Re: UFS API in the kernel

[subhashj]

On 2016-09-28 02:19, Joao Pinto wrote:
> 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!

You may use the SG_IO ioctl with sg device node for any data read/write 
operations.
http://www.tldp.org/HOWTO/SCSI-Generic-HOWTO/sg_io.html has some 
details.

> 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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