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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6632DC282E1 for ; Sat, 20 Apr 2019 02:15:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 363962183F for ; Sat, 20 Apr 2019 02:15:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727454AbfDTCPs (ORCPT ); Fri, 19 Apr 2019 22:15:48 -0400 Received: from icp-osb-irony-out1.external.iinet.net.au ([203.59.1.210]:42374 "EHLO icp-osb-irony-out1.external.iinet.net.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726088AbfDTCPs (ORCPT ); Fri, 19 Apr 2019 22:15:48 -0400 X-Greylist: delayed 556 seconds by postgrey-1.27 at vger.kernel.org; Fri, 19 Apr 2019 22:15:47 EDT X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: =?us-ascii?q?A2ACAAAffrpc/zXSMGcNWRkBAQEBAQE?= =?us-ascii?q?BAQEBAQEHAQEBAQEBgVIDAQEBAQELAYQkhA6TegaBCAglg12Fa48DgXuEfQK?= =?us-ascii?q?GPDUIDgEDAQEBBAEBAQEChl8BAQEBAgEjBBFBBQsLDQsCAiYCAlcGDQYCAQG?= =?us-ascii?q?DHoF1BaVPcXwzGoUthGaBCycBgVyKBHiBB4E4DIJfPodOglcEkliTeQmCCpI?= =?us-ascii?q?kIYwIA4kGojQBggwzGggoCIMnghoXjjFgkHIBAQ?= X-IPAS-Result: =?us-ascii?q?A2ACAAAffrpc/zXSMGcNWRkBAQEBAQEBAQEBAQEHAQEBA?= =?us-ascii?q?QEBgVIDAQEBAQELAYQkhA6TegaBCAglg12Fa48DgXuEfQKGPDUIDgEDAQEBB?= =?us-ascii?q?AEBAQEChl8BAQEBAgEjBBFBBQsLDQsCAiYCAlcGDQYCAQGDHoF1BaVPcXwzG?= =?us-ascii?q?oUthGaBCycBgVyKBHiBB4E4DIJfPodOglcEkliTeQmCCpIkIYwIA4kGojQBg?= =?us-ascii?q?gwzGggoCIMnghoXjjFgkHIBAQ?= X-IronPort-AV: E=Sophos;i="5.60,372,1549900800"; d="scan'208";a="184298678" Received: from unknown (HELO [10.44.0.192]) ([103.48.210.53]) by icp-osb-irony-out1.iinet.net.au with ESMTP; 20 Apr 2019 10:06:27 +0800 Subject: Re: [PATCH 5/6] ARM: ks8695, serial: skip manual tx IRQ ack To: Arnd Bergmann Cc: Linus Walleij , arm@kernel.org, Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190415202501.941196-1-arnd@arndb.de> <20190415202501.941196-5-arnd@arndb.de> From: Greg Ungerer Message-ID: Date: Sat, 20 Apr 2019 12:06:26 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190415202501.941196-5-arnd@arndb.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On 16/4/19 6:24 am, Arnd Bergmann wrote: > The TX interrupt is marked as edge triggered, so it will > already be acked by the top-level irq code, and does not > need the ack in the driver. > > Removing this avoids a nasty dependency on the regs-irq.h > file that is otherwise reserved for the interrupt controller > driver. > > Signed-off-by: Arnd Bergmann > --- > drivers/tty/serial/serial_ks8695.c | 5 ----- > 1 file changed, 5 deletions(-) > > diff --git a/drivers/tty/serial/serial_ks8695.c b/drivers/tty/serial/serial_ks8695.c > index b461d791188c..6c5e9900e69d 100644 > --- a/drivers/tty/serial/serial_ks8695.c > +++ b/drivers/tty/serial/serial_ks8695.c > @@ -21,7 +21,6 @@ > #include > > #include > -#include > > #if defined(CONFIG_SERIAL_KS8695_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) > #define SUPPORT_SYSRQ > @@ -52,8 +51,6 @@ > #define UART_GET_BRDR(p) __raw_readl((p)->membase + KS8695_URBD) > #define UART_PUT_BRDR(p, c) __raw_writel((c), (p)->membase + KS8695_URBD) > > -#define KS8695_CLR_TX_INT() __raw_writel(1 << KS8695_IRQ_UART_TX, KS8695_IRQ_VA + KS8695_INTST) > - > #define UART_DUMMY_LSR_RX 0x100 > #define UART_PORT_SIZE (KS8695_USR - KS8695_URRB + 4) > > @@ -207,7 +204,6 @@ static irqreturn_t ks8695uart_tx_chars(int irq, void *dev_id) > unsigned int count; > > if (port->x_char) { > - KS8695_CLR_TX_INT(); > UART_PUT_CHAR(port, port->x_char); > port->icount.tx++; > port->x_char = 0; > @@ -221,7 +217,6 @@ static irqreturn_t ks8695uart_tx_chars(int irq, void *dev_id) > > count = 16; /* fifo size */ > while (!uart_circ_empty(xmit) && (count-- > 0)) { > - KS8695_CLR_TX_INT(); I haven't looked at the ks8695 in quite a while... But I recall that this was very problematic at the time. Without this being done after each character it was very easy to get the transmitter to "hang" - and stop wanting to send any more characters. I'd like to test this before acking. Regards Greg > UART_PUT_CHAR(port, xmit->buf[xmit->tail]); > > xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); >