Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [RFC PATCH v1 2/2] scsi: ufs: ufs-exynos: implement exynos isr
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,
        cang@codeaurora.org, adrian.hunter@intel.com, sc.suh@samsung.com,
        hy50.seo@samsung.com, sh425.lee@samsung.com,
        bhoon95.kim@samsung.com
References: <cover.1628231581.git.kwmad.kim@samsung.com>
 <CGME20210806064925epcas2p2ba7e711758614384c17648d4924d025c@epcas2p2.samsung.com>
 <7d2030d91425a01f964f7a9309c1aa3a0ce6a2d6.1628231581.git.kwmad.kim@samsung.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <597a96f4-9cd4-c1bb-5c8d-dd5d00f0948d@acm.org>
Date:   Fri, 6 Aug 2021 09:37:08 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.12.0
MIME-Version: 1.0
In-Reply-To: <7d2030d91425a01f964f7a9309c1aa3a0ce6a2d6.1628231581.git.kwmad.kim@samsung.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 8/5/21 11:34 PM, Kiwoong Kim wrote:
> Based on some events in the real world

Which events? Please clarify.

> I implement
> this to block the host's working in some abnormal
> conditions using an vendor specific interrupt for
> cases that some contexts of a pending request in the
> host isn't the same with those of its corresponding UPIUs
> if they should have been the same exactly.

The entire patch description sounds very vague to me. Please make the 
description more clear.

> +enum exynos_ufs_vs_interrupt {
> +	/*
> +	 * This occurs when information of a pending request isn't
> +	 * the same with incoming UPIU for the request. For example,
> +	 * if UFS driver rings with task tag #1, subsequential UPIUs
> +	 * for this must have one as the value of task tag. But if
> +	 * it's corrutped until the host receives it or incoming UPIUs
> +	 * has an unexpected value for task tag, this raises.
> +	 */
> +	RX_UPIU_HIT_ERROR	= 1 << 19,
> +};

The above description needs to be improved. If a request is submitted 
with task tag one, only one UPIU can have that task tag instead of all 
subsequent UPIUs.

>   	hci_writel(ufs, UFS_SW_RST_MASK, HCI_SW_RST);
> -
>   	do {
>   		if (!(hci_readl(ufs, HCI_SW_RST) & UFS_SW_RST_MASK))
> -			goto out;
> +			return 0;
>   	} while (time_before(jiffies, timeout));

Since the above loop is a busy-waiting loop, please insert an msleep() 
or cpu_relax() call.

> +	 * some unexpected events could happen, such as tranferring
                                                         ^^^^^^^^^^^
Please fix the spelling of this word.

Thanks,

Bart.