netdev - Re: [PATCH v2 1/3] mctp pcc: Check before sending MCTP PCC response ACK

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Date: Mon, 3 Jun 2024 10:07:57 +0100
From: Sudeep Holla <sudeep.holla@....com>
To: admiyo@...amperecomputing.com
Cc: Jassi Brar <jassisinghbrar@...il.com>,
	Sudeep Holla <sudeep.holla@....com>,
	Robert Moore <robert.moore@...el.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Len Brown <lenb@...nel.org>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] mctp pcc: Check before sending MCTP PCC response
 ACK

On Tue, May 28, 2024 at 03:18:21PM -0400, admiyo@...amperecomputing.com wrote:
> From: Adam Young <admiyo@...erecomputing.com>
> 
> Type 4 PCC channels have an option to send back a response
> to the platform when they are done processing the request.
> The flag to indicate whether or not to respond is inside
> the message body, and thus is not available to the pcc
> mailbox.  Since only one message can be processed at once per
> channel, the value of this flag is checked during message processing
> and passed back via the channels global structure.
> 
> Ideally, the mailbox callback function would return a value
> indicating whether the message requires an ACK, but that
> would be a change to the mailbox API.  That would involve
> some change to all (about 12) of the mailbox based drivers,
> and the majority of them would not need to know about the
> ACK call.
>

I don't have all the 3 patches. Is this sent by error or am I expected
to just review this patch while other 2 are not mailbox related ?

> Signed-off-by: Adam Young <admiyo@...amperecomputing.com>
> ---
>  drivers/mailbox/pcc.c | 5 ++++-
>  include/acpi/pcc.h    | 1 +
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index 94885e411085..774727b89693 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -280,6 +280,7 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>  {
>  	struct pcc_chan_info *pchan;
>  	struct mbox_chan *chan = p;
> +	struct pcc_mbox_chan *pmchan;
>  	u64 val;
>  	int ret;
>  
> @@ -304,6 +305,8 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>  	if (pcc_chan_reg_read_modify_write(&pchan->plat_irq_ack))
>  		return IRQ_NONE;
>  
> +	pmchan = &pchan->chan;
> +	pmchan->ack_rx = true;  //TODO default to False

We need to remove this and detect when it can be true if the default expected
is false.

-- 
Regards,
Sudeep