[v7] rpmsg signaling/flowcontrol patches

[PATCH V7 2/3] rpmsg: glink: Add support to handle signals command

Posted by Sarannya S 2 years, 7 months ago

From: Chris Lew <quic_clew@quicinc.com>

Remote peripherals send signal notifications over glink with commandID 15.

Add support to send and receive the signal command and based signals
enable or disable flow control with remote host.

Signed-off-by: Chris Lew <quic_clew@quicinc.com>
Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
---
 drivers/rpmsg/qcom_glink_native.c | 64 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 01d2805..ff5e926 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -16,6 +16,7 @@
 #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>
 
@@ -197,9 +198,15 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops;
 #define GLINK_CMD_TX_DATA_CONT		12
 #define GLINK_CMD_READ_NOTIF		13
 #define GLINK_CMD_RX_DONE_W_REUSE	14
+#define GLINK_CMD_SIGNALS		15
 
 #define GLINK_FEATURE_INTENTLESS	BIT(1)
 
+#define NATIVE_DTR_SIG			NATIVE_DSR_SIG
+#define NATIVE_DSR_SIG			BIT(31)
+#define NATIVE_RTS_SIG			NATIVE_CTS_SIG
+#define NATIVE_CTS_SIG			BIT(30)
+
 static void qcom_glink_rx_done_work(struct work_struct *work);
 
 static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
@@ -1014,6 +1021,58 @@ 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
+ * @dst:	destination address of the endpoint
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool enable, u32 dst)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	struct glink_msg msg;
+	u32 sigs = 0;
+
+	if (enable)
+		sigs |= NATIVE_DTR_SIG | NATIVE_RTS_SIG;
+
+	msg.cmd = cpu_to_le16(GLINK_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;
+	bool enable = false;
+
+	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.flow_cb)
+		return 0;
+
+	if (sigs & (NATIVE_DSR_SIG | NATIVE_CTS_SIG))
+		enable = true;
+
+	channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
+
+	return 0;
+}
+
 void qcom_glink_native_rx(struct qcom_glink *glink)
 {
 	struct glink_msg msg;
@@ -1075,6 +1134,10 @@ void qcom_glink_native_rx(struct qcom_glink *glink)
 			qcom_glink_handle_intent_req_ack(glink, param1, param2);
 			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
 			break;
+		case GLINK_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;
@@ -1449,6 +1512,7 @@ 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)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH V7 2/3] rpmsg: glink: Add support to handle signals command

Posted by Bjorn Andersson 2 years, 6 months ago

On Sat, Apr 22, 2023 at 04:12:06PM +0530, Sarannya S wrote:
> From: Chris Lew <quic_clew@quicinc.com>
> 
> Remote peripherals send signal notifications over glink with commandID 15.
> 
> Add support to send and receive the signal command and based signals
> enable or disable flow control with remote host.
> 
> Signed-off-by: Chris Lew <quic_clew@quicinc.com>
> Signed-off-by: Deepak Kumar Singh <quic_deesin@quicinc.com>
> Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>
> ---
>  drivers/rpmsg/qcom_glink_native.c | 64 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 64 insertions(+)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index 01d2805..ff5e926 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -16,6 +16,7 @@
>  #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>
>  
> @@ -197,9 +198,15 @@ static const struct rpmsg_endpoint_ops glink_endpoint_ops;
>  #define GLINK_CMD_TX_DATA_CONT		12
>  #define GLINK_CMD_READ_NOTIF		13
>  #define GLINK_CMD_RX_DONE_W_REUSE	14
> +#define GLINK_CMD_SIGNALS		15
>  
>  #define GLINK_FEATURE_INTENTLESS	BIT(1)
>  
> +#define NATIVE_DTR_SIG			NATIVE_DSR_SIG
> +#define NATIVE_DSR_SIG			BIT(31)
> +#define NATIVE_RTS_SIG			NATIVE_CTS_SIG
> +#define NATIVE_CTS_SIG			BIT(30)
> +
>  static void qcom_glink_rx_done_work(struct work_struct *work);
>  
>  static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
> @@ -1014,6 +1021,58 @@ 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
> + * @dst:	destination address of the endpoint
> + *
> + * Return: 0 on success or standard Linux error code.
> + */
> +static int qcom_glink_set_flow_control(struct rpmsg_endpoint *ept, bool enable, u32 dst)
> +{
> +	struct glink_channel *channel = to_glink_channel(ept);
> +	struct qcom_glink *glink = channel->glink;
> +	struct glink_msg msg;
> +	u32 sigs = 0;
> +
> +	if (enable)
> +		sigs |= NATIVE_DTR_SIG | NATIVE_RTS_SIG;
> +
> +	msg.cmd = cpu_to_le16(GLINK_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;
> +	bool enable = false;
> +
> +	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;

You don't handle this return value, so this works fine. But the other
cases of returning an error to qcom_glink_native_rx() indicates that no
further messages should be processed (e.g. because there's no sufficient
data in the FIFO).

But getting a signal on a non-existing channel is not something that's
going to be resolved until we get the next interrupt, so I think you
shouldn't propagate this error.

Which means that it would be better to make the return type void of this
function.

> +	}
> +
> +	if (!channel->ept.flow_cb)
> +		return 0;
> +
> +	if (sigs & (NATIVE_DSR_SIG | NATIVE_CTS_SIG))
> +		enable = true;

I'd find it cleaner to skip the early initialization and have a single
point of assignment of enable, like:

	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;


And consolidate the flow_cb query/invocation to one place:
	if (channel->eptf.flow_cb)
		channel->ept.flow_cb(, enable);

Regards,
Bjorn

> +
> +	channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
> +
> +	return 0;
> +}
> +
>  void qcom_glink_native_rx(struct qcom_glink *glink)
>  {
>  	struct glink_msg msg;
> @@ -1075,6 +1134,10 @@ void qcom_glink_native_rx(struct qcom_glink *glink)
>  			qcom_glink_handle_intent_req_ack(glink, param1, param2);
>  			qcom_glink_rx_advance(glink, ALIGN(sizeof(msg), 8));
>  			break;
> +		case GLINK_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;
> @@ -1449,6 +1512,7 @@ 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)
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>

[PATCH V7 1/3] rpmsg: core: Add signal API support
[PATCH V7 2/3] rpmsg: glink: Add support to handle signals command
[PATCH V7 3/3] rpmsg: char: Add RPMSG GET/SET FLOWCONTROL IOCTL support