[U-Boot] UEFI on u-boot

[Udit Kumar]

Thanks Heinrich

> -----Original Message-----
> From: Heinrich Schuchardt [mailto:xypron.glpk at gmx.de]
> Sent: Tuesday, January 16, 2018 2:55 AM
> To: Udit Kumar <udit.kumar at nxp.com>; Alexander Graf <agraf at suse.de>
> Cc: u-boot at lists.denx.de
> Subject: Re: UEFI on u-boot
> 
> 
> 
> On 01/15/2018 10:32 AM, Udit Kumar wrote:
> > Hi Alex
> >
> >> -----Original Message-----
> >> From: Alexander Graf [mailto:agraf at suse.de]
> >> Sent: Monday, January 15, 2018 2:45 PM
> >> To: Udit Kumar <udit.kumar at nxp.com>
> >>
> >> Hi Udit,
> >>
> >> On 15.01.18 10:09, Udit Kumar wrote:
> >>> Hi Alex,
> >>> Hope you are doing great,
> >>>
> >>> Could you help on UEFI over the u-boot.
> >>> 1- I couldn't locate EFI_DXE_SERVICES in u-boot, do you have plan to
> >>> add those
> >>
> >> Right now the model is that all device drivers are implemented by
> >> U-Boot and that only exposes their interfaces to EFI applications.
> >> Implementing DXE in U-Boot would open quite a big can of worms, as it
> >> would really only be useful in compilation with PI which is a terrible
> interface :).
> >
> > Ok,
> >
> >>> 2- If I load  a driver (with bootefi) which install few protocols,
> >>> is this ok to do with u-boot
> 
> With the command bootefi you can load an executable that adds boottime
> or runtime services.
> 
> Unfortunatly there are some missing points:
> 
> When loading the image the memory category reserved for the image is not
> chosen in dependence of the image type. This will cause major trouble for
> runtime drivers.
> The exit() service does not call the unload function of the driver/application.

Thanks for warning, for the moment I am ok with simple driver 
 
> >>
> >> It depends on how much the driver does, but in general yes. Heinrich
> >> is currently working on making the iPXE iSCSI driver work, so his EFI
> >> payload would expose an EFI block device to yet another payload running
> after his.
> >
> > Thanks for this,
> > Heinrich,  in  this driver, are you accessing underneath hardware
> > register by UEFI-Driver and managing UEFI protocols or you are relying
> > on some h/w access exposed by u-boot driver
> >
> 
> U-Boot exposes the network interface as EFI simple network protocol.
> iPXE provides TCP and iSCSI on top of the SNP.
> It creates a handle and install the a block IO protocol on it.
> When ConnectController is called the U-Boot EFI block driver creates the
> partitions as children of aforementioned handle and installs the simple file
> protocol on the child handles.
> 
> See patch
> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.
> denx.de%2Fpipermail%2Fu-boot%2F2018-
> January%2F316708.html&data=02%7C01%7Cudit.kumar%40nxp.com%7Cc19b
> 8ec63abb4ee7ff1908d55c5e7be8%7C686ea1d3bc2b4c6fa92cd99c5c301635%7
> C0%7C0%7C636516483235326220&sdata=wUx1fErZM2G6xjB7Aq89ntqs5bRGt
> TXZKKcfLgWef4M%3D&reserved=0

Thanks, you rely on u-boot exports. Alex answered in previous post
as in UEFI driver MMIO read/write is allowed 
 
> Regards
> 
> Heinrich
> 
> >
> >
> >>> 3- if you say, 2 is ok then I hope these protocols are kept in some
> >>> data base, and this new protocol can be opened by an application
> >>
> >> Yes, the protocol database is now global and persistent across
> >> bootefi invocations.
> >
> > Thanks
> >
> >>> 4- if there is some known limitation, like we cannot run DXE_driver
> >>> etc
> >>
> >> What exactly are you trying to do? With the U-Boot UEFI
> >> implementation we're trying to find a sweet spot between implementing
> >> as much as makes sense, but not the whole UEFI world, as that would
> >> just bloat the code needlessly.
> >
> > I am trying to add a driver (DXE by definition) which
> > a) Access the hardware registers. (I said DXE could due to hardware
> > registers)
> > b) Update memory map as well (AddMemorySpace call)
> > c) Finally it export a protocol, which could be used by its test application.
> >
> > For b) I am not able to find function call, For a), if I say driver is
> > UEFI and accessing hardware register, will this be acceptable ?
> >
> >>
> >> Alex