v4.19.13 snapshot.
diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c
new file mode 100644
index 0000000..b089b13
--- /dev/null
+++ b/sound/xen/xen_snd_front.c
@@ -0,0 +1,397 @@
+// 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/interface/io/sndif.h>
+
+#include "xen_snd_front.h"
+#include "xen_snd_front_alsa.h"
+#include "xen_snd_front_evtchnl.h"
+#include "xen_snd_front_shbuf.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_snd_front_shbuf *sh_buf,
+ 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_snd_front_shbuf_get_dir_start(sh_buf);
+ 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)
+{
+ 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:
+ /* fall through */
+ case XenbusStateReconfigured:
+ /* fall through */
+ case XenbusStateInitialised:
+ /* fall through */
+ 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:
+ /* fall through */
+ 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,
+};
+
+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);
+MODULE_SUPPORTED_DEVICE("{{ALSA,Virtual soundcard}}");