Hi Jim,
On 6/23/23 19:23, Jim Shargo wrote:
This change adds the basic scaffolding for ConfigFS, including setting
up the default directories. It does not allow for the registration of
configfs-backed devices, which is complex and provided in a follow-up
commit.
This CL includes docs about using ConfigFS with VKMS, but I'll summarize
in brief here as well (assuming ConfigFS is mounted at /config/):
To create a new device, you can do so via `mkdir
/config/vkms/my-device`.
This will create a number of directories and files automatically:
/config
`-- vkms
`-- my-device
|-- connectors
|-- crtcs
|-- encoders
|-- planes
`-- enabled
You can then configure objects by mkdir'ing in each of the directories.
When you're satisfied, you can `echo 1 > /config/vkms/my-device/enabled`.
This will create a new device according to your configuration.
For now, this will fail, but the next change will add support for it.
Signed-off-by: Jim Shargo <jshargo@xxxxxxxxxxxx>
---
Documentation/gpu/vkms.rst | 17 +-
drivers/gpu/drm/Kconfig | 1 +
drivers/gpu/drm/vkms/Makefile | 1 +
drivers/gpu/drm/vkms/vkms_configfs.c | 646 +++++++++++++++++++++++++++
drivers/gpu/drm/vkms/vkms_drv.c | 52 ++-
drivers/gpu/drm/vkms/vkms_drv.h | 92 +++-
drivers/gpu/drm/vkms/vkms_output.c | 5 +
7 files changed, 799 insertions(+), 15 deletions(-)
create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index ba04ac7c2167..2c342ef0fb7b 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -51,6 +51,12 @@ To disable the driver, use ::
sudo modprobe -r vkms
+Configuration With ConfigFS
+===========================
+
+.. kernel-doc:: drivers/gpu/drm/vkms/vkms_configfs.c
+ :doc: ConfigFS Support for VKMS
+
Testing With IGT
================
@@ -135,22 +141,15 @@ project.
Runtime Configuration
---------------------
-We want to be able to reconfigure vkms instance without having to reload the
-module. Use/Test-cases:
+We want to vkms instances without having to reload the module. Such
I believe that there is a verb missing here.
+configuration can be added as extensions to vkms's ConfigFS support. Use-cases:
- Hotplug/hotremove connectors on the fly (to be able to test DP MST handling
of compositors).
-- Configure planes/crtcs/connectors (we'd need some code to have more than 1 of
- them first).
-
- Change output configuration: Plug/unplug screens, change EDID, allow changing
the refresh rate.
-The currently proposed solution is to expose vkms configuration through
-configfs. All existing module options should be supported through configfs
-too.
-
Writeback support
-----------------
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index afb3b2f5f425..71eb913b378f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -262,6 +262,7 @@ config DRM_VKMS
depends on DRM && MMU
select DRM_KMS_HELPER
select DRM_GEM_SHMEM_HELPER
+ select CONFIGFS_FS
select CRC32
default n
help
diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
index 1b28a6a32948..6b83907ad554 100644
--- a/drivers/gpu/drm/vkms/Makefile
+++ b/drivers/gpu/drm/vkms/Makefile
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
vkms-y := \
+ vkms_configfs.o \
vkms_drv.o \
vkms_plane.o \
vkms_output.o \
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
new file mode 100644
index 000000000000..544024735d19
--- /dev/null
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -0,0 +1,646 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/configfs.h>
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#include <drm/drm_plane.h>
+#include <drm/drm_print.h>
+
+#include "vkms_drv.h"
+
+/**
+ * DOC: ConfigFS Support for VKMS
+ *
+ * VKMS is instrumented with support for configuration via :doc:`ConfigFS
+ * <../filesystems/configfs>`.
+ *
+ * With VKMS installed, you can mount ConfigFS at ``/config/`` like so::
+ *
+ * mkdir -p /config/
+ * sudo mount -t configfs none /config
+ *
+ * This allows you to configure multiple virtual devices in addition to an
+ * immutable "default" device created by the driver at initialization time. Note
+ * that the default device is immutable because we cannot pre-populate ConfigFS
+ * directories with normal files.
+ *
+ * To set up a new device, create a new directory under the VKMS configfs
+ * directory::
+ *
+ * mkdir /config/vkms/test
+ *
+ * With your device created you'll find an new directory ready to be
+ * configured::
+ *
+ * /config
+ * `-- vkms
+ * |-- default
+ * | `-- enabled
+ * `-- test
+ * |-- connectors
+ * |-- crtcs
+ * |-- encoders
+ * |-- planes
+ * `-- enabled
I followed this steps and ended up with the following tree:
[root@fedora config]# tree vkms
vkms
└── test
├── connectors
├── crtcs
├── enabled
├── encoders
├── id
└── planes
I'm not sure if I did something wrong or if the folder "default" really
shouldn't show. If the folder "default" shouldn't show, it would be nice
to remove it from the docs.
+ *
+ * Each directory you add within the connectors, crtcs, encoders, and planes
+ * directories will let you configure a new object of that type. Adding new
+ * objects will automatically create a set of default files and folders you can
+ * use to configure that object.
+ *
+ * For instance, we can set up a two-output device like so::
+ *
+ * DRM_PLANE_TYPE_PRIMARY=1
+ * DRM_PLANE_TYPE_CURSOR=2
+ * DRM_PLANE_TYPE_OVERLAY=0
+ *
+ * mkdir /config/vkms/test/planes/primary
+ * echo $DRM_PLANE_TYPE_PRIMARY > /config/vkms/test/planes/primary/type
+ *
+ * mkdir /config/vkms/test/planes/other_primary
+ * echo $DRM_PLANE_TYPE_PRIMARY > /config/vkms/test/planes/other_primary/type
+ *
+ * mkdir /config/vkms/test/planes/cursor
+ * echo $DRM_PLANE_TYPE_CURSOR > /config/vkms/test/planes/cursor/type
+ *
+ * mkdir /config/vkms/test/planes/overlay
+ * echo $DRM_PLANE_TYPE_OVERLAY > /config/vkms/test/planes/overlay/type
+ *
+ * mkdir /config/vkms/test/crtcs/crtc
+ * mkdir /config/vkms/test/crtcs/crtc_other
+ * mkdir /config/vkms/test/encoders/encoder
+ * mkdir /config/vkms/test/connectors/connector
+ *
+ * You can see that specific attributes, such as ``.../<plane>/type``, can be
+ * configured by writing into them. Associating objects together can be done via
+ * symlinks::
+ *
+ * ln -s /config/vkms/test/encoders/encoder /config/vkms/test/connectors/connector/possible_encoders
+ *
+ * ln -s /config/vkms/test/crtcs/crtc /config/vkms/test/encoders/encoder/possible_crtcs/
+ * ln -s /config/vkms/test/crtcs/crtc /config/vkms/test/planes/primary/possible_crtcs/
+ * ln -s /config/vkms/test/crtcs/crtc /config/vkms/test/planes/cursor/possible_crtcs/
+ * ln -s /config/vkms/test/crtcs/crtc /config/vkms/test/planes/overlay/possible_crtcs/
+ *
+ * ln -s /config/vkms/test/crtcs/crtc_other /config/vkms/test/planes/overlay/possible_crtcs/
+ * ln -s /config/vkms/test/crtcs/crtc_other /config/vkms/test/planes/other_primary/possible_crtcs/
+ *
+ * Finally, to enable your configured device, just write 1 to the ``enabled``
+ * file::
+ *
+ * echo 1 > /config/vkms/test/enabled
+ *
+ * When you're done with the virtual device, you can clean up the device like
+ * so::
+ *
+ * echo 0 > /config/vkms/test/enabled
+ *
+ * rm /config/vkms/test/connectors/connector/possible_encoders/encoder
+ * rm /config/vkms/test/encoders/encoder/possible_crtcs/crtc
+ * rm /config/vkms/test/planes/primary/possible_crtcs/crtc
+ * rm /config/vkms/test/planes/cursor/possible_crtcs/crtc
+ * rm /config/vkms/test/planes/overlay/possible_crtcs/crtc
+ * rm /config/vkms/test/planes/overlay/possible_crtcs/crtc_other
+ * rm /config/vkms/test/planes/other_primary/possible_crtcs/crtc_other
+ *
+ * rmdir /config/vkms/test/planes/primary
+ * rmdir /config/vkms/test/planes/other_primary
+ * rmdir /config/vkms/test/planes/cursor
+ * rmdir /config/vkms/test/planes/overlay
+ * rmdir /config/vkms/test/crtcs/crtc
+ * rmdir /config/vkms/test/crtcs/crtc_other
+ * rmdir /config/vkms/test/encoders/encoder
+ * rmdir /config/vkms/test/connectors/connector
+ *
+ * rmdir /config/vkms/test
+ */
+
+/*
[...]
diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
index d43121addf66..1b5b7143792f 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.c
+++ b/drivers/gpu/drm/vkms/vkms_drv.c
@@ -9,7 +9,10 @@
* the GPU in DRM API tests.
*/
+#include <linux/configfs.h>
#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
@@ -152,8 +155,8 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
dev->mode_config.preferred_depth = 0;
dev->mode_config.helper_private = &vkms_mode_config_helpers;
- return vkmsdev->is_default ? vkms_output_init_default(vkmsdev) :
- -ENOSYS;
Is this middle step really needed?
Best Regards,
- Maíra
+ return vkmsdev->configfs ? vkms_output_init(vkmsdev) :
+ vkms_output_init_default(vkmsdev);
}
static int vkms_platform_probe(struct platform_device *pdev)
@@ -165,6 +168,7 @@ static int vkms_platform_probe(struct platform_device *pdev)
grp = devres_open_group(&pdev->dev, NULL, GFP_KERNEL);
if (!grp) {
+ DRM_ERROR("Could not open devres group\n");
return -ENOMEM;
}
@@ -179,7 +183,7 @@ static int vkms_platform_probe(struct platform_device *pdev)
vkms_device->config.cursor = enable_cursor;
vkms_device->config.writeback = enable_writeback;
vkms_device->config.overlay = enable_overlay;
- vkms_device->is_default = vkms_device_setup->is_default;
+ vkms_device->configfs = vkms_device_setup->configfs;
ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
DMA_BIT_MASK(64));
@@ -239,12 +243,43 @@ static struct platform_driver vkms_platform_driver = {
.driver.name = DRIVER_NAME,
};
+struct vkms_device *vkms_add_device(struct vkms_configfs *configfs)
+{
+ struct device *dev = NULL;
+ struct platform_device *pdev;
+ int max_id = 1;
+ struct vkms_device_setup vkms_device_setup = {
+ .configfs = configfs,
+ };
+
+ while ((dev = platform_find_device_by_driver(
+ dev, &vkms_platform_driver.driver))) {
+ pdev = to_platform_device(dev);
+ max_id = max(max_id, pdev->id);
+ }
+
+ pdev = platform_device_register_data(NULL, DRIVER_NAME, max_id + 1,
+ &vkms_device_setup,
+ sizeof(vkms_device_setup));
+ if (IS_ERR(pdev)) {
+ DRM_ERROR("Unable to register vkms device'\n");
+ return ERR_PTR(PTR_ERR(pdev));
+ }
+
+ return platform_get_drvdata(pdev);
+}
+
+void vkms_remove_device(struct vkms_device *vkms_device)
+{
+ platform_device_unregister(vkms_device->platform);
+}
+
static int __init vkms_init(void)
{
int ret;
struct platform_device *pdev;
struct vkms_device_setup vkms_device_setup = {
- .is_default = true,
+ .configfs = NULL,
};
ret = platform_driver_register(&vkms_platform_driver);
@@ -262,6 +297,13 @@ static int __init vkms_init(void)
return PTR_ERR(pdev);
}
+ ret = vkms_init_configfs();
+ if (ret) {
+ DRM_ERROR("Unable to initialize configfs\n");
+ platform_device_unregister(pdev);
+ platform_driver_unregister(&vkms_platform_driver);
+ }
+
return 0;
}
@@ -269,6 +311,8 @@ static void __exit vkms_exit(void)
{
struct device *dev;
+ vkms_unregister_configfs();
+
while ((dev = platform_find_device_by_driver(
NULL, &vkms_platform_driver.driver))) {
// platform_find_device_by_driver increments the refcount. Drop
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index 84b35aa1dc5a..3634eeeb4548 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -3,6 +3,7 @@
#ifndef _VKMS_DRV_H_
#define _VKMS_DRV_H_
+#include <linux/configfs.h>
#include <linux/hrtimer.h>
#include <drm/drm.h>
@@ -10,6 +11,7 @@
#include <drm/drm_gem.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_encoder.h>
+#include <drm/drm_plane.h>
#include <drm/drm_writeback.h>
#define XRES_MIN 10
@@ -127,14 +129,65 @@ struct vkms_config {
bool overlay;
};
+struct vkms_config_links {
+ struct config_group group;
+ unsigned long linked_object_bitmap;
+};
+
+struct vkms_config_connector {
+ struct config_group config_group;
+ struct vkms_config_links possible_encoders;
+};
+
+struct vkms_config_crtc {
+ struct config_group config_group;
+ unsigned long crtc_config_idx;
+};
+
+struct vkms_config_encoder {
+ struct config_group config_group;
+ struct vkms_config_links possible_crtcs;
+ unsigned long encoder_config_idx;
+};
+
+struct vkms_config_plane {
+ struct vkms_configfs *configfs;
+ struct config_group config_group;
+ struct vkms_config_links possible_crtcs;
+ enum drm_plane_type type;
+};
+
+struct vkms_configfs {
+ /* Directory group containing connector configs, e.g. /config/vkms/device/ */
+ struct config_group device_group;
+ /* Directory group containing connector configs, e.g. /config/vkms/device/connectors/ */
+ struct config_group connectors_group;
+ /* Directory group containing CRTC configs, e.g. /config/vkms/device/crtcs/ */
+ struct config_group crtcs_group;
+ /* Directory group containing encoder configs, e.g. /config/vkms/device/encoders/ */
+ struct config_group encoders_group;
+ /* Directory group containing plane configs, e.g. /config/vkms/device/planes/ */
+ struct config_group planes_group;
+
+ unsigned long allocated_crtcs;
+ unsigned long allocated_encoders;
+
+ struct mutex lock;
+
+ /* The platform device if this is registered, otherwise NULL */
+ struct vkms_device *vkms_device;
+};
+
struct vkms_device_setup {
- bool is_default;
+ // Is NULL in the case of the default card.
+ struct vkms_configfs *configfs;
};
struct vkms_device {
struct drm_device drm;
struct platform_device *platform;
- bool is_default;
+ // Is NULL in the case of the default card.
+ struct vkms_configfs *configfs;
struct vkms_output output;
struct vkms_config config;
};
@@ -153,11 +206,42 @@ struct vkms_device {
#define to_vkms_plane_state(target)\
container_of(target, struct vkms_plane_state, base.base)
+#define item_to_configfs(item) \
+ container_of(to_config_group(item), struct vkms_configfs, device_group)
+
+#define item_to_config_connector(item) \
+ container_of(to_config_group(item), struct vkms_config_connector, \
+ config_group)
+
+#define item_to_config_crtc(item) \
+ container_of(to_config_group(item), struct vkms_config_crtc, \
+ config_group)
+
+#define item_to_config_encoder(item) \
+ container_of(to_config_group(item), struct vkms_config_encoder, \
+ config_group)
+
+#define item_to_config_plane(item) \
+ container_of(to_config_group(item), struct vkms_config_plane, \
+ config_group)
+
+#define item_to_config_links(item) \
+ container_of(to_config_group(item), struct vkms_config_links, group)
+
+#define plane_item_to_configfs(item) \
+ container_of(to_config_group(item->ci_parent), struct vkms_configfs, \
+ planes_group)
+
+/* Devices */
+struct vkms_device *vkms_add_device(struct vkms_configfs *configfs);
+void vkms_remove_device(struct vkms_device *vkms_device);
+
/* CRTC */
struct vkms_crtc *vkms_crtc_init(struct vkms_device *vkmsdev,
struct drm_plane *primary,
struct drm_plane *cursor);
+int vkms_output_init(struct vkms_device *vkmsdev);
int vkms_output_init_default(struct vkms_device *vkmsdev);
struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
@@ -179,4 +263,8 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state
int vkms_enable_writeback_connector(struct vkms_device *vkmsdev,
struct vkms_crtc *vkms_crtc);
+/* ConfigFS Support */
+int vkms_init_configfs(void);
+void vkms_unregister_configfs(void);
+
#endif /* _VKMS_DRV_H_ */
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 3b5e272a8b33..c9e6c653de19 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -177,3 +177,8 @@ int vkms_output_init_default(struct vkms_device *vkmsdev)
return ret;
}
+
+int vkms_output_init(struct vkms_device *vkmsdev)
+{
+ return -ENOTSUPP;
+}
