Re: [PATCH 3/9] drm/xen-front: Read driver configuration from Xen store

[Boris Ostrovsky]

On 02/21/2018 03:03 AM, Oleksandr Andrushchenko wrote:
> +
> +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(_info->xb_dev->dev,
> + GFP_KERNEL, "%s/%d", path, index);
> + if (!connector_path)
> + return -ENOMEM;
> +
> + connector->xenstore_path = connector_path;
> + if (xenbus_scanf(XBT_NIL, connector_path, XENDISPL_FIELD_RESOLUTION,
> + "%d" XENDISPL_RESOLUTION_SEPARATOR "%d",
> + >width, >height) < 0) {
> + /* either no entry configured or wrong resolution set */
> + connector->width = 0;
> + connector->height = 0;

Do you also need to set connector->xenstore_path to NULL? Or maybe just
set it after xenbus_scanf() call.

-boris



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Re: [PATCH 3/9] drm/xen-front: Read driver configuration from Xen store

[Oleksandr Andrushchenko]

On 02/23/2018 01:20 AM, Boris Ostrovsky wrote:

On 02/21/2018 03:03 AM, Oleksandr Andrushchenko wrote:

+
+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(_info->xb_dev->dev,
+   GFP_KERNEL, "%s/%d", path, index);
+   if (!connector_path)
+   return -ENOMEM;
+
+   connector->xenstore_path = connector_path;
+   if (xenbus_scanf(XBT_NIL, connector_path, XENDISPL_FIELD_RESOLUTION,
+   "%d" XENDISPL_RESOLUTION_SEPARATOR "%d",
+   >width, >height) < 0) {
+   /* either no entry configured or wrong resolution set */
+   connector->width = 0;
+   connector->height = 0;

Do you also need to set connector->xenstore_path to NULL? Or maybe just
set it after xenbus_scanf() call.

Will move it down the code, after "if", thank you

-boris





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[PATCH 3/9] drm/xen-front: Read driver configuration from Xen store

[Oleksandr Andrushchenko]

From: Oleksandr Andrushchenko 

Read configuration values from Xen store according
to xen/interface/io/displif.h protocol:
  - read connector(s) configuration
  - read buffer allocation mode (backend/frontend)

Signed-off-by: Oleksandr Andrushchenko 
---
 drivers/gpu/drm/xen/Makefile|  3 +-
 drivers/gpu/drm/xen/xen_drm_front.c |  9 
 drivers/gpu/drm/xen/xen_drm_front.h |  3 ++
 drivers/gpu/drm/xen/xen_drm_front_cfg.c | 84 +
 drivers/gpu/drm/xen/xen_drm_front_cfg.h | 45 ++
 5 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/xen/xen_drm_front_cfg.c
 create mode 100644 drivers/gpu/drm/xen/xen_drm_front_cfg.h

diff --git a/drivers/gpu/drm/xen/Makefile b/drivers/gpu/drm/xen/Makefile
index 967074d348f6..0a2eae757f0c 100644
--- a/drivers/gpu/drm/xen/Makefile
+++ b/drivers/gpu/drm/xen/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-drm_xen_front-objs := xen_drm_front.o
+drm_xen_front-objs := xen_drm_front.o \
+ xen_drm_front_cfg.o
 
 obj-$(CONFIG_DRM_XEN_FRONTEND) += drm_xen_front.o
diff --git a/drivers/gpu/drm/xen/xen_drm_front.c 
b/drivers/gpu/drm/xen/xen_drm_front.c
index d0306f9d660d..0a90c474c7ce 100644
--- a/drivers/gpu/drm/xen/xen_drm_front.c
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -32,6 +32,15 @@ static void xen_drv_remove_internal(struct 
xen_drm_front_info *front_info)
 
 static int backend_on_initwait(struct xen_drm_front_info *front_info)
 {
+   struct xen_drm_front_cfg *cfg = _info->cfg;
+   int ret;
+
+   cfg->front_info = front_info;
+   ret = xen_drm_front_cfg_card(front_info, cfg);
+   if (ret < 0)
+   return ret;
+
+   DRM_INFO("Have %d conector(s)\n", cfg->num_connectors);
return 0;
 }
 
diff --git a/drivers/gpu/drm/xen/xen_drm_front.h 
b/drivers/gpu/drm/xen/xen_drm_front.h
index 8af46850f126..62b0d4e3e12b 100644
--- a/drivers/gpu/drm/xen/xen_drm_front.h
+++ b/drivers/gpu/drm/xen/xen_drm_front.h
@@ -19,8 +19,11 @@
 #ifndef __XEN_DRM_FRONT_H_
 #define __XEN_DRM_FRONT_H_
 
+#include "xen_drm_front_cfg.h"
+
 struct xen_drm_front_info {
struct xenbus_device *xb_dev;
+   struct xen_drm_front_cfg cfg;
 };
 
 #endif /* __XEN_DRM_FRONT_H_ */
diff --git a/drivers/gpu/drm/xen/xen_drm_front_cfg.c 
b/drivers/gpu/drm/xen/xen_drm_front_cfg.c
new file mode 100644
index ..58fe50bc52a5
--- /dev/null
+++ b/drivers/gpu/drm/xen/xen_drm_front_cfg.c
@@ -0,0 +1,84 @@
+/*
+ *  Xen para-virtual DRM device
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ * Copyright (C) 2016-2018 EPAM Systems Inc.
+ *
+ * Author: Oleksandr Andrushchenko 
+ */
+
+#include 
+
+#include 
+
+#include 
+#include 
+
+#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(_info->xb_dev->dev,
+   GFP_KERNEL, "%s/%d", path, index);
+   if (!connector_path)
+   return -ENOMEM;
+
+   connector->xenstore_path = connector_path;
+   if (xenbus_scanf(XBT_NIL, connector_path, XENDISPL_FIELD_RESOLUTION,
+   "%d" XENDISPL_RESOLUTION_SEPARATOR "%d",
+   >width, >height) < 0) {
+   /* either no entry configured or wrong resolution set */
+   connector->width = 0;
+   connector->height = 0;
+   return -EINVAL;
+   }
+
+   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,
+   >connectors[i],