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[2620:137:e000::3:7]) by mx.google.com with ESMTPS id a7-20020a170902b58700b001bba879700fsi2049570pls.514.2023.09.14.11.58.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Sep 2023 11:58:49 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=MQF5Uzr7; dkim=neutral (no key) header.i=@linutronix.de; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by snail.vger.email (Postfix) with ESMTP id BBDF48338168; Thu, 14 Sep 2023 11:42:10 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at snail.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242164AbjINSmE (ORCPT + 33 others); Thu, 14 Sep 2023 14:42:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37778 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241998AbjINSj6 (ORCPT ); Thu, 14 Sep 2023 14:39:58 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5A0CF2719; Thu, 14 Sep 2023 11:39:04 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1694716742; 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=xOwhgnLO7hOBwv7Kh3brBH5G3zRUgo+W3NYhrK110nQ=; b=MQF5Uzr7EmKQx14r1E/RhX/umHkyltViumcqQtzYlRu/cdZA5N1RelnJ4iu3xdbYGsublf AesvLXS2l1vgjY/3lJjgy3oS9Fa9CNIR9FdCDxd3xGmG0PqFn6mYkcJSIXcskbHkN10xH7 fjf6/nHuFw7FFrO4gx/WSOB8n7ykjp9NGoMsoeoOBZCgXHT+OEqemMupp1sBuPMJwRsuxf nU/nGrLUIfKTsfa4sHRdVUDDytrxtrfa0bYiOJQclsPYDWetbS6woG0hXVe80c083ykC0o LnHq5GziKgk/yioSaLz/v2WQTMBmpy3Te2MAeI6u0OokLmagDAUK+U749FyAYQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1694716742; 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=xOwhgnLO7hOBwv7Kh3brBH5G3zRUgo+W3NYhrK110nQ=; b=y4UPC3ayiwCpK2wUuae2l5tlzv/vgSHZnGxCpQZEdOHfUE6peDdmI2DaPnIbsoJ+GKOrLW l/Me65oUdGiBduAQ== To: Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Laxman Dewangan , Thierry Reding , Jonathan Hunter , linux-tegra@vger.kernel.org Subject: [PATCH tty v1 56/74] serial: tegra: Use port lock wrappers Date: Thu, 14 Sep 2023 20:44:13 +0206 Message-Id: <20230914183831.587273-57-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-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Thu, 14 Sep 2023 11:42:10 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777040547488857574 X-GMAIL-MSGID: 1777040547488857574 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/serial-tegra.c | 32 +++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index d4ec943cb8e9..6d4006b41975 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -411,7 +411,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) divisor = DIV_ROUND_CLOSEST(rate, baud * 16); } - spin_lock_irqsave(&tup->uport.lock, flags); + uart_port_lock_irqsave(&tup->uport, &flags); lcr = tup->lcr_shadow; lcr |= UART_LCR_DLAB; tegra_uart_write(tup, lcr, UART_LCR); @@ -424,7 +424,7 @@ static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud) /* Dummy read to ensure the write is posted */ tegra_uart_read(tup, UART_SCR); - spin_unlock_irqrestore(&tup->uport.lock, flags); + uart_port_unlock_irqrestore(&tup->uport, flags); tup->current_baud = baud; @@ -522,13 +522,13 @@ static void tegra_uart_tx_dma_complete(void *args) dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state); count = tup->tx_bytes_requested - state.residue; async_tx_ack(tup->tx_dma_desc); - spin_lock_irqsave(&tup->uport.lock, flags); + uart_port_lock_irqsave(&tup->uport, &flags); uart_xmit_advance(&tup->uport, count); tup->tx_in_progress = 0; if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(&tup->uport); tegra_uart_start_next_tx(tup); - spin_unlock_irqrestore(&tup->uport.lock, flags); + uart_port_unlock_irqrestore(&tup->uport, flags); } static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup, @@ -598,13 +598,13 @@ static unsigned int tegra_uart_tx_empty(struct uart_port *u) unsigned int ret = 0; unsigned long flags; - spin_lock_irqsave(&u->lock, flags); + uart_port_lock_irqsave(u, &flags); if (!tup->tx_in_progress) { unsigned long lsr = tegra_uart_read(tup, UART_LSR); if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS) ret = TIOCSER_TEMT; } - spin_unlock_irqrestore(&u->lock, flags); + uart_port_unlock_irqrestore(u, flags); return ret; } @@ -727,7 +727,7 @@ static void tegra_uart_rx_dma_complete(void *args) struct dma_tx_state state; enum dma_status status; - spin_lock_irqsave(&u->lock, flags); + uart_port_lock_irqsave(u, &flags); status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state); @@ -749,7 +749,7 @@ static void tegra_uart_rx_dma_complete(void *args) set_rts(tup, true); done: - spin_unlock_irqrestore(&u->lock, flags); + uart_port_unlock_irqrestore(u, flags); } static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup) @@ -836,7 +836,7 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) bool is_rx_int = false; unsigned long flags; - spin_lock_irqsave(&u->lock, flags); + uart_port_lock_irqsave(u, &flags); while (1) { iir = tegra_uart_read(tup, UART_IIR); if (iir & UART_IIR_NO_INT) { @@ -852,7 +852,7 @@ static irqreturn_t tegra_uart_isr(int irq, void *data) } else if (is_rx_start) { tegra_uart_start_rx_dma(tup); } - spin_unlock_irqrestore(&u->lock, flags); + uart_port_unlock_irqrestore(u, flags); return IRQ_HANDLED; } @@ -969,11 +969,11 @@ static void tegra_uart_hw_deinit(struct tegra_uart_port *tup) } } - spin_lock_irqsave(&tup->uport.lock, flags); + uart_port_lock_irqsave(&tup->uport, &flags); /* Reset the Rx and Tx FIFOs */ tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR); tup->current_baud = 0; - spin_unlock_irqrestore(&tup->uport.lock, flags); + uart_port_unlock_irqrestore(&tup->uport, flags); tup->rx_in_progress = 0; tup->tx_in_progress = 0; @@ -1292,7 +1292,7 @@ static void tegra_uart_set_termios(struct uart_port *u, int ret; max_divider *= 16; - spin_lock_irqsave(&u->lock, flags); + uart_port_lock_irqsave(u, &flags); /* Changing configuration, it is safe to stop any rx now */ if (tup->rts_active) @@ -1341,7 +1341,7 @@ static void tegra_uart_set_termios(struct uart_port *u, baud = uart_get_baud_rate(u, termios, oldtermios, parent_clk_rate/max_divider, parent_clk_rate/16); - spin_unlock_irqrestore(&u->lock, flags); + uart_port_unlock_irqrestore(u, flags); ret = tegra_set_baudrate(tup, baud); if (ret < 0) { dev_err(tup->uport.dev, "Failed to set baud rate\n"); @@ -1349,7 +1349,7 @@ static void tegra_uart_set_termios(struct uart_port *u, } if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); - spin_lock_irqsave(&u->lock, flags); + uart_port_lock_irqsave(u, &flags); /* Flow control */ if (termios->c_cflag & CRTSCTS) { @@ -1382,7 +1382,7 @@ static void tegra_uart_set_termios(struct uart_port *u, if (termios->c_iflag & IGNBRK) tup->uport.ignore_status_mask |= UART_LSR_BI; - spin_unlock_irqrestore(&u->lock, flags); + uart_port_unlock_irqrestore(u, flags); } static const char *tegra_uart_type(struct uart_port *u)