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

Arun Kumar Neelakantam
2018-10-08T06:38:15Z

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 8122807..3d7458a 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 0d791c3..033656d 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.
*
@@ -46,6 +47,8 @@ struct rpmsg_device_ops {
* @trysend: see @rpmsg_trysend(), required
* @trysendto: see @rpmsg_trysendto(), optional
* @trysend_offchannel: see @rpmsg_trysend_offchannel(), 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
@@ -65,6 +68,8 @@ 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 */
--
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