From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4B2CD433C4 for ; Tue, 29 Apr 2025 06:35:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745908527; cv=none; b=qZ7NGA2bzCBWM1KCFT9ngqe4WTJi+GvNaUbfBbVJFnwm9vQY4Ptf12kLtruy6PwQXXlHZJJkeHWRl5DQKRzSUVSxzd5qalqt0uLMlc28r85PmsZomuLxEC1G1hjF0j6D1Lu1ObhIJEfLz89Ud2iMM2vyHAZ1M2+WJvE/sPbJ8WE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745908527; c=relaxed/simple; bh=35F/Soy/Yi76+kq793Uoye6JRpINJXRb6U/bBHX4JxE=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=LviaOiUWbhDacmV3Nlje1lGmfED/5zz8Kiv9NUQkfMh56G7Uv4SMKJohO6JEOod383uBYoJVW23ds7zGIDU7HloQ7bHYR2JzjL6S6cthZjtm2OQcldknPxC29pKekYtEBvyo3MnaI3iunMpW14auarL2VRhz/9KnJeQfzHoGwEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jhrbuxkI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jhrbuxkI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07FF6C4CEE3; Tue, 29 Apr 2025 06:35:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745908526; bh=35F/Soy/Yi76+kq793Uoye6JRpINJXRb6U/bBHX4JxE=; h=Subject:To:Cc:From:Date:From; b=jhrbuxkIVlN5qh1sQaB8rxoSZ/T8dS/4sBZqCpsWm1e0yRPCIEioAUGF879g0Bx2H w2raJFmsxocUMqX5DfyhIokIFOeO+7jjvOFQE/eAC4pGNCQNL+40TmYi5ILtDmEFyH TxKpBSvcKuqBC9MPw94OgJgQ3UIq02uGfuKU6Elg= Subject: FAILED: patch "[PATCH] serial: msm: Configure correct working mode before starting" failed to apply to 5.10-stable tree To: stephan.gerhold@linaro.org,gregkh@linuxfoundation.org,neil.armstrong@linaro.org,stable@kernel.org Cc: From: Date: Tue, 29 Apr 2025 08:35:23 +0200 Message-ID: <2025042923-flagman-payroll-a044@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 7094832b5ac861b0bd7ed8866c93cb15ef619996 # git commit -s git send-email --to '' --in-reply-to '2025042923-flagman-payroll-a044@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 7094832b5ac861b0bd7ed8866c93cb15ef619996 Mon Sep 17 00:00:00 2001 From: Stephan Gerhold Date: Tue, 8 Apr 2025 19:22:47 +0200 Subject: [PATCH] serial: msm: Configure correct working mode before starting earlycon The MSM UART DM controller supports different working modes, e.g. DMA or the "single-character mode", where all reads/writes operate on a single character rather than 4 chars (32-bit) at once. When using earlycon, __msm_console_write() always writes 4 characters at a time, but we don't know which mode the bootloader was using and we don't set the mode either. This causes garbled output if the bootloader was using the single-character mode, because only every 4th character appears in the serial console, e.g. "[ 00oni pi 000xf0[ 00i s 5rm9(l)l s 1 1 SPMTA 7:C 5[ 00A ade k d[ 00ano:ameoi .Q1B[ 00ac _idaM00080oo'" If the bootloader was using the DMA ("DM") mode, output would likely fail entirely. Later, when the full serial driver probes, the port is re-initialized and output works as expected. Fix this also for earlycon by clearing the DMEN register and reset+re-enable the transmitter to apply the change. This ensures the transmitter is in the expected state before writing any output. Cc: stable Fixes: 0efe72963409 ("tty: serial: msm: Add earlycon support") Signed-off-by: Stephan Gerhold Reviewed-by: Neil Armstrong Link: https://lore.kernel.org/r/20250408-msm-serial-earlycon-v1-1-429080127530@linaro.org Signed-off-by: Greg Kroah-Hartman diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index 1b137e068444..3449945493ce 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -1746,6 +1746,12 @@ msm_serial_early_console_setup_dm(struct earlycon_device *device, if (!device->port.membase) return -ENODEV; + /* Disable DM / single-character modes */ + msm_write(&device->port, 0, UARTDM_DMEN); + msm_write(&device->port, MSM_UART_CR_CMD_RESET_RX, MSM_UART_CR); + msm_write(&device->port, MSM_UART_CR_CMD_RESET_TX, MSM_UART_CR); + msm_write(&device->port, MSM_UART_CR_TX_ENABLE, MSM_UART_CR); + device->con->write = msm_serial_early_write_dm; return 0; }