Re: [PATCH v5 09/16] ufs: core: mcq: Configure operation and runtime interface

From: Asutosh Das <quic_asutoshd@quicinc.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: <quic_cang@quicinc.com>, <martin.petersen@oracle.com>,
	<linux-scsi@vger.kernel.org>, <quic_nguyenb@quicinc.com>,
	<quic_xiaosenh@quicinc.com>, <stanley.chu@mediatek.com>,
	<eddie.huang@mediatek.com>, <daejun7.park@samsung.com>,
	<avri.altman@wdc.com>, <mani@kernel.org>, <beanhuo@micron.com>,
	<linux-arm-msm@vger.kernel.org>,
	Alim Akhtar <alim.akhtar@samsung.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@somainline.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
	Arthur Simchaev <Arthur.Simchaev@wdc.com>,
	Jinyoung Choi <j-young.choi@samsung.com>,
	Kiwoong Kim <kwmad.kim@samsung.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 09/16] ufs: core: mcq: Configure operation and runtime interface
Date: Mon, 28 Nov 2022 14:08:42 -0800	[thread overview]
Message-ID: <20221128220842.GE20677@asutoshd-linux1.qualcomm.com> (raw)
In-Reply-To: <ef519087-c302-3547-1419-2dcddfb4c646@acm.org>

On Fri, Nov 25 2022 at 17:28 -0800, Bart Van Assche wrote:
>On 11/22/22 20:10, Asutosh Das wrote:
>>+static void ufshcd_config_mcq(struct ufs_hba *hba)
>>+{
>>+	ufshcd_enable_intr(hba, UFSHCD_ENABLE_MCQ_INTRS);
>>+	ufshcd_mcq_make_queues_operational(hba);
>>+	ufshcd_mcq_config_mac(hba, hba->nutrs);
>>+
>>+	hba->host->can_queue = hba->nutrs - UFSHCD_NUM_RESERVED;
>>+	hba->reserved_slot = hba->nutrs - UFSHCD_NUM_RESERVED;
>>+	dev_info(hba->dev, "MCQ configured, nr_queues=%d, io_queues=%d, read_queue=%d, poll_queues=%d, queue_depth=%d\n",
>>+		 hba->nr_hw_queues, hba->nr_queues[HCTX_TYPE_DEFAULT],
>>+		 hba->nr_queues[HCTX_TYPE_READ], hba->nr_queues[HCTX_TYPE_POLL],
>>+		 hba->nutrs);
>>+}
>
Hello Bart,

>Please do not reserve a slot for device commands in MCQ mode but 
>instead queue device management commands on the device management 
>command queue in MCQ mode. Please also add WARN_ON_ONCE() statements 
>in the code that uses hba->reserved_slot to make sure that that 
>variable is not used in MCQ mode.

Now it is queued to device management command queue in MCQ mode.
However, a task tag is needed for device management commands.
Do you mean that the task tag of device management command be default to 0
instead in MCQ mode?

>
>Thanks,
>
>Bart.