linux-kernel - Re: [PATCH V2 2/3] rpmsg: glink: Add support to handle signals command

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Message-ID: <Yiu6guYrKYRhGtei@builder.lan>
Date:   Fri, 11 Mar 2022 15:09:22 -0600
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Deepak Kumar Singh <quic_deesin@...cinc.com>
Cc:     swboyd@...omium.org, quic_clew@...cinc.com,
        mathieu.poirier@...aro.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        Andy Gross <agross@...nel.org>,
        Ohad Ben-Cohen <ohad@...ery.com>
Subject: Re: [PATCH V2 2/3] rpmsg: glink: Add support to handle signals
 command

On Tue 18 Jan 13:43 CST 2022, Deepak Kumar Singh wrote:

> Remote peripherals send signal notifications over glink with commandID 15.
> 
> Add support to send and receive the signal command and convert the signals
> from NATIVE to TIOCM while receiving and vice versa while sending.
> 
> Signed-off-by: Chris Lew <quic_clew@...cinc.com>

Co-developed-by: seems appropriate here, or you need to ensure the
author remains Chris, as his S-o-b comes first.

> Signed-off-by: Deepak Kumar Singh <quic_deesin@...cinc.com>
> ---
>  drivers/rpmsg/qcom_glink_native.c | 77 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 77 insertions(+)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index 3f377a7..d673d65 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -17,6 +17,7 @@
>  #include <linux/rpmsg.h>
>  #include <linux/sizes.h>
>  #include <linux/slab.h>
> +#include <linux/termios.h>
>  #include <linux/workqueue.h>
>  #include <linux/mailbox_client.h>
>  
> @@ -205,9 +206,16 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops;
>  #define RPM_CMD_TX_DATA_CONT		12
>  #define RPM_CMD_READ_NOTIF		13
>  #define RPM_CMD_RX_DONE_W_REUSE		14
> +#define RPM_CMD_SIGNALS			15
>  
>  #define GLINK_FEATURE_INTENTLESS	BIT(1)
>  
> +#define NATIVE_DTR_SIG			BIT(31)

Seems reasonable to prefix these with GLINK_, perhaps GLINK_SIGNAL_DTR?

> +#define NATIVE_CTS_SIG			BIT(30)
> +#define NATIVE_CD_SIG			BIT(29)
> +#define NATIVE_RI_SIG			BIT(28)
> +#define	SIG_MASK			0x0fff;
> +
>  static void qcom_glink_rx_done_work(struct work_struct *work);
>  
>  static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
> @@ -1003,6 +1011,70 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
>  	return 0;
>  }
>  
> +/**
> + * qcom_glink_set_flow_control() - convert a signal cmd to wire format and
> + * 				   transmit
> + * @ept:	Rpmsg endpoint for channel.
> + * @enable:	True/False - enable or disable flow control

"enable flow control" sounds sufficient (i.e. no need for True/False)
part.

Regards,
Bjorn

> + *
> + * Return: 0 on success or standard Linux error code.
> + */
> +static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool enable)
> +{
> +	struct glink_channel *channel = to_glink_channel(ept);
> +	struct qcom_glink *glink = channel->glink;
> +	struct glink_msg msg;
> +	u32 sigs;
> +
> +	/**
> +	 * convert signals from TIOCM to NATIVE
> +	 * sigs = TIOCM_DTR|TIOCM_RTS
> +	 */
> +	if (enable)
> +		sigs |= NATIVE_DTR_SIG | NATIVE_CTS_SIG;
> +	else
> +		sigs |= ~(NATIVE_DTR_SIG | NATIVE_CTS_SIG);
> +
> +	msg.cmd = cpu_to_le16(RPM_CMD_SIGNALS);
> +	msg.param1 = cpu_to_le16(channel->lcid);
> +	msg.param2 = cpu_to_le32(sigs);
> +
> +	return qcom_glink_tx(glink, &msg, sizeof(msg), NULL, 0, true);
> +}
> +
> +static int qcom_glink_handle_signals(struct qcom_glink *glink,
> +				     unsigned int rcid, unsigned int sigs)
> +{
> +	struct glink_channel *channel;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&glink->idr_lock, flags);
> +	channel = idr_find(&glink->rcids, rcid);
> +	spin_unlock_irqrestore(&glink->idr_lock, flags);
> +	if (!channel) {
> +		dev_err(glink->dev, "signal for non-existing channel\n");
> +		return -EINVAL;
> +	}
> +
> +	if (!channel->ept.sig_cb)
> +		return 0;
> +
> +	/* convert signals from NATIVE to TIOCM */
> +	if (sigs & NATIVE_DTR_SIG)
> +		sigs |= TIOCM_DSR;
> +	if (sigs & NATIVE_CTS_SIG)
> +		sigs |= TIOCM_CTS;
> +	if (sigs & NATIVE_CD_SIG)
> +		sigs |= TIOCM_CD;
> +	if (sigs & NATIVE_RI_SIG)
> +		sigs |= TIOCM_RI;
> +	sigs &= SIG_MASK;
> +
> +	channel->ept.sig_cb(channel->ept.rpdev, channel->ept.priv, sigs);
> +
> +	return 0;
> +}
> +
>  static irqreturn_t qcom_glink_native_intr(int irq, void *data)
>  {
>  	struct qcom_glink *glink = data;
> @@ -1067,6 +1139,10 @@ static irqreturn_t qcom_glink_native_intr(int irq, void *data)
>  			qcom_glink_handle_intent_req_ack(glink, param1, param2);
>  			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
>  			break;
> +		case RPM_CMD_SIGNALS:
> +			qcom_glink_handle_signals(glink, param1, param2);
> +			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
> +			break;
>  		default:
>  			dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
>  			ret = -EINVAL;
> @@ -1442,6 +1518,7 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
>  	.sendto = qcom_glink_sendto,
>  	.trysend = qcom_glink_trysend,
>  	.trysendto = qcom_glink_trysendto,
> +	.set_flow_control = qcom_glink_set_flow_control,
>  };
>  
>  static void qcom_glink_rpdev_release(struct device *dev)
> -- 
> 2.7.4
>