On 17/04/18 10:58, Oleksandr Andrushchenko wrote:
> On 04/16/2018 04:12 PM, Juergen Gross wrote:
>> On 16/04/18 08:24, Oleksandr Andrushchenko wrote:
>>> From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
>>>
>>> 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_andrushche...@epam.com>
>>> ---
>>> sound/xen/Makefile | 3 +-
>>> sound/xen/xen_snd_front.c | 10 +-
>>> sound/xen/xen_snd_front.h | 7 +
>>> sound/xen/xen_snd_front_evtchnl.c | 474
>>> ++++++++++++++++++++++++++++++++++++++
>>> sound/xen/xen_snd_front_evtchnl.h | 92 ++++++++
>>> 5 files changed, 584 insertions(+), 2 deletions(-)
>>> create mode 100644 sound/xen/xen_snd_front_evtchnl.c
>>> create mode 100644 sound/xen/xen_snd_front_evtchnl.h
>>>
>>> diff --git a/sound/xen/Makefile b/sound/xen/Makefile
>>> index 06705bef61fa..03c669984000 100644
>>> --- a/sound/xen/Makefile
>>> +++ b/sound/xen/Makefile
>>> @@ -1,6 +1,7 @@
>>> # 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
>>> diff --git a/sound/xen/xen_snd_front.c b/sound/xen/xen_snd_front.c
>>> index 65d2494a9d14..eb46bf4070f9 100644
>>> --- a/sound/xen/xen_snd_front.c
>>> +++ b/sound/xen/xen_snd_front.c
>>> @@ -18,9 +18,11 @@
>>> #include <xen/interface/io/sndif.h>
>>> #include "xen_snd_front.h"
>>> +#include "xen_snd_front_evtchnl.h"
>> Does it really make sense to have multiple driver-private headers?
>>
>> I think those can be merged.
> I would really like to keep it separate as it clearly
> shows which stuff belongs to which modules.
> At least for me it is easier to maintain it this way.
>>
>>> 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)
>>> @@ -122,6 +129,7 @@ static int xen_drv_probe(struct xenbus_device
>>> *xb_dev,
>>> return -ENOMEM;
>>> front_info->xb_dev = xb_dev;
>>> + spin_lock_init(&front_info->io_lock);
>>> dev_set_drvdata(&xb_dev->dev, front_info);
>>> return xenbus_switch_state(xb_dev, XenbusStateInitialising);
>>> diff --git a/sound/xen/xen_snd_front.h b/sound/xen/xen_snd_front.h
>>> index b52226cb30bc..9c2ffbb4e4b8 100644
>>> --- a/sound/xen/xen_snd_front.h
>>> +++ b/sound/xen/xen_snd_front.h
>>> @@ -13,9 +13,16 @@
>>> #include "xen_snd_front_cfg.h"
>>> +struct xen_snd_front_evtchnl_pair;
>>> +
>>> struct xen_snd_front_info {
>>> struct xenbus_device *xb_dev;
>>> + /* serializer for backend IO: request/response */
>>> + spinlock_t io_lock;
>>> + int num_evt_pairs;
>>> + struct xen_snd_front_evtchnl_pair *evt_pairs;
>>> +
>>> struct xen_front_cfg_card cfg;
>>> };
>>> diff --git a/sound/xen/xen_snd_front_evtchnl.c
>>> b/sound/xen/xen_snd_front_evtchnl.c
>>> new file mode 100644
>>> index 000000000000..9ece39f938f8
>>> --- /dev/null
>>> +++ b/sound/xen/xen_snd_front_evtchnl.c
>>> @@ -0,0 +1,474 @@
>>> +// SPDX-License-Identifier: GPL-2.0 OR MIT
>>> +
>>> +/*
>>> + * Xen para-virtual sound device
>>> + *
>>> + * Copyright (C) 2016-2018 EPAM Systems Inc.
>>> + *
>>> + * Author: Oleksandr Andrushchenko <oleksandr_andrushche...@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;
>>> + unsigned long flags;
>>> +
>>> + if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
>>> + return IRQ_HANDLED;
>>> +
>>> + spin_lock_irqsave(&front_info->io_lock, flags);
>>> +
>>> +again:
>>> + rp = channel->u.req.ring.sring->rsp_prod;
>>> + /* ensure we see queued responses up to rp */
>>> + rmb();
>>> +
>>> + 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;
>>> + }
>>> +
>>> + spin_unlock_irqrestore(&front_info->io_lock, flags);
>>> + return IRQ_HANDLED;
>>> +}
>>> +
>>> +static irqreturn_t evtchnl_interrupt_evt(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_event_page *page = channel->u.evt.page;
>>> + u32 cons, prod;
>>> + unsigned long flags;
>>> +
>>> + if (unlikely(channel->state != EVTCHNL_STATE_CONNECTED))
>>> + return IRQ_HANDLED;
>>> +
>>> + spin_lock_irqsave(&front_info->io_lock, flags);
>>> +
>>> + prod = page->in_prod;
>>> + /* ensure we see ring contents up to prod */
>>> + virt_rmb();
>>> + if (prod == page->in_cons)
>>> + goto out;
>>> +
>>> + 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:
>>> + spin_unlock_irqrestore(&front_info->io_lock, flags);
>>> + 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);
>> Free page?
> According to [1] if page is provided to gnttab_end_foreign_access
> it will be freed. So, no need to free it manually
Either a free_page() is missing here in an else clause or the if is
not necessary.
Juergen
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