/*
* Virtio-based remote processor messaging bus
*
* Copyright (C) 2011 Texas Instruments, Inc.
* Copyright (C) 2011 Google, Inc.
*
* Ohad Ben-Cohen <ohad@wizery.com>
* Brian Swetland <swetland@google.com>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/jiffies.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/rpmsg.h>
#include <linux/mutex.h>
/**
* struct virtproc_info - virtual remote processor state
* @vdev: the virtio device
* @rvq: rx virtqueue
* @svq: tx virtqueue
* @rbufs: kernel address of rx buffers
* @sbufs: kernel address of tx buffers
* @last_sbuf: index of last tx buffer used
* @bufs_dma: dma base addr of the buffers
* @tx_lock: protects svq, sbufs and sleepers, to allow concurrent senders.
* sending a message might require waking up a dozing remote
* processor, which involves sleeping, hence the mutex.
* @endpoints: idr of local endpoints, allows fast retrieval
* @endpoints_lock: lock of the endpoints set
* @sendq: wait queue of sending contexts waiting for a tx buffers
* @sleepers: number of senders that are waiting for a tx buffer
* @ns_ept: the bus's name service endpoint
*
* This structure stores the rpmsg state of a given virtio remote processor
* device (there might be several virtio proc devices for each physical
* remote processor).
*/
struct virtproc_info {
struct virtio_device *vdev;
struct virtqueue *rvq, *svq;
void *rbufs, *sbufs;
int last_sbuf;
dma_addr_t bufs_dma;
struct mutex tx_lock;
struct idr endpoints;
struct mutex endpoints_lock;
wait_queue_head_t sendq;
atomic_t sleepers;
struct rpmsg_endpoint *ns_ept;
};
/**
* struct rpmsg_channel_info - internal channel info representation
* @name: name of service
* @src: local address
* @dst: destination address
*/
struct rpmsg_channel_info {
char name[RPMSG_NAME_SIZE];
u32 src;
u32 dst;
};
#define to_rpmsg_channel(d) container_of(d, struct rpmsg_channel, dev)
#define to_rpmsg_driver(d) container_of(d, struct rpmsg_driver, drv)
/*
* We're allocating 512 buffers of 512 bytes for communications, and then
* using the first 256 buffers for RX, and the last 256 buffers for TX.
*
* Each buffer will have 16 bytes for the msg header and 496 bytes for
* the payload.
*
* This will require a total space of 256KB for the buffers.
*
* We might also want to add support for user-provided buffers in time.
* This will allow bigger buffer size flexibility, and can also be used
* to achieve zero-copy messaging.
*
* Note that these numbers are purely a decision of this driver - we
* can change this without changing anything in the firmware of the remote
* processor.
*/
#define RPMSG_NUM_BUFS (512)
#define RPMSG_BUF_SIZE (512)
#define RPMSG_TOTAL_BUF_SPACE (RPMSG_NUM_BUFS * RPMSG_BUF_SIZE)
/*
* Local addresses are dynamically allocated on-demand.
* We do not dynamically assign addresses from the low 1024 range,
* in order to reserve that address range for predefined services.
*/
#define RPMSG_RESERVED_ADDRESSES (1024)
/* Address 53 is reserved for advertising remote services */
#define RPMSG_NS_ADDR (53)
/* sysfs show configuration fields */
#define rpmsg_show_attr(field, path, format_string) \
static ssize_t \
field##_show(struct device *dev, \
struct device_attribute *attr, char *buf) \
{ \
struct rpmsg_channel *rpdev = to_rpmsg_channel(dev); \
\
return sprintf(buf, format_string, rpdev->path); \
}
/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */
rpmsg_show_attr(name, id.name, "%s\n");
rpmsg_show_attr(src, src, "0x%x\n");
rpmsg_show_attr(dst, dst, "0x%x\n");
rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
/*
* Unique (and free running) index for rpmsg devices.
*
* Yeah, we're not recycling those numbers (yet?). will be easy
* to change if/when we want to.
*/
static unsigned int rpmsg_dev_index;
static ssize_t modalias_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
return sprintf(buf, RPMSG_DEVICE_MODALIAS_FMT "\n", rpdev->id.name);
}
static struct device_attribute rpmsg_dev_attrs[] = {
__ATTR_RO(name),
__ATTR_RO(modalias),
__ATTR_RO(dst),
__ATTR_RO(src),
__ATTR_RO(announce),
__ATTR_NULL
};
/* rpmsg devices and drivers are matched using the service name */
static inline int rpmsg_id_match(const struct rpmsg_channel *rpdev,
const struct rpmsg_device_id *id)
{
return strncmp(id->name, rpdev->id.name, RPMSG_NAME_SIZE) == 0;
}
/* match rpmsg channel and rpmsg driver */
static int rpmsg_dev_match(struct device *dev, struct device_driver *drv)
{
struct rpmsg_channel *rpdev = to_rpmsg_channel(dev);
struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
const struct rpmsg_device_id *ids = rpdrv->id_table;
unsigned int i;
for (i = 0; ids[i].name[0]; i++