[RFC,v2,2/3] accel: add dedicated minor for accelerator devices

Message ID	20221102203405.1797491-3-ogabbay@kernel.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <dri-devel-bounces@lists.freedesktop.org> From: Oded Gabbay <ogabbay@kernel.org> To: David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Arnd Bergmann <arnd@arndb.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Jason Gunthorpe <jgg@nvidia.com>, John Hubbard <jhubbard@nvidia.com>, Alex Deucher <alexander.deucher@amd.com> Subject: [RFC PATCH v2 2/3] accel: add dedicated minor for accelerator devices Date: Wed, 2 Nov 2022 22:34:04 +0200 Message-Id: <20221102203405.1797491-3-ogabbay@kernel.org> In-Reply-To: <20221102203405.1797491-1-ogabbay@kernel.org> References: <20221102203405.1797491-1-ogabbay@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: list Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>, Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>, Jeffrey Hugo <quic_jhugo@quicinc.com>, Jiho Chu <jiho.chu@samsung.com>, Christoph Hellwig <hch@infradead.org>, Thomas Zimmermann <tzimmermann@suse.de>, Kevin Hilman <khilman@baylibre.com>, Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>, Maciej Kwapulinski <maciej.kwapulinski@linux.intel.com>, Jagan Teki <jagan@amarulasolutions.com> Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" <dri-devel-bounces@lists.freedesktop.org>
Series	new subsystem for compute accelerator devices \| expand [RFC,v2,0/3] new subsystem for compute accelerator devices [RFC,v2,1/3] drivers/accel: define kconfig and register a new major [RFC,v2,2/3] accel: add dedicated minor for accelerator devices [RFC,v2,3/3] drm: initialize accel framework

diff --git a/drivers/accel/accel_drv.c b/drivers/accel/accel_drv.c index 6132765ea054..964a93799936 100644 --- a/drivers/accel/accel_drv.c +++ b/drivers/accel/accel_drv.c @@ -9,13 +9,22 @@ #include <linux/module.h> #include <linux/debugfs.h> #include <linux/device.h> +#include <linux/xarray.h> #include <drm/drm_accel.h> +#include <drm/drm_drv.h> +#include <drm/drm_file.h> #include <drm/drm_ioctl.h> #include <drm/drm_print.h> +static DEFINE_XARRAY_ALLOC(accel_minors_xa); + static struct dentry *accel_debugfs_root; -struct class *accel_class; +static struct class *accel_class; + +static struct device_type accel_sysfs_device_minor = { + .name = "accel_minor" +}; static char *accel_devnode(struct device *dev, umode_t *mode) { @@ -24,16 +33,6 @@ static char *accel_devnode(struct device *dev, umode_t *mode) static CLASS_ATTR_STRING(accel_version, 0444, "accel 1.0.0 20221018"); -/** - * accel_sysfs_init - initialize sysfs helpers - * - * This is used to create the ACCEL class, which is the implicit parent of any - * other top-level ACCEL sysfs objects. - * - * You must call accel_sysfs_destroy() to release the allocated resources. - * - * Return: 0 on success, negative error code on failure. - */ static int accel_sysfs_init(void) { int err; @@ -54,11 +53,6 @@ static int accel_sysfs_init(void) return 0; } -/** - * accel_sysfs_destroy - destroys ACCEL class - * - * Destroy the ACCEL device class. - */ static void accel_sysfs_destroy(void) { if (IS_ERR_OR_NULL(accel_class)) @@ -68,11 +62,185 @@ static void accel_sysfs_destroy(void) accel_class = NULL; } +/** + * accel_set_device_instance_params() - Set some device parameters for accel device + * @kdev: Pointer to the device instance. + * @index: The minor's index + * + * This function creates the dev_t of the device using the accel major and + * the device's minor number. In addition, it sets the class and type of the + * device instance to the accel sysfs class and device type, respectively. + */ +void accel_set_device_instance_params(struct device *kdev, int index) +{ + kdev->devt = MKDEV(ACCEL_MAJOR, index); + kdev->class = accel_class; + kdev->type = &accel_sysfs_device_minor; +} + +/** + * accel_minor_alloc() - Allocates a new accel minor + * + * This function access the accel minors xarray and allocates from it + * a new id to represent a new accel minor + * + * Return: A new id on success or error code in case xa_alloc failed + */ +int accel_minor_alloc(void) +{ + int rc, index; + + rc = xa_alloc(&accel_minors_xa, &index, NULL, + XA_LIMIT(0, ACCEL_MAX_MINORS - 1), GFP_KERNEL); + if (rc < 0) + return rc; + + return index; +} + +/** + * accel_minor_remove() - Remove an accel minor + * @index: The minor id to remove. + * + * This function access the accel minors xarray and removes from + * it the member with the id that is passed to this function. + */ +void accel_minor_remove(int index) +{ + xa_erase(&accel_minors_xa, index); +} + +/** + * accel_minor_replace() - Replace minor pointer in accel minors xarray. + * @minor: Pointer to the new minor. + * @index: The minor id to replace. + * + * This function access the accel minors xarray structure and replaces the pointer + * that is associated with an existing id. Because the minor pointer can be + * NULL, we need to explicitly pass the index. + * + * Return: 0 for success, negative value for error + */ +int accel_minor_replace(struct drm_minor *minor, int index) +{ + if (minor) { + void *entry; + + entry = xa_cmpxchg(&accel_minors_xa, index, NULL, minor, GFP_KERNEL); + if (xa_is_err(entry)) + return xa_err(entry); + } else { + xa_store(&accel_minors_xa, index, NULL, GFP_KERNEL); + } + + return 0; +} + +/* + * Looks up the given minor-ID and returns the respective DRM-minor object. The + * refence-count of the underlying device is increased so you must release this + * object with accel_minor_release(). + * + * The object can be only a drm_minor that represents an accel device. + * + * As long as you hold this minor, it is guaranteed that the object and the + * minor->dev pointer will stay valid! However, the device may get unplugged and + * unregistered while you hold the minor. + */ +static struct drm_minor *accel_minor_acquire(unsigned int minor_id) +{ + struct drm_minor *minor; + + xa_lock(&accel_minors_xa); + minor = xa_load(&accel_minors_xa, minor_id); + if (minor) + drm_dev_get(minor->dev); + xa_unlock(&accel_minors_xa); + + if (!minor) { + return ERR_PTR(-ENODEV); + } else if (drm_dev_is_unplugged(minor->dev)) { + drm_dev_put(minor->dev); + return ERR_PTR(-ENODEV); + } + + return minor; +} + +static void accel_minor_release(struct drm_minor *minor) +{ + drm_dev_put(minor->dev); +} + +/** + * accel_open - open method for ACCEL file + * @inode: device inode + * @filp: file pointer. + * + * This function must be used by drivers as their &file_operations.open method. + * It looks up the correct ACCEL device and instantiates all the per-file + * resources for it. It also calls the &drm_driver.open driver callback. + * + * Return: 0 on success or negative errno value on failure. + */ +int accel_open(struct inode *inode, struct file *filp) +{ + struct drm_device *dev; + struct drm_minor *minor; + int retcode; + + minor = accel_minor_acquire(iminor(inode)); + if (IS_ERR(minor)) + return PTR_ERR(minor); + + dev = minor->dev; + + atomic_fetch_inc(&dev->open_count); + + /* share address_space across all char-devs of a single device */ + filp->f_mapping = dev->anon_inode->i_mapping; + + retcode = drm_open_helper(filp, minor); + if (retcode) + goto err_undo; + + return 0; + +err_undo: + atomic_dec(&dev->open_count); + accel_minor_release(minor); + return retcode; +} +EXPORT_SYMBOL_GPL(accel_open); + static int accel_stub_open(struct inode *inode, struct file *filp) { - DRM_DEBUG("Operation not supported"); + const struct file_operations *new_fops; + struct drm_minor *minor; + int err; + + DRM_DEBUG("\n"); + + minor = accel_minor_acquire(iminor(inode)); + if (IS_ERR(minor)) + return PTR_ERR(minor); + + new_fops = fops_get(minor->dev->driver->fops); + if (!new_fops) { + err = -ENODEV; + goto out; + } + + replace_fops(filp, new_fops); + if (filp->f_op->open) + err = filp->f_op->open(inode, filp); + else + err = 0; + +out: + accel_minor_release(minor); - return -EOPNOTSUPP; + return err; } static const struct file_operations accel_stub_fops = { @@ -86,6 +254,7 @@ void accel_core_exit(void) unregister_chrdev(ACCEL_MAJOR, "accel"); debugfs_remove(accel_debugfs_root); accel_sysfs_destroy(); + WARN_ON(!xa_empty(&accel_minors_xa)); } int __init accel_core_init(void) diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index a8b4d918e9a3..64b4a3a87fbb 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -326,7 +326,7 @@ static int drm_cpu_valid(void) * Creates and initializes a drm_file structure for the file private data in \p * filp and add it into the double linked list in \p dev. */ -static int drm_open_helper(struct file *filp, struct drm_minor *minor) +int drm_open_helper(struct file *filp, struct drm_minor *minor) { struct drm_device *dev = minor->dev; struct drm_file *priv; diff --git a/include/drm/drm_accel.h b/include/drm/drm_accel.h index cf43a7b30f34..0c0ae387d075 100644 --- a/include/drm/drm_accel.h +++ b/include/drm/drm_accel.h @@ -8,12 +8,20 @@ #ifndef DRM_ACCEL_H_ #define DRM_ACCEL_H_ -#define ACCEL_MAJOR 261 +#include <drm/drm_file.h> + +#define ACCEL_MAJOR 261 +#define ACCEL_MAX_MINORS 256 #if IS_ENABLED(CONFIG_ACCEL) void accel_core_exit(void); int accel_core_init(void); +void accel_minor_remove(int index); +int accel_minor_alloc(void); +int accel_minor_replace(struct drm_minor *minor, int index); +void accel_set_device_instance_params(struct device *kdev, int index); +int accel_open(struct inode *inode, struct file *filp); #else @@ -23,9 +31,28 @@ static inline void accel_core_exit(void) static inline int __init accel_core_init(void) { + /* Return 0 to allow drm_core_init to complete successfully */ return 0; } +static inline void accel_minor_remove(int index) +{ +} + +static inline int accel_minor_alloc(void) +{ + return -EOPNOTSUPP; +} + +static inline int accel_minor_replace(struct drm_minor *minor, int index) +{ + return -EOPNOTSUPP; +} + +static inline void accel_set_device_instance_params(struct device *kdev, int index) +{ +} + #endif /* IS_ENABLED(CONFIG_ACCEL) */ #endif /* DRM_ACCEL_H_ */ diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index 9923c7a6885e..933ce2048e20 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -93,6 +93,9 @@ struct drm_device { /** @render: Render node */ struct drm_minor *render; + /** @accel: Compute Acceleration node */ + struct drm_minor *accel; + /** * @registered: * diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h index f6159acb8856..706e68ca5116 100644 --- a/include/drm/drm_drv.h +++ b/include/drm/drm_drv.h @@ -94,6 +94,14 @@ enum drm_driver_feature { * synchronization of command submission. */ DRIVER_SYNCOBJ_TIMELINE = BIT(6), + /** + * @DRIVER_COMPUTE_ACCEL: + * + * Driver supports compute acceleration devices. This flag is mutually exclusive with + * @DRIVER_RENDER and @DRIVER_MODESET. Devices that support both graphics and compute + * acceleration should be handled by two drivers that are connected using auxiliry bus. + */ + DRIVER_COMPUTE_ACCEL = BIT(7), /* IMPORTANT: Below are all the legacy flags, add new ones above. */ diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index d780fd151789..0d1f853092ab 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -51,11 +51,15 @@ struct file; /* Note that the order of this enum is ABI (it determines * /dev/dri/renderD* numbers). + * + * Setting DRM_MINOR_ACCEL to 32 gives enough space for more drm minors to + * be implemented before we hit any future */ enum drm_minor_type { DRM_MINOR_PRIMARY, DRM_MINOR_CONTROL, DRM_MINOR_RENDER, + DRM_MINOR_ACCEL = 32, }; /** @@ -70,7 +74,7 @@ enum drm_minor_type { struct drm_minor { /* private: */ int index; /* Minor device number */ - int type; /* Control or render */ + int type; /* Control or render or accel */ struct device *kdev; /* Linux device */ struct drm_device *dev; @@ -397,7 +401,22 @@ static inline bool drm_is_render_client(const struct drm_file *file_priv) return file_priv->minor->type == DRM_MINOR_RENDER; } +/** + * drm_is_accel_client - is this an open file of the compute acceleration node + * @file_priv: DRM file + * + * Returns true if this is an open file of the compute acceleration node, i.e. + * &drm_file.minor of @file_priv is a accel minor. + * + * See also the :ref:`section on accel nodes <drm_accel_node>`. + */ +static inline bool drm_is_accel_client(const struct drm_file *file_priv) +{ + return file_priv->minor->type == DRM_MINOR_ACCEL; +} + int drm_open(struct inode *inode, struct file *filp); +int drm_open_helper(struct file *filp, struct drm_minor *minor); ssize_t drm_read(struct file *filp, char __user *buffer, size_t count, loff_t *offset); int drm_release(struct inode *inode, struct file *filp);

[RFC,v2,2/3] accel: add dedicated minor for accelerator devices

Commit Message

Comments

Patch