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Date:   Mon, 08 Aug 2022 08:59:59 +0200
Message-Id: <CM0GBVEZHLBT.1V54N4FCEN7V6@otso>
Cc:     "Robin Reckmann" <robin.reckmann@gmail.com>,
        <linux-arm-msm@vger.kernel.org>, <linux-i2c@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-media@vger.kernel.org>,
        <dri-devel@lists.freedesktop.org>, <linaro-mm-sig@lists.linaro.org>
Subject: Re: [PATCH] i2c: qcom-geni: Fix GPI DMA buffer sync-back
From:   "Luca Weiss" <luca.weiss@fairphone.com>
To:     "Robin Reckmann" <robin.reckmann@googlemail.com>,
        "Andy Gross" <agross@kernel.org>,
        "Bjorn Andersson" <bjorn.andersson@linaro.org>,
        "Konrad Dybcio" <konrad.dybcio@somainline.org>,
        "Sumit Semwal" <sumit.semwal@linaro.org>,
        =?utf-8?q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>
References: <20220807140455.409417-1-robin.reckmann@gmail.com>
In-Reply-To: <20220807140455.409417-1-robin.reckmann@gmail.com>
Precedence: bulk

Hi Robin,

On Sun Aug 7, 2022 at 4:04 PM CEST, Robin Reckmann wrote:
> Fix i2c transfers using GPI DMA mode for all message types that do not se=
t
> the I2C_M_DMA_SAFE flag (e.g. SMBus "read byte").
>
> In this case a bounce buffer is returned by i2c_get_dma_safe_msg_buf(),
> and it has to synced back to the message after the transfer is done.
>
> Add missing assignment of dma buffer in geni_i2c_gpi().
>
> Set xferred in i2c_put_dma_safe_msg_buf() to true in case of no error to
> ensure the sync-back of this dma buffer to the message.
>
> Signed-off-by: Robin Reckmann <robin.reckmann@gmail.com>

This makes I2C with GPI DMA work on sm6350/sm7725 fairphone-fp4!
Thanks for fixing this!

Tested-by: Luca Weiss <luca.weiss@fairphone.com>

Regards
Luca

> ---
>  drivers/i2c/busses/i2c-qcom-geni.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-=
qcom-geni.c
> index 6ac402ea58fb..d3541e94794e 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -484,12 +484,12 @@ static void geni_i2c_gpi_unmap(struct geni_i2c_dev =
*gi2c, struct i2c_msg *msg,
>  {
>  	if (tx_buf) {
>  		dma_unmap_single(gi2c->se.dev->parent, tx_addr, msg->len, DMA_TO_DEVIC=
E);
> -		i2c_put_dma_safe_msg_buf(tx_buf, msg, false);
> +		i2c_put_dma_safe_msg_buf(tx_buf, msg, !gi2c->err);
>  	}
> =20
>  	if (rx_buf) {
>  		dma_unmap_single(gi2c->se.dev->parent, rx_addr, msg->len, DMA_FROM_DEV=
ICE);
> -		i2c_put_dma_safe_msg_buf(rx_buf, msg, false);
> +		i2c_put_dma_safe_msg_buf(rx_buf, msg, !gi2c->err);
>  	}
>  }
> =20
> @@ -553,6 +553,7 @@ static int geni_i2c_gpi(struct geni_i2c_dev *gi2c, st=
ruct i2c_msg *msg,
>  	desc->callback_param =3D gi2c;
> =20
>  	dmaengine_submit(desc);
> +	*buf =3D dma_buf;
>  	*dma_addr_p =3D addr;
> =20
>  	return 0;
> --=20
> 2.25.1