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Date:   Tue, 17 Oct 2023 16:10:07 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Frank Li <Frank.Li@nxp.com>
Cc:     alexandre.belloni@bootlin.com, conor.culhane@silvaco.com,
        joe@perches.com, linux-i3c@lists.infradead.org,
        linux-kernel@vger.kernel.org, imx@lists.linux.dev
Subject: Re: [PATCH 4/5] i3c: master: svc return actual transfer data len
Message-ID: <20231017161007.146a5199@xps-13>
In-Reply-To: <20231016154632.2851957-5-Frank.Li@nxp.com>
References: <20231016154632.2851957-1-Frank.Li@nxp.com>
        <20231016154632.2851957-5-Frank.Li@nxp.com>
Organization: Bootlin
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Hi Frank,

Frank.Li@nxp.com wrote on Mon, 16 Oct 2023 11:46:31 -0400:

> I3C allow devices early terminate data transfer. So set "actual" to
> indicate how much data get by i3c_priv_xfer.
>=20
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/i3c/master/svc-i3c-master.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>=20
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc=
-i3c-master.c
> index 3570b709cf60..444825aafa6f 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -138,6 +138,7 @@ struct svc_i3c_cmd {
>  	const void *out;
>  	unsigned int len;
>  	unsigned int actual_len;
> +	struct i3c_priv_xfer *xfer;
>  	bool continued;
>  };
> =20
> @@ -1045,6 +1046,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_maste=
r *master,
> =20
>  	if (readl(master->regs + SVC_I3C_MERRWARN) & SVC_I3C_MERRWARN_NACK) {
>  		ret =3D -ENXIO;
> +		*actual_len =3D 0;
>  		goto emit_stop;
>  	}
> =20
> @@ -1062,6 +1064,7 @@ static int svc_i3c_master_xfer(struct svc_i3c_maste=
r *master,
>  	 */
>  	if (SVC_I3C_MSTATUS_IBIWON(reg)) {
>  		ret =3D -ENXIO;
> +		*actual_len =3D 0;
>  		goto emit_stop;
>  	}
> =20
> @@ -1157,6 +1160,9 @@ static void svc_i3c_master_start_xfer_locked(struct=
 svc_i3c_master *master)
>  					  cmd->addr, cmd->in, cmd->out,
>  					  cmd->len, &cmd->actual_len,
>  					  cmd->continued);
> +		if (cmd->xfer)
> +			cmd->xfer->actual =3D cmd->actual_len;

Just to be sure, wouldn't it be more natural to always fill cmd->xfer
rather than checking it here?

> +
>  		if (ret)
>  			break;
>  	}
> @@ -1344,6 +1350,7 @@ static int svc_i3c_master_priv_xfers(struct i3c_dev=
_desc *dev,
>  	for (i =3D 0; i < nxfers; i++) {
>  		struct svc_i3c_cmd *cmd =3D &xfer->cmds[i];
> =20
> +		cmd->xfer =3D xfers + i;

Please follow the same pattern as below: =3D &xfers[i]

>  		cmd->addr =3D master->addrs[data->index];
>  		cmd->rnw =3D xfers[i].rnw;
>  		cmd->in =3D xfers[i].rnw ? xfers[i].data.in : NULL;


Thanks,
Miqu=C3=A8l