[RESEND PATCH V4 1/4] rpmsg: core: Add signal API support

[RESEND PATCH V4 1/4] rpmsg: core: Add signal API support

[Arun Kumar Neelakantam]

Some transports like Glink support the state notifications between
clients using signals similar to serial protocol signals.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_core.c     | 41 +++++++++++++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h |  5 +++++
 include/linux/rpmsg.h          | 26 ++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index d6c3275..453790b 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -2,6 +2,7 @@
 /*
  * remote processor messaging bus
  *
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  *
@@ -283,6 +284,42 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 }
 EXPORT_SYMBOL(rpmsg_trysend_offchannel);
 
+/**
+ * rpmsg_get_signals() - get the signals for this endpoint
+ * @ept:	the rpmsg endpoint
+ *
+ * Returns signal bits on success and an appropriate error value on failure.
+ */
+int rpmsg_get_signals(struct rpmsg_endpoint *ept)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->get_signals)
+		return -EOPNOTSUPP;
+
+	return ept->ops->get_signals(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_signals);
+
+/**
+ * rpmsg_set_signals() - set the remote signals for this endpoint
+ * @ept:	the rpmsg endpoint
+ * @set:	set mask for signals
+ * @clear:	clear mask for signals
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_set_signals(struct rpmsg_endpoint *ept, u32 set, u32 clear)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->set_signals)
+		return -EOPNOTSUPP;
+
+	return ept->ops->set_signals(ept, set, clear);
+}
+EXPORT_SYMBOL(rpmsg_set_signals);
+
 /*
  * match an rpmsg channel with a channel info struct.
  * this is used to make sure we're not creating rpmsg devices for channels
@@ -468,6 +505,10 @@ static int rpmsg_dev_probe(struct device *dev)
 
 		rpdev->ept = ept;
 		rpdev->src = ept->addr;
+
+		if (rpdrv->signals)
+			ept->sig_cb = rpdrv->signals;
+
 	}
 
 	err = rpdrv->probe(rpdev);
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 3fc83cd..8958d6c 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -2,6 +2,7 @@
 /*
  * remote processor messaging bus internals
  *
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  *
@@ -47,6 +48,8 @@ struct rpmsg_device_ops {
  * @trysendto:		see @rpmsg_trysendto(), optional
  * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
  * @poll:		see @rpmsg_poll(), optional
+ * @get_signals:	see @rpmsg_get_signals(), optional
+ * @set_signals:	see @rpmsg_set_signals(), optional
  *
  * Indirection table for the operations that a rpmsg backend should implement.
  * In addition to @destroy_ept, the backend must at least implement @send and
@@ -66,6 +69,8 @@ struct rpmsg_endpoint_ops {
 			     void *data, int len);
 	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
 			     poll_table *wait);
+	int (*get_signals)(struct rpmsg_endpoint *ept);
+	int (*set_signals)(struct rpmsg_endpoint *ept, u32 set, u32 clear);
 };
 
 int rpmsg_register_device(struct rpmsg_device *rpdev);
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 9fe156d..48c8ae3 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -2,6 +2,7 @@
 /*
  * Remote processor messaging
  *
+ * Copyright (c) 2018 The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  * All rights reserved.
@@ -60,6 +61,7 @@ struct rpmsg_device {
 };
 
 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
+typedef int (*rpmsg_rx_sig_t)(struct rpmsg_device *, void *, u32, u32);
 
 /**
  * struct rpmsg_endpoint - binds a local rpmsg address to its user
@@ -67,6 +69,7 @@ struct rpmsg_device {
  * @refcount: when this drops to zero, the ept is deallocated
  * @cb: rx callback handler
  * @cb_lock: must be taken before accessing/changing @cb
+ * @sig_cb: rx serial signal handler
  * @addr: local rpmsg address
  * @priv: private data for the driver's use
  *
@@ -89,6 +92,7 @@ struct rpmsg_endpoint {
 	struct kref refcount;
 	rpmsg_rx_cb_t cb;
 	struct mutex cb_lock;
+	rpmsg_rx_sig_t sig_cb;
 	u32 addr;
 	void *priv;
 
@@ -102,6 +106,7 @@ struct rpmsg_endpoint {
  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
  * @remove: invoked when the rpmsg channel is removed
  * @callback: invoked when an inbound message is received on the channel
+ * @signals: invoked when a serial signal change is received on the channel
  */
 struct rpmsg_driver {
 	struct device_driver drv;
@@ -109,6 +114,7 @@ struct rpmsg_driver {
 	int (*probe)(struct rpmsg_device *dev);
 	void (*remove)(struct rpmsg_device *dev);
 	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
+	int (*signals)(struct rpmsg_device *, void *, u32, u32);
 };
 
 #if IS_ENABLED(CONFIG_RPMSG)
@@ -135,6 +141,9 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 			poll_table *wait);
 
+int rpmsg_get_signals(struct rpmsg_endpoint *ept);
+int rpmsg_set_signals(struct rpmsg_endpoint *ept, u32 set, u32 clear);
+
 #else
 
 static inline int register_rpmsg_device(struct rpmsg_device *dev)
@@ -242,6 +251,23 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
 	return 0;
 }
 
+static inline int rpmsg_get_signals(struct rpmsg_endpoint *ept)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_set_signals(struct rpmsg_endpoint *ept,
+				    u32 set, u32 clear)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 
 /* use a macro to avoid include chaining to get THIS_MODULE */
-- 
1.9.1

[RESEND PATCH V4 1/4] rpmsg: core: Add signal API support

[Arun Kumar Neelakantam]

Some transports like Glink support the state notifications between
clients using signals similar to serial protocol signals.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_core.c     | 41 +++++++++++++++++++++++++++++++++++++++++
 drivers/rpmsg/rpmsg_internal.h |  5 +++++
 include/linux/rpmsg.h          | 26 ++++++++++++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index d6c3275..453790b 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -2,6 +2,7 @@
 /*
  * remote processor messaging bus
  *
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  *
@@ -283,6 +284,42 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 }
 EXPORT_SYMBOL(rpmsg_trysend_offchannel);
 
+/**
+ * rpmsg_get_signals() - get the signals for this endpoint
+ * @ept:	the rpmsg endpoint
+ *
+ * Returns signal bits on success and an appropriate error value on failure.
+ */
+int rpmsg_get_signals(struct rpmsg_endpoint *ept)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->get_signals)
+		return -EOPNOTSUPP;
+
+	return ept->ops->get_signals(ept);
+}
+EXPORT_SYMBOL(rpmsg_get_signals);
+
+/**
+ * rpmsg_set_signals() - set the remote signals for this endpoint
+ * @ept:	the rpmsg endpoint
+ * @set:	set mask for signals
+ * @clear:	clear mask for signals
+ *
+ * Returns 0 on success and an appropriate error value on failure.
+ */
+int rpmsg_set_signals(struct rpmsg_endpoint *ept, u32 set, u32 clear)
+{
+	if (WARN_ON(!ept))
+		return -EINVAL;
+	if (!ept->ops->set_signals)
+		return -EOPNOTSUPP;
+
+	return ept->ops->set_signals(ept, set, clear);
+}
+EXPORT_SYMBOL(rpmsg_set_signals);
+
 /*
  * match an rpmsg channel with a channel info struct.
  * this is used to make sure we're not creating rpmsg devices for channels
@@ -468,6 +505,10 @@ static int rpmsg_dev_probe(struct device *dev)
 
 		rpdev->ept = ept;
 		rpdev->src = ept->addr;
+
+		if (rpdrv->signals)
+			ept->sig_cb = rpdrv->signals;
+
 	}
 
 	err = rpdrv->probe(rpdev);
diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 3fc83cd..8958d6c 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -2,6 +2,7 @@
 /*
  * remote processor messaging bus internals
  *
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  *
@@ -47,6 +48,8 @@ struct rpmsg_device_ops {
  * @trysendto:		see @rpmsg_trysendto(), optional
  * @trysend_offchannel:	see @rpmsg_trysend_offchannel(), optional
  * @poll:		see @rpmsg_poll(), optional
+ * @get_signals:	see @rpmsg_get_signals(), optional
+ * @set_signals:	see @rpmsg_set_signals(), optional
  *
  * Indirection table for the operations that a rpmsg backend should implement.
  * In addition to @destroy_ept, the backend must at least implement @send and
@@ -66,6 +69,8 @@ struct rpmsg_endpoint_ops {
 			     void *data, int len);
 	__poll_t (*poll)(struct rpmsg_endpoint *ept, struct file *filp,
 			     poll_table *wait);
+	int (*get_signals)(struct rpmsg_endpoint *ept);
+	int (*set_signals)(struct rpmsg_endpoint *ept, u32 set, u32 clear);
 };
 
 int rpmsg_register_device(struct rpmsg_device *rpdev);
diff --git a/include/linux/rpmsg.h b/include/linux/rpmsg.h
index 9fe156d..48c8ae3 100644
--- a/include/linux/rpmsg.h
+++ b/include/linux/rpmsg.h
@@ -2,6 +2,7 @@
 /*
  * Remote processor messaging
  *
+ * Copyright (c) 2018 The Linux Foundation.
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
  * All rights reserved.
@@ -60,6 +61,7 @@ struct rpmsg_device {
 };
 
 typedef int (*rpmsg_rx_cb_t)(struct rpmsg_device *, void *, int, void *, u32);
+typedef int (*rpmsg_rx_sig_t)(struct rpmsg_device *, void *, u32, u32);
 
 /**
  * struct rpmsg_endpoint - binds a local rpmsg address to its user
@@ -67,6 +69,7 @@ struct rpmsg_device {
  * @refcount: when this drops to zero, the ept is deallocated
  * @cb: rx callback handler
  * @cb_lock: must be taken before accessing/changing @cb
+ * @sig_cb: rx serial signal handler
  * @addr: local rpmsg address
  * @priv: private data for the driver's use
  *
@@ -89,6 +92,7 @@ struct rpmsg_endpoint {
 	struct kref refcount;
 	rpmsg_rx_cb_t cb;
 	struct mutex cb_lock;
+	rpmsg_rx_sig_t sig_cb;
 	u32 addr;
 	void *priv;
 
@@ -102,6 +106,7 @@ struct rpmsg_endpoint {
  * @probe: invoked when a matching rpmsg channel (i.e. device) is found
  * @remove: invoked when the rpmsg channel is removed
  * @callback: invoked when an inbound message is received on the channel
+ * @signals: invoked when a serial signal change is received on the channel
  */
 struct rpmsg_driver {
 	struct device_driver drv;
@@ -109,6 +114,7 @@ struct rpmsg_driver {
 	int (*probe)(struct rpmsg_device *dev);
 	void (*remove)(struct rpmsg_device *dev);
 	int (*callback)(struct rpmsg_device *, void *, int, void *, u32);
+	int (*signals)(struct rpmsg_device *, void *, u32, u32);
 };
 
 #if IS_ENABLED(CONFIG_RPMSG)
@@ -135,6 +141,9 @@ int rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src, u32 dst,
 __poll_t rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,
 			poll_table *wait);
 
+int rpmsg_get_signals(struct rpmsg_endpoint *ept);
+int rpmsg_set_signals(struct rpmsg_endpoint *ept, u32 set, u32 clear);
+
 #else
 
 static inline int register_rpmsg_device(struct rpmsg_device *dev)
@@ -242,6 +251,23 @@ static inline __poll_t rpmsg_poll(struct rpmsg_endpoint *ept,
 	return 0;
 }
 
+static inline int rpmsg_get_signals(struct rpmsg_endpoint *ept)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
+static inline int rpmsg_set_signals(struct rpmsg_endpoint *ept,
+				    u32 set, u32 clear)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+
+	return -ENXIO;
+}
+
 #endif /* IS_ENABLED(CONFIG_RPMSG) */
 
 /* use a macro to avoid include chaining to get THIS_MODULE */
-- 
1.9.1

[RESEND PATCH V4 2/4] rpmsg: glink: Add support to handle signals command

[Arun Kumar Neelakantam]

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 <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 126 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 0ff4cbe..59c80f9 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (c) 2016-2017, Linaro Ltd
  */
 
@@ -17,6 +18,7 @@
 #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>
 
@@ -150,6 +152,8 @@ enum {
  * @intent_req_lock: Synchronises multiple intent requests
  * @intent_req_result: Result of intent request
  * @intent_req_comp: Completion for intent_req signalling
+ * @lsigs:	local side signals
+ * @rsigs:	remote side signals
  */
 struct glink_channel {
 	struct rpmsg_endpoint ept;
@@ -181,6 +185,10 @@ struct glink_channel {
 	struct mutex intent_req_lock;
 	bool intent_req_result;
 	struct completion intent_req_comp;
+
+	unsigned int lsigs;
+	unsigned int rsigs;
+
 };
 
 #define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
@@ -201,9 +209,15 @@ struct glink_channel {
 #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)
+#define NATIVE_CTS_SIG	BIT(30)
+#define NATIVE_CD_SIG	BIT(29)
+#define NATIVE_RI_SIG	BIT(28)
+
 static void qcom_glink_rx_done_work(struct work_struct *work);
 
 static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
@@ -954,6 +968,76 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
 	return 0;
 }
 
+/**
+ * qcom_glink_send_signals() - convert a signal  cmd to wire format and transmit
+ * @glink:	The transport to transmit on.
+ * @channel:	The glink channel
+ * @sigs:	The signals to encode.
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_send_signals(struct qcom_glink *glink,
+				   struct glink_channel *channel,
+				   u32 sigs)
+{
+	struct glink_msg msg;
+
+	/* convert signals from TIOCM to NATIVE */
+	sigs &= 0x0fff;
+	if (sigs & TIOCM_DTR)
+		sigs |= NATIVE_DTR_SIG;
+	if (sigs & TIOCM_RTS)
+		sigs |= NATIVE_CTS_SIG;
+	if (sigs & TIOCM_CD)
+		sigs |= NATIVE_CD_SIG;
+	if (sigs & TIOCM_RI)
+		sigs |= NATIVE_RI_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 signals)
+{
+	struct glink_channel *channel;
+	unsigned long flags;
+	u32 old;
+
+	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;
+	}
+
+	old = channel->rsigs;
+
+	/* convert signals from NATIVE to TIOCM */
+	if (signals & NATIVE_DTR_SIG)
+		signals |= TIOCM_DSR;
+	if (signals & NATIVE_CTS_SIG)
+		signals |= TIOCM_CTS;
+	if (signals & NATIVE_CD_SIG)
+		signals |= TIOCM_CD;
+	if (signals & NATIVE_RI_SIG)
+		signals |= TIOCM_RI;
+	signals &= 0x0fff;
+
+	channel->rsigs = signals;
+
+	if (channel->ept.sig_cb) {
+		channel->ept.sig_cb(channel->ept.rpdev, channel->ept.priv,
+				    old, channel->rsigs);
+	}
+
+	return 0;
+}
+
 static irqreturn_t qcom_glink_native_intr(int irq, void *data)
 {
 	struct qcom_glink *glink = data;
@@ -1015,6 +1099,10 @@ 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;
@@ -1320,6 +1408,42 @@ static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 	return __qcom_glink_send(channel, data, len, false);
 }
 
+static int qcom_glink_get_sigs(struct rpmsg_endpoint *ept)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return channel->rsigs;
+}
+
+static int qcom_glink_set_sigs(struct rpmsg_endpoint *ept, u32 set, u32 clear)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	u32 sigs = channel->lsigs;
+
+	if (set & TIOCM_DTR)
+		sigs |= TIOCM_DTR;
+	if (set & TIOCM_RTS)
+		sigs |= TIOCM_RTS;
+	if (set & TIOCM_CD)
+		sigs |= TIOCM_CD;
+	if (set & TIOCM_RI)
+		sigs |= TIOCM_RI;
+
+	if (clear & TIOCM_DTR)
+		sigs &= ~TIOCM_DTR;
+	if (clear & TIOCM_RTS)
+		sigs &= ~TIOCM_RTS;
+	if (clear & TIOCM_CD)
+		sigs &= ~TIOCM_CD;
+	if (clear & TIOCM_RI)
+		sigs &= ~TIOCM_RI;
+
+	channel->lsigs = sigs;
+
+	return qcom_glink_send_signals(glink, channel, sigs);
+}
+
 /*
  * Finds the device_node for the glink child interested in this channel.
  */
@@ -1353,6 +1477,8 @@ static struct device_node *qcom_glink_match_channel(struct device_node *node,
 	.destroy_ept = qcom_glink_destroy_ept,
 	.send = qcom_glink_send,
 	.trysend = qcom_glink_trysend,
+	.get_signals = qcom_glink_get_sigs,
+	.set_signals = qcom_glink_set_sigs,
 };
 
 static void qcom_glink_rpdev_release(struct device *dev)
-- 
1.9.1

[RESEND PATCH V4 2/4] rpmsg: glink: Add support to handle signals command

[Arun Kumar Neelakantam]

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 <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 126 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 0ff4cbe..59c80f9 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (c) 2016-2017, Linaro Ltd
  */
 
@@ -17,6 +18,7 @@
 #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>
 
@@ -150,6 +152,8 @@ enum {
  * @intent_req_lock: Synchronises multiple intent requests
  * @intent_req_result: Result of intent request
  * @intent_req_comp: Completion for intent_req signalling
+ * @lsigs:	local side signals
+ * @rsigs:	remote side signals
  */
 struct glink_channel {
 	struct rpmsg_endpoint ept;
@@ -181,6 +185,10 @@ struct glink_channel {
 	struct mutex intent_req_lock;
 	bool intent_req_result;
 	struct completion intent_req_comp;
+
+	unsigned int lsigs;
+	unsigned int rsigs;
+
 };
 
 #define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
@@ -201,9 +209,15 @@ struct glink_channel {
 #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)
+#define NATIVE_CTS_SIG	BIT(30)
+#define NATIVE_CD_SIG	BIT(29)
+#define NATIVE_RI_SIG	BIT(28)
+
 static void qcom_glink_rx_done_work(struct work_struct *work);
 
 static struct glink_channel *qcom_glink_alloc_channel(struct qcom_glink *glink,
@@ -954,6 +968,76 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
 	return 0;
 }
 
+/**
+ * qcom_glink_send_signals() - convert a signal  cmd to wire format and transmit
+ * @glink:	The transport to transmit on.
+ * @channel:	The glink channel
+ * @sigs:	The signals to encode.
+ *
+ * Return: 0 on success or standard Linux error code.
+ */
+static int qcom_glink_send_signals(struct qcom_glink *glink,
+				   struct glink_channel *channel,
+				   u32 sigs)
+{
+	struct glink_msg msg;
+
+	/* convert signals from TIOCM to NATIVE */
+	sigs &= 0x0fff;
+	if (sigs & TIOCM_DTR)
+		sigs |= NATIVE_DTR_SIG;
+	if (sigs & TIOCM_RTS)
+		sigs |= NATIVE_CTS_SIG;
+	if (sigs & TIOCM_CD)
+		sigs |= NATIVE_CD_SIG;
+	if (sigs & TIOCM_RI)
+		sigs |= NATIVE_RI_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 signals)
+{
+	struct glink_channel *channel;
+	unsigned long flags;
+	u32 old;
+
+	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;
+	}
+
+	old = channel->rsigs;
+
+	/* convert signals from NATIVE to TIOCM */
+	if (signals & NATIVE_DTR_SIG)
+		signals |= TIOCM_DSR;
+	if (signals & NATIVE_CTS_SIG)
+		signals |= TIOCM_CTS;
+	if (signals & NATIVE_CD_SIG)
+		signals |= TIOCM_CD;
+	if (signals & NATIVE_RI_SIG)
+		signals |= TIOCM_RI;
+	signals &= 0x0fff;
+
+	channel->rsigs = signals;
+
+	if (channel->ept.sig_cb) {
+		channel->ept.sig_cb(channel->ept.rpdev, channel->ept.priv,
+				    old, channel->rsigs);
+	}
+
+	return 0;
+}
+
 static irqreturn_t qcom_glink_native_intr(int irq, void *data)
 {
 	struct qcom_glink *glink = data;
@@ -1015,6 +1099,10 @@ 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;
@@ -1320,6 +1408,42 @@ static int qcom_glink_trysend(struct rpmsg_endpoint *ept, void *data, int len)
 	return __qcom_glink_send(channel, data, len, false);
 }
 
+static int qcom_glink_get_sigs(struct rpmsg_endpoint *ept)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+
+	return channel->rsigs;
+}
+
+static int qcom_glink_set_sigs(struct rpmsg_endpoint *ept, u32 set, u32 clear)
+{
+	struct glink_channel *channel = to_glink_channel(ept);
+	struct qcom_glink *glink = channel->glink;
+	u32 sigs = channel->lsigs;
+
+	if (set & TIOCM_DTR)
+		sigs |= TIOCM_DTR;
+	if (set & TIOCM_RTS)
+		sigs |= TIOCM_RTS;
+	if (set & TIOCM_CD)
+		sigs |= TIOCM_CD;
+	if (set & TIOCM_RI)
+		sigs |= TIOCM_RI;
+
+	if (clear & TIOCM_DTR)
+		sigs &= ~TIOCM_DTR;
+	if (clear & TIOCM_RTS)
+		sigs &= ~TIOCM_RTS;
+	if (clear & TIOCM_CD)
+		sigs &= ~TIOCM_CD;
+	if (clear & TIOCM_RI)
+		sigs &= ~TIOCM_RI;
+
+	channel->lsigs = sigs;
+
+	return qcom_glink_send_signals(glink, channel, sigs);
+}
+
 /*
  * Finds the device_node for the glink child interested in this channel.
  */
@@ -1353,6 +1477,8 @@ static struct device_node *qcom_glink_match_channel(struct device_node *node,
 	.destroy_ept = qcom_glink_destroy_ept,
 	.send = qcom_glink_send,
 	.trysend = qcom_glink_trysend,
+	.get_signals = qcom_glink_get_sigs,
+	.set_signals = qcom_glink_set_sigs,
 };
 
 static void qcom_glink_rpdev_release(struct device *dev)
-- 
1.9.1

[RESEND PATCH V4 3/4] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

[Arun Kumar Neelakantam]

Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes
to get/set the low level transport signals.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_char.c | 53 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index eea5ebb..07bce51 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (c) 2016, Linaro Ltd.
  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
  * Copyright (c) 2012, PetaLogix
@@ -19,6 +20,7 @@
 #include <linux/rpmsg.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
+#include <linux/termios.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/rpmsg.h>
 
@@ -271,15 +273,60 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 	return mask;
 }
 
+static int rpmsg_eptdev_tiocmset(struct file *fp, unsigned int cmd,
+				 int __user *arg)
+{
+	struct rpmsg_eptdev *eptdev = fp->private_data;
+	u32 set, clear, val;
+	int ret;
+
+	ret = get_user(val, arg);
+	if (ret)
+		return ret;
+	set = clear = 0;
+	switch (cmd) {
+	case TIOCMBIS:
+		set = val;
+		break;
+	case TIOCMBIC:
+		clear = val;
+		break;
+	case TIOCMSET:
+		set = val;
+		clear = ~val;
+		break;
+	}
+
+	set &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
+	clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
+
+	return rpmsg_set_signals(eptdev->ept, set, clear);
+}
+
 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 			       unsigned long arg)
 {
 	struct rpmsg_eptdev *eptdev = fp->private_data;
+	int ret;
 
-	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
-		return -EINVAL;
+	switch (cmd) {
+	case TIOCMGET:
+		ret = rpmsg_get_signals(eptdev->ept);
+		if (ret >= 0)
+			ret = put_user(ret, (int __user *)arg);
+		break;
+	case TIOCMSET:
+	case TIOCMBIS:
+	case TIOCMBIC:
+		ret = rpmsg_eptdev_tiocmset(fp, cmd, (int __user *)arg);
+		break;
+	case RPMSG_DESTROY_EPT_IOCTL:
+		ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
+	default:
+		ret = -EINVAL;
+	}
 
-	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
+	return ret;
 }
 
 static const struct file_operations rpmsg_eptdev_fops = {
-- 
1.9.1

Re: [RESEND PATCH V4 3/4] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2399 bytes --]

Hi Arun,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[also build test WARNING on v5.4-rc8 next-20191122]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Arun-Kumar-Neelakantam/rpmsg-core-Add-signal-API-support/20191124-174653
base:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 6b8a794678763130b7e7d049985008641dc494e8
config: riscv-defconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=riscv 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   drivers/rpmsg/rpmsg_char.c: In function 'rpmsg_eptdev_ioctl':
>> drivers/rpmsg/rpmsg_char.c:324:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
      ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
      ~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/rpmsg/rpmsg_char.c:325:2: note: here
     default:
     ^~~~~~~

vim +324 drivers/rpmsg/rpmsg_char.c

   305	
   306	static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
   307				       unsigned long arg)
   308	{
   309		struct rpmsg_eptdev *eptdev = fp->private_data;
   310		int ret;
   311	
   312		switch (cmd) {
   313		case TIOCMGET:
   314			ret = rpmsg_get_signals(eptdev->ept);
   315			if (ret >= 0)
   316				ret = put_user(ret, (int __user *)arg);
   317			break;
   318		case TIOCMSET:
   319		case TIOCMBIS:
   320		case TIOCMBIC:
   321			ret = rpmsg_eptdev_tiocmset(fp, cmd, (int __user *)arg);
   322			break;
   323		case RPMSG_DESTROY_EPT_IOCTL:
 > 324			ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
   325		default:
   326			ret = -EINVAL;
   327		}
   328	
   329		return ret;
   330	}
   331	

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 18623 bytes --]

[RESEND PATCH V4 3/4] rpmsg: char: Add TIOCMGET/TIOCMSET ioctl support

[Arun Kumar Neelakantam]

Add TICOMGET and TIOCMSET ioctl support for rpmsg char device nodes
to get/set the low level transport signals.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_char.c | 53 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index eea5ebb..07bce51 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
+ * Copyright (c) 2018, The Linux Foundation.
  * Copyright (c) 2016, Linaro Ltd.
  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
  * Copyright (c) 2012, PetaLogix
@@ -19,6 +20,7 @@
 #include <linux/rpmsg.h>
 #include <linux/skbuff.h>
 #include <linux/slab.h>
+#include <linux/termios.h>
 #include <linux/uaccess.h>
 #include <uapi/linux/rpmsg.h>
 
@@ -271,15 +273,60 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 	return mask;
 }
 
+static int rpmsg_eptdev_tiocmset(struct file *fp, unsigned int cmd,
+				 int __user *arg)
+{
+	struct rpmsg_eptdev *eptdev = fp->private_data;
+	u32 set, clear, val;
+	int ret;
+
+	ret = get_user(val, arg);
+	if (ret)
+		return ret;
+	set = clear = 0;
+	switch (cmd) {
+	case TIOCMBIS:
+		set = val;
+		break;
+	case TIOCMBIC:
+		clear = val;
+		break;
+	case TIOCMSET:
+		set = val;
+		clear = ~val;
+		break;
+	}
+
+	set &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
+	clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_CD | TIOCM_RI;
+
+	return rpmsg_set_signals(eptdev->ept, set, clear);
+}
+
 static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 			       unsigned long arg)
 {
 	struct rpmsg_eptdev *eptdev = fp->private_data;
+	int ret;
 
-	if (cmd != RPMSG_DESTROY_EPT_IOCTL)
-		return -EINVAL;
+	switch (cmd) {
+	case TIOCMGET:
+		ret = rpmsg_get_signals(eptdev->ept);
+		if (ret >= 0)
+			ret = put_user(ret, (int __user *)arg);
+		break;
+	case TIOCMSET:
+	case TIOCMBIS:
+	case TIOCMBIC:
+		ret = rpmsg_eptdev_tiocmset(fp, cmd, (int __user *)arg);
+		break;
+	case RPMSG_DESTROY_EPT_IOCTL:
+		ret = rpmsg_eptdev_destroy(&eptdev->dev, NULL);
+	default:
+		ret = -EINVAL;
+	}
 
-	return rpmsg_eptdev_destroy(&eptdev->dev, NULL);
+	return ret;
 }
 
 static const struct file_operations rpmsg_eptdev_fops = {
-- 
1.9.1

[RESEND PATCH V4 4/4] rpmsg: char: Add signal callback and POLLPRI support

[Arun Kumar Neelakantam]

Register a callback to get the signal notifications from rpmsg and
send POLLPRI mask to indicate the signal change in POLL system call.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_char.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 07bce51..8446c0b 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -64,6 +64,7 @@ struct rpmsg_ctrldev {
  * @queue_lock:	synchronization of @queue operations
  * @queue:	incoming message queue
  * @readq:	wait object for incoming queue
+ * @sig_pending:state of signal notification
  */
 struct rpmsg_eptdev {
 	struct device dev;
@@ -78,6 +79,8 @@ struct rpmsg_eptdev {
 	spinlock_t queue_lock;
 	struct sk_buff_head queue;
 	wait_queue_head_t readq;
+
+	bool sig_pending;
 };
 
 static int rpmsg_eptdev_destroy(struct device *dev, void *data)
@@ -122,6 +125,18 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
 	return 0;
 }
 
+static int rpmsg_sigs_cb(struct rpmsg_device *rpdev, void *priv,
+			 u32 old, u32 new)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+
+	eptdev->sig_pending = true;
+
+	/* wake up any blocking processes, waiting for signal notification */
+	wake_up_interruptible(&eptdev->readq);
+	return 0;
+}
+
 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 {
 	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
@@ -138,6 +153,7 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 		return -EINVAL;
 	}
 
+	ept->sig_cb = rpmsg_sigs_cb;
 	eptdev->ept = ept;
 	filp->private_data = eptdev;
 
@@ -157,6 +173,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 		eptdev->ept = NULL;
 	}
 	mutex_unlock(&eptdev->ept_lock);
+	eptdev->sig_pending = false;
 
 	/* Discard all SKBs */
 	while (!skb_queue_empty(&eptdev->queue)) {
@@ -268,6 +285,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 	if (!skb_queue_empty(&eptdev->queue))
 		mask |= EPOLLIN | EPOLLRDNORM;
 
+	if (eptdev->sig_pending)
+		mask |= POLLPRI;
+
 	mask |= rpmsg_poll(eptdev->ept, filp, wait);
 
 	return mask;
@@ -311,6 +331,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 
 	switch (cmd) {
 	case TIOCMGET:
+		eptdev->sig_pending = false;
 		ret = rpmsg_get_signals(eptdev->ept);
 		if (ret >= 0)
 			ret = put_user(ret, (int __user *)arg);
-- 
1.9.1

[RESEND PATCH V4 4/4] rpmsg: char: Add signal callback and POLLPRI support

[Arun Kumar Neelakantam]

Register a callback to get the signal notifications from rpmsg and
send POLLPRI mask to indicate the signal change in POLL system call.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_char.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 07bce51..8446c0b 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -64,6 +64,7 @@ struct rpmsg_ctrldev {
  * @queue_lock:	synchronization of @queue operations
  * @queue:	incoming message queue
  * @readq:	wait object for incoming queue
+ * @sig_pending:state of signal notification
  */
 struct rpmsg_eptdev {
 	struct device dev;
@@ -78,6 +79,8 @@ struct rpmsg_eptdev {
 	spinlock_t queue_lock;
 	struct sk_buff_head queue;
 	wait_queue_head_t readq;
+
+	bool sig_pending;
 };
 
 static int rpmsg_eptdev_destroy(struct device *dev, void *data)
@@ -122,6 +125,18 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len,
 	return 0;
 }
 
+static int rpmsg_sigs_cb(struct rpmsg_device *rpdev, void *priv,
+			 u32 old, u32 new)
+{
+	struct rpmsg_eptdev *eptdev = priv;
+
+	eptdev->sig_pending = true;
+
+	/* wake up any blocking processes, waiting for signal notification */
+	wake_up_interruptible(&eptdev->readq);
+	return 0;
+}
+
 static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 {
 	struct rpmsg_eptdev *eptdev = cdev_to_eptdev(inode->i_cdev);
@@ -138,6 +153,7 @@ static int rpmsg_eptdev_open(struct inode *inode, struct file *filp)
 		return -EINVAL;
 	}
 
+	ept->sig_cb = rpmsg_sigs_cb;
 	eptdev->ept = ept;
 	filp->private_data = eptdev;
 
@@ -157,6 +173,7 @@ static int rpmsg_eptdev_release(struct inode *inode, struct file *filp)
 		eptdev->ept = NULL;
 	}
 	mutex_unlock(&eptdev->ept_lock);
+	eptdev->sig_pending = false;
 
 	/* Discard all SKBs */
 	while (!skb_queue_empty(&eptdev->queue)) {
@@ -268,6 +285,9 @@ static __poll_t rpmsg_eptdev_poll(struct file *filp, poll_table *wait)
 	if (!skb_queue_empty(&eptdev->queue))
 		mask |= EPOLLIN | EPOLLRDNORM;
 
+	if (eptdev->sig_pending)
+		mask |= POLLPRI;
+
 	mask |= rpmsg_poll(eptdev->ept, filp, wait);
 
 	return mask;
@@ -311,6 +331,7 @@ static long rpmsg_eptdev_ioctl(struct file *fp, unsigned int cmd,
 
 	switch (cmd) {
 	case TIOCMGET:
+		eptdev->sig_pending = false;
 		ret = rpmsg_get_signals(eptdev->ept);
 		if (ret >= 0)
 			ret = put_user(ret, (int __user *)arg);
-- 
1.9.1