From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Hogan <james.hogan@imgtec.com>
Subject: Re: mmc: dw_mmc: miscaculated the fifo-depth with wrong bit operation
Date: Mon, 9 Jan 2012 09:41:15 +0000
Message-ID: <4F0AB63B.4030202@imgtec.com>
References: <4F0A3DA4.8010909@samsung.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
Return-path: <linux-mmc-owner@vger.kernel.org>
Received: from multi.imgtec.com ([194.200.65.239]:15453 "EHLO multi.imgtec.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752257Ab2AIJl1 (ORCPT <rfc822;linux-mmc@vger.kernel.org>);
	Mon, 9 Jan 2012 04:41:27 -0500
In-Reply-To: <4F0A3DA4.8010909@samsung.com>
Sender: linux-mmc-owner@vger.kernel.org
List-Id: linux-mmc@vger.kernel.org
To: Jaehoon Chung <jh80.chung@samsung.com>
Cc: linux-mmc <linux-mmc@vger.kernel.org>, Chris Ball <cjb@laptop.org>, Kyungmin Park <kyungmin.park@samsung.com>, Will Newton <will.newton@imgtec.com>

On 01/09/2012 01:06 AM, Jaehoon Chung wrote:
> In FIFOTH register, can find "bit[27:16] = FIFO_DEPTH - 1".
> Finally, FIFO_DEPTH = bit[27:16] + 1.
> 
> Now, Used the 0x7ff. but 0xfff is right.

Nice catch. The patch itself looks okay, but I don't think the commit
message is very understandable, maybe something like this would be better?:

In FIFOTH register, the RX_WMark field (bits[27:16]) defaults to
FIFO_DEPTH - 1. When reading it, bits[26:16] were being used, so fix it
to use the mask 0xfff instead of 0x7ff.

Cheers
James