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Subject: Re: [PATCH 1/3] spi: spi-geni-qcom: Use the FIFO even more
To:     Douglas Anderson <dianders@chromium.org>,
        Mark Brown <broonie@kernel.org>
Cc:     swboyd@chromium.org, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-spi@vger.kernel.org
References: <20200912140730.1.Ie67fa32009b94702d56232c064f1d89065ee8836@changeid>
From:   Akash Asthana <akashast@codeaurora.org>
Message-ID: <8aa6759a-3db9-97b6-7cad-6bd5d6a1c469@codeaurora.org>
Date:   Tue, 15 Sep 2020 13:00:00 +0530
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On 9/13/2020 2:37 AM, Douglas Anderson wrote:
> In commit 902481a78ee4 ("spi: spi-geni-qcom: Actually use our FIFO") I
> explained that the maximum size we could program the FIFO was
> "mas->tx_fifo_depth - 3" but that I chose "mas->tx_fifo_depth()"
> because I was worried about decreased bandwidth.
>
> Since that time:
> * All the interconnect patches have landed, making things run at the
>    proper speed.
> * I've done more measurements.
>
> This lets me confirm that there's really no downside of using the FIFO
> more.  Specifically I did "flashrom -p ec -r /tmp/foo.bin" on a
> Chromebook and averaged over several runs.
>
> Before: It took 6.66 seconds and 59669 interrupts fired.
> After:  It took 6.66 seconds and 47992 interrupts fired.

Reviewed-by: Akash Asthana <akashast@codeaurora.org>

> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> ---
>
>
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