From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH 4/4] cpufreq: arm_big_little: add SCPI interface driver Date: Fri, 01 May 2015 14:32:18 +0100 Message-ID: <55438062.8050309@arm.com> References: <1430134846-24320-1-git-send-email-sudeep.holla@arm.com> <1430134846-24320-5-git-send-email-sudeep.holla@arm.com> <1430486378.3045.56.camel@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:38463 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751311AbbEANcY (ORCPT ); Fri, 1 May 2015 09:32:24 -0400 In-Reply-To: <1430486378.3045.56.camel@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Jon Medhurst (Tixy)" Cc: Sudeep Holla , "linux-kernel@vger.kernel.org" , Liviu Dudau , Lorenzo Pieralisi , Viresh Kumar , "Rafael J. Wysocki" , "linux-pm@vger.kernel.org" On 01/05/15 14:19, Jon Medhurst (Tixy) wrote: > On Mon, 2015-04-27 at 12:40 +0100, Sudeep Holla wrote: >> On some ARM based systems, a separate Cortex-M based System Control >> Processor(SCP) provides the overall power, clock, reset and system >> control including CPU DVFS. SCPI Message Protocol is used to >> communicate with the SCPI. >> >> This patch adds a interface driver for adding OPPs and registering >> the arm_big_little cpufreq driver for such systems. >> >> Signed-off-by: Sudeep Holla >> Cc: Viresh Kumar >> Cc: "Rafael J. Wysocki" >> Cc: linux-pm@vger.kernel.org >> --- >> drivers/cpufreq/Kconfig.arm | 9 ++++ >> drivers/cpufreq/Makefile | 1 + >> drivers/cpufreq/scpi-cpufreq.c | 103 +++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 113 insertions(+) >> create mode 100644 drivers/cpufreq/scpi-cpufreq.c >> >> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm >> index 4f3dbc8cf729..9e678bf1687c 100644 >> --- a/drivers/cpufreq/Kconfig.arm >> +++ b/drivers/cpufreq/Kconfig.arm >> @@ -24,6 +24,15 @@ config ARM_VEXPRESS_SPC_CPUFREQ >> This add the CPUfreq driver support for Versatile Express >> big.LITTLE platforms using SPC for power management. >> >> +config ARM_SCPI_CPUFREQ >> + tristate "SCPI based CPUfreq driver" >> + depends on ARM_BIG_LITTLE_CPUFREQ && ARM_SCPI_PROTOCOL > > And ARM_BIG_LITTLE_CPUFREQ depends on CONFIG_ARM, so we can't build this > for arm64, which is the only platform (Juno) we have to run these > patches on. Yes I know > Unless you're prepared for a horrid hack... > https://github.com/ARM-software/linux/commit/b9ceaa0cbd7c57d57ee7e69146cc627697570f6e I need to check if it can be improved before I post on the list and hence dropped it in the first version of this patch-set. > or a pair of less horrid ones... > http://git.linaro.org/kernel/linux-linaro-tracking.git/commit/4b5dd8ff98613b7e90c8f3214522a00ab6900fe9 No not this one, this was already discussed long back I believe. It doesn't make sense to add bl-switcher for ARM64 IMO. > http://git.linaro.org/kernel/linux-linaro-tracking.git/commit/8641dbfe253f6a9061742ca11f769fc1d82c2aaa > Yes the Kconfig changes looks better than what I have now. > Any reason why the above two aren't suitable for mainline Linux? The > second was actually committed then reverted because it broke arm64 > builds, but the other patch fixes that. > Yes IMO since arm-big-little also supports multi-cluster cpufreq(yes I know it can be merged into cpufreq-dt once we have OPPv2 bindings, but until then), it should handle the config where CONFIG_BL_SWITCHER=n and that's what I have attempted in my patch above.