From patchwork Thu Sep 14 18:37:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 723028 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 74D1FEEAA63 for ; Thu, 14 Sep 2023 18:38:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241659AbjINSi6 (ORCPT ); Thu, 14 Sep 2023 14:38:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241612AbjINSix (ORCPT ); Thu, 14 Sep 2023 14:38:53 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E76262103; Thu, 14 Sep 2023 11:38:45 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716724; 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=VtioS1TmKY7HP/T4E5ia6bLpeGsG2aqw7oKrLcODTps=; b=KzR11aI9gMRB+jNxh73zf08f5zfu/h94i8WcA/3/y5qkyCNVrXvChwPbdJM9x207DuYSdm 5TnoMRJFSM0tSm8kxtFH60dMK6ATrKgzPAOqhAs/T5VKADPi7G0F8X0rcZWIPSN7uXsNMf xSeERMiAJPhFGYUXTISrHOmpAwvkN4GxihRhtbV/aBe2bqoUhBydbMagg2zV6sBnhZsm8o 9VQ3VavmlDH64IhR4lxTvzRanxQk1621jItnGZdIz7FBiyYLIrfZMG5X73rfXfrAZyaA4O 0tNytbsl8jFu9CQaJmYt4hcEHUm3VIWtDCl7OqYda7AOsn2bA/cDl9csUv19dA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716724; 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=VtioS1TmKY7HP/T4E5ia6bLpeGsG2aqw7oKrLcODTps=; b=r8qMy4Di9mr9YJgshOb2oXJhJVt0iIfP10UKioSN1o0mLawjFrtLrNOaRqGeDH1l6nHA1q UsuEvV98gwDm4PAQ== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Tobias Klauser Subject: [PATCH tty v1 14/74] serial: altera_jtaguart: Use port lock wrappers Date: Thu, 14 Sep 2023 20:43:31 +0206 Message-Id: <20230914183831.587273-15-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/altera_jtaguart.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/drivers/tty/serial/altera_jtaguart.c b/drivers/tty/serial/altera_jtaguart.c index 5fab4c978891..7090b251dd4d 100644 --- a/drivers/tty/serial/altera_jtaguart.c +++ b/drivers/tty/serial/altera_jtaguart.c @@ -147,14 +147,14 @@ static irqreturn_t altera_jtaguart_interrupt(int irq, void *data) isr = (readl(port->membase + ALTERA_JTAGUART_CONTROL_REG) >> ALTERA_JTAGUART_CONTROL_RI_OFF) & port->read_status_mask; - spin_lock(&port->lock); + uart_port_lock(port); if (isr & ALTERA_JTAGUART_CONTROL_RE_MSK) altera_jtaguart_rx_chars(port); if (isr & ALTERA_JTAGUART_CONTROL_WE_MSK) altera_jtaguart_tx_chars(port); - spin_unlock(&port->lock); + uart_port_unlock(port); return IRQ_RETVAL(isr); } @@ -180,14 +180,14 @@ static int altera_jtaguart_startup(struct uart_port *port) return ret; } - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Enable RX interrupts now */ port->read_status_mask = ALTERA_JTAGUART_CONTROL_RE_MSK; writel(port->read_status_mask, port->membase + ALTERA_JTAGUART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); return 0; } @@ -196,14 +196,14 @@ static void altera_jtaguart_shutdown(struct uart_port *port) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); /* Disable all interrupts now */ port->read_status_mask = 0; writel(port->read_status_mask, port->membase + ALTERA_JTAGUART_CONTROL_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); } @@ -264,33 +264,33 @@ static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c unsigned long flags; u32 status; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (!altera_jtaguart_tx_space(port, &status)) { - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0) { return; /* no connection activity */ } cpu_relax(); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #else static void altera_jtaguart_console_putc(struct uart_port *port, unsigned char c) { unsigned long flags; - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); while (!altera_jtaguart_tx_space(port, NULL)) { - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); cpu_relax(); - spin_lock_irqsave(&port->lock, flags); + uart_port_lock_irqsave(port, &flags); } writel(c, port->membase + ALTERA_JTAGUART_DATA_REG); - spin_unlock_irqrestore(&port->lock, flags); + uart_port_unlock_irqrestore(port, flags); } #endif