Re: UFS API in the kernel

[Joao Pinto]

Hi again!
Could you also send me an example of how you are using the IOCTL from your user
app (send/receive data)? I already have my implemented but you use a different
mechanism (I have checked your structures in uapi/scsi/ufs/) and I have to port
it! Thanks!


On 9/28/2016 10:06 AM, Joao Pinto wrote:
> 
> Hi Subhash,
> 
> On 9/28/2016 12:05 AM, subhashj@xxxxxxxxxxxxxx wrote:
>> Hi Joao,
>>
>>
>> On 2016-09-26 18:10, Kiwoong Kim wrote:
>>> Hi.
>>>
>>> If you want to declare some things for user interface,
>>> is it be better to put those thing include/uapi/linux/ than include/linux?
>>>
>>> Agreed with Mr. Pinto's opinion with respect to implementing additional ioctls.
>>
>> Yes, "scsi_host_template" allows the LLD's to export their ioctl callback and
>> then you can use the sg interface to issue UFS specific ioctls. We had
>> implemented similar ioctl for our use, here is the reference code:
>> https://source.codeaurora.org/quic/la/kernel/msm-3.18/tree/drivers/scsi/ufs/ufshcd.c?h=LA.HB.1.1.1.c2#n6791.
>> This was mainly done to  export the UFS query request interface to user space.
>> Declarations where exported under include/uapi/scsi/ufs/ . If you want to build
>> upon this already existing functionality, i can post the formal patch on mailing
>> list.
> 
> Yes, of course I have interest on building on top of what you have done already.
> Did yu submit this patch to the kernel already? Could you please send me the
> patch and kernel version to apply?
> 
> Thanks,
> Joao
> 
>>
>> Regards,
>> Subhash
>>
>>
>>>
>>> Regards.
>>>
>>>> -----Original Message-----
>>>> From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi-
>>>> owner@xxxxxxxxxxxxxxx] On Behalf Of Shaun Tancheff
>>>> Sent: Tuesday, September 27, 2016 4:23 AM
>>>> To: Joao Pinto
>>>> Cc: linux-scsi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
>>>> Subject: Re: UFS API in the kernel
>>>>
>>>> On Thu, Sep 22, 2016 at 10:21 AM, Joao Pinto <Joao.Pinto@xxxxxxxxxxxx>
>>>> wrote:
>>>>> Hi!
>>>>>
>>>>> I am designing an application that has the goal to be an utility for
>>>>> Unipro and UFS testing purposes. This application is going to run on
>>>>> top of a recent Linux Kernel containing the new UFS stack (including the
>>>> new DWC drivers).
>>>>>
>>>>> I am considering doing the following:
>>>>> a) Create a new config item called CONFIG_UFS_CHARDEV which is going
>>>>> to create a char device responsible to make some IOCTL available for
>>>>> user-space applications
>>>>> b) Create a linux/ufs.h header file that contains data structures
>>>>> declarations that will be needed in user-space applications
>>>>
>>>> I am not very familiar with UFS devices, that said you should have an sgX
>>>> chardev being created already so you can handle SG_IO requests.
>>>> There also appear to be some sysfs entries being created.
>>>>
>>>> So between sg and sysfs you should be able to handle any user-space out of
>>>> band requests without resorting to making a new chardev.
>>>>
>>>> Adding more sysfs entries, if you need them, should be fine.
>>>>
>>>> You may find it easier to expand on the existing interfaces than to get
>>>> consensus on a new driver and ioctls.
>>>>
>>>> Hope this helps,
>>>> Shaun
>>>>
>>>>> Could you please advise me about what the correct approach should be
>>>>> to make it as standard as possible and usable in the future?
>>>>>
>>>>> Thank you very much for your help!
>>>>>
>>>>> regards,
>>>>> Joao
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>>>>
>>>>
>>>>
>>>> -- 
>>>> Shaun Tancheff
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>>>
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