Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <3b0a9357-88a6-c435-34d6-c75e9dfe9aaa@acm.org>
Date:   Wed, 10 May 2023 11:53:52 -0700
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.9.1
Subject: Re: [RFC PATCH v1] ufs: poll HCS.UCRDY before issuing a UIC command
Content-Language: en-US
To:     Kiwoong Kim <kwmad.kim@samsung.com>, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org, alim.akhtar@samsung.com,
        avri.altman@wdc.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com, beanhuo@micron.com,
        adrian.hunter@intel.com, sc.suh@samsung.com, hy50.seo@samsung.com,
        sh425.lee@samsung.com, kwangwon.min@samsung.com
References: <CGME20230509083312epcas2p375f77d18a9026f7d263750baf9c9a5bb@epcas2p3.samsung.com>
 <1683620674-160173-1-git-send-email-kwmad.kim@samsung.com>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <1683620674-160173-1-git-send-email-kwmad.kim@samsung.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 5/9/23 01:24, Kiwoong Kim wrote:
> 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@samsung.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 96ce6af..fc79539 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -2368,7 +2368,18 @@ 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;
> +		usleep_range(500, 1000);
> +	} while (ktime_before(ktime_get(), timeout));
> +
> +	return val ? true : false;
>   }
>   
>   /**

Reviewed-by: Bart Van Assche <bvanassche@acm.org>