From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 9908525487C; Mon, 3 Aug 2026 04:46:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785732416; cv=none; b=rc8pxy1bzxB60kwoy2HnggEM7Q0sYwvxyqXLg8INI5Ia8tZmWUuX8QQnyz5pbVYZjlZ5jtJ1YaV5bvQV4DNOvt0Lida0spQxVhxpqR33ZEXvQtDkCj+h2FCxzfA2lppXb4CV7S+KT+GfzAF39svs6W4XNk9wU/teZnNtsYQ2nfM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785732416; c=relaxed/simple; bh=ssCjDaDCm81QLG8YnQ9oWOUT0noCAg1hmg5X8ReqBjU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=YBLGZ5EXvm6gFCK+qoAKzmj9nt7xYTG/uIuXM0iZ0gGhkVs4wuaCYzXNiiTuDQWFyZrOIWIq4mgorFzy6ytRiikGBDSNdfMFUZntgTJyKjiiU2dVKcU1xVvbIAbPUsbcN/2f2I0laQeLHbQ0ePbL1p9fGxGmqA46SC/sI3lWfME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=M8VoA1xo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="M8VoA1xo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D44A71F000E9; Mon, 3 Aug 2026 04:46:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785732415; bh=THNhJrW8qY0WU/HoVHqGfzwC7VukSSewoNV72JuUbSk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=M8VoA1xo85IoPPM138W4P5hR1bQL7tSYAbZl6WM6Kc+ADKVCuH6siNUBLBPxUXAwG z6BUkxum7eWvyBFBEbl31VMctiEdCyAWHQtxkPeNJNKMIJy3wYoDjo7cNpVXYo7rD3 kOOUdnWO3TrdbHtUwYYGsnvoUwENUORk+UY1NuIfXNK6z1JPV7HmeEPV2CQfBlPwZQ L1yzZ85XjUSPtxztHTzb1Rf3HQQER045vVVGs5YFTl8mNjSEccLpB4e2enUGYgTGuS zupYHC7O6e0Yl0MXF0Hjh2e6PCDM+Tml6ays7XFeojH3CGKru1nGmjueZ52cReWFBo IwQjZJ7wDcRNg== Message-ID: <7a4900a7-bd31-46ee-81ee-d597899a34de@kernel.org> Date: Mon, 3 Aug 2026 06:46:51 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 08/14] serial: 8250_mxpcie: speed up TX using memory-mapped FIFO window To: Andy Shevchenko , Crescent Hsieh Cc: Greg Kroah-Hartman , FangpingFP.Cheng@moxa.com, Epson.Chiang@moxa.com, EddieSY.Lin@moxa.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org References: <20260731074820.735619-1-crescentcy.hsieh@moxa.com> <20260731074820.735619-9-crescentcy.hsieh@moxa.com> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 02. 08. 26, 11:10, Andy Shevchenko wrote: > On Fri, Jul 31, 2026 at 10:49 AM Crescent Hsieh > wrote: >> >> The MUEx50 UART provides a memory-mapped TX FIFO data window along with >> a TX FIFO level counter. >> >> Fill the TX FIFO in bulk via the MMIO FIFO window based on available >> FIFO space, using uart_port_tx_limited() for the common serial-core TX >> handling. > > ... > >> +static void mxpcie8250_tx_chars(struct uart_8250_port *up) >> +{ >> + struct uart_port *port = &up->port; >> + unsigned int offset = 0; >> + unsigned char c; >> + >> + uart_port_tx_limited(port, c, port->fifosize - serial_in(up, MOXA_PUART_TX_FIFO_CNT), >> + true, >> + serial_out(up, MOXA_PUART_TX_FIFO_MEM + offset++, c), >> + ({})); >> +} > > At least three randomly chosen drivers use the empty tx_done, perhaps > it's time to have a helper that embeds this ugly piece in it and hides > from the driver? I haven't tried, can we make the helper a variadic macro? -- js suse labs