From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Frias Subject: Re: [RFC PATCH] always probe UART HW when options are not specified Date: Wed, 13 Jan 2016 12:14:04 +0100 Message-ID: <5696317C.4020709@laposte.net> References: <5672D18E.8000301@laposte.net> <5672E2CF.6080705@hurleysoftware.com> <5672E76A.3010506@laposte.net> <5672F588.8070503@hurleysoftware.com> <5672FD35.5070609@laposte.net> <56731689.70702@hurleysoftware.com> <56740FC3.50302@laposte.net> <5674204C.1000907@hurleysoftware.com> <56782DE5.7090708@laposte.net> <56798EC7.1030804@laposte.net> <5693C52B.90003@laposte.net> <5693D41E.8050601@hurleysoftware.com> <5693ECBA.50003@laposte.net> <5693FD3C.5080601@hurleysoftware.com> <5694C94B.3090405@free.fr> <56950C21.3010805@laposte.net> <5695584E.3040902@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5695584E.3040902@hurleysoftware.com> Sender: linux-kernel-owner@vger.kernel.org To: Peter Hurley Cc: Mason , Greg Kroah-Hartman , linux-serial@vger.kernel.org, LKML , Mans Rullgard List-Id: linux-serial@vger.kernel.org Hi Peter, On 01/12/2016 08:47 PM, Peter Hurley wrote: > On 01/12/2016 06:22 AM, Sebastian Frias wrote: >> >> For the record, I'm using a SoC emulator, and thus do not have a bootloader per se and there are a bunch of other things that I cannot count on. >> The emulator has the UART pre-setup, so I just need Linux to take over without changing the parameters. >> Ideally, I would like to have the same image of Linux+DT to start in any instance of the emulator or real chips, regardless of the clock ratios, that's why I sort of need Linux to not change the UART speed, which is quite tricky because there are no clock generators in the emulator. > > Got it, thanks for the info. > Please test the series I just cc'd you on plus the patch I sent > you yesterday. > > That should get you an earlycon up and running on that simulator; > let me know if it doesn't and we'll go from there. Ok, thanks. I will try as soon as we finish rebasing our changes on top of "mainline" (or HEAD, or is it "-next"? I don't know how you guys call the most recent code base for Linux) Actually, I tried yesterday on a 4.1.13 but "[drivers/tty/serial/earlycon.c:62] earlycon_map()" was still the last message I got, just as with the OF_EARLYCON_DECLARE hack I had previously talk about, and so I would like to test on the same conditions than you, mainline. > >> NOTE: on my tree I'm using the patch I previously submitted here, so Linux is probing the UART so it works for all my cases, but I would like to go back to a standard tree. > > I expect that patch to go into -next sometime during the 4.5-rc cycle. Sounds good! Thanks, Sebastian > > > Regards, > Peter Hurley > >>> Note: calling the UART driver "Au1x00/RT288x" is a bit of a misnomer, >>> as these are names of SoCs using that distinct register layout. >>> The actual IP is probably the 16550-compatible Palmchip BK-3103. >>> https://sites.google.com/a/palmchiptech.com/palmchiptech/product-services/hardware-services/ip-cores/bk-3103 >>> (Not sure that this website is legitimate, though.) >>> >>> When I need earlyprintk support, I use this patch from Mans: >>> http://thread.gmane.org/gmane.linux.kernel/2081016 >>> >>> Regards. >>> >