From patchwork Thu Sep 14 18:38:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723011 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 5F649EEAA62 for ; Thu, 14 Sep 2023 18:41:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242113AbjINSlZ (ORCPT ); Thu, 14 Sep 2023 14:41:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53406 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241654AbjINSjc (ORCPT ); Thu, 14 Sep 2023 14:39:32 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92B1C26B1; Thu, 14 Sep 2023 11:39:00 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716739; 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=fK/nNCe+HXlWYA1jtYpFGX+8N5k+z0c1fSpVRQqc2rk=; b=KnxkI6k/hF3y8+W7O9QIvNc+adMKQ2QUGFZ/3lmm0NgHEN3IJhCZI78LauOIiQoHvQlCZO Hzf8efjpxWAdhzn3geATG+Ctps4UM/4ayr1bJAd+pMiRBgAzT5I7slfldiaNYEAA3Hb0ZV PSIK+TrTGd0T+7ceE12dD1dRtG+iDCwdCwwSDCXCKywKzqeLbiI+F8q8EaYoXWDU7KbhkE LTc9cu2kxwqZHLRnjMAk5W4nK3HAI5zhl1zFYvSb7/R67E1o7cdHd1wHEzI+YlHcMudCvv PEMH4V6QM5UlR1pumuKByd4XaSgO41p1UNNJmA+p50Nmtlk/SQ3Bxb7tz3PQqQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716739; 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=fK/nNCe+HXlWYA1jtYpFGX+8N5k+z0c1fSpVRQqc2rk=; b=EHf+GclZBZ+3/IXgMoulZgM+BxHIK+t+y68aErfnSuGEgMXJaijQwUu7quwfYkLzVhYlRF 9A2MKiFd4Q9sqNDA== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Thierry Reding , Richard GENOUD Subject: [PATCH tty v1 48/74] serial: pxa: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:05 +0206 Message-Id: <20230914183831.587273-49-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/pxa.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/drivers/tty/serial/pxa.c b/drivers/tty/serial/pxa.c index 73c60f5ea027..46e70e155aab 100644 --- a/drivers/tty/serial/pxa.c +++ b/drivers/tty/serial/pxa.c @@ -225,14 +225,14 @@ static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id) iir = serial_in(up, UART_IIR); if (iir & UART_IIR_NO_INT) return IRQ_NONE; - spin_lock(&up->port.lock); + uart_port_lock(&up->port); lsr = serial_in(up, UART_LSR); if (lsr & UART_LSR_DR) receive_chars(up, &lsr); check_modem_status(up); if (lsr & UART_LSR_THRE) transmit_chars(up); - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); return IRQ_HANDLED; } @@ -242,9 +242,9 @@ static unsigned int serial_pxa_tx_empty(struct uart_port *port) unsigned long flags; unsigned int ret; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0; - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); return ret; } @@ -295,13 +295,13 @@ static void serial_pxa_break_ctl(struct uart_port *port, int break_state) struct uart_pxa_port *up = (struct uart_pxa_port *)port; unsigned long flags; - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); if (break_state == -1) up->lcr |= UART_LCR_SBC; else up->lcr &= ~UART_LCR_SBC; serial_out(up, UART_LCR, up->lcr); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static int serial_pxa_startup(struct uart_port *port) @@ -346,10 +346,10 @@ static int serial_pxa_startup(struct uart_port *port) */ serial_out(up, UART_LCR, UART_LCR_WLEN8); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); up->port.mctrl |= TIOCM_OUT2; serial_pxa_set_mctrl(&up->port, up->port.mctrl); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); /* * Finally, enable interrupts. Note: Modem status interrupts @@ -383,10 +383,10 @@ static void serial_pxa_shutdown(struct uart_port *port) up->ier = 0; serial_out(up, UART_IER, 0); - spin_lock_irqsave(&up->port.lock, flags); + uart_port_lock_irqsave(&up->port, &flags); up->port.mctrl &= ~TIOCM_OUT2; serial_pxa_set_mctrl(&up->port, up->port.mctrl); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); /* * Disable break condition and FIFOs @@ -434,7 +434,7 @@ serial_pxa_set_termios(struct uart_port *port, struct ktermios *termios, * 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); /* * Ensure the port will be enabled. @@ -504,7 +504,7 @@ serial_pxa_set_termios(struct uart_port *port, struct ktermios *termios, up->lcr = cval; /* Save LCR */ serial_pxa_set_mctrl(&up->port, up->port.mctrl); serial_out(up, UART_FCR, fcr); - spin_unlock_irqrestore(&up->port.lock, flags); + uart_port_unlock_irqrestore(&up->port, flags); } static void @@ -608,9 +608,9 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count) 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 @@ -628,7 +628,7 @@ serial_pxa_console_write(struct console *co, const char *s, unsigned int count) serial_out(up, UART_IER, ier); if (locked) - spin_unlock(&up->port.lock); + uart_port_unlock(&up->port); local_irq_restore(flags); clk_disable(up->clk);