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15fd943af5
When inbound messages arrive, rpmsg core looks up their associated endpoint (by destination address) and then invokes their callback. We've made sure that endpoints will never be de-allocated after they were found by rpmsg core, but we also need to protect against the (rare) scenario where the rpmsg driver was just removed, and its callback function isn't available anymore. This is achieved by introducing a callback mutex, which must be taken before the callback is invoked, and, obviously, before it is removed. Cc: stable <stable@vger.kernel.org> Reported-by: Fernando Guzman Lugo <fernando.lugo@ti.com> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
332 lines
11 KiB
C
332 lines
11 KiB
C
/*
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* Remote processor messaging
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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* Copyright (C) 2011 Google, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name Texas Instruments nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _LINUX_RPMSG_H
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#define _LINUX_RPMSG_H
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#include <linux/types.h>
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#include <linux/device.h>
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#include <linux/mod_devicetable.h>
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#include <linux/kref.h>
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#include <linux/mutex.h>
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/* The feature bitmap for virtio rpmsg */
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#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
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/**
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* struct rpmsg_hdr - common header for all rpmsg messages
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* @src: source address
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* @dst: destination address
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* @reserved: reserved for future use
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* @len: length of payload (in bytes)
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* @flags: message flags
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* @data: @len bytes of message payload data
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*
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* Every message sent(/received) on the rpmsg bus begins with this header.
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*/
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struct rpmsg_hdr {
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u32 src;
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u32 dst;
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u32 reserved;
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u16 len;
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u16 flags;
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u8 data[0];
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} __packed;
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/**
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* struct rpmsg_ns_msg - dynamic name service announcement message
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* @name: name of remote service that is published
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* @addr: address of remote service that is published
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* @flags: indicates whether service is created or destroyed
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*
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* This message is sent across to publish a new service, or announce
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* about its removal. When we receive these messages, an appropriate
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* rpmsg channel (i.e device) is created/destroyed. In turn, the ->probe()
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* or ->remove() handler of the appropriate rpmsg driver will be invoked
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* (if/as-soon-as one is registered).
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*/
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struct rpmsg_ns_msg {
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char name[RPMSG_NAME_SIZE];
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u32 addr;
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u32 flags;
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} __packed;
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/**
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* enum rpmsg_ns_flags - dynamic name service announcement flags
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*
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* @RPMSG_NS_CREATE: a new remote service was just created
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* @RPMSG_NS_DESTROY: a known remote service was just destroyed
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*/
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enum rpmsg_ns_flags {
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RPMSG_NS_CREATE = 0,
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RPMSG_NS_DESTROY = 1,
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};
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#define RPMSG_ADDR_ANY 0xFFFFFFFF
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struct virtproc_info;
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/**
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* rpmsg_channel - devices that belong to the rpmsg bus are called channels
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* @vrp: the remote processor this channel belongs to
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* @dev: the device struct
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* @id: device id (used to match between rpmsg drivers and devices)
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* @src: local address
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* @dst: destination address
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* @ept: the rpmsg endpoint of this channel
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* @announce: if set, rpmsg will announce the creation/removal of this channel
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*/
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struct rpmsg_channel {
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struct virtproc_info *vrp;
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struct device dev;
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struct rpmsg_device_id id;
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u32 src;
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u32 dst;
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struct rpmsg_endpoint *ept;
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bool announce;
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};
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typedef void (*rpmsg_rx_cb_t)(struct rpmsg_channel *, void *, int, void *, u32);
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/**
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* struct rpmsg_endpoint - binds a local rpmsg address to its user
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* @rpdev: rpmsg channel device
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* @refcount: when this drops to zero, the ept is deallocated
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* @cb: rx callback handler
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* @cb_lock: must be taken before accessing/changing @cb
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* @addr: local rpmsg address
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* @priv: private data for the driver's use
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*
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* In essence, an rpmsg endpoint represents a listener on the rpmsg bus, as
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* it binds an rpmsg address with an rx callback handler.
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*
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* Simple rpmsg drivers shouldn't use this struct directly, because
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* things just work: every rpmsg driver provides an rx callback upon
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* registering to the bus, and that callback is then bound to its rpmsg
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* address when the driver is probed. When relevant inbound messages arrive
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* (i.e. messages which their dst address equals to the src address of
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* the rpmsg channel), the driver's handler is invoked to process it.
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*
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* More complicated drivers though, that do need to allocate additional rpmsg
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* addresses, and bind them to different rx callbacks, must explicitly
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* create additional endpoints by themselves (see rpmsg_create_ept()).
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*/
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struct rpmsg_endpoint {
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struct rpmsg_channel *rpdev;
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struct kref refcount;
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rpmsg_rx_cb_t cb;
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struct mutex cb_lock;
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u32 addr;
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void *priv;
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};
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/**
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* struct rpmsg_driver - rpmsg driver struct
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* @drv: underlying device driver
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* @id_table: rpmsg ids serviced by this driver
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* @probe: invoked when a matching rpmsg channel (i.e. device) is found
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* @remove: invoked when the rpmsg channel is removed
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* @callback: invoked when an inbound message is received on the channel
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*/
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struct rpmsg_driver {
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struct device_driver drv;
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const struct rpmsg_device_id *id_table;
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int (*probe)(struct rpmsg_channel *dev);
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void (*remove)(struct rpmsg_channel *dev);
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void (*callback)(struct rpmsg_channel *, void *, int, void *, u32);
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};
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int register_rpmsg_device(struct rpmsg_channel *dev);
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void unregister_rpmsg_device(struct rpmsg_channel *dev);
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int register_rpmsg_driver(struct rpmsg_driver *drv);
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void unregister_rpmsg_driver(struct rpmsg_driver *drv);
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void rpmsg_destroy_ept(struct rpmsg_endpoint *);
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struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *,
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rpmsg_rx_cb_t cb, void *priv, u32 addr);
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int
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rpmsg_send_offchannel_raw(struct rpmsg_channel *, u32, u32, void *, int, bool);
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/**
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* rpmsg_send() - send a message across to the remote processor
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* @rpdev: the rpmsg channel
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len on the @rpdev channel.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to, using @rpdev's source and destination addresses.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline int rpmsg_send(struct rpmsg_channel *rpdev, void *data, int len)
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{
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u32 src = rpdev->src, dst = rpdev->dst;
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
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}
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/**
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* rpmsg_sendto() - send a message across to the remote processor, specify dst
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* @rpdev: the rpmsg channel
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* @data: payload of message
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* @len: length of payload
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* @dst: destination address
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*
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* This function sends @data of length @len to the remote @dst address.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to, using @rpdev's source address.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline
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int rpmsg_sendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
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{
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u32 src = rpdev->src;
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
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}
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/**
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* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
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* @rpdev: the rpmsg channel
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* @src: source address
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* @dst: destination address
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len to the remote @dst address,
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* and uses @src as the source address.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to.
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* In case there are no TX buffers available, the function will block until
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* one becomes available, or a timeout of 15 seconds elapses. When the latter
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* happens, -ERESTARTSYS is returned.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline
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int rpmsg_send_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
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void *data, int len)
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{
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
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}
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/**
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* rpmsg_send() - send a message across to the remote processor
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* @rpdev: the rpmsg channel
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len on the @rpdev channel.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to, using @rpdev's source and destination addresses.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline
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int rpmsg_trysend(struct rpmsg_channel *rpdev, void *data, int len)
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{
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u32 src = rpdev->src, dst = rpdev->dst;
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
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}
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/**
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* rpmsg_sendto() - send a message across to the remote processor, specify dst
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* @rpdev: the rpmsg channel
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* @data: payload of message
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* @len: length of payload
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* @dst: destination address
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*
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* This function sends @data of length @len to the remote @dst address.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to, using @rpdev's source address.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline
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int rpmsg_trysendto(struct rpmsg_channel *rpdev, void *data, int len, u32 dst)
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{
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u32 src = rpdev->src;
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
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}
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/**
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* rpmsg_send_offchannel() - send a message using explicit src/dst addresses
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* @rpdev: the rpmsg channel
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* @src: source address
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* @dst: destination address
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* @data: payload of message
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* @len: length of payload
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*
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* This function sends @data of length @len to the remote @dst address,
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* and uses @src as the source address.
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* The message will be sent to the remote processor which the @rpdev
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* channel belongs to.
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* In case there are no TX buffers available, the function will immediately
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* return -ENOMEM without waiting until one becomes available.
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*
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* Can only be called from process context (for now).
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*
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* Returns 0 on success and an appropriate error value on failure.
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*/
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static inline
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int rpmsg_trysend_offchannel(struct rpmsg_channel *rpdev, u32 src, u32 dst,
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void *data, int len)
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{
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return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
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}
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#endif /* _LINUX_RPMSG_H */
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