From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Date: Tue, 27 Feb 2018 22:56:27 +0100 Subject: [U-Boot] [PATCH 0/2] am335x_boneblack: Enable fastboot flash support In-Reply-To: <20180227214504.32572-1-semen.protsenko@linaro.org> References: <20180227214504.32572-1-semen.protsenko@linaro.org> Message-ID: <20180227225627.65b34c2f@jawa> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 Of course I also don't mind using fastboot - it depends on your use case. > > 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 -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 488 bytes Desc: OpenPGP digital signature URL: