// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Xen para-virtual sound device
*
* Copyright (C) 2016-2018 EPAM Systems Inc.
*
* Author: Oleksandr Andrushchenko <[email protected]>
*/
#include <xen/events.h>
#include <xen/grant_table.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include "xen_snd_front.h"
#include "xen_snd_front_alsa.h"
#include "xen_snd_front_cfg.h"
#include "xen_snd_front_evtchnl.h"
static irqreturn_t evtchnl_interrupt_req(int irq, void *dev_id)
{
struct xen_snd_front_evtchnl *channel = dev_id;
struct xen_snd_front_info *front_info = channel->front_info;
struct xensnd_resp *resp;
RING_IDX i, rp;
if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
return IRQ_HANDLED;
mutex_lock(&channel->ring_io_lock);
again:
rp = channel->u.req.ring.sring->rsp_prod;
/* Ensure we see queued responses up to rp. */
rmb();
/*
* Assume that the backend is trusted to always write sane values
* to the ring counters, so no overflow checks on frontend side
* are required.
*/
for (i = channel->u.req.ring.rsp_cons; i != rp; i++) {
resp = RING_GET_RESPONSE(&channel->u.req.ring, i);
if (resp->id != channel->evt_id)
continue;
switch (resp->operation) {
case XENSND_OP_OPEN:
case XENSND_OP_CLOSE:
case XENSND_OP_READ:
case XENSND_OP_WRITE:
case XENSND_OP_TRIGGER:
channel->u.req.resp_status = resp->status;
complete(&channel->u.req.completion);
break;
case XENSND_OP_HW_PARAM_QUERY:
channel->u.req.resp_status = resp->status;
channel->u.req.resp.hw_param =
resp->resp.hw_param;
complete(&channel->u.req.completion);
break;
default:
dev_err(&front_info->xb_dev->dev,
"Operation %d is not supported\n",
resp->operation);
break;
}
}
channel->u.req.ring.rsp_cons = i;
if (i != channel->u.req.ring.req_prod_pvt) {
int more_to_do;
RING_FINAL_CHECK_FOR_RESPONSES(&channel->u.req.ring,
more_to_do);
if (more_to_do)
goto again;
} else {
channel->u.req.ring.sring->rsp_event = i + 1;
}
mutex_unlock(&channel->ring_io_lock);
return IRQ_HANDLED;
}
static irqreturn_t evtchnl_interrupt_evt(int irq, void *dev_id)
{
struct xen_snd_front_evtchnl *channel = dev_id;
struct xensnd_event_page *page = channel->u.evt.page;
u32 cons, prod;
if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
return IRQ_HANDLED;
mutex_lock(&channel->ring_io_lock);
prod = page->in_prod;
/* Ensure we see ring contents up to prod. */
virt_rmb();
if (prod == page->in_cons)
goto out;
/*
* Assume that the backend is trusted to always write sane values
* to the ring counters, so no overflow checks on frontend side
* are required.
*/
for (cons = page->in_cons; cons != prod; cons++) {
struct xensnd_evt *event;
event = &XENSND_IN_RING_REF(page, cons);
if (unlikely(event->id != channel->evt_id++))
continue;
switch (event->type) {
case XENSND_EVT_CUR_POS:
xen_snd_front_alsa_handle_cur_pos(channel,
event->op.cur_pos.position);
break;
}
}
page->in_cons = cons;
/* Ensure ring contents. */
virt_wmb();
out:
mutex_unlock(&channel->ring_io_lock);
return IRQ_HANDLED;
}
void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
{
int notify;
channel->u.req.ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&channel->u.req.ring, notify);
if (notify)
notify_remote_via_irq(channel->irq);
}
static void evtchnl_free(struct xen_snd_front_info *front_info,
struct xen_snd_front_evtchnl *channel)
{
void *page = NULL;
if (channel->type == EVTCHNL_TYPE_REQ)
page = channel->u.req.ring.sring;
else if (channel->type == EVTCHNL_TYPE_EVT)
page = channel->u.evt.page;
if (!page)
return;
channel->state = EVTCHNL_STATE_DISCONNECTED;
if (channel->type == EVTCHNL_TYPE_REQ) {
/* Release all who still waits for response if any. */
channel->u.req.resp_status = -EIO;
complete_all(&channel->u.req.completion);
}
if (channel->irq)
unbind_from_irqhandler(channel->irq, channel);
if (channel->port)
xenbus_free_evtchn(front_info->xb_dev, channel->port);
/* End access and free the page. */
xenbus_teardown_ring(&page, 1, &channel->gref);
memset(channel, 0, sizeof(*channel));
}
void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info)
{
int i;
if (!front_info->evt_pairs)
return;
for (i = 0; i < front_info->num_evt_pairs; i++) {
evtchnl_free(front_info, &front_info->evt_pairs[i].req);
evtchnl_free(front_info, &front_info->evt_pairs[i].evt);
}
kfree(front_info->evt_pairs);
front_info->evt_pairs = NULL;
}
static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
struct xen_snd_front_evtchnl *channel,
enum xen_snd_front_evtchnl_type type)
{
struct xenbus_device *xb_dev = front_info->xb_dev;
void *page;
irq_handler_t handler;
char *handler_name = NULL;
int ret;
memset(channel, 0, sizeof(*channel));
channel->type = type;
channel->index = index;
channel->front_info = front_info;
channel->state = EVTCHNL_STATE_DISCONNECTED;
ret = xenbus_setup_ring(xb_dev, GFP_KERNEL, &page, 1, &channel->gref);
if (ret)
goto fail;
handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
type == EVTCHNL_TYPE_REQ ?
XENSND_FIELD_RING_REF :
XENSND_FIELD_EVT_RING_REF);
if (!handler_name) {
ret = -ENOMEM;
goto fail;
}
mutex_init(&channel->ring_io_lock);
if (type == EVTCHNL_TYPE_REQ) {
struct xen_sndif_sring *sring = page;
init_completion(&channel->u.req.completion);
mutex_init(&channel->u.req.req_io_lock);
XEN_FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
handler = evtchnl_interrupt_req;
} else {
channel->u.evt.page = page;
handler = evtchnl_interrupt_evt;
}
ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
if (ret < 0)
goto fail;
ret = bind_evtchn_to_irq(channel->port);
if (ret < 0) {
dev_err(&xb_dev->dev,
"Failed to bind IRQ for domid %d port %d: %d\n",
front_info->xb_dev->otherend_id, channel->port, ret);
goto fail;
}
channel->irq = ret;
ret = request_threaded_irq(channel->irq, NULL, handler,
IRQF_ONESHOT, handler_name, channel);
if (ret < 0) {
dev_err(&xb_dev->dev, "Failed to request IRQ %d: %d\n",
channel->irq, ret);
goto fail;
}
kfree(handler_name);
return 0;
fail:
kfree(handler_name);
dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
return ret;
}
int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
int num_streams)
{
struct xen_front_cfg_card *cfg = &front_info->cfg;
struct device *dev = &front_info->xb_dev->dev;
int d, ret = 0;
front_info->evt_pairs =
kcalloc(num_streams,
sizeof(struct xen_snd_front_evtchnl_pair),
GFP_KERNEL);
if (!front_info->evt_pairs)
return -ENOMEM;
/* Iterate over devices and their streams and create event channels. */
for (d = 0; d < cfg->num_pcm_instances; d++) {
struct xen_front_cfg_pcm_instance *pcm_instance;
int s, index;
pcm_instance = &cfg->pcm_instances[d];
for (s = 0; s < pcm_instance->num_streams_pb; s++) {
index = pcm_instance->streams_pb[s].index;
ret = evtchnl_alloc(front_info, index,
&front_info->evt_pairs[index].req,
EVTCHNL_TYPE_REQ);
if (ret < 0) {
dev_err(dev, "Error allocating control channel\n");
goto fail;
}
ret = evtchnl_alloc(front_info, index,
&front_info->evt_pairs[index].evt,
EVTCHNL_TYPE_EVT);
if (ret < 0) {
dev_err(dev, "Error allocating in-event channel\n");
goto fail;
}
}
for (s = 0; s < pcm_instance->num_streams_cap; s++) {
index = pcm_instance->streams_cap[s].index;
ret = evtchnl_alloc(front_info, index,
&front_info->evt_pairs[index].req,
EVTCHNL_TYPE_REQ);
if (ret < 0) {
dev_err(dev, "Error allocating control channel\n");
goto fail;
}
ret = evtchnl_alloc(front_info, index,
&front_info->evt_pairs[index].evt,
EVTCHNL_TYPE_EVT);
if (ret < 0) {
dev_err(dev, "Error allocating in-event channel\n");
goto fail;
}
}
}
front_info->num_evt_pairs = num_streams;
return 0;
fail:
xen_snd_front_evtchnl_free_all(front_info);
return ret;
}
static int evtchnl_publish(struct xenbus_transaction xbt,
struct xen_snd_front_evtchnl *channel,
const char *path, const char *node_ring,
const char *node_chnl)
{
struct xenbus_device *xb_dev = channel->front_info->xb_dev;
int ret;
/* Write control channel ring reference. */
ret = xenbus_printf(xbt, path, node_ring, "%u", channel->gref);
if (ret < 0) {
dev_err(&xb_dev->dev, "Error writing ring-ref: %d\n", ret);
return ret;
}
/* Write event channel ring reference. */
ret = xenbus_printf(xbt, path, node_chnl, "%u", channel->port);
if (ret < 0) {
dev_err(&xb_dev->dev, "Error writing event channel: %d\n", ret);
return ret;
}
return 0;
}
int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info)
{
struct xen_front_cfg_card *cfg = &front_info->cfg;
struct xenbus_transaction xbt;
int ret, d;
again:
ret = xenbus_transaction_start(&xbt);
if (ret < 0) {
xenbus_dev_fatal(front_info->xb_dev, ret,
"starting transaction");
return ret;
}
for (d = 0; d < cfg->num_pcm_instances; d++) {
struct xen_front_cfg_pcm_instance *pcm_instance;
int s, index;
pcm_instance = &cfg->pcm_instances[d];
for (s = 0; s < pcm_instance->num_streams_pb; s++) {
index = pcm_instance->streams_pb[s].index;
ret = evtchnl_publish(xbt,
&front_info->evt_pairs[index].req,
pcm_instance->streams_pb[s].xenstore_path,
XENSND_FIELD_RING_REF,
XENSND_FIELD_EVT_CHNL);
if (ret < 0)
goto fail;
ret = evtchnl_publish(xbt,
&front_info->evt_pairs[index].evt,
pcm_instance->streams_pb[s].xenstore_path,
XENSND_FIELD_EVT_RING_REF,
XENSND_FIELD_EVT_EVT_CHNL);
if (ret < 0)
goto fail;
}
for (s = 0; s < pcm_instance->num_streams_cap; s++) {
index = pcm_instance->streams_cap[s].index;
ret = evtchnl_publish(xbt,
&front_info->evt_pairs[index].req,
pcm_instance->streams_cap[s].xenstore_path,
XENSND_FIELD_RING_REF,
XENSND_FIELD_EVT_CHNL);
if (ret < 0)
goto fail;
ret = evtchnl_publish(xbt,
&front_info->evt_pairs[index].evt,
pcm_instance->streams_cap[s].xenstore_path,
XENSND_FIELD_EVT_RING_REF,
XENSND_FIELD_EVT_EVT_CHNL);
if (ret < 0)
goto fail;
}
}
ret = xenbus_transaction_end(xbt, 0);
if (ret < 0) {
if (ret == -EAGAIN)
goto again;
xenbus_dev_fatal(front_info->xb_dev, ret,
"completing transaction");
goto fail_to_end;
}
return 0;
fail:
xenbus_transaction_end(xbt, 1);
fail_to_end:
xenbus_dev_fatal(front_info->xb_dev, ret, "writing XenStore");
return ret;
}
void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
bool is_connected)
{
enum xen_snd_front_evtchnl_state state;
if (is_connected)
state = EVTCHNL_STATE_CONNECTED;
else
state = EVTCHNL_STATE_DISCONNECTED;
mutex_lock(&evt_pair->req.ring_io_lock);
evt_pair->req.state = state;
mutex_unlock(&evt_pair->req.ring_io_lock);
mutex_lock(&evt_pair->evt.ring_io_lock);
evt_pair->evt.state = state;
mutex_unlock(&evt_pair->evt.ring_io_lock);
}
void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair)
{
mutex_lock(&evt_pair->req.ring_io_lock);
evt_pair->req.evt_next_id = 0;
mutex_unlock(&evt_pair->req.ring_io_lock);
mutex_lock(&evt_pair->evt.ring_io_lock);
evt_pair->evt.evt_next_id = 0;
mutex_unlock(&evt_pair->evt.ring_io_lock);
}
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