From patchwork Mon Aug 1 09:37:19 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Viresh KUMAR X-Patchwork-Id: 1025642 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p719onnJ003090 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 1 Aug 2011 09:51:10 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1Qnp8F-0006uM-5w; Mon, 01 Aug 2011 09:49:56 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1Qnp1E-0006E7-Do; Mon, 01 Aug 2011 09:42:40 +0000 Received: from eu1sys200aog110.obsmtp.com ([207.126.144.129]) by canuck.infradead.org with smtps (Exim 4.76 #1 (Red Hat Linux)) id 1Qnoy4-0005Bj-KA for linux-arm-kernel@lists.infradead.org; Mon, 01 Aug 2011 09:39:28 +0000 Received: from beta.dmz-ap.st.com ([138.198.100.35]) (using TLSv1) by eu1sys200aob110.postini.com ([207.126.147.11]) with SMTP ID DSNKTjZ0Q1taRar94rusfoasw0Wze8/VQ+yc@postini.com; Mon, 01 Aug 2011 09:39:24 UTC Received: from zeta.dmz-ap.st.com (ns6.st.com [138.198.234.13]) by beta.dmz-ap.st.com (STMicroelectronics) with ESMTP id 6BDC2B3; Mon, 1 Aug 2011 09:39:12 +0000 (GMT) Received: from Webmail-ap.st.com (eapex1hubcas1.st.com [10.80.176.8]) by zeta.dmz-ap.st.com (STMicroelectronics) with ESMTP id 563C162D; Mon, 1 Aug 2011 09:39:12 +0000 (GMT) Received: from localhost (10.199.88.156) by Webmail-ap.st.com (10.80.176.7) with Microsoft SMTP Server (TLS) id 8.2.234.1; Mon, 1 Aug 2011 17:39:11 +0800 From: Viresh Kumar To: Subject: [PATCH V2 09/20] dmaengine/amba-pl08x: Simplify pl08x_ensure_on() Date: Mon, 1 Aug 2011 15:07:19 +0530 Message-ID: X-Mailer: git-send-email 1.7.2.2 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110801_053924_963894_6E4CB4D5 X-CRM114-Status: GOOD ( 15.76 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.126.144.129 listed in list.dnswl.org] Cc: pratyush.anand@st.com, rajeev-dlh.kumar@st.com, linux@arm.linux.org.uk, bhupesh.sharma@st.com, shiraz.hashim@st.com, vinod.koul@intel.com, linux-kernel@vger.kernel.org, vipin.kumar@st.com, armando.visconti@st.com, amit.virdi@st.com, vipulkumar.samar@st.com, viresh.linux@gmail.com, deepak.sikri@st.com, dan.j.williams@intel.com, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Mon, 01 Aug 2011 09:51:11 +0000 (UTC) Simply writing 1 on bit 0 is sufficient instead of reading and clearing bits. Also as per manual, for bit 3-31 of DMACConfiguration register: "read undefined, write as 0" So, we must not rely on values read from this registers bit 3-31. Signed-off-by: Viresh Kumar Acked-by: Linus Walleij --- drivers/dma/amba-pl08x.c | 8 +------- 1 files changed, 1 insertions(+), 7 deletions(-) diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index 428a67b..da17249 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -1507,13 +1507,7 @@ bool pl08x_filter_id(struct dma_chan *chan, void *chan_id) */ static void pl08x_ensure_on(struct pl08x_driver_data *pl08x) { - u32 val; - - val = readl(pl08x->base + PL080_CONFIG); - val &= ~(PL080_CONFIG_M2_BE | PL080_CONFIG_M1_BE | PL080_CONFIG_ENABLE); - /* We implicitly clear bit 1 and that means little-endian mode */ - val |= PL080_CONFIG_ENABLE; - writel(val, pl08x->base + PL080_CONFIG); + writel(PL080_CONFIG_ENABLE, pl08x->base + PL080_CONFIG); } static void pl08x_unmap_buffers(struct pl08x_txd *txd)