diff options
author | Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> | 2018-05-14 09:27:39 +0300 |
---|---|---|
committer | Takashi Iwai <tiwai@suse.de> | 2018-05-16 12:58:41 +0200 |
commit | 788ef64a2caee38cc4b8890abd3d7e54dfa3bcc9 (patch) | |
tree | d30d0a599df3ca130513ee7400ed266b8e4432d1 /sound/xen/xen_snd_front_evtchnl.c | |
parent | fd3b36045c2c612b5f44a47f388677af256d1d0a (diff) | |
download | linux-788ef64a2caee38cc4b8890abd3d7e54dfa3bcc9.tar.bz2 |
ALSA: xen-front: Implement Xen event channel handling
Handle Xen event channels:
- create for all configured streams and publish
corresponding ring references and event channels in Xen store,
so backend can connect
- implement event channels interrupt handlers
- create and destroy event channels with respect to Xen bus state
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/xen/xen_snd_front_evtchnl.c')
-rw-r--r-- | sound/xen/xen_snd_front_evtchnl.c | 494 |
1 files changed, 494 insertions, 0 deletions
diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c new file mode 100644 index 000000000000..1faafff08807 --- /dev/null +++ b/sound/xen/xen_snd_front_evtchnl.c @@ -0,0 +1,494 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT + +/* + * Xen para-virtual sound device + * + * Copyright (C) 2016-2018 EPAM Systems Inc. + * + * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> + */ + +#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_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: + /* fall through */ + case XENSND_OP_CLOSE: + /* fall through */ + case XENSND_OP_READ: + /* fall through */ + case XENSND_OP_WRITE: + /* fall through */ + 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: + /* Do nothing at the moment. */ + 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) +{ + unsigned long page = 0; + + if (channel->type == EVTCHNL_TYPE_REQ) + page = (unsigned long)channel->u.req.ring.sring; + else if (channel->type == EVTCHNL_TYPE_EVT) + page = (unsigned long)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. */ + if (channel->gref != GRANT_INVALID_REF) + gnttab_end_foreign_access(channel->gref, 0, page); + else + free_page(page); + + 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; + unsigned long page; + grant_ref_t gref; + 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; + channel->gref = GRANT_INVALID_REF; + page = get_zeroed_page(GFP_KERNEL); + if (!page) { + ret = -ENOMEM; + 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 = (struct xen_sndif_sring *)page; + + init_completion(&channel->u.req.completion); + mutex_init(&channel->u.req.req_io_lock); + SHARED_RING_INIT(sring); + FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE); + + ret = xenbus_grant_ring(xb_dev, sring, 1, &gref); + if (ret < 0) { + channel->u.req.ring.sring = NULL; + goto fail; + } + + handler = evtchnl_interrupt_req; + } else { + ret = gnttab_grant_foreign_access(xb_dev->otherend_id, + virt_to_gfn((void *)page), 0); + if (ret < 0) + goto fail; + + channel->u.evt.page = (struct xensnd_event_page *)page; + gref = ret; + handler = evtchnl_interrupt_evt; + } + + channel->gref = gref; + + 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: + if (page) + free_page(page); + 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; + } + } + } + if (ret < 0) + 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); +} + |