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path: root/drivers/gpu/drm/xen/xen_drm_front_evtchnl.c
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Diffstat (limited to 'drivers/gpu/drm/xen/xen_drm_front_evtchnl.c')
-rw-r--r--drivers/gpu/drm/xen/xen_drm_front_evtchnl.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/drivers/gpu/drm/xen/xen_drm_front_evtchnl.c b/drivers/gpu/drm/xen/xen_drm_front_evtchnl.c
new file mode 100644
index 000000000..e52afd792
--- /dev/null
+++ b/drivers/gpu/drm/xen/xen_drm_front_evtchnl.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+
+/*
+ * Xen para-virtual DRM device
+ *
+ * Copyright (C) 2016-2018 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
+ */
+
+#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;
+}