From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4C45680046; Mon, 8 Jul 2024 12:05:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720440355; cv=none; b=HZiaYgaE4pUeQJdVSITh++TmoCXmXx7iNjHTC1e+/BTWgcdZWwH94Xg+dX1cbQX4DcTZQQqqEV7bjpK5w3kIRFcjJ5YGUEytqEgeDpohZrnEVSQBRiVAtlBwn05/+H2u4FkPKufQnaGTdoTfwfaLKLEij7Khul93SsPRInPv4ZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720440355; c=relaxed/simple; bh=zYiZL26YpL9nyJBbsDP8s4nzF/bHXrFqq56T1M+s51E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cQl1JDn/iaifH6mY60F0ZjafawAj/aYQ1K7vUA7vbHNv4tvokzLG3VmMfLGxwUdYvYUG5DsH2Qv6cTjBDS95pHFpM4u0VlEflBWKYE0m1eyFe5RbcVU7g9xBOWRp35ahvYAmHLyIRs8O9qVOtSYEujrGc8r7EO8gmHOaJoh3iI4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CScz0WZ9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CScz0WZ9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64675C116B1; Mon, 8 Jul 2024 12:05:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720440354; bh=zYiZL26YpL9nyJBbsDP8s4nzF/bHXrFqq56T1M+s51E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CScz0WZ99qjtrVPURkXM/OG7BWNP/9toOwOYu6FHQmMXHVS6vkrvE9s+tv5Ag5GyX d+zy08c/3FCc+bWgUIJ7D1QfpyaxOclKyAHbpORvZQ3DzeBDFFpM9eKl8bF8rGjBxg O8elQO+czjq/PgK0FCDdM25lfRqHJ5rZnhexQ2hQloqpbDSQaznCXUIj6Kkm7W2zar NA8pOYoEg8GY9ARqy90GQp9O/yRmwRLa4w8v5X27EEMtbutKNUoe1k2Ys/mxs1z7WY Q5DiUvNWoCzrUZ0ZEEFqFibTyuflF0nlqRRMzfMh5DnQLLR9rKpBDr8DjJik3arWvl 3VRj9O/Fa7eQg== Date: Mon, 8 Jul 2024 19:51:43 +0800 From: Jisheng Zhang To: Yixun Lan Cc: Greg Kroah-Hartman , Jiri Slaby , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH] serial: 8250: move mmp|pxa uart earlycon code and add xscale earlycon Message-ID: References: <20240706101856.3077-1-jszhang@kernel.org> <20240706223323.GYA367.dlan.gentoo> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240706223323.GYA367.dlan.gentoo> On Sat, Jul 06, 2024 at 10:33:23PM +0000, Yixun Lan wrote: > Hi > On 18:18 Sat 06 Jul , Jisheng Zhang wrote: > > There are two other drivers that bind to "mrvl,mmp-uart": the 8250_of > > and the 8250_pxa. The previous one is generic and the latter is binded > > to ARCH_PXA || ARCH_MMP. Now we may have pxa programming compatible > > HW to support, making use of the generic 8250_of seems a good idea. > > However, there's no earlycon support if we go with this solution. So > > move the mmp|pxa-uart earlycon code to core 8250_early.c. > > > > At the same, add xscale earlycon support too, only build test since > > I have no xscale machine any more. > > > > Signed-off-by: Jisheng Zhang > > --- > > drivers/tty/serial/8250/8250_early.c | 11 +++++++++++ > > drivers/tty/serial/8250/8250_pxa.c | 16 ---------------- > > 2 files changed, 11 insertions(+), 16 deletions(-) > > > > diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c > > index e3f482fd3de4..6176083d0341 100644 > > --- a/drivers/tty/serial/8250/8250_early.c > > +++ b/drivers/tty/serial/8250/8250_early.c > > @@ -171,6 +171,17 @@ OF_EARLYCON_DECLARE(ns16550a, "ns16550a", early_serial8250_setup); > > OF_EARLYCON_DECLARE(uart, "nvidia,tegra20-uart", early_serial8250_setup); > > OF_EARLYCON_DECLARE(uart, "snps,dw-apb-uart", early_serial8250_setup); > > > > +static int __init early_serial8250_rs2_setup(struct earlycon_device *device, > > + const char *options) > > +{ > > + device->port.regshift = 2; > just wondering if possible to introduce a generic earlycon sub option? so kernel the 8250 ealycon can parse reg-shift from dt too, so no sub option is needed. The reason I hardcoded here is: pxa-uart and xscale-uart doesn't mandate "reg-shift" property in the binding, while I did see mmp-uart mentions "reg-shift" is required in the DT binding. > can parse reg-shift from command line parameter instead of hardcoding here, > which would benefit more drivers (potentially without adding more OF_EARLYCON_DECLAREs..) > > I mean something like this: > Documentation/admin-guide/kernel-parameters.txt > uart[8250],mmio32,[,options[,reg-shift=0,1,2,4 ..]] > > > + > > + return early_serial8250_setup(device, options); > > +} > > +OF_EARLYCON_DECLARE(uart, "intel,xscale-uart", early_serial8250_rs2_setup); > > +OF_EARLYCON_DECLARE(uart, "mrvl,mmp-uart", early_serial8250_rs2_setup); > > +OF_EARLYCON_DECLARE(uart, "mrvl,pxa-uart", early_serial8250_rs2_setup); > > + > > #ifdef CONFIG_SERIAL_8250_OMAP > > > > static int __init early_omap8250_setup(struct earlycon_device *device, > > diff --git a/drivers/tty/serial/8250/8250_pxa.c b/drivers/tty/serial/8250/8250_pxa.c > > index ba96fa913e7f..b5d937f6f3f9 100644 > > --- a/drivers/tty/serial/8250/8250_pxa.c > > +++ b/drivers/tty/serial/8250/8250_pxa.c > > @@ -165,22 +165,6 @@ static struct platform_driver serial_pxa_driver = { > > > > module_platform_driver(serial_pxa_driver); > > > > -#ifdef CONFIG_SERIAL_8250_CONSOLE > > -static int __init early_serial_pxa_setup(struct earlycon_device *device, > > - const char *options) > > -{ > > - struct uart_port *port = &device->port; > > - > > - if (!(device->port.membase || device->port.iobase)) > > - return -ENODEV; > > - > > - port->regshift = 2; > > - return early_serial8250_setup(device, NULL); > > -} > > -OF_EARLYCON_DECLARE(early_pxa, "mrvl,pxa-uart", early_serial_pxa_setup); > > -OF_EARLYCON_DECLARE(mmp, "mrvl,mmp-uart", early_serial_pxa_setup); > > -#endif > > - > > MODULE_AUTHOR("Sergei Ianovich"); > > MODULE_LICENSE("GPL"); > > MODULE_ALIAS("platform:pxa2xx-uart"); > > -- > > 2.43.0 > > > > -- > Yixun Lan (dlan) > Gentoo Linux Developer > GPG Key ID AABEFD55