From patchwork Wed May 19 00:07:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Jeffery X-Patchwork-Id: 12265813 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=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 4CF4AC43461 for ; Wed, 19 May 2021 00:09:48 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D49BC60FF1 for ; Wed, 19 May 2021 00:09:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D49BC60FF1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=aj.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fvXA46Vy+T9Gua8h679CWU/gD5XMF7InC+ye8HkzBtA=; b=ZXYpn53sZFoMBJjDMbIkVyO+r HunRRENwwswdMAcuGFwpAx05GhORNSX8T6yM62L+0/JjrYEA1IHdQuyicXOQBIGV9CkZeeZ8Ttgzk eD9J+KJoIPV9N4VRYRKWWwJC/G8dEMEK1E+CdmhlHO2IvL9rFLpOKtGzFcgUYL/4L/VDKM0EWTSA6 Ceud0rgW/VQNWIegd/il43JfRl+EsvCXSZXxAN0byoNNzeF5t6qQWjqV5HxsDPgf2AIJxx3/wicw4 4KknWkYNjDuINphpZbieVDElQAvP229REVbAJDiAbOnDIWsjsnJn9+PyjyGBr/juH1VFK88u+A6Mj 6DoY8A4jQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lj9kV-002EGA-CN; Wed, 19 May 2021 00:07:43 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lj9kK-002EFo-55 for linux-arm-kernel@desiato.infradead.org; Wed, 19 May 2021 00:07:32 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=qbFwjze46/G9LHZQ1bh1SZv0oKRVk2i2WcEWwa8CGts=; b=OUZFKgDdD3AU6/bvHRKub/SA4/ woFF+uLbRdSQkkhokkqxAQXzmtK+K1DODwaSUwXnpRHWBJl+0qpHmaz486E9z/hpIYK7W8T+FV7Du b8FU3veLKCo3JjCDfeT4SO6bWFtE/wEv+zMb/1DBGz3EqTh1jZVX1sHGOcA5ycem2G+0njMZs2d89 LrqB9yoVo0wQRQ7yZJX1fDn0yN6LPZBuq37lOoVVgsufOyjxp/Id9zDnXrLP+A40Ol+tHbn87rcKa tZkR5JGS+w7DEngYQP84y1LuDaUv/xxcyXctt96QQhc2BW4Zp93bd9+DFnWLoBY+xGj7d5FakcYoe EsCyVinw==; Received: from new1-smtp.messagingengine.com ([66.111.4.221]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lj9kH-00F2JT-G4 for linux-arm-kernel@lists.infradead.org; Wed, 19 May 2021 00:07:30 +0000 Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailnew.nyi.internal (Postfix) with ESMTP id DB98D580606; Tue, 18 May 2021 20:07:28 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute6.internal (MEProxy); Tue, 18 May 2021 20:07:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aj.id.au; h=from :to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=fm2; bh=qbFwjze46/G9L HZQ1bh1SZv0oKRVk2i2WcEWwa8CGts=; b=i8j2NcpFjmVgKwQKuI5AkOUR3RZvq Z/vnk56+F79Zdk+o6m/LDR8c6Pe6j0P5/AZE9W4cU511/qtuSFfdmJHSJuHyRaci 8wwdLgXbeO9tWVL4ocz+GQ5DnLsMGWELLWKaHOanjPvuovrTKIRMc5QXWoLeaE2X 257unsR+BiJyKuA0FuRLHL4ekCzx5EQTXbve+Ru7sgwWNrlbPP/1OOPZOZdsU6Uc 6u2ke6hYiZLR5Ajdbm+40iNRHMwg5c6EOfMkBJviH+QZyei0cdFekMUGqbgssioX apTv2i3bopYFxTyg3DINgqGIP5eIHQnglqigELQxLjcKZBj88aQSvCF8A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=qbFwjze46/G9LHZQ1bh1SZv0oKRVk2i2WcEWwa8CGts=; b=o+6g8Gpi kHi3XQXfiKtFWcFOgI8h11TLr3N4tLZsQQGVzZIllMdgvywz7yC4WCY4oPEOPNMs GnEnglxwKJB26jqq/7nZk7xnmVLNbG2XTmgjL/vPTKHRj2fMCe+vqua4pgy3PKPm j/izRfQjyXOkVkfy5WaPUSvAJKHCcygct+4AUBe3Prq2hjjG9f/XokAYAhxRMelq gDRbpecYGdI8d8Q63Y1TCCrEjIfdiS6Mg9sSQs11oKJllVmx5wM+SGv0KipgiklD 0UCM1zKjWfrXe9fLb8kdu2osw+iGau59nW/IZAg6exQWarbKVnXh38fQYSYvv5sK 0VhkE+ePfvXfLg== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvdeikedgvdejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkffojghfggfgsedtkeertdertddtnecuhfhrohhmpeetnhgurhgv ficulfgvfhhfvghrhicuoegrnhgurhgvfiesrghjrdhiugdrrghuqeenucggtffrrghtth gvrhhnpeehhfegffehvefhieejkedtvedvlefhgfeufedtgfetueevtedvffduffelleef heenucffohhmrghinhepphhorhhtrdguvghvnecukfhppedvtdefrdehjedrvdduhedrke enucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegrnhgu rhgvfiesrghjrdhiugdrrghu X-ME-Proxy: Received: from mistburn.lan (203-57-215-8.dyn.iinet.net.au [203.57.215.8]) by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 18 May 2021 20:07:23 -0400 (EDT) From: Andrew Jeffery To: linux-serial@vger.kernel.org Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org, joel@jms.id.au, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, openbmc@lists.ozlabs.org, jenmin_yuan@aspeedtech.com, ryan_chen@aspeedtech.com, miltonm@us.ibm.com, ChiaWei Wang Subject: [PATCH v2 1/2] serial: 8250: Add UART_BUG_TXRACE workaround for Aspeed VUART Date: Wed, 19 May 2021 09:37:03 +0930 Message-Id: <20210519000704.3661773-2-andrew@aj.id.au> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210519000704.3661773-1-andrew@aj.id.au> References: <20210519000704.3661773-1-andrew@aj.id.au> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210518_170729_625289_D87240F0 X-CRM114-Status: GOOD ( 16.02 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Aspeed Virtual UARTs directly bridge e.g. the system console UART on the LPC bus to the UART interface on the BMC's internal APB. As such there's no RS-232 signalling involved - the UART interfaces on each bus are directly connected as the producers and consumers of the one set of FIFOs. The APB in the AST2600 generally runs at 100MHz while the LPC bus peaks at 33MHz. The difference in clock speeds exposes a race in the VUART design where a Tx data burst on the APB interface can result in a byte lost on the LPC interface. The symptom is LSR[DR] remains clear on the LPC interface despite data being present in its Rx FIFO, while LSR[THRE] remains clear on the APB interface as the host has not consumed the data the BMC has transmitted. In this state, the UART has stalled and no further data can be transmitted without manual intervention (e.g. resetting the FIFOs, resulting in loss of data). The recommended work-around is to insert a read cycle on the APB interface between writes to THR. Cc: ChiaWei Wang Signed-off-by: Andrew Jeffery Reviewed-by: Joel Stanley --- drivers/tty/serial/8250/8250.h | 1 + drivers/tty/serial/8250/8250_aspeed_vuart.c | 1 + drivers/tty/serial/8250/8250_port.c | 10 ++++++++++ 3 files changed, 12 insertions(+) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 52bb21205bb6..34aa2714f3c9 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -88,6 +88,7 @@ struct serial8250_config { #define UART_BUG_NOMSR (1 << 2) /* UART has buggy MSR status bits (Au1x00) */ #define UART_BUG_THRE (1 << 3) /* UART has buggy THRE reassertion */ #define UART_BUG_PARITY (1 << 4) /* UART mishandles parity if FIFO enabled */ +#define UART_BUG_TXRACE (1 << 5) /* UART Tx fails to set remote DR */ #ifdef CONFIG_SERIAL_8250_SHARE_IRQ diff --git a/drivers/tty/serial/8250/8250_aspeed_vuart.c b/drivers/tty/serial/8250/8250_aspeed_vuart.c index a28a394ba32a..4caab8714e2c 100644 --- a/drivers/tty/serial/8250/8250_aspeed_vuart.c +++ b/drivers/tty/serial/8250/8250_aspeed_vuart.c @@ -440,6 +440,7 @@ static int aspeed_vuart_probe(struct platform_device *pdev) port.port.status = UPSTAT_SYNC_FIFO; port.port.dev = &pdev->dev; port.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); + port.bugs |= UART_BUG_TXRACE; rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group); if (rc < 0) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index d45dab1ab316..9d44b2b2ff18 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1809,6 +1809,16 @@ void serial8250_tx_chars(struct uart_8250_port *up) count = up->tx_loadsz; do { serial_out(up, UART_TX, xmit->buf[xmit->tail]); + if (up->bugs & UART_BUG_TXRACE) { + /* The Aspeed BMC virtual UARTs have a bug where data + * may get stuck in the BMC's Tx FIFO from bursts of + * writes on the APB interface. + * + * Delay back-to-back writes by a read cycle to avoid + * stalling the VUART. + */ + (void)serial_in(up, UART_SCR); + } xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); port->icount.tx++; if (uart_circ_empty(xmit)) From patchwork Wed May 19 00:07:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Jeffery X-Patchwork-Id: 12265809 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=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 7F885C433B4 for ; Wed, 19 May 2021 00:09:46 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1052460FF1 for ; Wed, 19 May 2021 00:09:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1052460FF1 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=aj.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=10okWOeCzYCeXOy3QgpfFAy1RPmaDwEFsB2anphOS7Y=; b=rB/v7jLB0HQ7fmbKbzhvx+e+c 14oE7fwa+pvXHomCtwHVkZoUrKu4LVUWMmAKkRTT0Woo58KdZrUAeP/0y5ceHHKNYnEllIeTxoyjN VYBX50baurQINn9dzl+XHfxw2sMRgs/6+0nrXpfZ11i6nuscKogwog0sGPQrB+Gjm+WVPULl2rdkD ISsE90//fUh2yK3avLGj6XBqECjS07nXVEol2H2M2eJ1qsrjByN7I2SOtQfqmgMFkKslxyh3SAyfB 3+L+tcYctwyapjCBBfBulSZ/vRnjwCtzK9o1EQew5ZtATAyb89HXm5ekvvI0EY7CBQ7gATW/vV6w9 qZsEBATLg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lj9ki-002EH7-FA; Wed, 19 May 2021 00:07:56 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lj9kO-002EFx-L9 for linux-arm-kernel@desiato.infradead.org; Wed, 19 May 2021 00:07:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=ZQpdzM6dhzIiOh3RhOhjIn/n8lrCmQ0vCBUyJ0+aRkQ=; b=AcPst1vpVBDeRuunIeiF3eBE9y 5OwzZEJIby4Si7Dr0m6UDnod0U+6xwv4mFnQuxVaGXL3h2/LMxQ4e9DWzvVEjl9ikUVboYiFDdEDD Rth4J4ju6omYJg0qXm+GMfdsYpTmtHoGyWKRl/phnQg+ONC0QfryXHyzFqUVZTfl6jBs1JDQCT6sa ltnFLq7gs4GSHNcVoCC5+PTfeyZvRFNa9gn7M0Fel/Db6gE+OMasFquUohURRXcP39euR+tqtlh87 b6yjHTbQAgrjerakoGeo4FUGQxuUIJ8e1mWwYFTZLqe5/zng6Qnx1tJ+xRQi20K55RWlfoVTr/S5k WEt9J6+A==; Received: from new1-smtp.messagingengine.com ([66.111.4.221]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lj9kM-00F2KL-0e for linux-arm-kernel@lists.infradead.org; Wed, 19 May 2021 00:07:35 +0000 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailnew.nyi.internal (Postfix) with ESMTP id 67976580606; Tue, 18 May 2021 20:07:33 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Tue, 18 May 2021 20:07:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aj.id.au; h=from :to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=fm2; bh=ZQpdzM6dhzIiO h3RhOhjIn/n8lrCmQ0vCBUyJ0+aRkQ=; b=IKPVqJBmeeRPT6yogAckd50jDOtYl ASjua4ps+81wElBClHLR97lY+/88nl/CSXw5v36lHlfB/camtJ7iMRc0HdifGMwu u9InIkmuHmu9BMOyXCgYRR74q6FDu76EqI2ovEE8riZvZJEoCN8lZeT0PEPicpHo 1bNpVNzIF2ei98ZEsUhXUKlCZx2Sc08fiqmLz+tuXttyfZlgm4rcwazvKpRu24XS AGAYbX38y7bJ58ifwg8Kziy0zBd1ceWwZR366a1h1vMjK7ODmeOfEOauL4j9rjNs tAmprJ5P9NX5EcfBAFYNtlFzLK+A6LqkJGX5EBZwiPkkudUqJR+dp0kIw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=ZQpdzM6dhzIiOh3RhOhjIn/n8lrCmQ0vCBUyJ0+aRkQ=; b=KmPyWLyj p81p0WFqTojCk1HRIrnLle1REIsGa+96bQt6Ht8W+jyNv7qq6UmazfHETqHf+SIZ ujon10qASwWtDGeTCq/+h1BDw7bGNvB5MhBzHiBxwMgBy+SJoHcdGQkAZQHr5YXB PVhAY/cE2R9tc/aJJeVOkMq2iIqpHcJ3IRZqi4YRa68bN24pDfPCyQEuAid4O046 RdyBKpovuNdB71CMdbleMrlWxGuWZFd0boDR+P3wLk7gOldkRvvIN97CDqVpejCR IsDQ+hEfmKKKuVf46L4dryx9GVnVUXhn4WEvV4et+SiP6XdeUvtzNrDPAr2z4GZA ovLH6BvjdNtvkw== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvdeikedgvdejucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvffufffkofgjfhgggfestdekre dtredttdenucfhrhhomheptehnughrvgifucflvghffhgvrhihuceorghnughrvgifsegr jhdrihgurdgruheqnecuggftrfgrthhtvghrnhepjefgvdevheetkeevgeegleelgfelte etjeffleffvdduudevieffgeetleevhfetnecukfhppedvtdefrdehjedrvdduhedrkeen ucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegrnhgurh gvfiesrghjrdhiugdrrghu X-ME-Proxy: Received: from mistburn.lan (203-57-215-8.dyn.iinet.net.au [203.57.215.8]) by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 18 May 2021 20:07:29 -0400 (EDT) From: Andrew Jeffery To: linux-serial@vger.kernel.org Cc: gregkh@linuxfoundation.org, jirislaby@kernel.org, joel@jms.id.au, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, openbmc@lists.ozlabs.org, jenmin_yuan@aspeedtech.com, ryan_chen@aspeedtech.com, miltonm@us.ibm.com Subject: [PATCH v2 2/2] serial: 8250: Use BIT(x) for UART_{CAP,BUG}_* Date: Wed, 19 May 2021 09:37:04 +0930 Message-Id: <20210519000704.3661773-3-andrew@aj.id.au> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210519000704.3661773-1-andrew@aj.id.au> References: <20210519000704.3661773-1-andrew@aj.id.au> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210518_170734_152301_D10C74C0 X-CRM114-Status: UNSURE ( 9.65 ) X-CRM114-Notice: Please train this message. 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org BIT(x) improves readability and safety with respect to shifts. Signed-off-by: Andrew Jeffery --- drivers/tty/serial/8250/8250.h | 33 +++++++++++++++++---------------- 1 file changed, 17 insertions(+), 16 deletions(-) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 34aa2714f3c9..4fbf1088fad8 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -7,6 +7,7 @@ * Copyright (C) 2001 Russell King. */ +#include #include #include #include @@ -70,25 +71,25 @@ struct serial8250_config { unsigned int flags; }; -#define UART_CAP_FIFO (1 << 8) /* UART has FIFO */ -#define UART_CAP_EFR (1 << 9) /* UART has EFR */ -#define UART_CAP_SLEEP (1 << 10) /* UART has IER sleep */ -#define UART_CAP_AFE (1 << 11) /* MCR-based hw flow control */ -#define UART_CAP_UUE (1 << 12) /* UART needs IER bit 6 set (Xscale) */ -#define UART_CAP_RTOIE (1 << 13) /* UART needs IER bit 4 set (Xscale, Tegra) */ -#define UART_CAP_HFIFO (1 << 14) /* UART has a "hidden" FIFO */ -#define UART_CAP_RPM (1 << 15) /* Runtime PM is active while idle */ -#define UART_CAP_IRDA (1 << 16) /* UART supports IrDA line discipline */ -#define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks: +#define UART_CAP_FIFO BIT(8) /* UART has FIFO */ +#define UART_CAP_EFR BIT(9) /* UART has EFR */ +#define UART_CAP_SLEEP BIT(10) /* UART has IER sleep */ +#define UART_CAP_AFE BIT(11) /* MCR-based hw flow control */ +#define UART_CAP_UUE BIT(12) /* UART needs IER bit 6 set (Xscale) */ +#define UART_CAP_RTOIE BIT(13) /* UART needs IER bit 4 set (Xscale, Tegra) */ +#define UART_CAP_HFIFO BIT(14) /* UART has a "hidden" FIFO */ +#define UART_CAP_RPM BIT(15) /* Runtime PM is active while idle */ +#define UART_CAP_IRDA BIT(16) /* UART supports IrDA line discipline */ +#define UART_CAP_MINI BIT(17) /* Mini UART on BCM283X family lacks: * STOP PARITY EPAR SPAR WLEN5 WLEN6 */ -#define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */ -#define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */ -#define UART_BUG_NOMSR (1 << 2) /* UART has buggy MSR status bits (Au1x00) */ -#define UART_BUG_THRE (1 << 3) /* UART has buggy THRE reassertion */ -#define UART_BUG_PARITY (1 << 4) /* UART mishandles parity if FIFO enabled */ -#define UART_BUG_TXRACE (1 << 5) /* UART Tx fails to set remote DR */ +#define UART_BUG_QUOT BIT(0) /* UART has buggy quot LSB */ +#define UART_BUG_TXEN BIT(1) /* UART has buggy TX IIR status */ +#define UART_BUG_NOMSR BIT(2) /* UART has buggy MSR status bits (Au1x00) */ +#define UART_BUG_THRE BIT(3) /* UART has buggy THRE reassertion */ +#define UART_BUG_PARITY BIT(4) /* UART mishandles parity if FIFO enabled */ +#define UART_BUG_TXRACE BIT(5) /* UART Tx fails to set remote DR */ #ifdef CONFIG_SERIAL_8250_SHARE_IRQ