 000000000..bef662260
>>> --- /dev/null
>>> +++ b/kernel/drivers/testing/latmus.c
>>> @@ -0,0 +1,1237 @@
>>> +/*
>>> + * SPDX-License-Identifier: GPL-2.0
>>> + *
>>> + * Derived from Xenomai Cobalt's autotune driver, https://xenomai.org/
>>> + * Copyright (C) 2014, 2018 Philippe Gerum  <rpm at xenomai.org>
>>> + */
>>> +
>>> +#include <linux/types.h>
>>> +#include <linux/init.h>
>>> +#include <linux/module.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/sort.h>
>>> +#include <linux/cdev.h>
>>> +#include <linux/fs.h>
>>> +#include <linux/fcntl.h>
>>> +#include <cobalt/kernel/pipe.h>
>>> +#include <cobalt/kernel/sched.h>

Do we need those two? RTDM should be the interface when possible. And if
some RTDM header is need of any of them, that would be a bug and a
separate patch.

>>> +#include <rtdm/ipc.h>
>>> +#include <rtdm/testing.h>
>>> +#include <rtdm/driver.h>
>>> +#include <rtdm/compat.h>
>>> +
>>> +#define ONE_BILLION  1000000000
>>> +#define TUNER_SAMPLING_TIME	500000000UL
>>> +#define TUNER_WARMUP_STEPS	10
>>> +#define TUNER_RESULT_STEPS	40
>>> +
>>> +#define progress(__runner, __fmt, __args...)				\
>>> +	do {								\
>>> +		if ((__runner)->verbosity > 1)				\
>>> +			printk(XENO_INFO "latmus(%s) " __fmt "\n",	\
>>> +			       (__runner)->name, ##__args);		\
>>> +	} while (0)
>>> +
>>> +#define cobalt_init_xntimer_on_cpu(__timer, __cpu, __handler)		\
>>> +		rtdm_timer_init_on_cpu(__timer, __handler,		\
>>> +			#__handler, __cpu)
>>
>> Why this wrapper? Why not calling rtdm_timer... directly?
> 
> Of course, we can call rtdm_timer... directly. My reason is : 
> 
> 1.  When I ported it from evl , I just want to align with original as I can 
>     to pass same number of parameters here to replace evl_init_timer_on_cpu.
> 2.  In addition ,when use this wrapper, caller may not need to care about
>     name when it does not matter for user because define would handle it by default.
>     

The current code is abstracting a single use case (you can't use the
code over evl as-is) - that is usually not a good idea. Once you have
two or more active use cases, abstraction can still be done.

Jan

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