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

Chen, Hongzhan hongzhan.chen at intel.com
Mon May 24 03:22:09 CEST 2021



>-----Original Message-----
>From: Philippe Gerum <rpm at xenomai.org> 
>Sent: Monday, May 24, 2021 12:51 AM
>To: Chen, Hongzhan <hongzhan.chen at intel.com>
>Cc: Jan Kiszka <jan.kiszka at siemens.com>; xenomai at xenomai.org
>Subject: Re: [PATCH V3 1/3] rtdm/testing: latmus: introduce latmus driver
>
>
>Chen, Hongzhan via Xenomai <xenomai at xenomai.org> writes:
>
>>>-----Original Message-----
>>>From: Jan Kiszka <jan.kiszka at siemens.com> 
>>>Sent: Friday, May 21, 2021 2:21 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 21.05.21 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.
>>
>> Thanks for your pointing out. Yes, we do not need sched.h here but we need pipe.h
>> because latmus make use of xnpipe.
>>
>>>
>>>>>> +#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.
>>
>> Is it better to move this wrapper to ./include/cobalt/kernel/rtdm/driver.h  just like evl_init_timer_on_rq
>> doing in include/evl/timer.h?
>>
>
>Generally speaking, I don't see any benefit in sharing a generic latmus
>implementation that would build on top of the Cobalt/EVL cores with no
>change.
>
>The version for Xenomai3 must stick with the RTDM interface, just like
>the Xenomai4 implementation will stay with the EVL kernel API. If
>services are missing in the current RTDM specs to support latmus, a
>discussion should take place so that we may propose them for integration
>into the CXP.

I saw that the latmus driver patch was already merged. Do I need to create a new patch based on latmus driver
 to fix it or resubmit the latmus driver patch including the fix?

Regards

Hongzhan Chen

>
>-- 
>Philippe.



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