From patchwork Thu Sep 14 18:38:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 13385829 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 313FCEEAA66 for ; Thu, 14 Sep 2023 18:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=bavwTYSiMsqvy4st0YSxZu4NiOb7IrD6LcuPT7j/RUw=; b=4RE11rw+kWY32a fVxrudQjPbOXyDas8AUkTruIqMaVfcMpCOpPNpnR7Nxlm4z6UJlRAC+fHMJ8irSzbANfzP+Uj5HMP XOlS++O6tqkrCXskbUCkwWNiMqcjJxMBOEepx01Me2BiESOfM8M+bqdmu3EGeAcJUSVGoXX+uSlxB xohU074SlSuGO+lCgzLaJakOFVQi1cP463TqC+qNY6yO4qHvddUDe5HOvzxPMkA6tLvBW80qIkUZ0 idR6NR5lrDhWieTwOyCPLz09FBSbnUuuAyaTeyTZ71bWyj36Q6CUU2KNfH20ashk9suxgDSnG6KCt vFDbo4Qd41+Agua5yjrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qgrFC-00951K-1D; Thu, 14 Sep 2023 18:39:14 +0000 Received: from galois.linutronix.de ([193.142.43.55]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qgrEx-0094pe-1O; Thu, 14 Sep 2023 18:39:02 +0000 From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716737; 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=wEegAouA6je3osDZUCJlEv4gB4p0igZuWACS++cZC6E=; b=P6M8uOs7G9Yh2dc008zF0jwOKeRh+0hdHCSyzdlotOmY0uNzJhA9n/z2Ghgw0hLD3btQN0 LU0PJMIUqY+PNsWpCt8Fgdf7vWhYkHrdBWXJKxjWs1S5osrUX1XYS+GxDXNIcZv0LNbInJ KyKAiaExHWIPnNXtopgW1ACgnMGNr2MU4hazjKE35Jr75Mq5heJ3rQ7TobgjB2ZOy1WOTs yRaZhaIr9Eg0ziMUyc7mkzNOKXtx9BXRb+CFh6CXdTf2hX6pmnGMnuLJZ/wuwmsSBL9NnF 2KwNuGN7Ys5NqQfLHT5AFK9JO+piH7H+1QZoujzVSxRXEdHXdAdeCPR0oEouzA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716737; 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=wEegAouA6je3osDZUCJlEv4gB4p0igZuWACS++cZC6E=; b=uBA+txHp6Ix/jsJ7gls3Uu83I1iuB3Kr/xTO5a038wo1mz94ZF0uGirU+OK9B6vKmLEgmR viMGeXnBcms8HvDg== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, =?utf-8?q?Andreas_F=C3=A4rber?= , Manivannan Sadhasivam , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org, linux-actions@lists.infradead.org Subject: [PATCH tty v1 44/74] serial: owl: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:01 +0206 Message-Id: <20230914183831.587273-45-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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230914_113859_773267_13196C8B X-CRM114-Status: GOOD ( 14.91 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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/owl-uart.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c index e99970a9437f..919f5e5aa0f1 100644 --- a/drivers/tty/serial/owl-uart.c +++ b/drivers/tty/serial/owl-uart.c @@ -125,12 +125,12 @@ static unsigned int owl_uart_tx_empty(struct uart_port *port) u32 val; unsigned int ret; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); val = owl_uart_read(port, OWL_UART_STAT); ret = (val & OWL_UART_STAT_TFES) ? TIOCSER_TEMT : 0; - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return ret; } @@ -232,7 +232,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id) unsigned long flags; u32 stat; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); stat = owl_uart_read(port, OWL_UART_STAT); @@ -246,7 +246,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id) stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP; owl_uart_write(port, stat, OWL_UART_STAT); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return IRQ_HANDLED; } @@ -256,14 +256,14 @@ static void owl_uart_shutdown(struct uart_port *port) u32 val; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); val = owl_uart_read(port, OWL_UART_CTL); val &= ~(OWL_UART_CTL_TXIE | OWL_UART_CTL_RXIE | OWL_UART_CTL_TXDE | OWL_UART_CTL_RXDE | OWL_UART_CTL_EN); owl_uart_write(port, val, OWL_UART_CTL); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); } @@ -279,7 +279,7 @@ static int owl_uart_startup(struct uart_port *port) if (ret) return ret; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); val = owl_uart_read(port, OWL_UART_STAT); val |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP @@ -291,7 +291,7 @@ static int owl_uart_startup(struct uart_port *port) val |= OWL_UART_CTL_EN; owl_uart_write(port, val, OWL_UART_CTL); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @@ -311,7 +311,7 @@ static void owl_uart_set_termios(struct uart_port *port, u32 ctl; unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); ctl = owl_uart_read(port, OWL_UART_CTL); @@ -371,7 +371,7 @@ static void owl_uart_set_termios(struct uart_port *port, uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } static void owl_uart_release_port(struct uart_port *port) @@ -515,9 +515,9 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, if (port->sysrq) locked = 0; else if (oops_in_progress) - locked = spin_trylock(&port->lock); + locked = uart_port_trylock(port); else { - spin_lock(&port->lock); + uart_port_lock(port); locked = 1; } @@ -541,7 +541,7 @@ static void owl_uart_port_write(struct uart_port *port, const char *s, owl_uart_write(port, old_ctl, OWL_UART_CTL); if (locked) - spin_unlock(&port->lock); + uart_port_unlock(port); local_irq_restore(flags); }