From mboxrd@z Thu Jan 1 00:00:00 1970 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 E5E13EE6421 for ; Fri, 15 Sep 2023 06:57:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232424AbjIOG5Z (ORCPT ); Fri, 15 Sep 2023 02:57:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232476AbjIOG5Y (ORCPT ); Fri, 15 Sep 2023 02:57:24 -0400 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BE8D2D58 for ; Thu, 14 Sep 2023 23:56:53 -0700 (PDT) Received: by mail-wr1-x42e.google.com with SMTP id ffacd0b85a97d-31adc5c899fso1601846f8f.2 for ; Thu, 14 Sep 2023 23:56:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1694761011; x=1695365811; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:organization:autocrypt :references:cc:to:content-language:subject:reply-to:from:user-agent :mime-version:date:message-id:from:to:cc:subject:date:message-id :reply-to; bh=j12oxEv4oQ9vPyiNgmw9xBXkHftj9B6rlt22/B5nTIU=; b=AilPSJDpSxRz1hj/ovhvXCrMPqXfkK+9WBGE73PznxEVPLGEA9Dq/CHFxvvMnK2hQO FQlRR+VVlCgLaga6rgYQE67O4Pkfj1wH1Dx3lYuO35nOIauYROcXqPgVmIctws6sEpOY iOFp9PzzXPkuTf9iNnJ0kcLXdJNV2QLke7gHr6qHCBL28ZBht/tLxhHkqUn58SfcixiU 3JhL3EHPbO0GcvOLiQ6ZQeNUSSYbqhUuz9ymyQ5pQ++oz2EU0oPWPFJc+m1cGe6ab/AY Hh8q9FiMNoBD29VWcq4WsOWH9ysLn1m1DdPXtZmSM9SdQ24gxu4LqTxWuxT0ScDGPcWq hkUA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694761011; x=1695365811; h=content-transfer-encoding:in-reply-to:organization:autocrypt :references:cc:to:content-language:subject:reply-to:from:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=j12oxEv4oQ9vPyiNgmw9xBXkHftj9B6rlt22/B5nTIU=; b=puT91rB7vQoLULzY90RJoz5un7jTtvXJc5ghLeqkMkOUDI3FRg0K5FZ2HDyEpm6BdY RyMdjhrNxF8dsV8yiWshhzm1N29UT77II2cgUj3Pu0MtZwvwX+z3SEsbn2bZCWSvMVV+ emELMxH8Rs/CGlTtUQFv1is4HvOYV9aBYxGHuSPy0lmec+GG/1i1q8xm/SRCcgk2NenT wgxjsa92q0LUWR38PXRT+wCi3pYZjCa+cNMHGZY9dt9vRRCgDdPdzt+mcOhCiZM5HJ45 Ou/vKhKNCNck4omR2oQkxOLGpn+zTx51WsTeg++C2W9+MmciIy+uSKCpj2mRHe+3skEc n91w== X-Gm-Message-State: AOJu0Yy6ewXjEwBROQ6P9Idhrz2Nq9Ea8RMWeSLt3AkZUxKaescD+kdE q0mwWDvmOK0uoPG+XLjay5EB/w== X-Google-Smtp-Source: AGHT+IF5bZDW17upZUyQuCXfWlfLN6eyzQLEiOGPo8/YwnqmLsw5emBhRDtJwlH6pFksTMU3pE88Yw== X-Received: by 2002:a05:6000:118d:b0:316:efb9:101d with SMTP id g13-20020a056000118d00b00316efb9101dmr712786wrx.25.1694761011484; Thu, 14 Sep 2023 23:56:51 -0700 (PDT) Received: from ?IPV6:2a01:e0a:982:cbb0:990a:74e6:266e:2294? ([2a01:e0a:982:cbb0:990a:74e6:266e:2294]) by smtp.gmail.com with ESMTPSA id t18-20020a5d5352000000b0031c3ee933b5sm3598140wrv.108.2023.09.14.23.56.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Sep 2023 23:56:51 -0700 (PDT) Message-ID: <5cd2ed15-949d-40b4-93fd-b1480f557b14@linaro.org> Date: Fri, 15 Sep 2023 08:56:49 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Neil Armstrong Reply-To: neil.armstrong@linaro.org Subject: Re: [PATCH tty v1 37/74] serial: meson: Use port lock wrappers Content-Language: en-US, fr To: John Ogness , Greg Kroah-Hartman Cc: Jiri Slaby , linux-serial@vger.kernel.org, Petr Mladek , Thomas Gleixner , linux-kernel@vger.kernel.org, Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Dmitry Rokosov , Lucas Tanure , =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org References: <20230914183831.587273-1-john.ogness@linutronix.de> <20230914183831.587273-38-john.ogness@linutronix.de> Autocrypt: addr=neil.armstrong@linaro.org; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKk5laWwgQXJtc3Ryb25nIDxuZWlsLmFybXN0cm9uZ0BsaW5hcm8ub3JnPsLAkQQTAQoA OwIbIwULCQgHAwUVCgkICwUWAgMBAAIeAQIXgBYhBInsPQWERiF0UPIoSBaat7Gkz/iuBQJk Q5wSAhkBAAoJEBaat7Gkz/iuyhMIANiD94qDtUTJRfEW6GwXmtKWwl/mvqQtaTtZID2dos04 YqBbshiJbejgVJjy+HODcNUIKBB3PSLaln4ltdsV73SBcwUNdzebfKspAQunCM22Mn6FBIxQ GizsMLcP/0FX4en9NaKGfK6ZdKK6kN1GR9YffMJd2P08EO8mHowmSRe/ExAODhAs9W7XXExw UNCY4pVJyRPpEhv373vvff60bHxc1k/FF9WaPscMt7hlkbFLUs85kHtQAmr8pV5Hy9ezsSRa GzJmiVclkPc2BY592IGBXRDQ38urXeM4nfhhvqA50b/nAEXc6FzqgXqDkEIwR66/Gbp0t3+r yQzpKRyQif3OwE0ETVkGzwEIALyKDN/OGURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYp QTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXMcoJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+ SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hiSvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY 4yG6xI99NIPEVE9lNBXBKIlewIyVlkOaYvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoM Mtsyw18YoX9BqMFInxqYQQ3j/HpVgTSvmo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUX oUk33HEAEQEAAcLAXwQYAQIACQUCTVkGzwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfn M7IbRuiSZS1unlySUVYu3SD6YBYnNi3G5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa3 3eDIHu/zr1HMKErm+2SD6PO9umRef8V82o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCS KmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy 4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJC3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTT QbM0WUIBIcGmq38+OgUsMYu4NzLu7uZFAcmp6h8g Organization: Linaro Developer Services In-Reply-To: <20230914183831.587273-38-john.ogness@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On 14/09/2023 20:37, John Ogness wrote: > 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/meson_uart.c | 30 +++++++++++++++--------------- > 1 file changed, 15 insertions(+), 15 deletions(-) > > diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c > index 790d910dafa5..45cc23e9e399 100644 > --- a/drivers/tty/serial/meson_uart.c > +++ b/drivers/tty/serial/meson_uart.c > @@ -129,14 +129,14 @@ static void meson_uart_shutdown(struct uart_port *port) > > free_irq(port->irq, port); > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > val = readl(port->membase + AML_UART_CONTROL); > val &= ~AML_UART_RX_EN; > val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN); > writel(val, port->membase + AML_UART_CONTROL); > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static void meson_uart_start_tx(struct uart_port *port) > @@ -238,7 +238,7 @@ static irqreturn_t meson_uart_interrupt(int irq, void *dev_id) > { > struct uart_port *port = (struct uart_port *)dev_id; > > - spin_lock(&port->lock); > + uart_port_lock(port); > > if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)) > meson_receive_chars(port); > @@ -248,7 +248,7 @@ static irqreturn_t meson_uart_interrupt(int irq, void *dev_id) > meson_uart_start_tx(port); > } > > - spin_unlock(&port->lock); > + uart_port_unlock(port); > > return IRQ_HANDLED; > } > @@ -284,7 +284,7 @@ static int meson_uart_startup(struct uart_port *port) > u32 val; > int ret = 0; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > val = readl(port->membase + AML_UART_CONTROL); > val |= AML_UART_CLEAR_ERR; > @@ -301,7 +301,7 @@ static int meson_uart_startup(struct uart_port *port) > val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2)); > writel(val, port->membase + AML_UART_MISC); > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > ret = request_irq(port->irq, meson_uart_interrupt, 0, > port->name, port); > @@ -341,7 +341,7 @@ static void meson_uart_set_termios(struct uart_port *port, > unsigned long flags; > u32 val; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > cflags = termios->c_cflag; > iflags = termios->c_iflag; > @@ -401,7 +401,7 @@ static void meson_uart_set_termios(struct uart_port *port, > AML_UART_FRAME_ERR; > > uart_update_timeout(port, termios->c_cflag, baud); > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > static int meson_uart_verify_port(struct uart_port *port, > @@ -460,14 +460,14 @@ static int meson_uart_poll_get_char(struct uart_port *port) > u32 c; > unsigned long flags; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY) > c = NO_POLL_CHAR; > else > c = readl(port->membase + AML_UART_RFIFO); > > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > > return c; > } > @@ -478,7 +478,7 @@ static void meson_uart_poll_put_char(struct uart_port *port, unsigned char c) > u32 reg; > int ret; > > - spin_lock_irqsave(&port->lock, flags); > + uart_port_lock_irqsave(port, &flags); > > /* Wait until FIFO is empty or timeout */ > ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg, > @@ -502,7 +502,7 @@ static void meson_uart_poll_put_char(struct uart_port *port, unsigned char c) > dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n"); > > out: > - spin_unlock_irqrestore(&port->lock, flags); > + uart_port_unlock_irqrestore(port, flags); > } > > #endif /* CONFIG_CONSOLE_POLL */ > @@ -559,9 +559,9 @@ static void meson_serial_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; > } > > @@ -573,7 +573,7 @@ static void meson_serial_port_write(struct uart_port *port, const char *s, > writel(val, port->membase + AML_UART_CONTROL); > > if (locked) > - spin_unlock(&port->lock); > + uart_port_unlock(port); > local_irq_restore(flags); > } > Acked-by: Neil Armstrong