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From: Hemant Kumar <quic_hemantk@quicinc.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	<mhi@lists.linux.dev>
Cc: <linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<quic_bbhatt@quicinc.com>, <loic.poulain@linaro.org>
Subject: Re: [PATCH 5/5] bus: mhi: host: Remove redundant dma_wmb() before ctx wp update
Date: Tue, 3 May 2022 19:22:28 -0700	[thread overview]
Message-ID: <fa92f431-500d-df0f-85f6-55cf5017a80b@quicinc.com> (raw)
In-Reply-To: <20220502104144.91806-6-manivannan.sadhasivam@linaro.org>


On 5/2/2022 3:41 AM, Manivannan Sadhasivam wrote:
> The endpoint device will only read the context wp when the host rings
> the doorbell. And moreover the doorbell write is using writel(). This
> guarantess that the prior writes will be completed before ringing
> doorbell.
>
> So there is no need of an additional dma_wmb() to order the coherent
> memory writes w.r.t each other. Even if the writes gets reordered, it
> won't affect the endpoint device.
>
> Cc: Loic Poulain <loic.poulain@linaro.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Reviewed by: Hemant Kumar <quic_hemantk@quicinc.com>
>

  reply	other threads:[~2022-05-04  2:22 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-02 10:41 [PATCH 0/5] MHI host cleanups Manivannan Sadhasivam
2022-05-02 10:41 ` [PATCH 1/5] bus: mhi: host: Rename process_db callback to ring_db Manivannan Sadhasivam
2022-05-02 10:41 ` [PATCH 2/5] bus: mhi: host: Rename mhi_db_brstmode() and mhi_db_brstmode_disable() Manivannan Sadhasivam
2022-05-02 10:41 ` [PATCH 3/5] bus: mhi: host: Use {READ/WITE}_ONCE macros for db_mode and db_val Manivannan Sadhasivam
2022-05-02 10:41 ` [PATCH 4/5] bus: mhi: host: Rename parse_{rsc/xfer}_event to process{rsc/xfer}_event Manivannan Sadhasivam
2022-05-02 10:41 ` [PATCH 5/5] bus: mhi: host: Remove redundant dma_wmb() before ctx wp update Manivannan Sadhasivam
2022-05-04  2:22   ` Hemant Kumar [this message]
2022-05-04  7:21   ` Loic Poulain
2022-05-04  8:17     ` Manivannan Sadhasivam
2022-05-04  9:25       ` Loic Poulain
2022-05-04 15:58         ` Manivannan Sadhasivam
     [not found]           ` <514326aa-49eb-2b07-b99e-53899722c7e2@quicinc.com>
2022-05-06 18:01             ` Hemant Kumar
2022-05-09  6:47               ` Loic Poulain

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