Quelle  xen_drm_front_cfg.c   Sprache: C

// 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/device.h>

#include <drm/drm_print.h>

#include <xen/interface/io/displif.h>
#include <xen/xenbus.h>

#include "xen_drm_front.h"
#include "xen_drm_front_cfg.h"

static int cfg_connector(struct xen_drm_front_info *front_info,
    struct xen_drm_front_cfg_connector *connector,
    const char *path, int index)
{
 char *connector_path;

 connector_path = devm_kasprintf(&front_info->xb_dev->dev,
     GFP_KERNEL, "%s/%d", path, index);
 if (!connector_path)
  return -ENOMEM;

 if (xenbus_scanf(XBT_NIL, connector_path, XENDISPL_FIELD_RESOLUTION,
    "%d" XENDISPL_RESOLUTION_SEPARATOR "%d",
    &connector->width, &connector->height) < 0) {
  /* either no entry configured or wrong resolution set */
  connector->width = 0;
  connector->height = 0;
  return -EINVAL;
 }

 connector->xenstore_path = connector_path;

 DRM_INFO("Connector %s: resolution %dx%d\n",
   connector_path, connector->width, connector->height);
 return 0;
}

int xen_drm_front_cfg_card(struct xen_drm_front_info *front_info,
      struct xen_drm_front_cfg *cfg)
{
 struct xenbus_device *xb_dev = front_info->xb_dev;
 int ret, i;

 if (xenbus_read_unsigned(front_info->xb_dev->nodename,
     XENDISPL_FIELD_BE_ALLOC, 0)) {
  DRM_INFO("Backend can provide display buffers\n");
  cfg->be_alloc = true;
 }

 cfg->num_connectors = 0;
 for (i = 0; i < ARRAY_SIZE(cfg->connectors); i++) {
  ret = cfg_connector(front_info, &cfg->connectors[i],
        xb_dev->nodename, i);
  if (ret < 0)
   break;
  cfg->num_connectors++;
 }

 if (!cfg->num_connectors) {
  DRM_ERROR("No connector(s) configured at %s\n",
     xb_dev->nodename);
  return -ENODEV;
 }

 return 0;
}