From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752230AbeC2W5t (ORCPT ); Thu, 29 Mar 2018 18:57:49 -0400 Received: from mga02.intel.com ([134.134.136.20]:17179 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751189AbeC2W5s (ORCPT ); Thu, 29 Mar 2018 18:57:48 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,378,1517904000"; d="scan'208";a="30064043" Reply-To: thor.thayer@linux.intel.com From: Thor Thayer Subject: RFC: Using regmap in ARM64 for EL3 register access To: Mark Brown , "linux-arm-kernel@lists.infradead.org" Cc: "linux-kernel@vger.kernel.org" Message-ID: <0cf26fec-a702-9d57-c7e0-85064690133c@linux.intel.com> Date: Thu, 29 Mar 2018 18:00:30 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I'm working on an ARM64 architecture that needs to manipulate some protected registers that are only accessible in EL3. Linux is running at EL1 which doesn't have the proper permissions for these registers. Since U-Boot is running at the higher EL3, we communicate to the U-Boot functions through a SMC mechanism. The regmap framework seems like a good match for accessing these registers. We need the same functionality as I2C and SPI regmaps - read, write, and update registers. Any comments or suggestions about using regmap for this purpose? Is there a better method? Thanks, Thor