LXR linux/drivers/gpu/drm/xen/xen_drm_front

   1// SPDX-License-Identifier: GPL-2.0 OR MIT
   2
   3/*
   4 *  Xen para-virtual DRM device
   5 *
   6 * Copyright (C) 2016-2018 EPAM Systems Inc.
   7 *
   8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
   9 */
  10
  11#include <linux/device.h>
  12
  13#include <drm/drm_print.h>
  14
  15#include <xen/interface/io/displif.h>
  16#include <xen/xenbus.h>
  17
  18#include "xen_drm_front.h"
  19#include "xen_drm_front_cfg.h"
  20
  21static int cfg_connector(struct xen_drm_front_info *front_info,
  22                         struct xen_drm_front_cfg_connector *connector,
  23                         const char *path, int index)
  24{
  25        char *connector_path;
  26
  27        connector_path = devm_kasprintf(&front_info->xb_dev->dev,
  28                                        GFP_KERNEL, "%s/%d", path, index);
  29        if (!connector_path)
  30                return -ENOMEM;
  31
  32        if (xenbus_scanf(XBT_NIL, connector_path, XENDISPL_FIELD_RESOLUTION,
  33                         "%d" XENDISPL_RESOLUTION_SEPARATOR "%d",
  34                         &connector->width, &connector->height) < 0) {
  35                /* either no entry configured or wrong resolution set */
  36                connector->width = 0;
  37                connector->height = 0;
  38                return -EINVAL;
  39        }
  40
  41        connector->xenstore_path = connector_path;
  42
  43        DRM_INFO("Connector %s: resolution %dx%d\n",
  44                 connector_path, connector->width, connector->height);
  45        return 0;
  46}
  47
  48int xen_drm_front_cfg_card(struct xen_drm_front_info *front_info,
  49                           struct xen_drm_front_cfg *cfg)
  50{
  51        struct xenbus_device *xb_dev = front_info->xb_dev;
  52        int ret, i;
  53
  54        if (xenbus_read_unsigned(front_info->xb_dev->nodename,
  55                                 XENDISPL_FIELD_BE_ALLOC, 0)) {
  56                DRM_INFO("Backend can provide display buffers\n");
  57                cfg->be_alloc = true;
  58        }
  59
  60        cfg->num_connectors = 0;
  61        for (i = 0; i < ARRAY_SIZE(cfg->connectors); i++) {
  62                ret = cfg_connector(front_info, &cfg->connectors[i],
  63                                    xb_dev->nodename, i);
  64                if (ret < 0)
  65                        break;
  66                cfg->num_connectors++;
  67        }
  68
  69        if (!cfg->num_connectors) {
  70                DRM_ERROR("No connector(s) configured at %s\n",
  71                          xb_dev->nodename);
  72                return -ENODEV;
  73        }
  74
  75        return 0;
  76}
  77
  78