[U-Boot] [PATCH 0/2] am335x_boneblack: Enable fastboot flash support

[Lukasz Majewski]

Hi Sam,

> On 27 February 2018 at 23:56, Lukasz Majewski <lukma at denx.de> wrote:
> > Hi Sam,
> >  
> >> Standard and recommended way to upgrade the firmware is DFU. But
> >> DFU has extremely low transmission speed (around 150 KiB/sec),
> >> thus it's a bad fit for flashing big images (like rootfs). Low DFU
> >> speed is mostly due to next reasons (kudos to Ruslan Bilovol for
> >> investigation): 1. DFU works only via EP0, per DFU specification
> >> [1]. But AM335x doesn't have DMA for EP0, according to AM335x TRM
> >> [2]: from section 16.2:
> >>
> >>       "The CPPI DMA can be used to service Endpoints 1 to 15 not
> >>        Endpoint 0. CPU access method is used to service Endpoint 0
> >>        transactions."
> >>
> >>  2. Max transmission packet size via EP0 is 64 bytes, whereas for
> >> other endpoints max transmission packet size is 512 bytes  
> >
> > DFU was (and still is) supposed to work on all devices - even those
> > with very tiny resources (like st microcontrollers).
> >
> > According to USB spec, EP0 is mandatory, so that is the reason for
> > using it as a common denominator.
> >
> > Just for the record - fastboot is one of the options here.
> >
> > For BBB you may want to look at "dfu tftp" - which uses ETH's tftp
> > protocol with dfu backend. It is supposed to be a remedy for problem
> > described above.
> >
> > More information at:
> > ./doc/README.dfutftp
> >  
> 
> Thank you for the explanation, Lukasz! Didn't know that "dfu tftp" was
> designed to overcome that slow speed issue. Will try that.

You may also want to try UMS (USB Mass Storage) - "ums".

It will export your BBB to be visible as USB Mass Storage device (like
a pendrive).

From that point you can use dd to write MBR, rootfs, u-boot to it.


Another - good option for flashing is SWUpdate SW:

https://github.com/sbabic/swupdate

It allows very easy integration with OE/Yocto and Buildroot.
What is even more important - it supports BBB out of the box:

https://github.com/sbabic/meta-swupdate-boards/tree/master/recipes-support/swupdate/swupdate

SWUpdate is a versatile tool with a loot of nice features - please read:
https://sbabic.github.io/swupdate/

> 
> >
> > Of course I also don't mind using fastboot - it depends on your use
> > case.
> >  
> 
> Yes, I'm trying to make BBB board to be a good educational platform
> (we are working on some corporate courses). Main points are it's an
> open hardware, has a good support in upstream and has a good pricing.
> Anyway, my idea is to show people all the conventional methods for
> flashing the board, so I need both Ethernet and USB ways working.
> 
> Also, I noticed that Debian rootfs is recommended to be flashed to
> eMMC using SD card (and flashing is done from booted system, not from
> U-Boot). Although I understand that this may be easier for an end user
> (as it closely resembles PC way), still I can't say that I
> particularly like or approve that method (especially for development
> purposes). That's why I think that having functional USB link would be
> beneficial for BBB.
> 
> >>
> >> fastboot specification [3], on the other hand, says nothing about
> >> which EP should be used (and I see that EP1 is used on BBB board).
> >> So let's enable fastboot flash support on BeagleBone Black board to
> >> provide a better way to flash big images via USB.
> >>
> >> [1] www.usb.org/developers/docs/devclass_docs/DFU_1.1.pdf
> >> [2] www.ti.com/lit/ug/spruh73p/spruh73p.pdf
> >> [3]
> >> https://android.googlesource.com/platform/system/core/+/master/fastboot/README.md
> >>
> >> Sam Protsenko (2):
> >>   omap: Fix AM335x build with enabled fastboot flash
> >>   configs: am335x_boneblack: Enable fastboot flash capability
> >>
> >>  arch/arm/mach-omap2/utils.c        | 2 ++
> >>  configs/am335x_boneblack_defconfig | 2 ++
> >>  2 files changed, 4 insertions(+)
> >>  
> >
> >
> >
> >
> > Best regards,
> >
> > Lukasz Majewski
> >
> > --
> >
> > DENX Software Engineering GmbH,      Managing Director: Wolfgang
> > Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell,
> > Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email:
> > wd at denx.de  




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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