From patchwork Thu Sep 14 18:37:41 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723023 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 96624EEAA64 for ; Thu, 14 Sep 2023 18:39:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241656AbjINSjE (ORCPT ); Thu, 14 Sep 2023 14:39:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241739AbjINSi6 (ORCPT ); Thu, 14 Sep 2023 14:38:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1BFB1FFB; Thu, 14 Sep 2023 11:38:49 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716728; 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=lSEvjVL+BxuTqhoV6y++5iFzUZwHV0OnCUueADVyxEA=; b=IVquxk0Z+ro6LFHKJw51lwIPigfWCMfmclUU2+JcehI3LOaX5BkNwJRLblrY0cbagILQic RqiElXu91Wnj1AhvgvDxpBl8H4wZs16fjHk6JDxf7RHlZytj1RGhivPhRjLqRbQGhMxpEy vg/kQ1k3mVm1xZnPUIn7+mrqPqddMnw5g3lnvkbYeAfM5GK9kjiAKhJJO1cRKYHo3CMe2D bbcknb4FzDKQZjdNHh8XHtx01Lip0J/J3MtvXpgDJScQb8lF5ZDAXULO+IUJr1FN+XgeG5 WasYgGIMC0IPIVLI1Q5P/xd2hLixAvMXU+m/Fa8R6mu0GRkyln7ivVnmHKqBqA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716728; 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=lSEvjVL+BxuTqhoV6y++5iFzUZwHV0OnCUueADVyxEA=; b=r6+fh09oHfENkWCN4lF8MffdwEGUKNIjvSkxoPrQxnv1rhnu/nekiAEHappQ9NFpa+bmJT nA9poxy/eDhflsDg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Baruch Siach , Tobias Klauser , Richard GENOUD , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org Subject: [PATCH tty v1 24/74] serial: digicolor: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:41 +0206 Message-Id: <20230914183831.587273-25-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/digicolor-usart.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/digicolor-usart.c b/drivers/tty/serial/digicolor-usart.c index 128b5479e813..5004125f3045 100644 --- a/drivers/tty/serial/digicolor-usart.c +++ b/drivers/tty/serial/digicolor-usart.c @@ -133,7 +133,7 @@ static void digicolor_uart_rx(struct uart_port *port) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (1) { u8 status, ch, ch_flag; @@ -172,7 +172,7 @@ static void digicolor_uart_rx(struct uart_port *port) ch_flag); } - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); tty_flip_buffer_push(&port->state->port); } @@ -185,7 +185,7 @@ static void digicolor_uart_tx(struct uart_port *port) if (digicolor_uart_tx_full(port)) return; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); if (port->x_char) { writeb_relaxed(port->x_char, port->membase + UA_EMI_REC); @@ -211,7 +211,7 @@ static void digicolor_uart_tx(struct uart_port *port) uart_write_wakeup(port); out: - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static irqreturn_t digicolor_uart_int(int irq, void *dev_id) @@ -333,7 +333,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, port->ignore_status_mask |= UA_STATUS_OVERRUN_ERR | UA_STATUS_PARITY_ERR | UA_STATUS_FRAME_ERR; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_update_timeout(port, termios->c_cflag, baud); @@ -341,7 +341,7 @@ static void digicolor_uart_set_termios(struct uart_port *port, writeb_relaxed(divisor & 0xff, port->membase + UA_HBAUD_LO); writeb_relaxed(divisor >> 8, port->membase + UA_HBAUD_HI); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static const char *digicolor_uart_type(struct uart_port *port) @@ -398,14 +398,14 @@ static void digicolor_uart_console_write(struct console *co, const char *c, int locked = 1; if (oops_in_progress) - locked = spin_trylock_irqsave(&port->lock, flags); + locked = uart_port_trylock_irqsave(port, &flags); else - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); uart_console_write(port, c, n, digicolor_uart_console_putchar); if (locked) - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); /* Wait for transmitter to become empty */ do {