Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964991AbbDIJhg (ORCPT ); Thu, 9 Apr 2015 05:37:36 -0400 Received: from mail-la0-f47.google.com ([209.85.215.47]:33501 "EHLO mail-la0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964983AbbDIJhG (ORCPT ); Thu, 9 Apr 2015 05:37:06 -0400 MIME-Version: 1.0 X-Originating-IP: [36.239.215.205] In-Reply-To: <1428569224-23820-115-git-send-email-lizf@kernel.org> References: <1428569028-23762-1-git-send-email-lizf@kernel.org> <1428569224-23820-115-git-send-email-lizf@kernel.org> Date: Thu, 9 Apr 2015 17:37:03 +0800 Message-ID: Subject: Re: [PATCH 3.4 115/176] spi: dw: Fix detecting FIFO depth From: Axel Lin To: lizf@kernel.org Cc: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Mark Brown , Zefan Li Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1606 Lines: 37 2015-04-09 16:46 GMT+08:00 : > From: Axel Lin > > 3.4.107-rc1 review patch. If anyone has any objections, please let me know. > > ------------------ > > > commit d297933cc7fcfbaaf2d37570baac73287bf0357d upstream. > > Current code tries to find the highest valid fifo depth by checking the value > it wrote to DW_SPI_TXFLTR. There are a few problems in current code: > 1) There is an off-by-one in dws->fifo_len setting because it assumes the latest > register write fails so the latest valid value should be fifo - 1. > 2) We know the depth could be from 2 to 256 from HW spec, so it is not necessary > to test fifo == 257. In the case fifo is 257, it means the latest valid > setting is fifo = 256. So after the for loop iteration, we should check > fifo == 2 case instead of fifo == 257 if detecting the FIFO depth fails. > This patch fixes above issues. > > Signed-off-by: Axel Lin > Reviewed-and-tested-by: Andy Shevchenko > Signed-off-by: Mark Brown > [lizf: Backported to 3.4: adjust context] > Signed-off-by: Zefan Li Hi, This patch needs below fix: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/spi/spi-dw.c?id=9d239d353c319f9ff884c287ce47feb7cdf60ddc Thanks, Axel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/