From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergey Lapin Date: Tue, 31 Jan 2012 09:25:03 -0500 Subject: [U-Boot] mx28: booting u-boot via USB In-Reply-To: <4F27F4CB.8090306@esd.eu> References: <4F27F4CB.8090306@esd.eu> Message-ID: <20120131142503.GI2056@build.ihdev.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, Jan 31, 2012 at 03:03:55PM +0100, Matthias Fuchs wrote: > Hi, > > I have a problem booting the current u-boot-imx version > on a MX28EVK via USB. The i.MX28 CPU supports a special boot mode > where the image (sb boot stream) is downloaded via USB device > (all DIP switches in position 'off' on the EVK). The > CPU's internal bootrom implements a HID device in this mode. > Freescale provides a download tool "sb_loader" for this purpose. > There is also a GPL'd implementation based on libusb. Could you please provide link to GPL tool? > > So back to my problem: > > I build u-boot from the u-boot-imx repository. This runs fine > when booting from SD/MMC or SPI-flash. But the console stays dark > when using the USB download mode. USB download works fine with the > Freescale provided U-Boot sources together with the imx-bootlets > SPL code. > > Now I digged a little bit deeper to find out the cause: > > When downloading via USB I saw the SPL running correctly. > board_init_ll() (arch/arm/cpu/arm926ejs/mx28/start.S) runs through > correctly. Then control is passed back to the bootrom. That's > where things end as far as I can see. > > The 2nd stage of u-boot is not started. > > The USB boot mechanism is not documented that detailed. > Is it possible that the SPL code overwrites the bootroms ivt and > in consequence crashes the bootrom's USB code? Any further ideas? I'd look at difference in linking scripts and addresses in freescale u-boot and new u-boot. This might be some memory addressing issues. Had some of this with i.MX23. Also, some hardware might be not powered on or is powered off by SPL. S.