From patchwork Mon Oct 31 20:18:29 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ondrej Zary X-Patchwork-Id: 9406413 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 011FB60585 for ; Mon, 31 Oct 2016 20:18:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E2BC328C44 for ; Mon, 31 Oct 2016 20:18:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D745C28C53; Mon, 31 Oct 2016 20:18:53 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C2E1728C44 for ; Mon, 31 Oct 2016 20:18:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S946216AbcJaUSv (ORCPT ); Mon, 31 Oct 2016 16:18:51 -0400 Received: from ns.gsystem.sk ([62.176.172.50]:36104 "EHLO gsystem.sk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S946328AbcJaUSt (ORCPT ); Mon, 31 Oct 2016 16:18:49 -0400 Received: from stip-static-68.213-81-217.telecom.sk ([213.81.217.68] helo=gsql.ggedos.sk) by gsystem.sk with esmtpsa (TLS1.1:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1c1J2Z-0001DX-Gb; Mon, 31 Oct 2016 21:18:43 +0100 From: Ondrej Zary To: Christoph Hellwig Cc: Finn Thain , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/6] g_NCR5380: Check for chip presence before calling NCR5380_init() Date: Mon, 31 Oct 2016 21:18:29 +0100 Message-Id: <1477945112-25659-4-git-send-email-linux@rainbow-software.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1477945112-25659-1-git-send-email-linux@rainbow-software.org> References: <1477945112-25659-1-git-send-email-linux@rainbow-software.org> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Write and read back MODE_REG to check if the chip is really there before doing more initialization. This prevents hang when incorrect I/O address was specified by user (in the most common case where no device is present there so all reads result in 0xff). Signed-off-by: Ondrej Zary --- drivers/scsi/g_NCR5380.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c index 0d1f6ad..e713dba 100644 --- a/drivers/scsi/g_NCR5380.c +++ b/drivers/scsi/g_NCR5380.c @@ -322,6 +322,13 @@ static int generic_NCR5380_init_one(struct scsi_host_template *tpnt, } } + /* check if the chip is really there */ + NCR5380_write(MODE_REG, 0); + if (NCR5380_read(MODE_REG) != 0) { + ret = -ENODEV; + goto out_unregister; + } + ret = NCR5380_init(instance, flags | FLAG_LATE_DMA_SETUP); if (ret) goto out_unregister;