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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,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 9C5E1C34031 for ; Wed, 19 Feb 2020 01:10:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7057E24655 for ; Wed, 19 Feb 2020 01:10:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=megous.com header.i=@megous.com header.b="QHSn0XjA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727845AbgBSBKB (ORCPT ); Tue, 18 Feb 2020 20:10:01 -0500 Received: from vps.xff.cz ([195.181.215.36]:54202 "EHLO vps.xff.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726761AbgBSBKB (ORCPT ); Tue, 18 Feb 2020 20:10:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megous.com; s=mail; t=1582074599; bh=Aeuv5iYbaAp7rr6i5ZST/n1JdcOfY/hR+2BNrgy8C+E=; h=From:To:Cc:Subject:Date:From; b=QHSn0XjACs3lffkvnSFb2Pb78S1/c0rmc4BVbXsaxeakyWxv3Mh/uhDOckugdgAqZ FcC8PID+c6c6kZWMrj4KvwtCzGJHnr4igAaFwpP17DnZYrxwk+t60tjSDIqWrlF0aD UjWgeF7tQbJzZPcmQflTg7yTojktxGRiFa4KFSkY= From: Ondrej Jirman To: linux-sunxi@googlegroups.com Cc: Ondrej Jirman , Maxime Ripard , Chen-Yu Tsai , Samuel Holland , Stephen Boyd , linux-arm-kernel@lists.infradead.org (moderated list:ARM/Allwinner sunXi SoC support), linux-kernel@vger.kernel.org (open list) Subject: [PATCH] bus: sunxi-rsb: Return correct data when mixing 16-bit and 8-bit reads Date: Wed, 19 Feb 2020 02:09:50 +0100 Message-Id: <20200219010951.395599-1-megous@megous.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When doing a 16-bit read that returns data in the MSB byte, the RSB_DATA register will keep the MSB byte unchanged when doing the following 8-bit read. sunxi_rsb_read() will then return a result that contains high byte from 16-bit read mixed with the 8-bit result. The consequence is that after this happens the PMIC's regmap will look like this: (0x33 is the high byte from the 16-bit read) % cat /sys/kernel/debug/regmap/sunxi-rsb-3a3/registers 00: 33 01: 33 02: 33 03: 33 04: 33 05: 33 06: 33 07: 33 08: 33 09: 33 0a: 33 0b: 33 0c: 33 0d: 33 0e: 33 [snip] Fix this by masking the result of the read with the correct mask based on the size of the read. There are no 16-bit users in the mainline kernel, so this doesn't need to get into the stable tree. Signed-off-by: Ondrej Jirman --- drivers/bus/sunxi-rsb.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c index b8043b58568ac..8ab6a3865f569 100644 --- a/drivers/bus/sunxi-rsb.c +++ b/drivers/bus/sunxi-rsb.c @@ -316,6 +316,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr, { u32 cmd; int ret; + u32 mask; if (!buf) return -EINVAL; @@ -323,12 +324,15 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr, switch (len) { case 1: cmd = RSB_CMD_RD8; + mask = 0xffu; break; case 2: cmd = RSB_CMD_RD16; + mask = 0xffffu; break; case 4: cmd = RSB_CMD_RD32; + mask = 0xffffffffu; break; default: dev_err(rsb->dev, "Invalid access width: %zd\n", len); @@ -345,7 +349,7 @@ static int sunxi_rsb_read(struct sunxi_rsb *rsb, u8 rtaddr, u8 addr, if (ret) goto unlock; - *buf = readl(rsb->regs + RSB_DATA); + *buf = readl(rsb->regs + RSB_DATA) & mask; unlock: mutex_unlock(&rsb->lock); -- 2.25.1