linux-kernel - Re: [PATCH v3] cdx: add MSI support for CDX bus

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Message-ID: <eac35f48-8683-3d3a-fa04-2adf20d3380f@amd.com>
Date:   Fri, 11 Aug 2023 16:49:27 +0530
From:   "Gupta, Nipun" <nipun.gupta@....com>
To:     gregkh@...uxfoundation.org, maz@...nel.org, tglx@...utronix.de,
        jgg@...pe.ca, linux-kernel@...r.kernel.org
Cc:     git@....com, harpreet.anand@....com,
        pieter.jansen-van-vuuren@....com, nikhil.agarwal@....com,
        michal.simek@....com, abhijit.gangurde@....com
Subject: Re: [PATCH v3] cdx: add MSI support for CDX bus



On 7/10/2023 4:58 PM, Nipun Gupta wrote:
> Add CDX-MSI domain per CDX controller with gic-its domain as
> a parent, to support MSI for CDX devices. CDX devices allocate
> MSIs from the CDX domain. Also, introduce APIs to alloc and free
> IRQs for CDX domain.
> 
> In CDX subsystem firmware is a controller for all devices and
> their configuration. CDX bus controller sends all the write_msi_msg
> commands to firmware running on RPU and the firmware interfaces with
> actual devices to pass this information to devices
> 
> Since, CDX controller is the only way to communicate with the Firmware
> for MSI write info, CDX domain per controller required in contrast to
> having a CDX domain per device.
> 
> Co-developed-by: Nikhil Agarwal <nikhil.agarwal@....com>
> Signed-off-by: Nikhil Agarwal <nikhil.agarwal@....com>
> Co-developed-by: Abhijit Gangurde <abhijit.gangurde@....com>
> Signed-off-by: Abhijit Gangurde <abhijit.gangurde@....com>
> Signed-off-by: Nipun Gupta <nipun.gupta@....com>
> Reviewed-by: Pieter Jansen van Vuuren <pieter.jansen-van-vuuren@....com>
> Tested-by: Nikhil Agarwal <nikhil.agarwal@....com>
> ---
> 
> Changes v2->v3:
> - Rebased on Linux 6.5rc1
> - Used FW provided 'msi_dev_id' as device ID for GIC instead of 'req_id'.
> 
> Changes v1->v2:
> - fixed scenario where msi write was called asyncronously in
>    an atomic context, by using irq_chip_(un)lock, and using sync
>    MCDI API for write MSI message.
> - fixed broken Signed-off-by chain.

Hi Thomas,

Upon reviewing your comments again on the version v1, I couldn't 
identify any oversights. All the review comments you provided earlier on 
v1 have been incorporated by using irq_chip_(un)lock and sync MCDI API 
for write MSI message.

However, there might be aspects that we've missed in this patch. I would 
greatly appreciate your suggestions on how we might enhance the 
acceptability of this patch.

Thanks,
Nipun