From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from b.relay.invitel.net ([62.77.203.4]:41852 "EHLO b.relay.invitel.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752651Ab2A3MmP (ORCPT ); Mon, 30 Jan 2012 07:42:15 -0500 Date: Mon, 30 Jan 2012 13:35:45 +0100 From: Heiko Schocher Subject: Re: [PATCH] drivers, char: add U-Boot bootcount driver In-reply-to: <4EDEA3BF.6020507@gmail.com> To: Rob Herring Cc: Wolfram Sang , Wolfgang Denk , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, Vitaly Bordug , linux-watchdog@vger.kernel.org Reply-to: hs@denx.de Message-id: <4F268EA1.3090907@denx.de> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7BIT References: <1322991921-21096-1-git-send-email-hs@denx.de> <20111204114741.GA5788@pengutronix.de> <4EDCD7B2.5030409@denx.de> <20111206215056.GD14154@pengutronix.de> <20111206215609.5D1FF1A32820@gemini.denx.de> <20111206220620.GF14154@pengutronix.de> <4EDEA3BF.6020507@gmail.com> Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org Hello Rob, Sorry for the late reply ... Rob Herring wrote: > On 12/06/2011 04:06 PM, Wolfram Sang wrote: >>>> bootcount itself is not a device. It is a feature of certain devices. And that >>>> needs to be implemented; possibly generic enough that it can work for register >>>> based, i2c based, and so forth, accesses. >>> If "boot counter" is not a good name for such a device, then what name >>> would you suggest? >> None. >> >>> Or do you think a counter (which can be implemented in a number of >>> different ways, depending on hardware specifics) is not a device? >> Yes. >> >>> What would be such a device, then? >> "maxim,ds1338" >> >> Please have a look at the devicetree.org-wiki-page I just mentioned: >> >> http://devicetree.org/Device_Tree_Usage >> > > Perhaps fs/pstore would be a good choice for the user space interface > (defining a new file bootcount). This can support any arbitrary backing > device although pretty much only ACPI is implemented. I tried to use fs/pstore for the bootcount feature, and I can mount and read the bootcount value from the file, I created. But I could not write to that file ... I only see the callback from include/linux/pstore.h struct pstore_info { [...] int (*write)(enum pstore_type_id type, enum kmsg_dump_reason reason, u64 *id, unsigned int part, size_t size, struct pstore_info *psi); called, if I reboot ... do I miss something? Or is it not possible to write to the files created through fs/pstore? bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany