From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759943AbdACRMG (ORCPT ); Tue, 3 Jan 2017 12:12:06 -0500 Received: from mga11.intel.com ([192.55.52.93]:21072 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759911AbdACRLy (ORCPT ); Tue, 3 Jan 2017 12:11:54 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,456,1477983600"; d="scan'208";a="1078767818" Date: Tue, 3 Jan 2017 19:11:49 +0200 From: Jarkko Sakkinen To: Jiandi An Cc: Jason Gunthorpe , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [tpmdd-devel] [PATCH] tpm, tpm_crb: Handle 64-bit resource in crb_check_resource() Message-ID: <20170103171149.pwrbhy5uw4cqvwn4@intel.com> References: <1482121253-924-1-git-send-email-anjiandi@codeaurora.org> <20161219135624.2e7okpswnbqbvic7@intel.com> <5858CD6F.5000909@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5858CD6F.5000909@codeaurora.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 20, 2016 at 12:19:27AM -0600, Jiandi An wrote: > The control area buffer is specified in the TPM2.0 static ACPI table. TPM > CRB driver maps the control area address and reads out cmd and rsp buffer > addresses and maps them. There is no requirement in the TCG TPM ACPI spec > for specifying _CRS to describe the control area buffer. When I rebased > the early prototype for CRB driver ARM64 enablement to the latest kernel, > I hit this issue where I have to specify _CRS method. So in _CRS method > I specify the same control area address that's in the TPM2.0 static ACPI table. > > I see the _CRS requirement in the CRB driver is for resource synchronization > between the TIS and CRB drivers to support force mode in TIS. Could I get some > background on that so I could be more careful not breaking TIS while making > changes to CRB driver for ARM64 enablement? At least couple of reasons: - _CRS is required to access locality registers (check my patch set that is waiting for review/testing). - On x86 and PTT _CRS always exists and that's the only platform where this driver has been used so far. /Jarkko