diff options
Diffstat (limited to 'sound/xen/xen_snd_front.c')
| -rw-r--r-- | sound/xen/xen_snd_front.c | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c new file mode 100644 index 000000000..4041748c1 --- /dev/null +++ b/sound/xen/xen_snd_front.c @@ -0,0 +1,394 @@ +// 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 <linux/delay.h> +#include <linux/module.h> + +#include <xen/page.h> +#include <xen/platform_pci.h> +#include <xen/xen.h> +#include <xen/xenbus.h> + +#include <xen/xen-front-pgdir-shbuf.h> +#include <xen/interface/io/sndif.h> + +#include "xen_snd_front.h" +#include "xen_snd_front_alsa.h" +#include "xen_snd_front_evtchnl.h" + +static struct xensnd_req * +be_stream_prepare_req(struct xen_snd_front_evtchnl *evtchnl, u8 operation) +{ + struct xensnd_req *req; + + req = RING_GET_REQUEST(&evtchnl->u.req.ring, + evtchnl->u.req.ring.req_prod_pvt); + req->operation = operation; + req->id = evtchnl->evt_next_id++; + evtchnl->evt_id = req->id; + return req; +} + +static int be_stream_do_io(struct xen_snd_front_evtchnl *evtchnl) +{ + if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED)) + return -EIO; + + reinit_completion(&evtchnl->u.req.completion); + xen_snd_front_evtchnl_flush(evtchnl); + return 0; +} + +static int be_stream_wait_io(struct xen_snd_front_evtchnl *evtchnl) +{ + if (wait_for_completion_timeout(&evtchnl->u.req.completion, + msecs_to_jiffies(VSND_WAIT_BACK_MS)) <= 0) + return -ETIMEDOUT; + + return evtchnl->u.req.resp_status; +} + +int xen_snd_front_stream_query_hw_param(struct xen_snd_front_evtchnl *evtchnl, + struct xensnd_query_hw_param *hw_param_req, + struct xensnd_query_hw_param *hw_param_resp) +{ + struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_HW_PARAM_QUERY); + req->op.hw_param = *hw_param_req; + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + if (ret == 0) + *hw_param_resp = evtchnl->u.req.resp.hw_param; + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +int xen_snd_front_stream_prepare(struct xen_snd_front_evtchnl *evtchnl, + struct xen_front_pgdir_shbuf *shbuf, + u8 format, unsigned int channels, + unsigned int rate, u32 buffer_sz, + u32 period_sz) +{ + struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_OPEN); + req->op.open.pcm_format = format; + req->op.open.pcm_channels = channels; + req->op.open.pcm_rate = rate; + req->op.open.buffer_sz = buffer_sz; + req->op.open.period_sz = period_sz; + req->op.open.gref_directory = + xen_front_pgdir_shbuf_get_dir_start(shbuf); + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +int xen_snd_front_stream_close(struct xen_snd_front_evtchnl *evtchnl) +{ + __always_unused struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_CLOSE); + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +int xen_snd_front_stream_write(struct xen_snd_front_evtchnl *evtchnl, + unsigned long pos, unsigned long count) +{ + struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_WRITE); + req->op.rw.length = count; + req->op.rw.offset = pos; + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +int xen_snd_front_stream_read(struct xen_snd_front_evtchnl *evtchnl, + unsigned long pos, unsigned long count) +{ + struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_READ); + req->op.rw.length = count; + req->op.rw.offset = pos; + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +int xen_snd_front_stream_trigger(struct xen_snd_front_evtchnl *evtchnl, + int type) +{ + struct xensnd_req *req; + int ret; + + mutex_lock(&evtchnl->u.req.req_io_lock); + + mutex_lock(&evtchnl->ring_io_lock); + req = be_stream_prepare_req(evtchnl, XENSND_OP_TRIGGER); + req->op.trigger.type = type; + mutex_unlock(&evtchnl->ring_io_lock); + + ret = be_stream_do_io(evtchnl); + + if (ret == 0) + ret = be_stream_wait_io(evtchnl); + + mutex_unlock(&evtchnl->u.req.req_io_lock); + return ret; +} + +static void xen_snd_drv_fini(struct xen_snd_front_info *front_info) +{ + xen_snd_front_alsa_fini(front_info); + xen_snd_front_evtchnl_free_all(front_info); +} + +static int sndback_initwait(struct xen_snd_front_info *front_info) +{ + int num_streams; + int ret; + + ret = xen_snd_front_cfg_card(front_info, &num_streams); + if (ret < 0) + return ret; + + /* create event channels for all streams and publish */ + ret = xen_snd_front_evtchnl_create_all(front_info, num_streams); + if (ret < 0) + return ret; + + return xen_snd_front_evtchnl_publish_all(front_info); +} + +static int sndback_connect(struct xen_snd_front_info *front_info) +{ + return xen_snd_front_alsa_init(front_info); +} + +static void sndback_disconnect(struct xen_snd_front_info *front_info) +{ + xen_snd_drv_fini(front_info); + xenbus_switch_state(front_info->xb_dev, XenbusStateInitialising); +} + +static void sndback_changed(struct xenbus_device *xb_dev, + enum xenbus_state backend_state) +{ + struct xen_snd_front_info *front_info = dev_get_drvdata(&xb_dev->dev); + int ret; + + dev_dbg(&xb_dev->dev, "Backend state is %s, front is %s\n", + xenbus_strstate(backend_state), + xenbus_strstate(xb_dev->state)); + + switch (backend_state) { + case XenbusStateReconfiguring: + case XenbusStateReconfigured: + case XenbusStateInitialised: + break; + + case XenbusStateInitialising: + /* Recovering after backend unexpected closure. */ + sndback_disconnect(front_info); + break; + + case XenbusStateInitWait: + /* Recovering after backend unexpected closure. */ + sndback_disconnect(front_info); + + ret = sndback_initwait(front_info); + if (ret < 0) + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); + else + xenbus_switch_state(xb_dev, XenbusStateInitialised); + break; + + case XenbusStateConnected: + if (xb_dev->state != XenbusStateInitialised) + break; + + ret = sndback_connect(front_info); + if (ret < 0) + xenbus_dev_fatal(xb_dev, ret, "initializing frontend"); + else + xenbus_switch_state(xb_dev, XenbusStateConnected); + break; + + case XenbusStateClosing: + /* + * In this state backend starts freeing resources, + * so let it go into closed state first, so we can also + * remove ours. + */ + break; + + case XenbusStateUnknown: + case XenbusStateClosed: + if (xb_dev->state == XenbusStateClosed) + break; + + sndback_disconnect(front_info); + break; + } +} + +static int xen_drv_probe(struct xenbus_device *xb_dev, + const struct xenbus_device_id *id) +{ + struct xen_snd_front_info *front_info; + + front_info = devm_kzalloc(&xb_dev->dev, + sizeof(*front_info), GFP_KERNEL); + if (!front_info) + return -ENOMEM; + + front_info->xb_dev = xb_dev; + dev_set_drvdata(&xb_dev->dev, front_info); + + return xenbus_switch_state(xb_dev, XenbusStateInitialising); +} + +static int xen_drv_remove(struct xenbus_device *dev) +{ + struct xen_snd_front_info *front_info = dev_get_drvdata(&dev->dev); + int to = 100; + + xenbus_switch_state(dev, XenbusStateClosing); + + /* + * On driver removal it is disconnected from XenBus, + * so no backend state change events come via .otherend_changed + * callback. This prevents us from exiting gracefully, e.g. + * signaling the backend to free event channels, waiting for its + * state to change to XenbusStateClosed and cleaning at our end. + * Normally when front driver removed backend will finally go into + * XenbusStateInitWait state. + * + * Workaround: read backend's state manually and wait with time-out. + */ + while ((xenbus_read_unsigned(front_info->xb_dev->otherend, "state", + XenbusStateUnknown) != XenbusStateInitWait) && + --to) + msleep(10); + + if (!to) { + unsigned int state; + + state = xenbus_read_unsigned(front_info->xb_dev->otherend, + "state", XenbusStateUnknown); + pr_err("Backend state is %s while removing driver\n", + xenbus_strstate(state)); + } + + xen_snd_drv_fini(front_info); + xenbus_frontend_closed(dev); + return 0; +} + +static const struct xenbus_device_id xen_drv_ids[] = { + { XENSND_DRIVER_NAME }, + { "" } +}; + +static struct xenbus_driver xen_driver = { + .ids = xen_drv_ids, + .probe = xen_drv_probe, + .remove = xen_drv_remove, + .otherend_changed = sndback_changed, + .not_essential = true, +}; + +static int __init xen_drv_init(void) +{ + if (!xen_domain()) + return -ENODEV; + + if (!xen_has_pv_devices()) + return -ENODEV; + + /* At the moment we only support case with XEN_PAGE_SIZE == PAGE_SIZE */ + if (XEN_PAGE_SIZE != PAGE_SIZE) { + pr_err(XENSND_DRIVER_NAME ": different kernel and Xen page sizes are not supported: XEN_PAGE_SIZE (%lu) != PAGE_SIZE (%lu)\n", + XEN_PAGE_SIZE, PAGE_SIZE); + return -ENODEV; + } + + pr_info("Initialising Xen " XENSND_DRIVER_NAME " frontend driver\n"); + return xenbus_register_frontend(&xen_driver); +} + +static void __exit xen_drv_fini(void) +{ + pr_info("Unregistering Xen " XENSND_DRIVER_NAME " frontend driver\n"); + xenbus_unregister_driver(&xen_driver); +} + +module_init(xen_drv_init); +module_exit(xen_drv_fini); + +MODULE_DESCRIPTION("Xen virtual sound device frontend"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("xen:" XENSND_DRIVER_NAME); |