linux-kernel - Re: [PATCH v1] scsi: ufs: mcq: add 1 to the max Queues value

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Message-ID: <CAGaU9a-k9iDUNeT0s85o0GEeXSWsi98_QC+nK=jT9Yb1V=-SZA@mail.gmail.com>
Date:   Wed, 19 Apr 2023 18:32:56 +0800
From:   Stanley Chu <chu.stanley@...il.com>
To:     SEO HOYOUNG <hy50.seo@...sung.com>
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        alim.akhtar@...sung.com, avri.altman@....com, jejb@...ux.ibm.com,
        martin.petersen@...cle.com, beanhuo@...ron.com, bvanassche@....org,
        bhoon95.kim@...sung.com, kwmad.kim@...sung.com, sc.suh@...sung.com,
        quic_nguyenb@...cinc.com, Po-Wen Kao <powen.kao@...iatek.com>,
        peter.wang@...iatek.com
Subject: Re: [PATCH v1] scsi: ufs: mcq: add 1 to the max Queues value

Hi,

SEO HOYOUNG <hy50.seo@...sung.com> 於 2023年4月19日 週三 下午5:56寫道：
>
> If read the MAXQ field value verbatim, can use a value
> that is one less than the supported Queue.
> So read the MAXQ field value and incremented it by one
>
> below is the specification
> Maximum number of Queues (MAXQ):
> Maximum number of Queues this controller can support.
> In this version of specification, maximum value is 31.
>
> NOTE To support 1:1 topology, the Host HW controller must support
> HW resources for MAXQ number of Completion Queues too.
> Host SW may use less number of completion queues for N:1 topology..:1 Queue
> 0: 1 Queue
> 1: 2 Queues
> …
> 31: 32 Queues
> 32-255 : reserved
>
> Signed-off-by: SEO HOYOUNG <hy50.seo@...sung.com>
> ---
>  drivers/ufs/core/ufs-mcq.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
> index 31df052fbc41..a1ee3318c605 100644
> --- a/drivers/ufs/core/ufs-mcq.c
> +++ b/drivers/ufs/core/ufs-mcq.c
> @@ -150,7 +150,7 @@ static int ufshcd_mcq_config_nr_queues(struct ufs_hba *hba)
>         u32 hba_maxq, rem, tot_queues;
>         struct Scsi_Host *host = hba->host;
>
> -       hba_maxq = FIELD_GET(MAX_QUEUE_SUP, hba->mcq_capabilities);
> +       hba_maxq = FIELD_GET(MAX_QUEUE_SUP, hba->mcq_capabilities) + 1;
>
>         tot_queues = UFS_MCQ_NUM_DEV_CMD_QUEUES + read_queues + poll_queues +
>                         rw_queues;
> --
> 2.26.0
>

This seems to be the same patch uploaded by Powen:
https://patchwork.kernel.org/project/linux-scsi/patch/20230307065448.15279-4-powen.kao@mediatek.com/