From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Berger Subject: [PATCH 0/3] libata: prevent writes to read-only registers Date: Wed, 21 Jun 2017 16:20:11 -0700 Message-ID: <20170621232014.27790-1-opendmb@gmail.com> Return-path: Received: from mail-qk0-f193.google.com ([209.85.220.193]:32962 "EHLO mail-qk0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750936AbdFUXUf (ORCPT ); Wed, 21 Jun 2017 19:20:35 -0400 Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: tj@kernel.org Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Doug Berger Recent Broadcom SoCs allow for the trapping of write accesses to read-only registers. This is only useful if such accesses are exceptional, so it is desirable to prevent such accesses in normal operation. To that end, this set of commits proposes adding two flags to the libata core. The first allows for a quirk that exists in some Broadcom devices that are capable of supporting Aggresive Link Power Management even though it is not reported by their read-only capability register. This removes a need for the Broadcom driver to write to it's read-only capability register. The second is a notification to the libata-core that it should not write to any standard registers that are defined to be read-only. The Broadcom driver is then modified to use these two general purpose flags. Doug Berger (3): libata: Add the AHCI_HFLAG_YES_ALPM flag libata: Add the AHCI_HFLAG_NO_WRITE_TO_RO flag ata: ahci_brcm: Avoid writing to read-only registers drivers/ata/ahci.h | 3 +++ drivers/ata/ahci_brcm.c | 12 ++++-------- drivers/ata/libahci.c | 8 +++++++- 3 files changed, 14 insertions(+), 9 deletions(-) -- 2.13.0