linux-kernel - Re: [RFC PATCH 2/8] firmware: arm_scmi: add basic driver infrastructure for SCMI

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Date:   Thu, 8 Jun 2017 10:28:17 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Roy Franz <rfranz@...ium.com>
Cc:     Sudeep Holla <sudeep.holla@....com>, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, Roy Franz <roy.franz@...ium.com>,
        Harb Abdulhamid <harba@...eaurora.org>,
        Nishanth Menon <nm@...com>, Arnd Bergmann <arnd@...db.de>
Subject: Re: [RFC PATCH 2/8] firmware: arm_scmi: add basic driver
 infrastructure for SCMI

Hi Roy,

On 07/06/17 20:18, Roy Franz wrote:
> On Wed, Jun 7, 2017 at 9:10 AM, Sudeep Holla <sudeep.holla@....com> wrote:
>> The SCMI is intended to allow OSPM to manage various functions that are
>> provided by the hardware platform it is running on, including power and
>> performance functions. SCMI provides two levels of abstraction, protocols
>> and transports. Protocols define individual groups of system control and
>> management messages. A protocol specification describes the messages
>> that it supports. Transports describe the method by which protocol
>> messages are communicated between agents and the platform.
>>
>> This patch adds basic infrastructure to manage the message allocation,
>> initialisation, packing/unpacking and shared memory management.
>>
>> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
>> ---
>>  drivers/firmware/Kconfig           |  21 ++
>>  drivers/firmware/Makefile          |   1 +
>>  drivers/firmware/arm_scmi/Makefile |   2 +
>>  drivers/firmware/arm_scmi/common.h |  74 ++++
>>  drivers/firmware/arm_scmi/driver.c | 737 +++++++++++++++++++++++++++++++++++++
>>  include/linux/scmi_protocol.h      |  48 +++
>>  6 files changed, 883 insertions(+)
>>  create mode 100644 drivers/firmware/arm_scmi/Makefile
>>  create mode 100644 drivers/firmware/arm_scmi/common.h
>>  create mode 100644 drivers/firmware/arm_scmi/driver.c
>>  create mode 100644 include/linux/scmi_protocol.h
>>

[...]

>> +
>> +#define client_to_scmi_info(c) container_of(c, struct scmi_info, cl)
>> +#define handle_to_scmi_info(h) container_of(h, struct scmi_info, handle)
>> +
>> +/*
>> + * The SCP firmware only executes in little-endian mode, so any buffers
>> + * shared through SCMI should have their contents converted to little-endian
>> + */
> 
> nit:
> This really has more to do with the SCMI protocol defining everything
> as little endian, rather the endian-ness of the SCP, right?  There could be SCP
> implementations that are not Cortex M3s or little endian.
> 

Thanks for taking time to review this RFC, much appreciated. All valid
points(on this and other patches) and fixed locally now. Also thanks for
saving time in debugging these issues. I should be able to do some
testing next week.

-- 
Regards,
Sudeep