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From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: Udit Kumar <udit.kumar@nxp.com>
Cc: Pankaj Bansal <pankaj.bansal@nxp.com>,
	Andrew Fish <afish@apple.com>,
	 "Olivier.Martin@arm.com" <Olivier.Martin@arm.com>,
	 Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>,
	 "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Subject: Re: Storing Non volatile variables on SD/NAND
Date: Wed, 20 Sep 2017 10:39:03 -0700	[thread overview]
Message-ID: <CAKv+Gu8-hC9+rCwUw-j+CATfiAA+zO=s=LRH_zD5cZfU9M-aLw@mail.gmail.com> (raw)
In-Reply-To: <AM6PR0402MB3334AB92C375D0855CA39F7B91610@AM6PR0402MB3334.eurprd04.prod.outlook.com>

On 20 September 2017 at 10:34, Udit Kumar <udit.kumar@nxp.com> wrote:
>
> When we want to have UEFI and OS accessing same media ,
> Possibilities I see
>
> 1- Patch OS For status check of media (diversion from generic OS), Good case will be modify low level driver.
> But we may end up some surprises on synchronization.
>
> 2- no runtime service for OS . I guess this will not be possible
>
> 3- Way the  Vladimir implemented for eMMC, This has risk of losing data in case of AC power off.
>
> 4- update hardware with dual view (Ard suggestion)
>

5 - abstract direct block device access into a firmware service that
is exposed via a DXE_RUNTIME_DRIVER.

The UEFI spec allows you to expose entry points into a
DXE_RUNTIME_DRIVER module via a UEFI configuration table, and the OS
can use a driver that uses the abstracted device rather than the real
device. Performance is going to be terrible, probably, and lots of
things that are specific to SD/MMC will no longer work, but it is a
possibility nonetheless.


  reply	other threads:[~2017-09-20 17:35 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-18 13:52 Storing Non volatile variables on SD/NAND Udit Kumar
2017-09-18 15:43 ` Ard Biesheuvel
2017-09-18 16:52   ` Vladimir Olovyannikov
2017-09-19  5:28     ` Udit Kumar
2017-09-19 16:38       ` Ard Biesheuvel
2017-09-20  4:27         ` Udit Kumar
2017-09-20  4:47           ` Andrew Fish
2017-09-20  5:09             ` Udit Kumar
2017-09-20  5:17               ` Andrew Fish
2017-09-20 14:51                 ` Pankaj Bansal
2017-09-20 17:34                   ` Udit Kumar
2017-09-20 17:39                     ` Ard Biesheuvel [this message]
2017-09-20 17:39                       ` Ard Biesheuvel
2017-09-20 17:46                         ` Andrew Fish
2017-10-27  9:35                           ` Udit Kumar
2017-10-27  9:37                       ` Udit Kumar
2017-10-27 13:20                         ` Ard Biesheuvel
2017-10-27 17:46                       ` Jeremy Linton
2017-10-28  3:09                         ` Udit Kumar
2017-10-30 23:10                           ` Jeremy Linton
2017-10-31  4:25                             ` Udit Kumar
2017-09-20 17:34                   ` Andrew Fish
2017-09-18 20:47   ` Jeremy Linton
2017-09-18 20:53     ` Ard Biesheuvel
2017-09-19  5:27       ` Udit Kumar

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