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 8CEBEC433EF for ; Thu, 10 Feb 2022 07:40:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236256AbiBJHkq (ORCPT ); Thu, 10 Feb 2022 02:40:46 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:51540 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234737AbiBJHko (ORCPT ); Thu, 10 Feb 2022 02:40:44 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34A60C5A; Wed, 9 Feb 2022 23:40:46 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8CBE961BAC; Thu, 10 Feb 2022 07:40:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 138DCC004E1; Thu, 10 Feb 2022 07:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644478844; bh=N8/bXTmvWY7W+wVw+ygNVKaot4xb1H7ai8HRw78A9YQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wr9iaSYKDze12KSvH+58tFW6xNQOBvBlJaBUaBfC1TGzuJiKEY2exs+gXUlxUM/MY FrrSAXChq1k1wFXB2Jip2PXCmlfCjRKrSHT9LlJNvOQ8RhGMv+oVuB41k+Uir/l+T/ 1TXK2CHKx5mLeoALUH8qRvKL0c7qBpRJRs4FhthM= Date: Thu, 10 Feb 2022 08:40:42 +0100 From: Greg Kroah-Hartman To: Zev Weiss Cc: Joel Stanley , Andrew Jeffery , Jiri Slaby , Andy Shevchenko , Konstantin Aladyshev , Oskar Senft , openbmc@lists.ozlabs.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type Message-ID: References: <20220209203414.23491-1-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220209203414.23491-1-zev@bewilderbeest.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 09, 2022 at 12:34:14PM -0800, Zev Weiss wrote: > Commit 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to > set up register mapping") fixed a bug that had, as a side-effect, > prevented the 8250_aspeed_vuart driver from enabling the VUART's > FIFOs. However, fixing that (and hence enabling the FIFOs) has in > turn revealed what appears to be a hardware bug in the ASPEED VUART in > which the host-side THRE bit doesn't get if the BMC-side receive FIFO > trigger level is set to anything but one byte. This causes problems > for polled-mode writes from the host -- for example, Linux kernel > console writes proceed at a glacial pace (less than 100 bytes per > second) because the write path waits for a 10ms timeout to expire > after every character instead of being able to continue on to the next > character upon seeing THRE asserted. (GRUB behaves similarly.) > > As a workaround, introduce a new port type for the ASPEED VUART that's > identical to PORT_16550A as it had previously been using, but with > UART_FCR_R_TRIG_00 instead to set the receive FIFO trigger level to > one byte, which (experimentally) seems to avoid the problematic THRE > behavior. > > Signed-off-by: Zev Weiss > Tested-by: Konstantin Aladyshev Do we need a "Fixes:" tag here as well? > --- > drivers/tty/serial/8250/8250_aspeed_vuart.c | 2 +- > drivers/tty/serial/8250/8250_port.c | 8 ++++++++ > include/uapi/linux/serial_core.h | 3 +++ > 3 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c > index 2350fb3bb5e4..c2cecc6f47db 100644 > --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c > +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c > @@ -487,7 +487,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev) > port.port.irq = irq_of_parse_and_map(np, 0); > port.port.handle_irq = aspeed_vuart_handle_irq; > port.port.iotype = UPIO_MEM; > - port.port.type = PORT_16550A; > + port.port.type = PORT_ASPEED_VUART; > port.port.uartclk = clk; > port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP > | UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST; > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 3b12bfc1ed67..973870ebff69 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -307,6 +307,14 @@ static const struct serial8250_config uart_config[] = { > .rxtrig_bytes = {1, 32, 64, 112}, > .flags = UART_CAP_FIFO | UART_CAP_SLEEP, > }, > + [PORT_ASPEED_VUART] = { > + .name = "ASPEED VUART", > + .fifo_size = 16, > + .tx_loadsz = 16, > + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00, > + .rxtrig_bytes = {1, 4, 8, 14}, > + .flags = UART_CAP_FIFO, > + }, > }; > > /* Uart divisor latch read */ > diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h > index c4042dcfdc0c..cd11748833e6 100644 > --- a/include/uapi/linux/serial_core.h > +++ b/include/uapi/linux/serial_core.h > @@ -274,4 +274,7 @@ > /* Freescale LINFlexD UART */ > #define PORT_LINFLEXUART 122 > > +/* ASPEED AST2x00 virtual UART */ > +#define PORT_ASPEED_VUART 123 Why does this value have to be in a uapi header file? What userspace tool is going to need this? thanks, greg k-h 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EF066C433EF for ; Thu, 10 Feb 2022 07:41:31 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4JvTG205zKz3bcj for ; Thu, 10 Feb 2022 18:41:30 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=wr9iaSYK; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linuxfoundation.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=gregkh@linuxfoundation.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=wr9iaSYK; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4JvTFF1Bgtz301M; Thu, 10 Feb 2022 18:40:47 +1100 (AEDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7BDF361D1E; Thu, 10 Feb 2022 07:40:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 138DCC004E1; Thu, 10 Feb 2022 07:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644478844; bh=N8/bXTmvWY7W+wVw+ygNVKaot4xb1H7ai8HRw78A9YQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wr9iaSYKDze12KSvH+58tFW6xNQOBvBlJaBUaBfC1TGzuJiKEY2exs+gXUlxUM/MY FrrSAXChq1k1wFXB2Jip2PXCmlfCjRKrSHT9LlJNvOQ8RhGMv+oVuB41k+Uir/l+T/ 1TXK2CHKx5mLeoALUH8qRvKL0c7qBpRJRs4FhthM= Date: Thu, 10 Feb 2022 08:40:42 +0100 From: Greg Kroah-Hartman To: Zev Weiss Subject: Re: [PATCH] serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type Message-ID: References: <20220209203414.23491-1-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220209203414.23491-1-zev@bewilderbeest.net> X-BeenThere: openbmc@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development list for OpenBMC List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-aspeed@lists.ozlabs.org, Konstantin Aladyshev , Andrew Jeffery , openbmc@lists.ozlabs.org, linux-kernel@vger.kernel.org, Oskar Senft , linux-serial@vger.kernel.org, Andy Shevchenko , Jiri Slaby , linux-arm-kernel@lists.infradead.org Errors-To: openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org Sender: "openbmc" On Wed, Feb 09, 2022 at 12:34:14PM -0800, Zev Weiss wrote: > Commit 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to > set up register mapping") fixed a bug that had, as a side-effect, > prevented the 8250_aspeed_vuart driver from enabling the VUART's > FIFOs. However, fixing that (and hence enabling the FIFOs) has in > turn revealed what appears to be a hardware bug in the ASPEED VUART in > which the host-side THRE bit doesn't get if the BMC-side receive FIFO > trigger level is set to anything but one byte. This causes problems > for polled-mode writes from the host -- for example, Linux kernel > console writes proceed at a glacial pace (less than 100 bytes per > second) because the write path waits for a 10ms timeout to expire > after every character instead of being able to continue on to the next > character upon seeing THRE asserted. (GRUB behaves similarly.) > > As a workaround, introduce a new port type for the ASPEED VUART that's > identical to PORT_16550A as it had previously been using, but with > UART_FCR_R_TRIG_00 instead to set the receive FIFO trigger level to > one byte, which (experimentally) seems to avoid the problematic THRE > behavior. > > Signed-off-by: Zev Weiss > Tested-by: Konstantin Aladyshev Do we need a "Fixes:" tag here as well? > --- > drivers/tty/serial/8250/8250_aspeed_vuart.c | 2 +- > drivers/tty/serial/8250/8250_port.c | 8 ++++++++ > include/uapi/linux/serial_core.h | 3 +++ > 3 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c > index 2350fb3bb5e4..c2cecc6f47db 100644 > --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c > +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c > @@ -487,7 +487,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev) > port.port.irq = irq_of_parse_and_map(np, 0); > port.port.handle_irq = aspeed_vuart_handle_irq; > port.port.iotype = UPIO_MEM; > - port.port.type = PORT_16550A; > + port.port.type = PORT_ASPEED_VUART; > port.port.uartclk = clk; > port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP > | UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST; > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 3b12bfc1ed67..973870ebff69 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -307,6 +307,14 @@ static const struct serial8250_config uart_config[] = { > .rxtrig_bytes = {1, 32, 64, 112}, > .flags = UART_CAP_FIFO | UART_CAP_SLEEP, > }, > + [PORT_ASPEED_VUART] = { > + .name = "ASPEED VUART", > + .fifo_size = 16, > + .tx_loadsz = 16, > + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00, > + .rxtrig_bytes = {1, 4, 8, 14}, > + .flags = UART_CAP_FIFO, > + }, > }; > > /* Uart divisor latch read */ > diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h > index c4042dcfdc0c..cd11748833e6 100644 > --- a/include/uapi/linux/serial_core.h > +++ b/include/uapi/linux/serial_core.h > @@ -274,4 +274,7 @@ > /* Freescale LINFlexD UART */ > #define PORT_LINFLEXUART 122 > > +/* ASPEED AST2x00 virtual UART */ > +#define PORT_ASPEED_VUART 123 Why does this value have to be in a uapi header file? What userspace tool is going to need this? thanks, greg k-h 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2DDE8C433F5 for ; Thu, 10 Feb 2022 07:42:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=cp8teXqD1PTJ86mEJizhlD4KCfM8o2tybmj5UPUa2yU=; b=caOd+IizAi9ZLv l4TFUFOFH3rsmLXsSbFtz9gkbyqojSZ3Hi64x8jUlQnynkkjTT4l+xNNFGSJ5ovrwgqMv5IaFnAsx WWFCUlUk+ekN7NKy9hVUwoooPDCWgr6kS/EZnkfqzSl/jvaUFZlpS7RI1DWftEpDUw67hrj2MVDC0 Q4R8R7EQYzLiuFi/oXVisGI9WU8r+75TrEHcRFEYj7oh0pj9Hx+y18XuHiGeihJjNv5cBkQJHrcJl qpliJbsVfvyfU48V3GOch3BkS4sFZXZCTUbE4VQy4Bw4oPtrW2an6YMOHZPqGs2/29qYwX29eIy7y ZzWFkFoUSw6XKABApL7A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nI44P-002tny-ML; Thu, 10 Feb 2022 07:40:49 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nI44M-002tnW-NA for linux-arm-kernel@lists.infradead.org; Thu, 10 Feb 2022 07:40:48 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7BDF361D1E; Thu, 10 Feb 2022 07:40:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 138DCC004E1; Thu, 10 Feb 2022 07:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644478844; bh=N8/bXTmvWY7W+wVw+ygNVKaot4xb1H7ai8HRw78A9YQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=wr9iaSYKDze12KSvH+58tFW6xNQOBvBlJaBUaBfC1TGzuJiKEY2exs+gXUlxUM/MY FrrSAXChq1k1wFXB2Jip2PXCmlfCjRKrSHT9LlJNvOQ8RhGMv+oVuB41k+Uir/l+T/ 1TXK2CHKx5mLeoALUH8qRvKL0c7qBpRJRs4FhthM= Date: Thu, 10 Feb 2022 08:40:42 +0100 From: Greg Kroah-Hartman To: Zev Weiss Cc: Joel Stanley , Andrew Jeffery , Jiri Slaby , Andy Shevchenko , Konstantin Aladyshev , Oskar Senft , openbmc@lists.ozlabs.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] serial: 8250_aspeed_vuart: add PORT_ASPEED_VUART port type Message-ID: References: <20220209203414.23491-1-zev@bewilderbeest.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220209203414.23491-1-zev@bewilderbeest.net> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220209_234046_856620_6DC0BF9D X-CRM114-Status: GOOD ( 29.82 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Feb 09, 2022 at 12:34:14PM -0800, Zev Weiss wrote: > Commit 54da3e381c2b ("serial: 8250_aspeed_vuart: use UPF_IOREMAP to > set up register mapping") fixed a bug that had, as a side-effect, > prevented the 8250_aspeed_vuart driver from enabling the VUART's > FIFOs. However, fixing that (and hence enabling the FIFOs) has in > turn revealed what appears to be a hardware bug in the ASPEED VUART in > which the host-side THRE bit doesn't get if the BMC-side receive FIFO > trigger level is set to anything but one byte. This causes problems > for polled-mode writes from the host -- for example, Linux kernel > console writes proceed at a glacial pace (less than 100 bytes per > second) because the write path waits for a 10ms timeout to expire > after every character instead of being able to continue on to the next > character upon seeing THRE asserted. (GRUB behaves similarly.) > > As a workaround, introduce a new port type for the ASPEED VUART that's > identical to PORT_16550A as it had previously been using, but with > UART_FCR_R_TRIG_00 instead to set the receive FIFO trigger level to > one byte, which (experimentally) seems to avoid the problematic THRE > behavior. > > Signed-off-by: Zev Weiss > Tested-by: Konstantin Aladyshev Do we need a "Fixes:" tag here as well? > --- > drivers/tty/serial/8250/8250_aspeed_vuart.c | 2 +- > drivers/tty/serial/8250/8250_port.c | 8 ++++++++ > include/uapi/linux/serial_core.h | 3 +++ > 3 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c > index 2350fb3bb5e4..c2cecc6f47db 100644 > --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c > +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c > @@ -487,7 +487,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev) > port.port.irq = irq_of_parse_and_map(np, 0); > port.port.handle_irq = aspeed_vuart_handle_irq; > port.port.iotype = UPIO_MEM; > - port.port.type = PORT_16550A; > + port.port.type = PORT_ASPEED_VUART; > port.port.uartclk = clk; > port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP > | UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST; > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index 3b12bfc1ed67..973870ebff69 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -307,6 +307,14 @@ static const struct serial8250_config uart_config[] = { > .rxtrig_bytes = {1, 32, 64, 112}, > .flags = UART_CAP_FIFO | UART_CAP_SLEEP, > }, > + [PORT_ASPEED_VUART] = { > + .name = "ASPEED VUART", > + .fifo_size = 16, > + .tx_loadsz = 16, > + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00, > + .rxtrig_bytes = {1, 4, 8, 14}, > + .flags = UART_CAP_FIFO, > + }, > }; > > /* Uart divisor latch read */ > diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h > index c4042dcfdc0c..cd11748833e6 100644 > --- a/include/uapi/linux/serial_core.h > +++ b/include/uapi/linux/serial_core.h > @@ -274,4 +274,7 @@ > /* Freescale LINFlexD UART */ > #define PORT_LINFLEXUART 122 > > +/* ASPEED AST2x00 virtual UART */ > +#define PORT_ASPEED_VUART 123 Why does this value have to be in a uapi header file? What userspace tool is going to need this? thanks, greg k-h _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel