linux-kernel - RE: [PATCH v2 2/3] ufs: poll HCS.UCRDY before issuing a UIC command

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Date:   Mon, 5 Jun 2023 07:05:58 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     Kiwoong Kim <kwmad.kim@...sung.com>,
        "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "alim.akhtar@...sung.com" <alim.akhtar@...sung.com>,
        "bvanassche@....org" <bvanassche@....org>,
        "jejb@...ux.ibm.com" <jejb@...ux.ibm.com>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "beanhuo@...ron.com" <beanhuo@...ron.com>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "sc.suh@...sung.com" <sc.suh@...sung.com>,
        "hy50.seo@...sung.com" <hy50.seo@...sung.com>,
        "sh425.lee@...sung.com" <sh425.lee@...sung.com>,
        "kwangwon.min@...sung.com" <kwangwon.min@...sung.com>,
        "junwoo80.lee@...sung.com" <junwoo80.lee@...sung.com>
Subject: RE: [PATCH v2 2/3] ufs: poll HCS.UCRDY before issuing a UIC command

 
> v1 -> v2: replace usleep_range with udelay because it's a sleepable period.
> 
> With auto hibern8 enabled, UIC could be working for a while to process a
> hibern8 operation and HCI reports UIC not ready for a short term through
> HCS.UCRDY.
> And UFS driver can't recognize the operation.
> UFSHCI spec specifies UCRDY like this:
> whether the host controller is ready to process UIC COMMAND
> 
> The 'ready' could be seen as many different meanings. If the meaning includes
> not processing any request from HCI, processing a hibern8 operation can be
> 'not ready'. In this situation, the driver needs to wait until the operations is
> completed.
> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@...sung.com>
> ---
>  drivers/ufs/core/ufshcd.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index
> a89d39a..1f58a20 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -2365,7 +2365,18 @@ static inline int ufshcd_hba_capabilities(struct
> ufs_hba *hba)
>   */
>  static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)  {
> -       return ufshcd_readl(hba, REG_CONTROLLER_STATUS) &
> UIC_COMMAND_READY;
> +       ktime_t timeout = ktime_add_ms(ktime_get(), UIC_CMD_TIMEOUT);
> +       u32 val = 0;
> +
> +       do {
> +               val = ufshcd_readl(hba, REG_CONTROLLER_STATUS) &
> +                       UIC_COMMAND_READY;
> +               if (val)
> +                       break;
> +               udelay(500);
> +       } while (ktime_before(ktime_get(), timeout));
> +
> +       return val ? true : false;
>  }
Can you use read_poll_timeout() instead?

Thanks,
Avri

> 
>  /**
> --
> 2.7.4