ALSA: xen-front: Implement Xen event channel handling (788ef64a) · Commits · e / devices / android_kernel_xiaomi_nabu

sound/xen/Makefile

+2 −1

Original line number	Diff line number	Diff line
		# SPDX-License-Identifier: GPL-2.0 OR MIT

		snd_xen_front-objs := xen_snd_front.o \
		xen_snd_front_cfg.o
		xen_snd_front_cfg.o \
		xen_snd_front_evtchnl.o

		obj-$(CONFIG_SND_XEN_FRONTEND) += snd_xen_front.o

sound/xen/xen_snd_front.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -18,9 +18,11 @@
		#include <xen/interface/io/sndif.h>

		#include "xen_snd_front.h"
		#include "xen_snd_front_evtchnl.h"

		static void xen_snd_drv_fini(struct xen_snd_front_info *front_info)
		{
		xen_snd_front_evtchnl_free_all(front_info);
		}

		static int sndback_initwait(struct xen_snd_front_info *front_info)
		@@ -32,7 +34,12 @@ static int sndback_initwait(struct xen_snd_front_info *front_info)
		if (ret < 0)
		return ret;

		return 0;
		/* 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)

sound/xen/xen_snd_front.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -13,9 +13,14 @@

		#include "xen_snd_front_cfg.h"

		struct xen_snd_front_evtchnl_pair;

		struct xen_snd_front_info {
		struct xenbus_device *xb_dev;

		int num_evt_pairs;
		struct xen_snd_front_evtchnl_pair *evt_pairs;

		struct xen_front_cfg_card cfg;
		};

sound/xen/xen_snd_front_evtchnl.c

0 → 100644

+494 −0

Original line number	Diff line number	Diff line
		// 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);
		}

sound/xen/xen_snd_front_evtchnl.h

0 → 100644

+95 −0

Original line number	Diff line number	Diff line
		/* 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>
		*/

		#ifndef __XEN_SND_FRONT_EVTCHNL_H
		#define __XEN_SND_FRONT_EVTCHNL_H

		#include <xen/interface/io/sndif.h>

		struct xen_snd_front_info;

		#ifndef GRANT_INVALID_REF
		/*
		* FIXME: usage of grant reference 0 as invalid grant reference:
		* grant reference 0 is valid, but never exposed to a PV driver,
		* because of the fact it is already in use/reserved by the PV console.
		*/
		#define GRANT_INVALID_REF 0
		#endif

		/* Timeout in ms to wait for backend to respond. */
		#define VSND_WAIT_BACK_MS 3000

		enum xen_snd_front_evtchnl_state {
		EVTCHNL_STATE_DISCONNECTED,
		EVTCHNL_STATE_CONNECTED,
		};

		enum xen_snd_front_evtchnl_type {
		EVTCHNL_TYPE_REQ,
		EVTCHNL_TYPE_EVT,
		};

		struct xen_snd_front_evtchnl {
		struct xen_snd_front_info *front_info;
		int gref;
		int port;
		int irq;
		int index;
		/* State of the event channel. */
		enum xen_snd_front_evtchnl_state state;
		enum xen_snd_front_evtchnl_type type;
		/* Either response id or incoming event id. */
		u16 evt_id;
		/* Next request id or next expected event id. */
		u16 evt_next_id;
		/* Shared ring access lock. */
		struct mutex ring_io_lock;
		union {
		struct {
		struct xen_sndif_front_ring ring;
		struct completion completion;
		/* Serializer for backend IO: request/response. */
		struct mutex req_io_lock;

		/* Latest response status. */
		int resp_status;
		union {
		struct xensnd_query_hw_param hw_param;
		} resp;
		} req;
		struct {
		struct xensnd_event_page *page;
		/* This is needed to handle XENSND_EVT_CUR_POS event. */
		struct snd_pcm_substream *substream;
		} evt;
		} u;
		};

		struct xen_snd_front_evtchnl_pair {
		struct xen_snd_front_evtchnl req;
		struct xen_snd_front_evtchnl evt;
		};

		int xen_snd_front_evtchnl_create_all(struct xen_snd_front_info *front_info,
		int num_streams);

		void xen_snd_front_evtchnl_free_all(struct xen_snd_front_info *front_info);

		int xen_snd_front_evtchnl_publish_all(struct xen_snd_front_info *front_info);

		void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *evtchnl);

		void xen_snd_front_evtchnl_pair_set_connected(struct xen_snd_front_evtchnl_pair *evt_pair,
		bool is_connected);

		void xen_snd_front_evtchnl_pair_clear(struct xen_snd_front_evtchnl_pair *evt_pair);

		#endif /* __XEN_SND_FRONT_EVTCHNL_H */