From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40E4FC2D0A3 for ; Tue, 3 Nov 2020 18:39:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E06E520757 for ; Tue, 3 Nov 2020 18:39:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727883AbgKCSjW (ORCPT ); Tue, 3 Nov 2020 13:39:22 -0500 Received: from imap2.colo.codethink.co.uk ([78.40.148.184]:49586 "EHLO imap2.colo.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728621AbgKCSjW (ORCPT ); Tue, 3 Nov 2020 13:39:22 -0500 Received: from cpc79921-stkp12-2-0-cust288.10-2.cable.virginm.net ([86.16.139.33] helo=[192.168.0.10]) by imap2.colo.codethink.co.uk with esmtpsa (Exim 4.92 #3 (Debian)) id 1ka1D4-0001Og-J3; Tue, 03 Nov 2020 18:39:10 +0000 Subject: Re: [RFC PATCH 2/3] RISC-V: Initial DTS for Microchip ICICLE board To: Atish Patra Cc: Cyril.Jean@microchip.com, devicetree@vger.kernel.org, Albert Ou , Daire McNamara , Anup Patel , "linux-kernel@vger.kernel.org List" , Atish Patra , Rob Herring , Alistair Francis , Paul Walmsley , Palmer Dabbelt , linux-riscv , Padmarao Begari References: <20201028232759.1928479-1-atish.patra@wdc.com> <20201028232759.1928479-3-atish.patra@wdc.com> <41f1248b-78c6-bac1-410b-9e222368c5f6@codethink.co.uk> <2d7cc829-5df6-6b94-4c8f-9bae6080444e@codethink.co.uk> From: Ben Dooks Organization: Codethink Limited. Message-ID: <22800ecc-a91b-ee3c-4717-4ee8802f31a2@codethink.co.uk> Date: Tue, 3 Nov 2020 18:39:09 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 03/11/2020 18:36, Atish Patra wrote: > On Tue, Nov 3, 2020 at 10:28 AM Ben Dooks wrote: >> >> On 03/11/2020 18:10, Cyril.Jean@microchip.com wrote: >>> On 11/3/20 3:07 PM, Atish Patra wrote: >>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe >>>> >>>> On Fri, Oct 30, 2020 at 2:20 PM Ben Dooks wrote: >> >> ,snip[ >> >>>>>> @Cyril : Can we enable both eMMC & sdcard at the same time ? >>>>> I would put /both/ in but only enable the one in use for the moment. >>>>> Our boards are booting of eMMC as supplied, so this isn't going to work >>>>> as well. The eMMC is 8bit wide, and thus is only delivering 11MB/sec >>>>> instead of 22MB/sec. This performance is still not great, but losing >>>>> half the data-rate is just not good. >>>>> >>>> I am not sure what should be enabled by default. Updating sdcard is much >>>> easier than eMMC card and we use that approach. >>>> >>>> @Cyril: Is there a way that we can enable both ? >>>> >>> Yes, we can enable both but this requires a modification to the FPGA >>> design. One of the guys prototyped this while I was away. We will move >>> this along. This will require reprogramming the FPGA with a new design >>> and HSS version. >>> >>> Regards, >>> >>> Cyril. >> >> I either missed or couldn't find a way of forcing the boot mode to be >> from the SD slot. Have I missed something? At the moment we'd like to >> have more storage available as the ~7G free on the eMMC is not enough. >> > > I use tftpboot to load the kernel & DT from the network. SD card is > enabled in this DT and Linux > kernel uses SD slot instead of eMMC. > > To summarize, eMMC is used for HSS & U-Boot while SD card is used for > Linux which makes > more storage available to Linux. > > IMO, we should enable the sdcard for Linux DT until updated FPGA > design & HSS is available. Interesting as for me the default is for Linux to use the eMMC as well. I can't see any way for forcing the selection lines in the DT to say eMMC vs SD. If there is a way of controlling the selection lines then it might be possible to have both cards enabled with a bus selection MUX in software. -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius https://www.codethink.co.uk/privacy.html