accel: add accel dummy driver This commit is only intended as a reference of how to add a new accelerator driver. It is not intended to be merged. The dummy driver defines the new DRIVER_COMPUTE_ACCEL flag as its feature and registers to the drm subsystem. Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
diff --git a/drivers/accel/Kconfig b/drivers/accel/Kconfig index 282ea24..588f311 100644 --- a/drivers/accel/Kconfig +++ b/drivers/accel/Kconfig
@@ -22,3 +22,5 @@ major number than GPUs, and will be exposed to user-space using different device files, called accel/accel* (in /dev, sysfs and debugfs) + +source "drivers/accel/dummy/Kconfig"
diff --git a/drivers/accel/Makefile b/drivers/accel/Makefile index b5b7d81..171191e 100644 --- a/drivers/accel/Makefile +++ b/drivers/accel/Makefile
@@ -8,3 +8,6 @@ accel_drv.o obj-$(CONFIG_ACCEL) += accel.o + +obj-$(CONFIG_ACCEL_DUMMY) += dummy/ +
diff --git a/drivers/accel/dummy/Kconfig b/drivers/accel/dummy/Kconfig new file mode 100644 index 0000000..7723d4c --- /dev/null +++ b/drivers/accel/dummy/Kconfig
@@ -0,0 +1,15 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +config ACCEL_DUMMY + tristate "Drive for a dummy compute accelerator" + depends on ACCEL + help + An example of a compute accelerator driver that registers with drm + as a compute accelerator. + + This driver does not actually do anything. + + If unsure, say N. + + To compile this driver as a module, choose M here: the + module will be called accel_dummy.
diff --git a/drivers/accel/dummy/Makefile b/drivers/accel/dummy/Makefile new file mode 100644 index 0000000..c2b9706 --- /dev/null +++ b/drivers/accel/dummy/Makefile
@@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0-only + +accel_dummy-y += dummy_drv.o + +obj-$(CONFIG_ACCEL_DUMMY) := accel_dummy.o
diff --git a/drivers/accel/dummy/dummy_drv.c b/drivers/accel/dummy/dummy_drv.c new file mode 100644 index 0000000..da516f7 --- /dev/null +++ b/drivers/accel/dummy/dummy_drv.c
@@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/module.h> +#include <linux/platform_device.h> + +#include <drm/drm_accel.h> +#include <drm/drm_drv.h> +#include <drm/drm_ioctl.h> +#include <drm/drm_print.h> + +#define DRIVER_NAME "accel_dummy" +#define DRIVER_DESC "Driver for a dummy compute accelerator" +#define DRIVER_DATE "20221022" +#define DRIVER_MAJOR 1 +#define DRIVER_MINOR 0 + +MODULE_AUTHOR("Oded Gabbay"); +MODULE_DESCRIPTION("Driver for a dummy compute accelerator"); +MODULE_LICENSE("GPL"); + +struct accel_dummy_device { + struct drm_device drm; + struct platform_device *platform; +}; + +static struct accel_dummy_device *add; + +static void accel_dummy_release(struct drm_device *dev) +{ + DRM_INFO("%s called", __func__); +} + +static void accel_dummy_debugfs_init(struct drm_minor *minor) +{ + DRM_INFO("%s called", __func__); +} + +static const struct file_operations accel_dummy_driver_fops = { + .owner = THIS_MODULE, + .open = accel_open, + .release = drm_release, + .unlocked_ioctl = drm_ioctl, + .poll = drm_poll, + .read = drm_read, + .llseek = noop_llseek +}; + +static const struct drm_driver accel_dummy_driver = { + .driver_features = DRIVER_COMPUTE_ACCEL, + .release = accel_dummy_release, + .fops = &accel_dummy_driver_fops, + .debugfs_init = accel_dummy_debugfs_init, + .name = DRIVER_NAME, + .desc = DRIVER_DESC, + .date = DRIVER_DATE, + .major = DRIVER_MAJOR, + .minor = DRIVER_MINOR, +}; + +static void __exit accel_dummy_exit(void) +{ + struct platform_device *pdev; + + DRM_INFO("%s called", __func__); + + if (IS_ERR_OR_NULL(add)) { + DRM_INFO("accel_dummy_device wasn't initialized\n"); + return; + } + + pdev = add->platform; + + drm_dev_unregister(&add->drm); + devres_release_group(&pdev->dev, NULL); + platform_device_unregister(pdev); + + kfree(add); + add = NULL; +} + +static int __init accel_dummy_init(void) +{ + struct platform_device *pdev; + int ret; + + DRM_INFO("%s called", __func__); + + pdev = platform_device_register_simple(DRIVER_NAME, -1, NULL, 0); + if (IS_ERR(pdev)) + return PTR_ERR(pdev); + + if (!devres_open_group(&pdev->dev, NULL, GFP_KERNEL)) { + ret = -ENOMEM; + goto out_unregister; + } + + add = devm_drm_dev_alloc(&pdev->dev, &accel_dummy_driver, + struct accel_dummy_device, drm); + if (IS_ERR(add)) { + ret = PTR_ERR(add); + goto out_devres; + } + add->platform = pdev; + + ret = drm_dev_register(&add->drm, 0); + if (ret) + goto out_devres; + + return 0; + +out_devres: + devres_release_group(&pdev->dev, NULL); +out_unregister: + platform_device_unregister(pdev); + return ret; +} + +module_init(accel_dummy_init); +module_exit(accel_dummy_exit);