From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Date: Mon, 13 Aug 2012 15:18:58 -0500 Subject: [U-Boot] u-boot preventing access to NAND chip on imx28evk board Message-ID: <50296132.2010704@techsi.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de All, I'm needing to access the NAND chip on the imx28evk board with the Linux (Freescale Kernel - FSL). I've compiled a recent version of the mainstream u-boot with the NAND switches and U-boot works fine. The U-boot also allows me access to the NAND chip and also boots the FSL kernel just fine. However, once the kernel is running, it can not "see" the /dev/mtdX devices. However, if I boot the *same* kernel directly (no U-boot - and attach boot-stream to kernel) the FSL kernel works fine and can gets the /dev/mtdX etc devices. I tracked this down to a couple of differences that are output during the kernel booting process. I also can replicate this problem with no NAND chip in the socket. I can do this by using the script that comes with the imx28evk that is used for formatting the SDCard for booting. The mk_mx28_sd script writes the uboot, kernel, and rootfs to an SDcard depending on the parameters. So if I write the uboot to the card and boot the imx28 from uboot and network boot uImage I get the error. If I write the kernel to the card and boot the imx28 with it I get no error (Using the same kernel). Here are the steps 1. Setup card for kernel boot - run mk_mx28_sd -b /dev/sdb (only writes kernel with bootstream on card) - place card in imx28 and boot it - the kernel (while booting) outputs these lines: ... ... i.MX GPMI NFC NFC: Version 1, 8-chip GPMI and BCH Boot ROM: Version 1, Single-chip boot area, block mark swapping supported Scanning for NAND Flash chips... No NAND device found. gpmi-nfc gpmi-nfc.0: Chip scan failed ... ... 2. Setup card for uboot -setup your host ubuntu so uboot can tftp your kernel -use *same* kernel from #1 (but use uImage) -run mk_mx28_sd -u -b /dev/sdb (only writes uboot with bootstream on card) -place card in imx28 and boot it -you may have to edit uboot parms to get your uImage from your host -Allow kernel to boot, it will output these lines: ... i.MX GPMI NFC NFC: Version 1, 8-chip GPMI and BCH gpmi-nfc: probe of gpmi-nfc.0 failed with error 1 ... ... So maybe U-boot does some things that prevents kernel from working or the kernel with the boot stream added on does the right things ? Thanks, Bill