rpmsg: glink: Add support to handle signals command

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>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/1688679698-31274-3-git-send-email-quic_sarannya@quicinc.com
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 1beb40a..2db82f6 100644 (file)
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -200,9 +200,15 @@ 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,
@@ -1025,6 +1031,50 @@ 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.
+ * @pause:     Pause transmission
+ * @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 pause, u32 dst)
+{
+       struct glink_channel *channel = to_glink_channel(ept);
+       struct qcom_glink *glink = channel->glink;
+       struct glink_msg msg;
+       u32 sigs = 0;
+
+       if (pause)
+               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 void qcom_glink_handle_signals(struct qcom_glink *glink,
+                                     unsigned int rcid, unsigned int sigs)
+{
+       struct glink_channel *channel;
+       unsigned long flags;
+       bool enable;
+
+       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");
+
+       enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;
+
+       if (channel->ept.flow_cb)
+               channel->ept.flow_cb(channel->ept.rpdev, channel->ept.priv, enable);
+}
+
 void qcom_glink_native_rx(struct qcom_glink *glink)
 {
        struct glink_msg msg;
@@ -1086,6 +1136,10 @@ 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;
@@ -1446,6 +1500,7 @@ 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)