linux-stable/drivers/rpmsg/virtio_rpmsg_bus.c
Arnaud Pouliquen 950a7388f0 rpmsg: Turn name service into a stand alone driver
Make the RPMSG name service announcement a stand alone driver so that it
can be reused by other subsystems.  It is also the first step in making the
functionatlity transport independent, i.e that is not tied to virtIO.

Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Tested-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Co-developed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Co-developed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Link: https://lore.kernel.org/r/20201120214245.172963-9-mathieu.poirier@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
2020-11-24 10:11:59 -06:00

1021 lines
29 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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>
*/
#define pr_fmt(fmt) "%s: " fmt, __func__
#include <linux/dma-mapping.h>
#include <linux/idr.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_device.h>
#include <linux/rpmsg.h>
#include <linux/rpmsg/byteorder.h>
#include <linux/rpmsg/ns.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
#include <linux/wait.h>
#include "rpmsg_internal.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
* @num_bufs: total number of buffers for rx and tx
* @buf_size: size of one rx or tx buffer
* @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
*
* 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;
unsigned int num_bufs;
unsigned int buf_size;
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;
};
/* The feature bitmap for virtio rpmsg */
#define VIRTIO_RPMSG_F_NS 0 /* RP supports name service notifications */
/**
* struct rpmsg_hdr - common header for all rpmsg messages
* @src: source address
* @dst: destination address
* @reserved: reserved for future use
* @len: length of payload (in bytes)
* @flags: message flags
* @data: @len bytes of message payload data
*
* Every message sent(/received) on the rpmsg bus begins with this header.
*/
struct rpmsg_hdr {
__rpmsg32 src;
__rpmsg32 dst;
__rpmsg32 reserved;
__rpmsg16 len;
__rpmsg16 flags;
u8 data[];
} __packed;
/**
* struct virtio_rpmsg_channel - rpmsg channel descriptor
* @rpdev: the rpmsg channel device
* @vrp: the virtio remote processor device this channel belongs to
*
* This structure stores the channel that links the rpmsg device to the virtio
* remote processor device.
*/
struct virtio_rpmsg_channel {
struct rpmsg_device rpdev;
struct virtproc_info *vrp;
};
#define to_virtio_rpmsg_channel(_rpdev) \
container_of(_rpdev, struct virtio_rpmsg_channel, rpdev)
/*
* We're allocating buffers of 512 bytes each for communications. The
* number of buffers will be computed from the number of buffers supported
* by the vring, upto a maximum of 512 buffers (256 in each direction).
*
* Each buffer will have 16 bytes for the msg header and 496 bytes for
* the payload.
*
* This will utilize a maximum 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 MAX_RPMSG_NUM_BUFS (512)
#define MAX_RPMSG_BUF_SIZE (512)
/*
* 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)
static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept);
static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len);
static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
u32 dst);
static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
u32 dst, void *data, int len);
static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);
static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
int len, u32 dst);
static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
u32 dst, void *data, int len);
static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,
struct rpmsg_channel_info *chinfo);
static const struct rpmsg_endpoint_ops virtio_endpoint_ops = {
.destroy_ept = virtio_rpmsg_destroy_ept,
.send = virtio_rpmsg_send,
.sendto = virtio_rpmsg_sendto,
.send_offchannel = virtio_rpmsg_send_offchannel,
.trysend = virtio_rpmsg_trysend,
.trysendto = virtio_rpmsg_trysendto,
.trysend_offchannel = virtio_rpmsg_trysend_offchannel,
};
/**
* rpmsg_sg_init - initialize scatterlist according to cpu address location
* @sg: scatterlist to fill
* @cpu_addr: virtual address of the buffer
* @len: buffer length
*
* An internal function filling scatterlist according to virtual address
* location (in vmalloc or in kernel).
*/
static void
rpmsg_sg_init(struct scatterlist *sg, void *cpu_addr, unsigned int len)
{
if (is_vmalloc_addr(cpu_addr)) {
sg_init_table(sg, 1);
sg_set_page(sg, vmalloc_to_page(cpu_addr), len,
offset_in_page(cpu_addr));
} else {
WARN_ON(!virt_addr_valid(cpu_addr));
sg_init_one(sg, cpu_addr, len);
}
}
/**
* __ept_release() - deallocate an rpmsg endpoint
* @kref: the ept's reference count
*
* This function deallocates an ept, and is invoked when its @kref refcount
* drops to zero.
*
* Never invoke this function directly!
*/
static void __ept_release(struct kref *kref)
{
struct rpmsg_endpoint *ept = container_of(kref, struct rpmsg_endpoint,
refcount);
/*
* At this point no one holds a reference to ept anymore,
* so we can directly free it
*/
kfree(ept);
}
/* for more info, see below documentation of rpmsg_create_ept() */
static struct rpmsg_endpoint *__rpmsg_create_ept(struct virtproc_info *vrp,
struct rpmsg_device *rpdev,
rpmsg_rx_cb_t cb,
void *priv, u32 addr)
{
int id_min, id_max, id;
struct rpmsg_endpoint *ept;
struct device *dev = rpdev ? &rpdev->dev : &vrp->vdev->dev;
ept = kzalloc(sizeof(*ept), GFP_KERNEL);
if (!ept)
return NULL;
kref_init(&ept->refcount);
mutex_init(&ept->cb_lock);
ept->rpdev = rpdev;
ept->cb = cb;
ept->priv = priv;
ept->ops = &virtio_endpoint_ops;
/* do we need to allocate a local address ? */
if (addr == RPMSG_ADDR_ANY) {
id_min = RPMSG_RESERVED_ADDRESSES;
id_max = 0;
} else {
id_min = addr;
id_max = addr + 1;
}
mutex_lock(&vrp->endpoints_lock);
/* bind the endpoint to an rpmsg address (and allocate one if needed) */
id = idr_alloc(&vrp->endpoints, ept, id_min, id_max, GFP_KERNEL);
if (id < 0) {
dev_err(dev, "idr_alloc failed: %d\n", id);
goto free_ept;
}
ept->addr = id;
mutex_unlock(&vrp->endpoints_lock);
return ept;
free_ept:
mutex_unlock(&vrp->endpoints_lock);
kref_put(&ept->refcount, __ept_release);
return NULL;
}
static struct rpmsg_device *virtio_rpmsg_create_channel(struct rpmsg_device *rpdev,
struct rpmsg_channel_info *chinfo)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
struct virtproc_info *vrp = vch->vrp;
return __rpmsg_create_channel(vrp, chinfo);
}
static int virtio_rpmsg_release_channel(struct rpmsg_device *rpdev,
struct rpmsg_channel_info *chinfo)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
struct virtproc_info *vrp = vch->vrp;
return rpmsg_unregister_device(&vrp->vdev->dev, chinfo);
}
static struct rpmsg_endpoint *virtio_rpmsg_create_ept(struct rpmsg_device *rpdev,
rpmsg_rx_cb_t cb,
void *priv,
struct rpmsg_channel_info chinfo)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
return __rpmsg_create_ept(vch->vrp, rpdev, cb, priv, chinfo.src);
}
/**
* __rpmsg_destroy_ept() - destroy an existing rpmsg endpoint
* @vrp: virtproc which owns this ept
* @ept: endpoing to destroy
*
* An internal function which destroy an ept without assuming it is
* bound to an rpmsg channel. This is needed for handling the internal
* name service endpoint, which isn't bound to an rpmsg channel.
* See also __rpmsg_create_ept().
*/
static void
__rpmsg_destroy_ept(struct virtproc_info *vrp, struct rpmsg_endpoint *ept)
{
/* make sure new inbound messages can't find this ept anymore */
mutex_lock(&vrp->endpoints_lock);
idr_remove(&vrp->endpoints, ept->addr);
mutex_unlock(&vrp->endpoints_lock);
/* make sure in-flight inbound messages won't invoke cb anymore */
mutex_lock(&ept->cb_lock);
ept->cb = NULL;
mutex_unlock(&ept->cb_lock);
kref_put(&ept->refcount, __ept_release);
}
static void virtio_rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(ept->rpdev);
__rpmsg_destroy_ept(vch->vrp, ept);
}
static int virtio_rpmsg_announce_create(struct rpmsg_device *rpdev)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
struct virtproc_info *vrp = vch->vrp;
struct device *dev = &rpdev->dev;
int err = 0;
/* need to tell remote processor's name service about this channel ? */
if (rpdev->announce && rpdev->ept &&
virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
struct rpmsg_ns_msg nsm;
strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_CREATE);
err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
if (err)
dev_err(dev, "failed to announce service %d\n", err);
}
return err;
}
static int virtio_rpmsg_announce_destroy(struct rpmsg_device *rpdev)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
struct virtproc_info *vrp = vch->vrp;
struct device *dev = &rpdev->dev;
int err = 0;
/* tell remote processor's name service we're removing this channel */
if (rpdev->announce && rpdev->ept &&
virtio_has_feature(vrp->vdev, VIRTIO_RPMSG_F_NS)) {
struct rpmsg_ns_msg nsm;
strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
nsm.addr = cpu_to_rpmsg32(rpdev, rpdev->ept->addr);
nsm.flags = cpu_to_rpmsg32(rpdev, RPMSG_NS_DESTROY);
err = rpmsg_sendto(rpdev->ept, &nsm, sizeof(nsm), RPMSG_NS_ADDR);
if (err)
dev_err(dev, "failed to announce service %d\n", err);
}
return err;
}
static const struct rpmsg_device_ops virtio_rpmsg_ops = {
.create_channel = virtio_rpmsg_create_channel,
.release_channel = virtio_rpmsg_release_channel,
.create_ept = virtio_rpmsg_create_ept,
.announce_create = virtio_rpmsg_announce_create,
.announce_destroy = virtio_rpmsg_announce_destroy,
};
static void virtio_rpmsg_release_device(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
kfree(vch);
}
/*
* 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_device *__rpmsg_create_channel(struct virtproc_info *vrp,
struct rpmsg_channel_info *chinfo)
{
struct virtio_rpmsg_channel *vch;
struct rpmsg_device *rpdev;
struct device *tmp, *dev = &vrp->vdev->dev;
int ret;
/* make sure a similar channel doesn't already exist */
tmp = rpmsg_find_device(dev, chinfo);
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;
}
vch = kzalloc(sizeof(*vch), GFP_KERNEL);
if (!vch)
return NULL;
/* Link the channel to our vrp */
vch->vrp = vrp;
/* Assign public information to the rpmsg_device */
rpdev = &vch->rpdev;
rpdev->src = chinfo->src;
rpdev->dst = chinfo->dst;
rpdev->ops = &virtio_rpmsg_ops;
rpdev->little_endian = virtio_is_little_endian(vrp->vdev);
/*
* rpmsg server channels has predefined local address (for now),
* and their existence needs to be announced remotely
*/
rpdev->announce = rpdev->src != RPMSG_ADDR_ANY;
strncpy(rpdev->id.name, chinfo->name, RPMSG_NAME_SIZE);
rpdev->dev.parent = &vrp->vdev->dev;
rpdev->dev.release = virtio_rpmsg_release_device;
ret = rpmsg_register_device(rpdev);
if (ret)
return NULL;
return rpdev;
}
/* 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 + vrp->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.
*/
static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev,
u32 src, u32 dst,
void *data, int len, bool wait)
{
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
struct virtproc_info *vrp = vch->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 > vrp->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 = cpu_to_rpmsg16(rpdev, len);
msg->flags = 0;
msg->src = cpu_to_rpmsg32(rpdev, src);
msg->dst = cpu_to_rpmsg32(rpdev, 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",
src, dst, len, msg->flags, msg->reserved);
#if defined(CONFIG_DYNAMIC_DEBUG)
dynamic_hex_dump("rpmsg_virtio TX: ", DUMP_PREFIX_NONE, 16, 1,
msg, sizeof(*msg) + len, true);
#endif
rpmsg_sg_init(&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;
}
static int virtio_rpmsg_send(struct rpmsg_endpoint *ept, void *data, int len)
{
struct rpmsg_device *rpdev = ept->rpdev;
u32 src = ept->addr, dst = rpdev->dst;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len,
u32 dst)
{
struct rpmsg_device *rpdev = ept->rpdev;
u32 src = ept->addr;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
static int virtio_rpmsg_send_offchannel(struct rpmsg_endpoint *ept, u32 src,
u32 dst, void *data, int len)
{
struct rpmsg_device *rpdev = ept->rpdev;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, true);
}
static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len)
{
struct rpmsg_device *rpdev = ept->rpdev;
u32 src = ept->addr, dst = rpdev->dst;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,
int len, u32 dst)
{
struct rpmsg_device *rpdev = ept->rpdev;
u32 src = ept->addr;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
static int virtio_rpmsg_trysend_offchannel(struct rpmsg_endpoint *ept, u32 src,
u32 dst, void *data, int len)
{
struct rpmsg_device *rpdev = ept->rpdev;
return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);
}
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;
bool little_endian = virtio_is_little_endian(vrp->vdev);
unsigned int msg_len = __rpmsg16_to_cpu(little_endian, msg->len);
int err;
dev_dbg(dev, "From: 0x%x, To: 0x%x, Len: %d, Flags: %d, Reserved: %d\n",
__rpmsg32_to_cpu(little_endian, msg->src),
__rpmsg32_to_cpu(little_endian, msg->dst), msg_len,
__rpmsg16_to_cpu(little_endian, msg->flags),
__rpmsg32_to_cpu(little_endian, msg->reserved));
#if defined(CONFIG_DYNAMIC_DEBUG)
dynamic_hex_dump("rpmsg_virtio RX: ", DUMP_PREFIX_NONE, 16, 1,
msg, sizeof(*msg) + msg_len, true);
#endif
/*
* We currently use fixed-sized buffers, so trivially sanitize
* the reported payload length.
*/
if (len > vrp->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, __rpmsg32_to_cpu(little_endian, 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,
__rpmsg32_to_cpu(little_endian, 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 */
rpmsg_sg_init(&sg, msg, vrp->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);
}
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;
struct virtio_rpmsg_channel *vch;
struct rpmsg_device *rpdev_ns;
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 = virtio_find_vqs(vdev, 2, vqs, vq_cbs, names, NULL);
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;
vrp->buf_size = MAX_RPMSG_BUF_SIZE;
total_buf_space = vrp->num_bufs * vrp->buf_size;
/* allocate coherent memory for the buffers */
bufs_va = dma_alloc_coherent(vdev->dev.parent,
total_buf_space, &vrp->bufs_dma,
GFP_KERNEL);
if (!bufs_va) {
err = -ENOMEM;
goto vqs_del;
}
dev_dbg(&vdev->dev, "buffers: va %pK, dma %pad\n",
bufs_va, &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 * vrp->buf_size;
rpmsg_sg_init(&sg, cpu_addr, vrp->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)) {
vch = kzalloc(sizeof(*vch), GFP_KERNEL);
if (!vch) {
err = -ENOMEM;
goto free_coherent;
}
/* Link the channel to our vrp */
vch->vrp = vrp;
/* Assign public information to the rpmsg_device */
rpdev_ns = &vch->rpdev;
rpdev_ns->ops = &virtio_rpmsg_ops;
rpdev_ns->little_endian = virtio_is_little_endian(vrp->vdev);
rpdev_ns->dev.parent = &vrp->vdev->dev;
rpdev_ns->dev.release = virtio_rpmsg_release_device;
err = rpmsg_ns_register_device(rpdev_ns);
if (err)
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:
kfree(vch);
dma_free_coherent(vdev->dev.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 * vrp->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);
idr_destroy(&vrp->endpoints);
vdev->config->del_vqs(vrp->vdev);
dma_free_coherent(vdev->dev.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 = register_virtio_driver(&virtio_ipc_driver);
if (ret)
pr_err("failed to register virtio driver: %d\n", ret);
return ret;
}
subsys_initcall(rpmsg_init);
static void __exit rpmsg_fini(void)
{
unregister_virtio_driver(&virtio_ipc_driver);
}
module_exit(rpmsg_fini);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio-based remote processor messaging bus");
MODULE_LICENSE("GPL v2");