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=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 19E66C43461 for ; Sat, 15 May 2021 12:17:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F1DB3613D0 for ; Sat, 15 May 2021 12:17:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231791AbhEOMSk (ORCPT ); Sat, 15 May 2021 08:18:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57688 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230144AbhEOMSj (ORCPT ); Sat, 15 May 2021 08:18:39 -0400 Received: from mail-qt1-x82b.google.com (mail-qt1-x82b.google.com [IPv6:2607:f8b0:4864:20::82b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A793CC061573; Sat, 15 May 2021 05:17:25 -0700 (PDT) Received: by mail-qt1-x82b.google.com with SMTP id 1so1613288qtb.0; Sat, 15 May 2021 05:17:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DPoGlMS/oCbgWHNPbUx7scOgPtN4DdBoyWnSloUqTQw=; b=Vo8sGSPnG2sneOjS72HFiXr0WgvO+KnNFs8J1kFYeCimMYwaIg9sP4LSLRBogdeEBJ /2bfN7emebEMroR3MGjZl+5okEEnASuaMmWbo25dYwprM3BfddVBEPbP0B0LHaoutj/i xsp6Ap8A1mwB+5FXzav5/5IAcRsq4WosFmZ79DJyrcjayO2a5Eg2BC8CHxD4rcR/Qxpm m9cDPDxYjKxN2wBT0rAiIPOnYmYMPAOqqeMfbq1WLqY5wBIoWKMaN8711LcOqo8CZ+Ju 0y+yrQwrRwB+C+j7BNJd4EZnVsHhbypMPdzNkBea2944IddEhue3BgeohHzMBFbXmA4v k12g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DPoGlMS/oCbgWHNPbUx7scOgPtN4DdBoyWnSloUqTQw=; b=JJQB/F93DS3vHsaLH4nPOPfCkVP5lGpPHFxeM5EIwsAI/Kdu/pUe+zqkpAoO2voB4O 0igEA8PJBCdgoOdFQwE32qOJBBr141PvPr1hwSHhEFn2h95GS24pl46sFa1y7tr97APR amLVA1oZNVfqJT8AStfpR11Bb4E2S02fKWASAWyU73KZivA+RO5wbyd16D3UoLXb845+ HyxDWg9O3Rs/rftAvxgS3Nxyxz35jmAsy6jvK1K8huoS5UA+iuCJ4vvUnZKTq12C0DKH VCqxSdHccFkWTe88vPRlDQ28MqMDQ4qeOQgxyRYRLmv5I49RXAxa9o+fthnvxpWe8wrG rhTQ== X-Gm-Message-State: AOAM531IzYAIomW/sGTY00KhdJLoOEstoNpoHC5yrvZa+lBT3aIqd1L/ 3xE+mERJlbb5fm/7PmeEoTU= X-Google-Smtp-Source: ABdhPJwCy7Hg0PI8WYcO8+4B7gcsS26JbgGagbutHc/rU9q5/hKRp9x0eGrzmlAbISIBe3ODazf2rg== X-Received: by 2002:ac8:5d16:: with SMTP id f22mr24989947qtx.84.1621081044752; Sat, 15 May 2021 05:17:24 -0700 (PDT) Received: from errol.ini.cmu.edu (pool-108-39-255-32.pitbpa.fios.verizon.net. [108.39.255.32]) by smtp.gmail.com with ESMTPSA id d16sm6570349qtw.23.2021.05.15.05.17.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 15 May 2021 05:17:24 -0700 (PDT) Date: Sat, 15 May 2021 08:17:17 -0400 From: "Gabriel L. Somlo" To: Stafford Horne Cc: LKML , Florent Kermarrec , Mateusz Holenko , Joel Stanley , Jonathan Corbet , Greg Kroah-Hartman , Jiri Slaby , Karol Gugala , "Paul E. McKenney" , Randy Dunlap , Andrew Morton , Thomas Gleixner , Viresh Kumar , Mike Kravetz , Peter Zijlstra , linux-doc@vger.kernel.org, linux-serial@vger.kernel.org Subject: Re: [PATCH] serial/liteuart; Add support for earlycon Message-ID: References: <20210515084519.167343-1-shorne@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210515084519.167343-1-shorne@gmail.com> X-Clacks-Overhead: GNU Terry Pratchett Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 15, 2021 at 05:45:18PM +0900, Stafford Horne wrote: > Most litex boards using RISC-V soft cores us the sbi earlycon, however > this is not available for non RISC-V litex SoC. This patch enables > earlycon for liteuart which is available on all Litex SoC's making > support for earycon debugging more widely available. > > Signed-off-by: Stafford Horne > Cc: Florent Kermarrec > Cc: Mateusz Holenko > Cc: Joel Stanley > Cc: Gabriel L. Somlo > --- > .../admin-guide/kernel-parameters.txt | 5 +++ > drivers/tty/serial/Kconfig | 1 + > drivers/tty/serial/liteuart.c | 31 +++++++++++++++++++ > 3 files changed, 37 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index 04545725f187..2d4a43af8de2 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -1084,6 +1084,11 @@ > the driver will use only 32-bit accessors to read/write > the device registers. > > + liteuart, > + Start an early console on a litex serial port at the > + specified address. The serial port must already be > + setup and configured. Options are not yet supported. > + > meson, > Start an early, polled-mode console on a meson serial > port at the specified address. The serial port must > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig > index 0c4cd4a348f4..9ceffe6ab6fd 100644 > --- a/drivers/tty/serial/Kconfig > +++ b/drivers/tty/serial/Kconfig > @@ -1531,6 +1531,7 @@ config SERIAL_LITEUART > depends on OF || COMPILE_TEST > depends on LITEX > select SERIAL_CORE > + select SERIAL_EARLYCON > help > This driver is for the FPGA-based LiteUART serial controller from LiteX > SoC builder. > diff --git a/drivers/tty/serial/liteuart.c b/drivers/tty/serial/liteuart.c > index 64842f3539e1..38c472487e68 100644 > --- a/drivers/tty/serial/liteuart.c > +++ b/drivers/tty/serial/liteuart.c > @@ -372,6 +372,37 @@ static int __init liteuart_console_init(void) > console_initcall(liteuart_console_init); > #endif /* CONFIG_SERIAL_LITEUART_CONSOLE */ > > +#ifdef CONFIG_SERIAL_EARLYCON > +static void early_liteuart_putc(struct uart_port *port, int c) > +{ > + while (litex_read8(port->membase + OFF_TXFULL)) > + cpu_relax(); > + > + litex_write8(port->membase + OFF_RXTX, c); > +} > + > +static void early_liteuart_write(struct console *console, const char *s, > + unsigned int count) > +{ > + struct earlycon_device *device = console->data; > + struct uart_port *port = &device->port; > + > + uart_console_write(port, s, count, early_liteuart_putc); > +} > + > +static int __init early_liteuart_setup(struct earlycon_device *device, > + const char *options) > +{ > + if (!device->port.membase) > + return -ENODEV; > + > + device->con->write = early_liteuart_write; > + return 0; > +} > + > +OF_EARLYCON_DECLARE(liteuart, "litex,liteuart", early_liteuart_setup); > +#endif /* CONFIG_SERIAL_EARLYCON */ > + > static int __init liteuart_init(void) > { > int res; > -- > 2.31.1 FWIW: Reviewed-and-tested-by: Gabriel Somlo Thanks, --Gabriel