linux-kernel - Re: [PATCH v2 06/13] mailbox: pcc: Refactor error handling in irq handler into separate function

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Message-ID: <880286ec-b499-4edb-bb22-c42bf5a64e2c@amperemail.onmicrosoft.com>
Date: Wed, 12 Mar 2025 18:28:34 -0400
From: Adam Young <admiyo@...eremail.onmicrosoft.com>
To: Sudeep Holla <sudeep.holla@....com>, linux-acpi@...r.kernel.org,
 linux-kernel@...r.kernel.org
Cc: Jassi Brar <jassisinghbrar@...il.com>, Huisong Li <lihuisong@...wei.com>,
 Adam Young <admiyo@...amperecomputing.com>,
 Robbie King <robbiek@...ghtlabs.com>
Subject: Re: [PATCH v2 06/13] mailbox: pcc: Refactor error handling in irq
 handler into separate function


On 3/5/25 11:38, Sudeep Holla wrote:
> The existing error handling logic in pcc_mbox_irq() is intermixed with the
> main flow of the function. The command complete check and the complete
> complete update/acknowledgment are nicely factored into separate functions.
>
> Moves error detection and clearing logic into a separate function called:
> pcc_mbox_error_check_and_clear() by extracting error-handling logic from
> pcc_mbox_irq().
>
> This ensures error checking and clearing are handled separately and it
> improves maintainability by keeping the IRQ handler focused on processing
> events.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>   drivers/mailbox/pcc.c | 30 ++++++++++++++++++++----------
>   1 file changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> index b1b8223b5da7002fc522523dbc82f6124215439a..41bd14851216e8c4f03052c81aaf938a5e5c5343 100644
> --- a/drivers/mailbox/pcc.c
> +++ b/drivers/mailbox/pcc.c
> @@ -269,6 +269,25 @@ static bool pcc_mbox_cmd_complete_check(struct pcc_chan_info *pchan)
>   	return !!val;
>   }
>   
> +static int pcc_mbox_error_check_and_clear(struct pcc_chan_info *pchan)
> +{
> +	u64 val;
> +	int ret;
> +
> +	ret = pcc_chan_reg_read(&pchan->error, &val);
> +	if (ret)
> +		return ret;
> +
> +	val &= pchan->error.status_mask;
> +	if (val) {
> +		val &= ~pchan->error.status_mask;
> +		pcc_chan_reg_write(&pchan->error, val);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
>   static void check_and_ack(struct pcc_chan_info *pchan, struct mbox_chan *chan)
>   {
>   	struct acpi_pcct_ext_pcc_shared_memory pcc_hdr;
> @@ -309,8 +328,6 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>   {
>   	struct pcc_chan_info *pchan;
>   	struct mbox_chan *chan = p;
> -	u64 val;
> -	int ret;
>   
>   	pchan = chan->con_priv;
>   
> @@ -324,15 +341,8 @@ static irqreturn_t pcc_mbox_irq(int irq, void *p)
>   	if (!pcc_mbox_cmd_complete_check(pchan))
>   		return IRQ_NONE;
>   
> -	ret = pcc_chan_reg_read(&pchan->error, &val);
> -	if (ret)
> +	if (pcc_mbox_error_check_and_clear(pchan))
>   		return IRQ_NONE;
> -	val &= pchan->error.status_mask;
> -	if (val) {
> -		val &= ~pchan->error.status_mask;
> -		pcc_chan_reg_write(&pchan->error, val);
> -		return IRQ_NONE;
> -	}
>   
>   	/*
>   	 * Clear this flag immediately after updating interrupt ack register
>

tested-by: Adam Young <admiyo@...amperecomputing.com>