From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Lin Subject: Re: [RFC PATCH 2/4] mmc: core: implement enhanced strobe support Date: Fri, 4 Mar 2016 10:00:52 +0800 Message-ID: <56D8EC54.7040902@kernel-upstream.org> References: <1456972557-7994-1-git-send-email-shawn.lin@rock-chips.com> <1456972596-8077-1-git-send-email-shawn.lin@rock-chips.com> <56D83E09.70008@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from m199-177.yeah.net ([123.58.177.199]:57479 "EHLO m199-177.yeah.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754648AbcCDCCr (ORCPT ); Thu, 3 Mar 2016 21:02:47 -0500 In-Reply-To: <56D83E09.70008@intel.com> Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Adrian Hunter , Shawn Lin Cc: Ulf Hansson , Michal Simek , soren.brinkmann@xilinx.com, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Hi Adrian, On 2016/3/3 21:37, Adrian Hunter wrote: > On 03/03/16 04:36, Shawn Lin wrote: >> Controllers use data strobe line to latch data from devices >> under hs400 mode, but not for cmd line. So from emmc 5.1, JEDEC >> introduces enhanced strobe mode for latching cmd response from >> emmc devices to host controllers. This new feature is optional. > > As I currently understand it, HS400ES does not require tuning. > Consequently you can go straight to HS400ES and do not need to do > HS200 first. If that is the case then more changes are needed. > That's the case, and it's already in my plan before I going to remove "RFC" prefix. From my experience of developing emmc-device firmware, the only reason we need tuning for HS200 before we switch it into HS400 is that although data-line can be latched by DS but the cmd-line is still in SDR mode when runing in HS400. With hs400-es setuped, tuning and retune stuff is meaningless. ALl the SI should be guranteed by HW design to regulate the PCB payload. > Also it would be nice if the transfer mode displayed reflected enhanced > strobe e.g. Great idea! And maybe more thing should be done for core/debugfs.c It seems to big change for init_card, so I need more time to split my step for changing it to make the change will not do any side effect from non-hs400es procedure. :) Thanks. > > Currently > > mmc1: new HS400 MMC card at address 0001 > > Change for enhance strobe supported > > mmc1: new HS400ES MMC card at address 0001 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >