From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lukasz Majewski Date: Thu, 02 Jun 2016 16:14:45 +0200 Subject: [U-Boot] [RFC PATCH 1/5] spl: dfu: add dfu support in SPL In-Reply-To: <6C6B28D4DC342643927BEAFCE8707BF676219F3F@DBDE04.ent.ti.com> References: <1464356373-8375-1-git-send-email-ravibabu@ti.com> <1464356373-8375-2-git-send-email-ravibabu@ti.com> <20160530135400.63d7e020@amdc2363> <7DD822BE-D1C3-452B-A3E4-3F7929B2C832@ti.com> <20160530165902.232ea870@amdc2363> <6C6B28D4DC342643927BEAFCE8707BF67620E21B@DBDE04.ent.ti.com> <20160531103933.54d3509a@amdc2363> <6C6B28D4DC342643927BEAFCE8707BF67620F9F8@DBDE04.ent.ti.com> <20160531115526.1e8f4fc0@amdc2363> <6C6B28D4DC342643927BEAFCE8707BF67620FE98@DBDE04.ent.ti.com> <20160531144732.7464f21e@amdc2363> <6C6B28D4DC342643927BEAFCE8707BF676210794@DBDE04.ent.ti.com> <20160531171300.4e019dc1@amdc2363> <6C6B28D4DC342643927BEAFCE8707BF676219F3F@DBDE04.ent.ti.com> Message-ID: <20160602161445.4d429760@amdc2363> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi Ravi, > Hi Lukasz > > >> The problem here is, how o flash the images first time to fresh > >> boards to QSPI or eMMC device, where there is no MMC/SD > >> boot option available. The solution to this problem is use > >> peripheral USB boot mode (configuring sysboot switches), where the > >> ROM loads the intial SPL(+DFU builtin for spi/eMMC) to IRAM, then > >> run dfu/sf or dfu/eMMC to flash the binaries from PC using USB > >> interface. Refer to SPL-DFU support based on 2014.07 u-boot > >> http://www.ti.com/lit/an/sprac33/sprac33.pdf. > > >I know about similar bootstrap (on TI board), which uses serial > >instead of USB. > > >In this approach MLO was loaded by serial, then it loaded u-boot, > >which was responsible for factory setting of the device (flashing > >rootfs, boot and other partitions). > > >One question: > > >Would it be possible to develop SPL (MLO) for your platform, which > >does following things: > > >1. Loads the full-fledge u-boot to SDRAM 2. Starts the u-boot and 3. > >u-boot flash all the needed stuff > > >By using such approach we could restrict our dfu support in SPL > >u-boot only to receiving data and uploading it to SDRAM (i.e. we > >wouldn't need to add write support for ext, fat and eMMC). > > > This is not possible, because combining MLO and u-boot.img will not > fit in IRAM (512k). The u-boot.img itself is around 640K. My point here is to first load SPL u-boot (which size is around 110 KiB), and then download via DFU full-featured u-boot, which would be placed in SDRAM. Then u-boot downloads and flash all needed images. One big advantage is that our SPL DFU support can be minimal - we don't need to implement fat, ext ,emmc write support. > > Regards > Ravi > -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group