1146 строки
32 KiB
C
1146 строки
32 KiB
C
/*
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* Virtio-based remote processor messaging bus
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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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*
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* Ohad Ben-Cohen <ohad@wizery.com>
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* Brian Swetland <swetland@google.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) "%s: " fmt, __func__
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/virtio.h>
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#include <linux/virtio_ids.h>
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#include <linux/virtio_config.h>
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#include <linux/scatterlist.h>
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#include <linux/dma-mapping.h>
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <linux/jiffies.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/rpmsg.h>
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#include <linux/mutex.h>
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/**
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* struct virtproc_info - virtual remote processor state
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* @vdev: the virtio device
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* @rvq: rx virtqueue
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* @svq: tx virtqueue
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* @rbufs: kernel address of rx buffers
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* @sbufs: kernel address of tx buffers
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* @num_bufs: total number of buffers for rx and tx
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* @last_sbuf: index of last tx buffer used
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* @bufs_dma: dma base addr of the buffers
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* @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
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* sending a message might require waking up a dozing remote
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* processor, which involves sleeping, hence the mutex.
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* @endpoints: idr of local endpoints, allows fast retrieval
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* @endpoints_lock: lock of the endpoints set
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* @sendq: wait queue of sending contexts waiting for a tx buffers
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* @sleepers: number of senders that are waiting for a tx buffer
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* @ns_ept: the bus's name service endpoint
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*
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* This structure stores the rpmsg state of a given virtio remote processor
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* device (there might be several virtio proc devices for each physical
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* remote processor).
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*/
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struct virtproc_info {
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struct virtio_device *vdev;
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struct virtqueue *rvq, *svq;
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void *rbufs, *sbufs;
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unsigned int num_bufs;
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int last_sbuf;
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dma_addr_t bufs_dma;
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struct mutex tx_lock;
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struct idr endpoints;
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struct mutex endpoints_lock;
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wait_queue_head_t sendq;
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atomic_t sleepers;
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struct rpmsg_endpoint *ns_ept;
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};
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/**
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* struct rpmsg_channel_info - internal channel info representation
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* @name: name of service
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* @src: local address
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* @dst: destination address
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*/
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struct rpmsg_channel_info {
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char name[RPMSG_NAME_SIZE];
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u32 src;
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u32 dst;
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};
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#define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev)
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#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
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/*
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* We're allocating buffers of 512 bytes each for communications. The
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* number of buffers will be computed from the number of buffers supported
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* by the vring, upto a maximum of 512 buffers (256 in each direction).
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*
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* Each buffer will have 16 bytes for the msg header and 496 bytes for
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* the payload.
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*
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* This will utilize a maximum total space of 256KB for the buffers.
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*
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* We might also want to add support for user-provided buffers in time.
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* This will allow bigger buffer size flexibility, and can also be used
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* to achieve zero-copy messaging.
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*
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* Note that these numbers are purely a decision of this driver - we
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* can change this without changing anything in the firmware of the remote
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* processor.
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*/
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#define MAX_RPMSG_NUM_BUFS (512)
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#define RPMSG_BUF_SIZE (512)
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/*
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* Local addresses are dynamically allocated on-demand.
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* We do not dynamically assign addresses from the low 1024 range,
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* in order to reserve that address range for predefined services.
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*/
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#define RPMSG_RESERVED_ADDRESSES (1024)
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/* Address 53 is reserved for advertising remote services */
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#define RPMSG_NS_ADDR (53)
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/* sysfs show configuration fields */
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#define rpmsg_show_attr(field, path, format_string) \
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static ssize_t \
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field##_show(struct device *dev, \
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struct device_attribute *attr, char *buf) \
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{ \
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \
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\
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return sprintf(buf, format_string, rpdev->path); \
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}
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/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
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rpmsg_show_attr(name, id.name, "%s\n");
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rpmsg_show_attr(src, src, "0x%x\n");
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rpmsg_show_attr(dst, dst, "0x%x\n");
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rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
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/*
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* Unique (and free running) index for rpmsg devices.
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*
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* Yeah, we're not recycling those numbers (yet?). will be easy
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* to change if/when we want to.
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*/
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static unsigned int rpmsg_dev_index;
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static ssize_t modalias_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
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}
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static struct device_attribute rpmsg_dev_attrs[] = {
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__ATTR_RO(name),
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__ATTR_RO(modalias),
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__ATTR_RO(dst),
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__ATTR_RO(src),
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__ATTR_RO(announce),
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__ATTR_NULL
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};
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/* rpmsg devices and drivers are matched using the service name */
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static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev,
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const struct rpmsg_device_id *id)
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{
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return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
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}
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/* match rpmsg channel and rpmsg driver */
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static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
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const struct rpmsg_device_id *ids = rpdrv->id_table;
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unsigned int i;
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for (i = 0; ids[i].name[0]; i++)
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if (rpmsg_id_match(rpdev, &ids[i]))
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return 1;
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return 0;
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}
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static int rpmsg_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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return add_uevent_var(env, "MODALIAS=" RPMSG_DEVICE_MODALIAS_FMT,
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rpdev->id.name);
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}
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/**
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* __ept_release() - deallocate an rpmsg endpoint
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* @kref: the ept's reference count
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*
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* This function deallocates an ept, and is invoked when its @kref refcount
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* drops to zero.
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*
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* Never invoke this function directly!
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*/
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static void __ept_release(struct kref *kref)
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{
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struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
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refcount);
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/*
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* At this point no one holds a reference to ept anymore,
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* so we can directly free it
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*/
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kfree(ept);
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}
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/* for more info, see below documentation of rpmsg_create_ept() */
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static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
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struct rpmsg_channel *rpdev, rpmsg_rx_cb_t cb,
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void *priv, u32 addr)
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{
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int id_min, id_max, id;
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struct rpmsg_endpoint *ept;
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struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
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ept = kzalloc(sizeof(*ept), GFP_KERNEL);
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if (!ept) {
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dev_err(dev, "failed to kzalloc a new ept\n");
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return NULL;
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}
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kref_init(&ept->refcount);
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mutex_init(&ept->cb_lock);
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ept->rpdev = rpdev;
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ept->cb = cb;
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ept->priv = priv;
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/* do we need to allocate a local address ? */
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if (addr == RPMSG_ADDR_ANY) {
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id_min = RPMSG_RESERVED_ADDRESSES;
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id_max = 0;
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} else {
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id_min = addr;
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id_max = addr + 1;
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}
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mutex_lock(&vrp->endpoints_lock);
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/* bind the endpoint to an rpmsg address (and allocate one if needed) */
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id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL);
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if (id < 0) {
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dev_err(dev, "idr_alloc failed: %d\n", id);
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goto free_ept;
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}
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ept->addr = id;
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mutex_unlock(&vrp->endpoints_lock);
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return ept;
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free_ept:
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mutex_unlock(&vrp->endpoints_lock);
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kref_put(&ept->refcount, __ept_release);
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return NULL;
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}
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/**
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* rpmsg_create_ept() - create a new rpmsg_endpoint
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* @rpdev: rpmsg channel device
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* @cb: rx callback handler
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* @priv: private data for the driver's use
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* @addr: local rpmsg address to bind with @cb
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*
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* Every rpmsg address in the system is bound to an rx callback (so when
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* inbound messages arrive, they are dispatched by the rpmsg bus using the
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* appropriate callback handler) by means of an rpmsg_endpoint struct.
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*
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* This function allows drivers to create such an endpoint, and by that,
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* bind a callback, and possibly some private data too, to an rpmsg address
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* (either one that is known in advance, or one that will be dynamically
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* assigned for them).
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*
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* Simple rpmsg drivers need not call rpmsg_create_ept, because an endpoint
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* is already created for them when they are probed by the rpmsg bus
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* (using the rx callback provided when they registered to the rpmsg bus).
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*
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* So things should just work for simple drivers: they already have an
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* endpoint, their rx callback is bound to their rpmsg address, and when
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* relevant inbound messages arrive (i.e. messages which their dst address
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* equals to the src address of their rpmsg channel), the driver's handler
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* is invoked to process it.
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*
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* That said, more complicated drivers might do need to allocate
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* additional rpmsg addresses, and bind them to different rx callbacks.
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* To accomplish that, those drivers need to call this function.
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*
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* Drivers should provide their @rpdev channel (so the new endpoint would belong
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* to the same remote processor their channel belongs to), an rx callback
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* function, an optional private data (which is provided back when the
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* rx callback is invoked), and an address they want to bind with the
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* callback. If @addr is RPMSG_ADDR_ANY, then rpmsg_create_ept will
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* dynamically assign them an available rpmsg address (drivers should have
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* a very good reason why not to always use RPMSG_ADDR_ANY here).
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*
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* Returns a pointer to the endpoint on success, or NULL on error.
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*/
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struct rpmsg_endpoint *rpmsg_create_ept(struct rpmsg_channel *rpdev,
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rpmsg_rx_cb_t cb, void *priv, u32 addr)
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{
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return __rpmsg_create_ept(rpdev->vrp, rpdev, cb, priv, addr);
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}
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EXPORT_SYMBOL(rpmsg_create_ept);
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/**
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* __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
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* @vrp: virtproc which owns this ept
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* @ept: endpoing to destroy
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*
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* An internal function which destroy an ept without assuming it is
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* bound to an rpmsg channel. This is needed for handling the internal
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* name service endpoint, which isn't bound to an rpmsg channel.
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* See also __rpmsg_create_ept().
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*/
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static void
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__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
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{
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/* make sure new inbound messages can't find this ept anymore */
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mutex_lock(&vrp->endpoints_lock);
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idr_remove(&vrp->endpoints, ept->addr);
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mutex_unlock(&vrp->endpoints_lock);
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/* make sure in-flight inbound messages won't invoke cb anymore */
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mutex_lock(&ept->cb_lock);
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ept->cb = NULL;
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mutex_unlock(&ept->cb_lock);
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kref_put(&ept->refcount, __ept_release);
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}
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/**
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* rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
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* @ept: endpoing to destroy
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*
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* Should be used by drivers to destroy an rpmsg endpoint previously
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* created with rpmsg_create_ept().
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*/
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void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
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{
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__rpmsg_destroy_ept(ept->rpdev->vrp, ept);
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}
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EXPORT_SYMBOL(rpmsg_destroy_ept);
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/*
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* when an rpmsg driver is probed with a channel, we seamlessly create
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* it an endpoint, binding its rx callback to a unique local rpmsg
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* address.
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*
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* if we need to, we also announce about this channel to the remote
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* processor (needed in case the driver is exposing an rpmsg service).
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*/
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static int rpmsg_dev_probe(struct device *dev)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
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struct virtproc_info *vrp = rpdev->vrp;
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struct rpmsg_endpoint *ept;
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int err;
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ept = rpmsg_create_ept(rpdev, rpdrv->callback, NULL, rpdev->src);
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if (!ept) {
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dev_err(dev, "failed to create endpoint\n");
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err = -ENOMEM;
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goto out;
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}
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rpdev->ept = ept;
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rpdev->src = ept->addr;
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err = rpdrv->probe(rpdev);
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if (err) {
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dev_err(dev, "%s: failed: %d\n", __func__, err);
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rpmsg_destroy_ept(ept);
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goto out;
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}
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/* need to tell remote processor's name service about this channel ? */
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if (rpdev->announce &&
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virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
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struct rpmsg_ns_msg nsm;
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strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
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nsm.addr = rpdev->src;
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nsm.flags = RPMSG_NS_CREATE;
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err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
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if (err)
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dev_err(dev, "failed to announce service %d\n", err);
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}
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out:
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return err;
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}
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static int rpmsg_dev_remove(struct device *dev)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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struct rpmsg_driver *rpdrv = to_rpmsg_driver(rpdev->dev.driver);
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struct virtproc_info *vrp = rpdev->vrp;
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int err = 0;
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/* tell remote processor's name service we're removing this channel */
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if (rpdev->announce &&
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virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
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struct rpmsg_ns_msg nsm;
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strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
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nsm.addr = rpdev->src;
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nsm.flags = RPMSG_NS_DESTROY;
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err = rpmsg_sendto(rpdev, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
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if (err)
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dev_err(dev, "failed to announce service %d\n", err);
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}
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rpdrv->remove(rpdev);
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rpmsg_destroy_ept(rpdev->ept);
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return err;
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}
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static struct bus_type rpmsg_bus = {
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.name = "rpmsg",
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.match = rpmsg_dev_match,
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.dev_attrs = rpmsg_dev_attrs,
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.uevent = rpmsg_uevent,
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.probe = rpmsg_dev_probe,
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.remove = rpmsg_dev_remove,
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};
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/**
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* register_rpmsg_driver() - register an rpmsg driver with the rpmsg bus
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* @rpdrv: pointer to a struct rpmsg_driver
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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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int register_rpmsg_driver(struct rpmsg_driver *rpdrv)
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{
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rpdrv->drv.bus = &rpmsg_bus;
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return driver_register(&rpdrv->drv);
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}
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EXPORT_SYMBOL(register_rpmsg_driver);
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/**
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* unregister_rpmsg_driver() - unregister an rpmsg driver from the rpmsg bus
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* @rpdrv: pointer to a struct rpmsg_driver
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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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void unregister_rpmsg_driver(struct rpmsg_driver *rpdrv)
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{
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driver_unregister(&rpdrv->drv);
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}
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EXPORT_SYMBOL(unregister_rpmsg_driver);
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static void rpmsg_release_device(struct device *dev)
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{
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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kfree(rpdev);
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}
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/*
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* match an rpmsg channel with a channel info struct.
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* this is used to make sure we're not creating rpmsg devices for channels
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* that already exist.
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*/
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static int rpmsg_channel_match(struct device *dev, void *data)
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{
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struct rpmsg_channel_info *chinfo = data;
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struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
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if (chinfo->src != RPMSG_ADDR_ANY && chinfo->src != rpdev->src)
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return 0;
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if (chinfo->dst != RPMSG_ADDR_ANY && chinfo->dst != rpdev->dst)
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return 0;
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if (strncmp(chinfo->name, rpdev->id.name, RPMSG_NAME_SIZE))
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return 0;
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/* found a match ! */
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return 1;
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}
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|
|
/*
|
|
* create an rpmsg channel using its name and address info.
|
|
* this function will be used to create both static and dynamic
|
|
* channels.
|
|
*/
|
|
static struct rpmsg_channel *rpmsg_create_channel(struct virtproc_info *vrp,
|
|
struct rpmsg_channel_info *chinfo)
|
|
{
|
|
struct rpmsg_channel *rpdev;
|
|
struct device *tmp, *dev = &vrp->vdev->dev;
|
|
int ret;
|
|
|
|
/* make sure a similar channel doesn't already exist */
|
|
tmp = device_find_child(dev, chinfo, rpmsg_channel_match);
|
|
if (tmp) {
|
|
/* decrement the matched device's refcount back */
|
|
put_device(tmp);
|
|
dev_err(dev, "channel %s:%x:%x already exist\n",
|
|
chinfo->name, chinfo->src, chinfo->dst);
|
|
return NULL;
|
|
}
|
|
|
|
rpdev = kzalloc(sizeof(struct rpmsg_channel), GFP_KERNEL);
|
|
if (!rpdev) {
|
|
pr_err("kzalloc failed\n");
|
|
return NULL;
|
|
}
|
|
|
|
rpdev->vrp = vrp;
|
|
rpdev->src = chinfo->src;
|
|
rpdev->dst = chinfo->dst;
|
|
|
|
/*
|
|
* rpmsg server channels has predefined local address (for now),
|
|
* and their existence needs to be announced remotely
|
|
*/
|
|
rpdev->announce = rpdev->src != RPMSG_ADDR_ANY ? true : false;
|
|
|
|
strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
|
|
|
|
/* very simple device indexing plumbing which is enough for now */
|
|
dev_set_name(&rpdev->dev, "rpmsg%d", rpmsg_dev_index++);
|
|
|
|
rpdev->dev.parent = &vrp->vdev->dev;
|
|
rpdev->dev.bus = &rpmsg_bus;
|
|
rpdev->dev.release = rpmsg_release_device;
|
|
|
|
ret = device_register(&rpdev->dev);
|
|
if (ret) {
|
|
dev_err(dev, "device_register failed: %d\n", ret);
|
|
put_device(&rpdev->dev);
|
|
return NULL;
|
|
}
|
|
|
|
return rpdev;
|
|
}
|
|
|
|
/*
|
|
* find an existing channel using its name + address properties,
|
|
* and destroy it
|
|
*/
|
|
static int rpmsg_destroy_channel(struct virtproc_info *vrp,
|
|
struct rpmsg_channel_info *chinfo)
|
|
{
|
|
struct virtio_device *vdev = vrp->vdev;
|
|
struct device *dev;
|
|
|
|
dev = device_find_child(&vdev->dev, chinfo, rpmsg_channel_match);
|
|
if (!dev)
|
|
return -EINVAL;
|
|
|
|
device_unregister(dev);
|
|
|
|
put_device(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* super simple buffer "allocator" that is just enough for now */
|
|
static void *get_a_tx_buf(struct virtproc_info *vrp)
|
|
{
|
|
unsigned int len;
|
|
void *ret;
|
|
|
|
/* support multiple concurrent senders */
|
|
mutex_lock(&vrp->tx_lock);
|
|
|
|
/*
|
|
* either pick the next unused tx buffer
|
|
* (half of our buffers are used for sending messages)
|
|
*/
|
|
if (vrp->last_sbuf < vrp->num_bufs / 2)
|
|
ret = vrp->sbufs + RPMSG_BUF_SIZE * vrp->last_sbuf++;
|
|
/* or recycle a used one */
|
|
else
|
|
ret = virtqueue_get_buf(vrp->svq, &len);
|
|
|
|
mutex_unlock(&vrp->tx_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed
|
|
* @vrp: virtual remote processor state
|
|
*
|
|
* This function is called before a sender is blocked, waiting for
|
|
* a tx buffer to become available.
|
|
*
|
|
* If we already have blocking senders, this function merely increases
|
|
* the "sleepers" reference count, and exits.
|
|
*
|
|
* Otherwise, if this is the first sender to block, we also enable
|
|
* virtio's tx callbacks, so we'd be immediately notified when a tx
|
|
* buffer is consumed (we rely on virtio's tx callback in order
|
|
* to wake up sleeping senders as soon as a tx buffer is used by the
|
|
* remote processor).
|
|
*/
|
|
static void rpmsg_upref_sleepers(struct virtproc_info *vrp)
|
|
{
|
|
/* support multiple concurrent senders */
|
|
mutex_lock(&vrp->tx_lock);
|
|
|
|
/* are we the first sleeping context waiting for tx buffers ? */
|
|
if (atomic_inc_return(&vrp->sleepers) == 1)
|
|
/* enable "tx-complete" interrupts before dozing off */
|
|
virtqueue_enable_cb(vrp->svq);
|
|
|
|
mutex_unlock(&vrp->tx_lock);
|
|
}
|
|
|
|
/**
|
|
* rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed
|
|
* @vrp: virtual remote processor state
|
|
*
|
|
* This function is called after a sender, that waited for a tx buffer
|
|
* to become available, is unblocked.
|
|
*
|
|
* If we still have blocking senders, this function merely decreases
|
|
* the "sleepers" reference count, and exits.
|
|
*
|
|
* Otherwise, if there are no more blocking senders, we also disable
|
|
* virtio's tx callbacks, to avoid the overhead incurred with handling
|
|
* those (now redundant) interrupts.
|
|
*/
|
|
static void rpmsg_downref_sleepers(struct virtproc_info *vrp)
|
|
{
|
|
/* support multiple concurrent senders */
|
|
mutex_lock(&vrp->tx_lock);
|
|
|
|
/* are we the last sleeping context waiting for tx buffers ? */
|
|
if (atomic_dec_and_test(&vrp->sleepers))
|
|
/* disable "tx-complete" interrupts */
|
|
virtqueue_disable_cb(vrp->svq);
|
|
|
|
mutex_unlock(&vrp->tx_lock);
|
|
}
|
|
|
|
/**
|
|
* rpmsg_send_offchannel_raw() - send a message across to the remote processor
|
|
* @rpdev: the rpmsg channel
|
|
* @src: source address
|
|
* @dst: destination address
|
|
* @data: payload of message
|
|
* @len: length of payload
|
|
* @wait: indicates whether caller should block in case no TX buffers available
|
|
*
|
|
* This function is the base implementation for all of the rpmsg sending API.
|
|
*
|
|
* It will send @data of length @len to @dst, and say it's from @src. The
|
|
* message will be sent to the remote processor which the @rpdev channel
|
|
* belongs to.
|
|
*
|
|
* The message is sent using one of the TX buffers that are available for
|
|
* communication with this remote processor.
|
|
*
|
|
* If @wait is true, the caller will be blocked until either a TX buffer is
|
|
* available, or 15 seconds elapses (we don't want callers to
|
|
* sleep indefinitely due to misbehaving remote processors), and in that
|
|
* case -ERESTARTSYS is returned. The number '15' itself was picked
|
|
* arbitrarily; there's little point in asking drivers to provide a timeout
|
|
* value themselves.
|
|
*
|
|
* Otherwise, if @wait is false, and there are no TX buffers available,
|
|
* the function will immediately fail, and -ENOMEM will be returned.
|
|
*
|
|
* Normally drivers shouldn't use this function directly; instead, drivers
|
|
* should use the appropriate rpmsg_{try}send{to, _offchannel} API
|
|
* (see include/linux/rpmsg.h).
|
|
*
|
|
* Returns 0 on success and an appropriate error value on failure.
|
|
*/
|
|
int rpmsg_send_offchannel_raw(struct rpmsg_channel *rpdev, u32 src, u32 dst,
|
|
void *data, int len, bool wait)
|
|
{
|
|
struct virtproc_info *vrp = rpdev->vrp;
|
|
struct device *dev = &rpdev->dev;
|
|
struct scatterlist sg;
|
|
struct rpmsg_hdr *msg;
|
|
int err;
|
|
|
|
/* bcasting isn't allowed */
|
|
if (src == RPMSG_ADDR_ANY || dst == RPMSG_ADDR_ANY) {
|
|
dev_err(dev, "invalid addr (src 0x%x, dst 0x%x)\n", src, dst);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* We currently use fixed-sized buffers, and therefore the payload
|
|
* length is limited.
|
|
*
|
|
* One of the possible improvements here is either to support
|
|
* user-provided buffers (and then we can also support zero-copy
|
|
* messaging), or to improve the buffer allocator, to support
|
|
* variable-length buffer sizes.
|
|
*/
|
|
if (len > RPMSG_BUF_SIZE - sizeof(struct rpmsg_hdr)) {
|
|
dev_err(dev, "message is too big (%d)\n", len);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
/* grab a buffer */
|
|
msg = get_a_tx_buf(vrp);
|
|
if (!msg && !wait)
|
|
return -ENOMEM;
|
|
|
|
/* no free buffer ? wait for one (but bail after 15 seconds) */
|
|
while (!msg) {
|
|
/* enable "tx-complete" interrupts, if not already enabled */
|
|
rpmsg_upref_sleepers(vrp);
|
|
|
|
/*
|
|
* sleep until a free buffer is available or 15 secs elapse.
|
|
* the timeout period is not configurable because there's
|
|
* little point in asking drivers to specify that.
|
|
* if later this happens to be required, it'd be easy to add.
|
|
*/
|
|
err = wait_event_interruptible_timeout(vrp->sendq,
|
|
(msg = get_a_tx_buf(vrp)),
|
|
msecs_to_jiffies(15000));
|
|
|
|
/* disable "tx-complete" interrupts if we're the last sleeper */
|
|
rpmsg_downref_sleepers(vrp);
|
|
|
|
/* timeout ? */
|
|
if (!err) {
|
|
dev_err(dev, "timeout waiting for a tx buffer\n");
|
|
return -ERESTARTSYS;
|
|
}
|
|
}
|
|
|
|
msg->len = len;
|
|
msg->flags = 0;
|
|
msg->src = src;
|
|
msg->dst = dst;
|
|
msg->reserved = 0;
|
|
memcpy(msg->data, data, len);
|
|
|
|
dev_dbg(dev, "TX From 0x%x, To 0x%x, Len %d, Flags %d, Reserved %d\n",
|
|
msg->src, msg->dst, msg->len,
|
|
msg->flags, msg->reserved);
|
|
print_hex_dump(KERN_DEBUG, "rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
|
|
msg, sizeof(*msg) + msg->len, true);
|
|
|
|
sg_init_one(&sg, msg, sizeof(*msg) + len);
|
|
|
|
mutex_lock(&vrp->tx_lock);
|
|
|
|
/* add message to the remote processor's virtqueue */
|
|
err = virtqueue_add_outbuf(vrp->svq, &sg, 1, msg, GFP_KERNEL);
|
|
if (err) {
|
|
/*
|
|
* need to reclaim the buffer here, otherwise it's lost
|
|
* (memory won't leak, but rpmsg won't use it again for TX).
|
|
* this will wait for a buffer management overhaul.
|
|
*/
|
|
dev_err(dev, "virtqueue_add_outbuf failed: %d\n", err);
|
|
goto out;
|
|
}
|
|
|
|
/* tell the remote processor it has a pending message to read */
|
|
virtqueue_kick(vrp->svq);
|
|
out:
|
|
mutex_unlock(&vrp->tx_lock);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(rpmsg_send_offchannel_raw);
|
|
|
|
static int rpmsg_recv_single(struct virtproc_info *vrp, struct device *dev,
|
|
struct rpmsg_hdr *msg, unsigned int len)
|
|
{
|
|
struct rpmsg_endpoint *ept;
|
|
struct scatterlist sg;
|
|
int err;
|
|
|
|
dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
|
|
msg->src, msg->dst, msg->len,
|
|
msg->flags, msg->reserved);
|
|
print_hex_dump(KERN_DEBUG, "rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
|
|
msg, sizeof(*msg) + msg->len, true);
|
|
|
|
/*
|
|
* We currently use fixed-sized buffers, so trivially sanitize
|
|
* the reported payload length.
|
|
*/
|
|
if (len > RPMSG_BUF_SIZE ||
|
|
msg->len > (len - sizeof(struct rpmsg_hdr))) {
|
|
dev_warn(dev, "inbound msg too big: (%d, %d)\n", len, msg->len);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* use the dst addr to fetch the callback of the appropriate user */
|
|
mutex_lock(&vrp->endpoints_lock);
|
|
|
|
ept = idr_find(&vrp->endpoints, msg->dst);
|
|
|
|
/* let's make sure no one deallocates ept while we use it */
|
|
if (ept)
|
|
kref_get(&ept->refcount);
|
|
|
|
mutex_unlock(&vrp->endpoints_lock);
|
|
|
|
if (ept) {
|
|
/* make sure ept->cb doesn't go away while we use it */
|
|
mutex_lock(&ept->cb_lock);
|
|
|
|
if (ept->cb)
|
|
ept->cb(ept->rpdev, msg->data, msg->len, ept->priv,
|
|
msg->src);
|
|
|
|
mutex_unlock(&ept->cb_lock);
|
|
|
|
/* farewell, ept, we don't need you anymore */
|
|
kref_put(&ept->refcount, __ept_release);
|
|
} else
|
|
dev_warn(dev, "msg received with no recipient\n");
|
|
|
|
/* publish the real size of the buffer */
|
|
sg_init_one(&sg, msg, RPMSG_BUF_SIZE);
|
|
|
|
/* add the buffer back to the remote processor's virtqueue */
|
|
err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, msg, GFP_KERNEL);
|
|
if (err < 0) {
|
|
dev_err(dev, "failed to add a virtqueue buffer: %d\n", err);
|
|
return err;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* called when an rx buffer is used, and it's time to digest a message */
|
|
static void rpmsg_recv_done(struct virtqueue *rvq)
|
|
{
|
|
struct virtproc_info *vrp = rvq->vdev->priv;
|
|
struct device *dev = &rvq->vdev->dev;
|
|
struct rpmsg_hdr *msg;
|
|
unsigned int len, msgs_received = 0;
|
|
int err;
|
|
|
|
msg = virtqueue_get_buf(rvq, &len);
|
|
if (!msg) {
|
|
dev_err(dev, "uhm, incoming signal, but no used buffer ?\n");
|
|
return;
|
|
}
|
|
|
|
while (msg) {
|
|
err = rpmsg_recv_single(vrp, dev, msg, len);
|
|
if (err)
|
|
break;
|
|
|
|
msgs_received++;
|
|
|
|
msg = virtqueue_get_buf(rvq, &len);
|
|
};
|
|
|
|
dev_dbg(dev, "Received %u messages\n", msgs_received);
|
|
|
|
/* tell the remote processor we added another available rx buffer */
|
|
if (msgs_received)
|
|
virtqueue_kick(vrp->rvq);
|
|
}
|
|
|
|
/*
|
|
* This is invoked whenever the remote processor completed processing
|
|
* a TX msg we just sent it, and the buffer is put back to the used ring.
|
|
*
|
|
* Normally, though, we suppress this "tx complete" interrupt in order to
|
|
* avoid the incurred overhead.
|
|
*/
|
|
static void rpmsg_xmit_done(struct virtqueue *svq)
|
|
{
|
|
struct virtproc_info *vrp = svq->vdev->priv;
|
|
|
|
dev_dbg(&svq->vdev->dev, "%s\n", __func__);
|
|
|
|
/* wake up potential senders that are waiting for a tx buffer */
|
|
wake_up_interruptible(&vrp->sendq);
|
|
}
|
|
|
|
/* invoked when a name service announcement arrives */
|
|
static void rpmsg_ns_cb(struct rpmsg_channel *rpdev, void *data, int len,
|
|
void *priv, u32 src)
|
|
{
|
|
struct rpmsg_ns_msg *msg = data;
|
|
struct rpmsg_channel *newch;
|
|
struct rpmsg_channel_info chinfo;
|
|
struct virtproc_info *vrp = priv;
|
|
struct device *dev = &vrp->vdev->dev;
|
|
int ret;
|
|
|
|
print_hex_dump(KERN_DEBUG, "NS announcement: ",
|
|
DUMP_PREFIX_NONE, 16, 1,
|
|
data, len, true);
|
|
|
|
if (len != sizeof(*msg)) {
|
|
dev_err(dev, "malformed ns msg (%d)\n", len);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* the name service ept does _not_ belong to a real rpmsg channel,
|
|
* and is handled by the rpmsg bus itself.
|
|
* for sanity reasons, make sure a valid rpdev has _not_ sneaked
|
|
* in somehow.
|
|
*/
|
|
if (rpdev) {
|
|
dev_err(dev, "anomaly: ns ept has an rpdev handle\n");
|
|
return;
|
|
}
|
|
|
|
/* don't trust the remote processor for null terminating the name */
|
|
msg->name[RPMSG_NAME_SIZE - 1] = '\0';
|
|
|
|
dev_info(dev, "%sing channel %s addr 0x%x\n",
|
|
msg->flags & RPMSG_NS_DESTROY ? "destroy" : "creat",
|
|
msg->name, msg->addr);
|
|
|
|
strncpy(chinfo.name, msg->name, sizeof(chinfo.name));
|
|
chinfo.src = RPMSG_ADDR_ANY;
|
|
chinfo.dst = msg->addr;
|
|
|
|
if (msg->flags & RPMSG_NS_DESTROY) {
|
|
ret = rpmsg_destroy_channel(vrp, &chinfo);
|
|
if (ret)
|
|
dev_err(dev, "rpmsg_destroy_channel failed: %d\n", ret);
|
|
} else {
|
|
newch = rpmsg_create_channel(vrp, &chinfo);
|
|
if (!newch)
|
|
dev_err(dev, "rpmsg_create_channel failed\n");
|
|
}
|
|
}
|
|
|
|
static int rpmsg_probe(struct virtio_device *vdev)
|
|
{
|
|
vq_callback_t *vq_cbs[] = { rpmsg_recv_done, rpmsg_xmit_done };
|
|
static const char * const names[] = { "input", "output" };
|
|
struct virtqueue *vqs[2];
|
|
struct virtproc_info *vrp;
|
|
void *bufs_va;
|
|
int err = 0, i;
|
|
size_t total_buf_space;
|
|
bool notify;
|
|
|
|
vrp = kzalloc(sizeof(*vrp), GFP_KERNEL);
|
|
if (!vrp)
|
|
return -ENOMEM;
|
|
|
|
vrp->vdev = vdev;
|
|
|
|
idr_init(&vrp->endpoints);
|
|
mutex_init(&vrp->endpoints_lock);
|
|
mutex_init(&vrp->tx_lock);
|
|
init_waitqueue_head(&vrp->sendq);
|
|
|
|
/* We expect two virtqueues, rx and tx (and in this order) */
|
|
err = vdev->config->find_vqs(vdev, 2, vqs, vq_cbs, names);
|
|
if (err)
|
|
goto free_vrp;
|
|
|
|
vrp->rvq = vqs[0];
|
|
vrp->svq = vqs[1];
|
|
|
|
/* we expect symmetric tx/rx vrings */
|
|
WARN_ON(virtqueue_get_vring_size(vrp->rvq) !=
|
|
virtqueue_get_vring_size(vrp->svq));
|
|
|
|
/* we need less buffers if vrings are small */
|
|
if (virtqueue_get_vring_size(vrp->rvq) < MAX_RPMSG_NUM_BUFS / 2)
|
|
vrp->num_bufs = virtqueue_get_vring_size(vrp->rvq) * 2;
|
|
else
|
|
vrp->num_bufs = MAX_RPMSG_NUM_BUFS;
|
|
|
|
total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
|
|
|
|
/* allocate coherent memory for the buffers */
|
|
bufs_va = dma_alloc_coherent(vdev->dev.parent->parent,
|
|
total_buf_space, &vrp->bufs_dma,
|
|
GFP_KERNEL);
|
|
if (!bufs_va) {
|
|
err = -ENOMEM;
|
|
goto vqs_del;
|
|
}
|
|
|
|
dev_dbg(&vdev->dev, "buffers: va %p, dma 0x%llx\n", bufs_va,
|
|
(unsigned long long)vrp->bufs_dma);
|
|
|
|
/* half of the buffers is dedicated for RX */
|
|
vrp->rbufs = bufs_va;
|
|
|
|
/* and half is dedicated for TX */
|
|
vrp->sbufs = bufs_va + total_buf_space / 2;
|
|
|
|
/* set up the receive buffers */
|
|
for (i = 0; i < vrp->num_bufs / 2; i++) {
|
|
struct scatterlist sg;
|
|
void *cpu_addr = vrp->rbufs + i * RPMSG_BUF_SIZE;
|
|
|
|
sg_init_one(&sg, cpu_addr, RPMSG_BUF_SIZE);
|
|
|
|
err = virtqueue_add_inbuf(vrp->rvq, &sg, 1, cpu_addr,
|
|
GFP_KERNEL);
|
|
WARN_ON(err); /* sanity check; this can't really happen */
|
|
}
|
|
|
|
/* suppress "tx-complete" interrupts */
|
|
virtqueue_disable_cb(vrp->svq);
|
|
|
|
vdev->priv = vrp;
|
|
|
|
/* if supported by the remote processor, enable the name service */
|
|
if (virtio_has_feature(vdev, VIRTIO_RPMSG_F_NS)) {
|
|
/* a dedicated endpoint handles the name service msgs */
|
|
vrp->ns_ept = __rpmsg_create_ept(vrp, NULL, rpmsg_ns_cb,
|
|
vrp, RPMSG_NS_ADDR);
|
|
if (!vrp->ns_ept) {
|
|
dev_err(&vdev->dev, "failed to create the ns ept\n");
|
|
err = -ENOMEM;
|
|
goto free_coherent;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Prepare to kick but don't notify yet - we can't do this before
|
|
* device is ready.
|
|
*/
|
|
notify = virtqueue_kick_prepare(vrp->rvq);
|
|
|
|
/* From this point on, we can notify and get callbacks. */
|
|
virtio_device_ready(vdev);
|
|
|
|
/* tell the remote processor it can start sending messages */
|
|
/*
|
|
* this might be concurrent with callbacks, but we are only
|
|
* doing notify, not a full kick here, so that's ok.
|
|
*/
|
|
if (notify)
|
|
virtqueue_notify(vrp->rvq);
|
|
|
|
dev_info(&vdev->dev, "rpmsg host is online\n");
|
|
|
|
return 0;
|
|
|
|
free_coherent:
|
|
dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
|
|
bufs_va, vrp->bufs_dma);
|
|
vqs_del:
|
|
vdev->config->del_vqs(vrp->vdev);
|
|
free_vrp:
|
|
kfree(vrp);
|
|
return err;
|
|
}
|
|
|
|
static int rpmsg_remove_device(struct device *dev, void *data)
|
|
{
|
|
device_unregister(dev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void rpmsg_remove(struct virtio_device *vdev)
|
|
{
|
|
struct virtproc_info *vrp = vdev->priv;
|
|
size_t total_buf_space = vrp->num_bufs * RPMSG_BUF_SIZE;
|
|
int ret;
|
|
|
|
vdev->config->reset(vdev);
|
|
|
|
ret = device_for_each_child(&vdev->dev, NULL, rpmsg_remove_device);
|
|
if (ret)
|
|
dev_warn(&vdev->dev, "can't remove rpmsg device: %d\n", ret);
|
|
|
|
if (vrp->ns_ept)
|
|
__rpmsg_destroy_ept(vrp, vrp->ns_ept);
|
|
|
|
idr_destroy(&vrp->endpoints);
|
|
|
|
vdev->config->del_vqs(vrp->vdev);
|
|
|
|
dma_free_coherent(vdev->dev.parent->parent, total_buf_space,
|
|
vrp->rbufs, vrp->bufs_dma);
|
|
|
|
kfree(vrp);
|
|
}
|
|
|
|
static struct virtio_device_id id_table[] = {
|
|
{ VIRTIO_ID_RPMSG, VIRTIO_DEV_ANY_ID },
|
|
{ 0 },
|
|
};
|
|
|
|
static unsigned int features[] = {
|
|
VIRTIO_RPMSG_F_NS,
|
|
};
|
|
|
|
static struct virtio_driver virtio_ipc_driver = {
|
|
.feature_table = features,
|
|
.feature_table_size = ARRAY_SIZE(features),
|
|
.driver.name = KBUILD_MODNAME,
|
|
.driver.owner = THIS_MODULE,
|
|
.id_table = id_table,
|
|
.probe = rpmsg_probe,
|
|
.remove = rpmsg_remove,
|
|
};
|
|
|
|
static int __init rpmsg_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = bus_register(&rpmsg_bus);
|
|
if (ret) {
|
|
pr_err("failed to register rpmsg bus: %d\n", ret);
|
|
return ret;
|
|
}
|
|
|
|
ret = register_virtio_driver(&virtio_ipc_driver);
|
|
if (ret) {
|
|
pr_err("failed to register virtio driver: %d\n", ret);
|
|
bus_unregister(&rpmsg_bus);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
subsys_initcall(rpmsg_init);
|
|
|
|
static void __exit rpmsg_fini(void)
|
|
{
|
|
unregister_virtio_driver(&virtio_ipc_driver);
|
|
bus_unregister(&rpmsg_bus);
|
|
}
|
|
module_exit(rpmsg_fini);
|
|
|
|
MODULE_DEVICE_TABLE(virtio, id_table);
|
|
MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
|
|
MODULE_LICENSE("GPL v2");
|