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;
DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org BE9E5C433CA
Subject: Re: [PATCH] spi: spi-geni-qcom: Don't wait to start 1st transfer if
 transmitting
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: <20200912111716.1.Ied5e843fad0d6b733a1fb8bcfb364dd2fa889eb3@changeid>
From:   Akash Asthana <akashast@codeaurora.org>
Message-ID: <838a6074-73e6-a48b-2684-5ea2ebff443a@codeaurora.org>
Date:   Mon, 14 Sep 2020 18:39:25 +0530
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101
 Thunderbird/68.12.0
MIME-Version: 1.0
In-Reply-To: <20200912111716.1.Ied5e843fad0d6b733a1fb8bcfb364dd2fa889eb3@changeid>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 9/12/2020 11:47 PM, Douglas Anderson wrote:
> If we're sending bytes over SPI, we know the FIFO is empty at the
> start of the transfer.  There's no reason to wait for the interrupt
> telling us to start--we can just start right away.  Then if we
> transmit everything in one swell foop we don't even need to bother
> listening for TX interrupts.
>
> In a test of "flashrom -p ec -r /tmp/foo.bin" interrupts were reduced
> from ~30560 to ~29730, about a 3% savings.
>
> This patch looks bigger than it is because I moved a few functions
> rather than adding a forward declaration.  The only actual change to
> geni_spi_handle_tx() was to make it return a bool indicating if there
> is more to tx.
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
> Signed-off-by: Douglas Anderson<dianders@chromium.org>

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,\na Linux Foundation Collaborative Project