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