Re: [PATCH v3 0/3] Add qcom hvc/shmem transport

From: Nikunj Kela <quic_nkela@quicinc.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	<cristian.marussi@arm.com>, <robh+dt@kernel.org>,
	<krzysztof.kozlowski+dt@linaro.org>, <conor+dt@kernel.org>,
	<agross@kernel.org>, <andersson@kernel.org>,
	<konrad.dybcio@linaro.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH v3 0/3] Add qcom hvc/shmem transport
Date: Thu, 7 Sep 2023 07:20:00 -0700	[thread overview]
Message-ID: <d79fe150-9930-d351-f096-7d2216526587@quicinc.com> (raw)
In-Reply-To: <20230907103619.2kqh7tfivwdfm5rd@bogus>

On 9/7/2023 3:36 AM, Sudeep Holla wrote:
> On Tue, Sep 05, 2023 at 06:37:14PM +0200, Krzysztof Kozlowski wrote:
>> On 05/09/2023 18:06, Nikunj Kela wrote:
>>> On 8/11/2023 10:57 AM, Nikunj Kela wrote:
>>>> This change introduce a new transport channel for Qualcomm virtual
>>>> platforms. The transport is mechanically similar to ARM_SCMI_TRANSPORT_SMC.
>>>> The difference between the two transports is that a parameter is passed in
>>>> the hypervisor call to identify which doorbell to assert. This parameter is
>>>> dynamically generated at runtime on the device and insuitable to pass via
>>>> the devicetree.
>>>>
>>>> The function ID and parameter are stored by firmware in the shmem region.
>>>>
>>>> This has been tested on ARM64 virtual Qualcomm platform.
>>>>
>>>> ---
>>>> v3 -> fix the compilation error reported by the test bot,
>>>>         add support for polling based instances
>>>>
>>>> v2 -> use allOf construct in dtb schema,
>>>>         remove wrappers from mutexes,
>>>>         use architecture independent channel layout
>>>>
>>>> v1 -> original patches
>>>>
>>>> Nikunj Kela (3):
>>>>     dt-bindings: arm: convert nested if-else construct to allOf
>>>>     dt-bindings: arm: Add qcom specific hvc transport for SCMI
>>>>     firmware: arm_scmi: Add qcom hvc/shmem transport
>>>>
>>>>    .../bindings/firmware/arm,scmi.yaml           |  67 ++---
>>>>    drivers/firmware/arm_scmi/Kconfig             |  13 +
>>>>    drivers/firmware/arm_scmi/Makefile            |   2 +
>>>>    drivers/firmware/arm_scmi/common.h            |   3 +
>>>>    drivers/firmware/arm_scmi/driver.c            |   4 +
>>>>    drivers/firmware/arm_scmi/qcom_hvc.c          | 232 ++++++++++++++++++
>>>>    6 files changed, 293 insertions(+), 28 deletions(-)
>>>>    create mode 100644 drivers/firmware/arm_scmi/qcom_hvc.c
>>> Gentle Ping!
> Pong !
>
>> It's third ping these two weeks from Qualcomm. Folks, it is merge
>> window. What do you think will happen with your ping during this time?
>>
> +1
>
> Okay, here is the deal with this patch set. As you are aware that a previous
> merged solution was abandoned by Qcom in a single kernel release cycle. So
> I decided to ignore this for one or 2 kernel release cycle to make sure
> Qcom makes up their mind on the design and then we can see how to proceed.
> Qcom must understand upstream kernel is not a playground to push their
> design which they might decided to drop support for in such short period.
> Please understand the upstream kernel supports platforms that are more than
> few decades old. It is not like the mobile platforms that are hardly supported
> for couple of years. And similarly, we push core support if and only if we
> know for sure it will be used on some platform. I trusted Qcom with the
> previous extension of SMC/HVC transport but I was proven wrong.
>
> Also, I definitely don't like the way you have copied the whole smc.c
> and changed it to Qcom's need and made it qcom_hvc.c. Just add the required
> changes in smc.c.
>
> --
> Regards,
> Sudeep

Completely understand your concerns and extending my apologies once 
again on the patch that was abandoned. I will rework the patch to 
include changes in smc.c. Thanks so much for your response!

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