From patchwork Thu Sep 14 18:37:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723026 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 EF121EEAA5D for ; Thu, 14 Sep 2023 18:38:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241808AbjINSjA (ORCPT ); Thu, 14 Sep 2023 14:39:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241649AbjINSix (ORCPT ); Thu, 14 Sep 2023 14:38:53 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF6B2210C; Thu, 14 Sep 2023 11:38:47 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716726; 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=XEd2RSJzhntSqK11XG0KTVZ8R/Gb2qOWG3w4Nfiax6M=; b=F7L7IR2eKfSOVFtuX4pQzhKiSs62AY/3etTgDhxEVqQIBaQVBBD+jnWGxhvpj3j/8Ufb5y uDdZnKOiQoUL/Kw8C3ieYB4aP2IFqldUQzXjM/wZhl7CEu8PqftaSW2pfakgw9azzENni4 CQeznE9cVGPo350Gj5199BAJ150xLfDJcvEWx1xkItuMkLrBywJDLYn0Dxm9cp4W6Dkd/Q Mnnm9LhFV4Of+kbmHSAuztVeAk31dfX+ESOSmQ8q60q6Euxy4CWDXMPBVtz7vMHvohQeZI 8sn/dvHyoYaee8iHprsz+iesZmucTBZjtDtFsWfcmJ4TN0FF/EoQkI3HJgIjZA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716726; 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=XEd2RSJzhntSqK11XG0KTVZ8R/Gb2qOWG3w4Nfiax6M=; b=NKcbiC3CuQI7grUBjp9Qs9w9XdzcJTBkNz781YXADwy6HZ43g3o02oPyyFKranKsUoRIwK ZyT+Wy/WXLcs/dAw== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Yangtao Li , Lukas Wunner Subject: [PATCH tty v1 19/74] serial: ar933x: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:36 +0206 Message-Id: <20230914183831.587273-20-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/ar933x_uart.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c index 924c1a89347c..ffd234673177 100644 --- a/drivers/tty/serial/ar933x_uart.c +++ b/drivers/tty/serial/ar933x_uart.c @@ -133,9 +133,9 @@ static unsigned int ar933x_uart_tx_empty(struct uart_port *port) unsigned long flags; unsigned int rdata; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT; } @@ -220,14 +220,14 @@ static void ar933x_uart_break_ctl(struct uart_port *port, int break_state) container_of(port, struct ar933x_uart_port, port); unsigned long flags; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); if (break_state == -1) ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, AR933X_UART_CS_TX_BREAK); else ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, AR933X_UART_CS_TX_BREAK); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } /* @@ -318,7 +318,7 @@ static void ar933x_uart_set_termios(struct uart_port *port, * Ok, we're now changing the port state. Do it with * interrupts disabled. */ - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* disable the UART */ ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, @@ -352,7 +352,7 @@ static void ar933x_uart_set_termios(struct uart_port *port, AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S, AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); if (tty_termios_baud_rate(new)) tty_termios_encode_baud_rate(new, baud, baud); @@ -450,7 +450,7 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) if ((status & AR933X_UART_CS_HOST_INT) == 0) return IRQ_NONE; - spin_lock(&up->port.lock); + uart_port_lock(&up->port); status = ar933x_uart_read(up, AR933X_UART_INT_REG); status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG); @@ -468,7 +468,7 @@ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) ar933x_uart_tx_chars(up); } - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); return IRQ_HANDLED; } @@ -485,7 +485,7 @@ static int ar933x_uart_startup(struct uart_port *port) if (ret) return ret; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); /* Enable HOST interrupts */ ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, @@ -498,7 +498,7 @@ static int ar933x_uart_startup(struct uart_port *port) /* Enable RX interrupts */ ar933x_uart_start_rx_interrupt(up); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return 0; } @@ -632,9 +632,9 @@ static void ar933x_uart_console_write(struct console *co, const char *s, if (up->port.sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock(&up->port.lock); + locked = uart_port_trylock(&up->port); else - spin_lock(&up->port.lock); + uart_port_lock(&up->port); /* * First save the IER then disable the interrupts @@ -654,7 +654,7 @@ static void ar933x_uart_console_write(struct console *co, const char *s, ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); if (locked) - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); local_irq_restore(flags); }