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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 9372FC31E46 for ; Wed, 12 Jun 2019 09:16:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73BDA20874 for ; Wed, 12 Jun 2019 09:16:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437339AbfFLJQZ (ORCPT ); Wed, 12 Jun 2019 05:16:25 -0400 Received: from mga06.intel.com ([134.134.136.31]:18157 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730353AbfFLJQZ (ORCPT ); Wed, 12 Jun 2019 05:16:25 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 12 Jun 2019 02:16:24 -0700 X-ExtLoop1: 1 Received: from smile.fi.intel.com (HELO smile) ([10.237.68.145]) by orsmga006.jf.intel.com with ESMTP; 12 Jun 2019 02:16:21 -0700 Received: from andy by smile with local (Exim 4.92) (envelope-from ) id 1hazMj-00077D-8W; Wed, 12 Jun 2019 12:16:21 +0300 Date: Wed, 12 Jun 2019 12:16:21 +0300 From: Andy Shevchenko To: Stefan Roese Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Yegor Yefremov , Mika Westerberg , Giulio Benetti , Greg Kroah-Hartman Subject: Re: [PATCH 2/2 v5] tty/serial/8250: use mctrl_gpio helpers Message-ID: <20190612091621.GA9224@smile.fi.intel.com> References: <20190611105603.4435-1-sr@denx.de> <20190611105603.4435-2-sr@denx.de> <20190611124415.GT9224@smile.fi.intel.com> <85f0d39c-e5d8-320b-e611-d956630a629f@denx.de> <20190611144828.GX9224@smile.fi.intel.com> <12e5180e-b4a0-e5fa-bcad-ddc8103d644c@denx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <12e5180e-b4a0-e5fa-bcad-ddc8103d644c@denx.de> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 12, 2019 at 10:13:05AM +0200, Stefan Roese wrote: > On 11.06.19 16:48, Andy Shevchenko wrote: > > On Tue, Jun 11, 2019 at 04:02:54PM +0200, Stefan Roese wrote: > > > On 11.06.19 14:44, Andy Shevchenko wrote: > > > > On Tue, Jun 11, 2019 at 12:56:03PM +0200, Stefan Roese wrote: > > > > > > > static inline void serial8250_out_MCR(struct uart_8250_port *up, int value) > > > > > { > > > > > serial_out(up, UART_MCR, value); > > > > > + > > > > > + if (up->gpios) { > > > > > + int mctrl_gpio = 0; > > > > > + > > > > > + if (value & UART_MCR_RTS) > > > > > + mctrl_gpio |= TIOCM_RTS; > > > > > + if (value & UART_MCR_DTR) > > > > > + mctrl_gpio |= TIOCM_DTR; > > > > > + > > > > > + mctrl_gpio_set(up->gpios, mctrl_gpio); > > > > > + } > > > > > } > > > > > > > static inline int serial8250_in_MCR(struct uart_8250_port *up) > > > > > { > > > > > - return serial_in(up, UART_MCR); > > > > > + int mctrl; > > > > > + > > > > > + mctrl = serial_in(up, UART_MCR); > > > > > + > > > > > + if (up->gpios) { > > > > > + int mctrl_gpio = 0; > > > > > + > > > > > + /* save current MCR values */ > > > > > + if (mctrl & UART_MCR_RTS) > > > > > + mctrl_gpio |= TIOCM_RTS; > > > > > + if (mctrl & UART_MCR_DTR) > > > > > + mctrl_gpio |= TIOCM_DTR; > > > > > + > > > > > + mctrl_gpio = mctrl_gpio_get_outputs(up->gpios, &mctrl_gpio); > > > > > + if (mctrl_gpio & TIOCM_RTS) > > > > > + mctrl |= UART_MCR_RTS; > > > > > + else > > > > > + mctrl &= ~UART_MCR_RTS; > > > > > + > > > > > + if (mctrl_gpio & TIOCM_DTR) > > > > > + mctrl |= UART_MCR_DTR; > > > > > + else > > > > > + mctrl &= ~UART_MCR_DTR; > > > > > + } > > > > > + > > > > > + return mctrl; > > > > > } > > > > > > > > These are using OR logic with potentially volatile data. Shouldn't we mask > > > > unused bits in UART_MCR in case of up->gpios != NULL? > > > > > > Sorry, I don't see, which bits you are referring to? Could you please be > > > a bit more specific with the variable / macro meant (example)? > > > > I meant that we double write values in the out() which might have some > > consequences, though I hope nothing wrong with it happens. > > Where is the double write to a register? Sorry, I fail to spot it. Not to the one register. From the functional point of view the same signal is set up twice: once per UART register, once per GPIO pins. > > In the in() we read the all bits in the register. > > > > As now I look at the implementation of mctrl_gpio_get_outputs(), > > I think we rather get helpers for conversion between TIOCM and UART_MCR values, > > so, they can be used in get_mctrl() / set_mctrl() and above. > > Do you something like this in mind? More likely static inline int serial8250_MCR_to_TIOCM(int mcr) { int tiocm = 0; if (mcr & ...) tiocm |= ...; ... return tiocm; } static inline int serial8250_TIOCM_to_MCR(int tiocm) { ... in a similar way ... } > Plus the use of these macros in this patch of course. No macros, please. -- With Best Regards, Andy Shevchenko