linux-kernel - Re: [PATCH v3 3/6] bus: mhi: core: Offload register accesses to the controller

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Message-ID: <ba5e3217-afa0-95ae-406a-034d88d979b0@codeaurora.org>
Date:   Tue, 28 Apr 2020 11:56:03 -0700
From:   Hemant Kumar <hemantk@...eaurora.org>
To:     Jeffrey Hugo <jhugo@...eaurora.org>,
        manivannan.sadhasivam@...aro.org
Cc:     bbhatt@...eaurora.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/6] bus: mhi: core: Offload register accesses to the
 controller



On 4/27/20 8:59 AM, Jeffrey Hugo wrote:
> When reading or writing MHI registers, the core assumes that the physical
> link is a memory mapped PCI link.  This assumption may not hold for all
> MHI devices.  The controller knows what is the physical link (ie PCI, I2C,
> SPI, etc), and therefore knows the proper methods to access that link.
> The controller can also handle link specific error scenarios, such as
> reading -1 when the PCI link went down.
> 
> Therefore, it is appropriate that the MHI core requests the controller to
> make register accesses on behalf of the core, which abstracts the core
> from link specifics, and end up removing an unnecessary assumption.
> 
> Signed-off-by: Jeffrey Hugo <jhugo@...eaurora.org>
> ---
Reviewed-by: Hemant Kumar <hemantk@...eaurora.org>

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