From mboxrd@z Thu Jan 1 00:00:00 1970 From: Angelo Dureghello Subject: emmc 4.4x fast boot question Date: Wed, 22 Apr 2015 15:11:24 +0200 Message-ID: <55379DFC.4040907@sysam.it> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from tbjjbihbhdcag.turbo-smtp.net ([199.187.173.206]:17470 "HELO tbjjbihbhdcag.turbo-smtp.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1756802AbbDVNSA (ORCPT ); Wed, 22 Apr 2015 09:18:00 -0400 Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: linux-mmc@vger.kernel.org hi experts, trying to use imx6q "eMMC Fast Boot" mode without success. Can't get any clarification from freescale still, so i try here. From the imx6q boot flow diagram seems there can be some gain using it. Once studying on the Micron eMMC i have connected to imx6q, (as per TN-52-06: Booting from Embedded MMC - JEDEC 4.41 online pdf) i see this mode is just called "boot mode" or "alternate boot mode", and seems to allow to boot from SLC mmcblk0boot0 or mmcblk0boot1 partitions setting EXT_CSD[179] partition to 1 or 2 in bits 3to5. In this way i can boot from mmcblk0boot0. but if i enable the hw imx6q GPIO BOOT_CFG1[4] "Fast Boot" mode, i cannot boot anymore. If i look signal with scope, booting i don't see the initial CMD pulled low as should be for the Boot mode. If i enable imx6q "fast boot" (BOOT_CFG1[4]) i just see a continuos and long train of bits on both CMD and CLK from the reset. So i can boot from special SLC mmcblk0boot0 but without imx6 "Fast Boot" enabled. So i am trying to understand why this Fast Boot feature (BOOT_CFG1[4] set) can't be used. In case you can give any help on this it will be really appreciated. Best regards, Angelo Dureghello