// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
* Xen para-virtual DRM device
*
* Copyright (C) 2016-2018 EPAM Systems Inc.
*
* Author: Oleksandr Andrushchenko <[email protected]>
*/
#include <linux/errno.h>
#include <linux/irq.h>
#include <drm/drm_print.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/grant_table.h>
#include "xen_drm_front.h"
#include "xen_drm_front_evtchnl.h"
static irqreturn_t evtchnl_interrupt_ctrl(int irq, void *dev_id)
{
struct xen_drm_front_evtchnl *evtchnl = dev_id;
struct xen_drm_front_info *front_info = evtchnl->front_info;
struct xendispl_resp *resp;
RING_IDX i, rp;
unsigned long flags;
if (unlikely(evtchnl->state != EVTCHNL_STATE_CONNECTED))
return IRQ_HANDLED;
spin_lock_irqsave(&front_info->io_lock, flags);
again:
rp = evtchnl->u.req.ring.sring->rsp_prod;
/* ensure we see queued responses up to rp */
virt_rmb();
for (i = evtchnl->u.req.ring.rsp_cons; i != rp; i++) {
resp = RING_GET_RESPONSE(&evtchnl->u.req.ring, i);
if (unlikely(resp->id != evtchnl->evt_id))
continue;
switch (resp->operation) {
case XENDISPL_OP_PG_FLIP:
case XENDISPL_OP_FB_ATTACH:
case XENDISPL_OP_FB_DETACH:
case XENDISPL_OP_DBUF_CREATE:
case XENDISPL_OP_DBUF_DESTROY:
case XENDISPL_OP_SET_CONFIG:
evtchnl->u.req.resp_status = resp->status;
complete(&evtchnl->u.req.completion);
break;
default:
DRM_ERROR("Operation %d is not supported\n",
resp->operation);
break;
}
}
evtchnl->u.req.ring.rsp_cons = i;
if (i != evtchnl->u.req.ring.req_prod_pvt) {
int more_to_do;
RING_FINAL_CHECK_FOR_RESPONSES(&evtchnl->u.req.ring,
more_to_do);
if (more_to_do)
goto again;
} else {
evtchnl->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_drm_front_evtchnl *evtchnl = dev_id;
struct xen_drm_front_info *front_info = evtchnl->front_info;
struct xendispl_event_page *page = evtchnl->u.evt.page;
u32 cons, prod;
unsigned long flags;
if (unlikely(evtchnl->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 xendispl_evt *event;
event = &XENDISPL_IN_RING_REF(page, cons);
if (unlikely(event->id != evtchnl->evt_id++))
continue;
switch (event->type) {
case XENDISPL_EVT_PG_FLIP:
xen_drm_front_on_frame_done(front_info, evtchnl->index,
event->op.pg_flip.fb_cookie);
break;
}
}
page->in_cons = cons;
/* ensure ring contents */
virt_wmb();
out:
spin_unlock_irqrestore(&front_info->io_lock, flags);
return IRQ_HANDLED;
}
static void evtchnl_free(struct xen_drm_front_info *front_info,
struct xen_drm_front_evtchnl *evtchnl)
{
void *page = NULL;
if (evtchnl->type == EVTCHNL_TYPE_REQ)
page = evtchnl->u.req.ring.sring;
else if (evtchnl->type == EVTCHNL_TYPE_EVT)
page = evtchnl->u.evt.page;
if (!page)
return;
evtchnl->state = EVTCHNL_STATE_DISCONNECTED;
if (evtchnl->type == EVTCHNL_TYPE_REQ) {
/* release all who still waits for response if any */
evtchnl->u.req.resp_status = -EIO;
complete_all(&evtchnl->u.req.completion);
}
if (evtchnl->irq)
unbind_from_irqhandler(evtchnl->irq, evtchnl);
if (evtchnl->port)
xenbus_free_evtchn(front_info->xb_dev, evtchnl->port);
/* end access and free the page */
xenbus_teardown_ring(&page, 1, &evtchnl->gref);
memset(evtchnl, 0, sizeof(*evtchnl));
}
static int evtchnl_alloc(struct xen_drm_front_info *front_info, int index,
struct xen_drm_front_evtchnl *evtchnl,
enum xen_drm_front_evtchnl_type type)
{
struct xenbus_device *xb_dev = front_info->xb_dev;
void *page;
irq_handler_t handler;
int ret;
memset(evtchnl, 0, sizeof(*evtchnl));
evtchnl->type = type;
evtchnl->index = index;
evtchnl->front_info = front_info;
evtchnl->state = EVTCHNL_STATE_DISCONNECTED;
ret = xenbus_setup_ring(xb_dev, GFP_NOIO | __GFP_HIGH, &page,
1, &evtchnl->gref);
if (ret)
goto fail;
if (type == EVTCHNL_TYPE_REQ) {
struct xen_displif_sring *sring;
init_completion(&evtchnl->u.req.completion);
mutex_init(&evtchnl->u.req.req_io_lock);
sring = page;
XEN_FRONT_RING_INIT(&evtchnl->u.req.ring, sring, XEN_PAGE_SIZE);
handler = evtchnl_interrupt_ctrl;
} else {
evtchnl->u.evt.page = page;
handler = evtchnl_interrupt_evt;
}
ret = xenbus_alloc_evtchn(xb_dev, &evtchnl->port);
if (ret < 0)
goto fail;
ret = bind_evtchn_to_irqhandler(evtchnl->port,
handler, 0, xb_dev->devicetype,
evtchnl);
if (ret < 0)
goto fail;
evtchnl->irq = ret;
return 0;
fail:
DRM_ERROR("Failed to allocate ring: %d\n", ret);
return ret;
}
int xen_drm_front_evtchnl_create_all(struct xen_drm_front_info *front_info)
{
struct xen_drm_front_cfg *cfg;
int ret, conn;
cfg = &front_info->cfg;
front_info->evt_pairs =
kcalloc(cfg->num_connectors,
sizeof(struct xen_drm_front_evtchnl_pair),
GFP_KERNEL);
if (!front_info->evt_pairs) {
ret = -ENOMEM;
goto fail;
}
for (conn = 0; conn < cfg->num_connectors; conn++) {
ret = evtchnl_alloc(front_info, conn,
&front_info->evt_pairs[conn].req,
EVTCHNL_TYPE_REQ);
if (ret < 0) {
DRM_ERROR("Error allocating control channel\n");
goto fail;
}
ret = evtchnl_alloc(front_info, conn,
&front_info->evt_pairs[conn].evt,
EVTCHNL_TYPE_EVT);
if (ret < 0) {
DRM_ERROR("Error allocating in-event channel\n");
goto fail;
}
}
front_info->num_evt_pairs = cfg->num_connectors;
return 0;
fail:
xen_drm_front_evtchnl_free_all(front_info);
return ret;
}
static int evtchnl_publish(struct xenbus_transaction xbt,
struct xen_drm_front_evtchnl *evtchnl,
const char *path, const char *node_ring,
const char *node_chnl)
{
struct xenbus_device *xb_dev = evtchnl->front_info->xb_dev;
int ret;
/* write control channel ring reference */
ret = xenbus_printf(xbt, path, node_ring, "%u", evtchnl->gref);
if (ret < 0) {
xenbus_dev_error(xb_dev, ret, "writing ring-ref");
return ret;
}
/* write event channel ring reference */
ret = xenbus_printf(xbt, path, node_chnl, "%u", evtchnl->port);
if (ret < 0) {
xenbus_dev_error(xb_dev, ret, "writing event channel");
return ret;
}
return 0;
}
int xen_drm_front_evtchnl_publish_all(struct xen_drm_front_info *front_info)
{
struct xenbus_transaction xbt;
struct xen_drm_front_cfg *plat_data;
int ret, conn;
plat_data = &front_info->cfg;
again:
ret = xenbus_transaction_start(&xbt);
if (ret < 0) {
xenbus_dev_fatal(front_info->xb_dev, ret,
"starting transaction");
return ret;
}
for (conn = 0; conn < plat_data->num_connectors; conn++) {
ret = evtchnl_publish(xbt, &front_info->evt_pairs[conn].req,
plat_data->connectors[conn].xenstore_path,
XENDISPL_FIELD_REQ_RING_REF,
XENDISPL_FIELD_REQ_CHANNEL);
if (ret < 0)
goto fail;
ret = evtchnl_publish(xbt, &front_info->evt_pairs[conn].evt,
plat_data->connectors[conn].xenstore_path,
XENDISPL_FIELD_EVT_RING_REF,
XENDISPL_FIELD_EVT_CHANNEL);
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 Xen store");
return ret;
}
void xen_drm_front_evtchnl_flush(struct xen_drm_front_evtchnl *evtchnl)
{
int notify;
evtchnl->u.req.ring.req_prod_pvt++;
RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&evtchnl->u.req.ring, notify);
if (notify)
notify_remote_via_irq(evtchnl->irq);
}
void xen_drm_front_evtchnl_set_state(struct xen_drm_front_info *front_info,
enum xen_drm_front_evtchnl_state state)
{
unsigned long flags;
int i;
if (!front_info->evt_pairs)
return;
spin_lock_irqsave(&front_info->io_lock, flags);
for (i = 0; i < front_info->num_evt_pairs; i++) {
front_info->evt_pairs[i].req.state = state;
front_info->evt_pairs[i].evt.state = state;
}
spin_unlock_irqrestore(&front_info->io_lock, flags);
}
void xen_drm_front_evtchnl_free_all(struct xen_drm_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;
}
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