From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C79B92C007A for ; Wed, 13 Nov 2013 18:33:14 +1100 (EST) Date: Wed, 13 Nov 2013 08:32:59 +0100 From: Anatolij Gustschin To: neorf3k Subject: Re: Problem reading and programming memory location... Message-ID: <20131113083259.1b69ed18@crub> In-Reply-To: <985685C7-0122-4D45-96D1-4412E9774A5D@gmail.com> References: <985685C7-0122-4D45-96D1-4412E9774A5D@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Linux Ppc Dev List Dev List List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 12 Nov 2013 20:23:20 +0100 neorf3k wrote: > we have tried to read and program an 8bit register with 32bit address. > we have mapped it with: ioremap, kmalloc etc=E2=80=A6 and then using: out= b, > iowrite8 etc.. but when we write to it, the value doesn=E2=80=99t change= =E2=80=A6 > with other memory location is ok. > That is an 8 bit register, located at 0x10020000 in a mpc5200b > architecture. we are using kernel 2.6.33.=20 > what could be? 0x10020000 is not in the internal register memory map, so it is probably a device on the LocalPlus bus. Did you configure the chip select parameters for this device and did you enable the associated chip select? =20 HTH, Anatolij