From patchwork Thu Sep 14 18:37:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723016 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B2967EEAA64 for ; Thu, 14 Sep 2023 18:39:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241999AbjINSj6 (ORCPT ); Thu, 14 Sep 2023 14:39:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241819AbjINSjB (ORCPT ); Thu, 14 Sep 2023 14:39:01 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F673211E; Thu, 14 Sep 2023 11:38:56 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716734; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E9wzJpM/hTGvGG40vNbVTUQjpkMtUAUxayMtXjZuHUE=; b=u8PiurzFnDC29q45800AqAXE7kZ5IcrLh5PgFkXFWnEqN2WMaBEoxskCMMi9QcukzjXvo8 zxNMY05yrq8L33TVpXER2JxgNUc1E/xhYJMwu4sd4HpsDc0MKIuaWzFMfoPsnme259Cobp iFCIpRAsH76Pf0EeGsYgvm7fR3aWBRfh1G80WueS2pdN+4BoyuaGhYWLdUKqmAySZCqsP5 xXwV5U0TC7WQVjC1oTM9nmcHz5iVLKEzG8NsdnzS8r8t1UW1grEEDkSSsaHK9ioYWVbh1d cPSA2ZtEx9keDZud6890yVfuNfEzSbJ1Ewwhyu4E/NT7s9FAi1m0qLuQ3yqVLw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716734; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E9wzJpM/hTGvGG40vNbVTUQjpkMtUAUxayMtXjZuHUE=; b=Z1W6hSbtxnVWbn5OWCbxj/FFJw4sMBXi9W6Yl6ggduNuUlI6W1LsbgMRHOWu1h1acXbZjn dfA/izrV71PNwOAw== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Taichi Sugaya , Takao Orito , Thierry Reding , Richard GENOUD , "Maciej W. Rozycki" , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org Subject: [PATCH tty v1 38/74] serial: milbeaut_usio: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:55 +0206 Message-Id: <20230914183831.587273-39-john.ogness@linutronix.de> In-Reply-To: <20230914183831.587273-1-john.ogness@linutronix.de> References: <20230914183831.587273-1-john.ogness@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org From: Thomas Gleixner When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner --- drivers/tty/serial/milbeaut_usio.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/tty/serial/milbeaut_usio.c b/drivers/tty/serial/milbeaut_usio.c index 70a910085e93..db3b81f2aa57 100644 --- a/drivers/tty/serial/milbeaut_usio.c +++ b/drivers/tty/serial/milbeaut_usio.c @@ -207,9 +207,9 @@ static irqreturn_t mlb_usio_rx_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; - spin_lock(&port->lock); + uart_port_lock(port); mlb_usio_rx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -218,10 +218,10 @@ static irqreturn_t mlb_usio_tx_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; - spin_lock(&port->lock); + uart_port_lock(port); if (readb(port->membase + MLB_USIO_REG_SSR) & MLB_USIO_SSR_TBI) mlb_usio_tx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_HANDLED; } @@ -267,7 +267,7 @@ static int mlb_usio_startup(struct uart_port *port) escr = readb(port->membase + MLB_USIO_REG_ESCR); if (of_property_read_bool(port->dev->of_node, "auto-flow-control")) escr |= MLB_USIO_ESCR_FLWEN; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); writeb(0, port->membase + MLB_USIO_REG_SCR); writeb(escr, port->membase + MLB_USIO_REG_ESCR); writeb(MLB_USIO_SCR_UPCL, port->membase + MLB_USIO_REG_SCR); @@ -282,7 +282,7 @@ static int mlb_usio_startup(struct uart_port *port) writeb(MLB_USIO_SCR_TXE | MLB_USIO_SCR_RIE | MLB_USIO_SCR_TBIE | MLB_USIO_SCR_RXE, port->membase + MLB_USIO_REG_SCR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @@ -337,7 +337,7 @@ static void mlb_usio_set_termios(struct uart_port *port, else quot = 0; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_update_timeout(port, termios->c_cflag, baud); port->read_status_mask = MLB_USIO_SSR_ORE | MLB_USIO_SSR_RDRF | MLB_USIO_SSR_TDRE; @@ -367,7 +367,7 @@ static void mlb_usio_set_termios(struct uart_port *port, writew(BIT(12), port->membase + MLB_USIO_REG_FBYTE); writeb(MLB_USIO_SCR_RIE | MLB_USIO_SCR_RXE | MLB_USIO_SCR_TBIE | MLB_USIO_SCR_TXE, port->membase + MLB_USIO_REG_SCR); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *mlb_usio_type(struct uart_port *port)