/* * Created: Fri Jan 19 10:48:35 2001 by [email protected] * * Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California. * All Rights Reserved. * * Author Rickard E. (Rik) Faith <[email protected]> * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ #include <linux/debugfs.h> #include <linux/fs.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/mount.h> #include <linux/pseudo_fs.h> #include <linux/slab.h> #include <linux/srcu.h> #include <linux/xarray.h> #include <drm/drm_accel.h> #include <drm/drm_cache.h> #include <drm/drm_client.h> #include <drm/drm_color_mgmt.h> #include <drm/drm_drv.h> #include <drm/drm_file.h> #include <drm/drm_managed.h> #include <drm/drm_mode_object.h> #include <drm/drm_panic.h> #include <drm/drm_print.h> #include <drm/drm_privacy_screen_machine.h> #include "drm_crtc_internal.h" #include "drm_internal.h" MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; DEFINE_XARRAY_ALLOC(…); /* * If the drm core fails to init for whatever reason, * we should prevent any drivers from registering with it. * It's best to check this at drm_dev_init(), as some drivers * prefer to embed struct drm_device into their own device * structure and call drm_dev_init() themselves. */ static bool drm_core_init_complete; static struct dentry *drm_debugfs_root; DEFINE_STATIC_SRCU(…); /* * DRM Minors * A DRM device can provide several char-dev interfaces on the DRM-Major. Each * of them is represented by a drm_minor object. Depending on the capabilities * of the device-driver, different interfaces are registered. * * Minors can be accessed via dev->$minor_name. This pointer is either * NULL or a valid drm_minor pointer and stays valid as long as the device is * valid. This means, DRM minors have the same life-time as the underlying * device. However, this doesn't mean that the minor is active. Minors are * registered and unregistered dynamically according to device-state. */ static struct xarray *drm_minor_get_xa(enum drm_minor_type type) { … } static struct drm_minor **drm_minor_get_slot(struct drm_device *dev, enum drm_minor_type type) { … } static void drm_minor_alloc_release(struct drm_device *dev, void *data) { … } /* * DRM used to support 64 devices, for backwards compatibility we need to maintain the * minor allocation scheme where minors 0-63 are primary nodes, 64-127 are control nodes, * and 128-191 are render nodes. * After reaching the limit, we're allocating minors dynamically - first-come, first-serve. * Accel nodes are using a distinct major, so the minors are allocated in continuous 0-MAX * range. */ #define DRM_MINOR_LIMIT(t) … #define DRM_EXTENDED_MINOR_LIMIT … static int drm_minor_alloc(struct drm_device *dev, enum drm_minor_type type) { … } static int drm_minor_register(struct drm_device *dev, enum drm_minor_type type) { … } static void drm_minor_unregister(struct drm_device *dev, enum drm_minor_type type) { … } /* * 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 drm_minor_release(). * * 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. */ struct drm_minor *drm_minor_acquire(struct xarray *minor_xa, unsigned int minor_id) { … } void drm_minor_release(struct drm_minor *minor) { … } /** * DOC: driver instance overview * * A device instance for a drm driver is represented by &struct drm_device. This * is allocated and initialized with devm_drm_dev_alloc(), usually from * bus-specific ->probe() callbacks implemented by the driver. The driver then * needs to initialize all the various subsystems for the drm device like memory * management, vblank handling, modesetting support and initial output * configuration plus obviously initialize all the corresponding hardware bits. * Finally when everything is up and running and ready for userspace the device * instance can be published using drm_dev_register(). * * There is also deprecated support for initializing device instances using * bus-specific helpers and the &drm_driver.load callback. But due to * backwards-compatibility needs the device instance have to be published too * early, which requires unpretty global locking to make safe and is therefore * only support for existing drivers not yet converted to the new scheme. * * When cleaning up a device instance everything needs to be done in reverse: * First unpublish the device instance with drm_dev_unregister(). Then clean up * any other resources allocated at device initialization and drop the driver's * reference to &drm_device using drm_dev_put(). * * Note that any allocation or resource which is visible to userspace must be * released only when the final drm_dev_put() is called, and not when the * driver is unbound from the underlying physical struct &device. Best to use * &drm_device managed resources with drmm_add_action(), drmm_kmalloc() and * related functions. * * devres managed resources like devm_kmalloc() can only be used for resources * directly related to the underlying hardware device, and only used in code * paths fully protected by drm_dev_enter() and drm_dev_exit(). * * Display driver example * ~~~~~~~~~~~~~~~~~~~~~~ * * The following example shows a typical structure of a DRM display driver. * The example focus on the probe() function and the other functions that is * almost always present and serves as a demonstration of devm_drm_dev_alloc(). * * .. code-block:: c * * struct driver_device { * struct drm_device drm; * void *userspace_facing; * struct clk *pclk; * }; * * static const struct drm_driver driver_drm_driver = { * [...] * }; * * static int driver_probe(struct platform_device *pdev) * { * struct driver_device *priv; * struct drm_device *drm; * int ret; * * priv = devm_drm_dev_alloc(&pdev->dev, &driver_drm_driver, * struct driver_device, drm); * if (IS_ERR(priv)) * return PTR_ERR(priv); * drm = &priv->drm; * * ret = drmm_mode_config_init(drm); * if (ret) * return ret; * * priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL); * if (!priv->userspace_facing) * return -ENOMEM; * * priv->pclk = devm_clk_get(dev, "PCLK"); * if (IS_ERR(priv->pclk)) * return PTR_ERR(priv->pclk); * * // Further setup, display pipeline etc * * platform_set_drvdata(pdev, drm); * * drm_mode_config_reset(drm); * * ret = drm_dev_register(drm); * if (ret) * return ret; * * drm_fbdev_{...}_setup(drm, 32); * * return 0; * } * * // This function is called before the devm_ resources are released * static int driver_remove(struct platform_device *pdev) * { * struct drm_device *drm = platform_get_drvdata(pdev); * * drm_dev_unregister(drm); * drm_atomic_helper_shutdown(drm) * * return 0; * } * * // This function is called on kernel restart and shutdown * static void driver_shutdown(struct platform_device *pdev) * { * drm_atomic_helper_shutdown(platform_get_drvdata(pdev)); * } * * static int __maybe_unused driver_pm_suspend(struct device *dev) * { * return drm_mode_config_helper_suspend(dev_get_drvdata(dev)); * } * * static int __maybe_unused driver_pm_resume(struct device *dev) * { * drm_mode_config_helper_resume(dev_get_drvdata(dev)); * * return 0; * } * * static const struct dev_pm_ops driver_pm_ops = { * SET_SYSTEM_SLEEP_PM_OPS(driver_pm_suspend, driver_pm_resume) * }; * * static struct platform_driver driver_driver = { * .driver = { * [...] * .pm = &driver_pm_ops, * }, * .probe = driver_probe, * .remove = driver_remove, * .shutdown = driver_shutdown, * }; * module_platform_driver(driver_driver); * * Drivers that want to support device unplugging (USB, DT overlay unload) should * use drm_dev_unplug() instead of drm_dev_unregister(). The driver must protect * regions that is accessing device resources to prevent use after they're * released. This is done using drm_dev_enter() and drm_dev_exit(). There is one * shortcoming however, drm_dev_unplug() marks the drm_device as unplugged before * drm_atomic_helper_shutdown() is called. This means that if the disable code * paths are protected, they will not run on regular driver module unload, * possibly leaving the hardware enabled. */ /** * drm_put_dev - Unregister and release a DRM device * @dev: DRM device * * Called at module unload time or when a PCI device is unplugged. * * Cleans up all DRM device, calling drm_lastclose(). * * Note: Use of this function is deprecated. It will eventually go away * completely. Please use drm_dev_unregister() and drm_dev_put() explicitly * instead to make sure that the device isn't userspace accessible any more * while teardown is in progress, ensuring that userspace can't access an * inconsistent state. */ void drm_put_dev(struct drm_device *dev) { … } EXPORT_SYMBOL(…); /** * drm_dev_enter - Enter device critical section * @dev: DRM device * @idx: Pointer to index that will be passed to the matching drm_dev_exit() * * This function marks and protects the beginning of a section that should not * be entered after the device has been unplugged. The section end is marked * with drm_dev_exit(). Calls to this function can be nested. * * Returns: * True if it is OK to enter the section, false otherwise. */ bool drm_dev_enter(struct drm_device *dev, int *idx) { … } EXPORT_SYMBOL(…); /** * drm_dev_exit - Exit device critical section * @idx: index returned from drm_dev_enter() * * This function marks the end of a section that should not be entered after * the device has been unplugged. */ void drm_dev_exit(int idx) { … } EXPORT_SYMBOL(…); /** * drm_dev_unplug - unplug a DRM device * @dev: DRM device * * This unplugs a hotpluggable DRM device, which makes it inaccessible to * userspace operations. Entry-points can use drm_dev_enter() and * drm_dev_exit() to protect device resources in a race free manner. This * essentially unregisters the device like drm_dev_unregister(), but can be * called while there are still open users of @dev. */ void drm_dev_unplug(struct drm_device *dev) { … } EXPORT_SYMBOL(…); /* * DRM internal mount * We want to be able to allocate our own "struct address_space" to control * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow * stand-alone address_space objects, so we need an underlying inode. As there * is no way to allocate an independent inode easily, we need a fake internal * VFS mount-point. * * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free() * frees it again. You are allowed to use iget() and iput() to get references to * the inode. But each drm_fs_inode_new() call must be paired with exactly one * drm_fs_inode_free() call (which does not have to be the last iput()). * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it * between multiple inode-users. You could, technically, call * iget() + drm_fs_inode_free() directly after alloc and sometime later do an * iput(), but this way you'd end up with a new vfsmount for each inode. */ static int drm_fs_cnt; static struct vfsmount *drm_fs_mnt; static int drm_fs_init_fs_context(struct fs_context *fc) { … } static struct file_system_type drm_fs_type = …; static struct inode *drm_fs_inode_new(void) { … } static void drm_fs_inode_free(struct inode *inode) { … } /** * DOC: component helper usage recommendations * * DRM drivers that drive hardware where a logical device consists of a pile of * independent hardware blocks are recommended to use the :ref:`component helper * library<component>`. For consistency and better options for code reuse the * following guidelines apply: * * - The entire device initialization procedure should be run from the * &component_master_ops.master_bind callback, starting with * devm_drm_dev_alloc(), then binding all components with * component_bind_all() and finishing with drm_dev_register(). * * - The opaque pointer passed to all components through component_bind_all() * should point at &struct drm_device of the device instance, not some driver * specific private structure. * * - The component helper fills the niche where further standardization of * interfaces is not practical. When there already is, or will be, a * standardized interface like &drm_bridge or &drm_panel, providing its own * functions to find such components at driver load time, like * drm_of_find_panel_or_bridge(), then the component helper should not be * used. */ static void drm_dev_init_release(struct drm_device *dev, void *res) { … } static int drm_dev_init(struct drm_device *dev, const struct drm_driver *driver, struct device *parent) { … } static void devm_drm_dev_init_release(void *data) { … } static int devm_drm_dev_init(struct device *parent, struct drm_device *dev, const struct drm_driver *driver) { … } void *__devm_drm_dev_alloc(struct device *parent, const struct drm_driver *driver, size_t size, size_t offset) { … } EXPORT_SYMBOL(…); /** * drm_dev_alloc - Allocate new DRM device * @driver: DRM driver to allocate device for * @parent: Parent device object * * This is the deprecated version of devm_drm_dev_alloc(), which does not support * subclassing through embedding the struct &drm_device in a driver private * structure, and which does not support automatic cleanup through devres. * * RETURNS: * Pointer to new DRM device, or ERR_PTR on failure. */ struct drm_device *drm_dev_alloc(const struct drm_driver *driver, struct device *parent) { … } EXPORT_SYMBOL(…); static void drm_dev_release(struct kref *ref) { … } /** * drm_dev_get - Take reference of a DRM device * @dev: device to take reference of or NULL * * This increases the ref-count of @dev by one. You *must* already own a * reference when calling this. Use drm_dev_put() to drop this reference * again. * * This function never fails. However, this function does not provide *any* * guarantee whether the device is alive or running. It only provides a * reference to the object and the memory associated with it. */ void drm_dev_get(struct drm_device *dev) { … } EXPORT_SYMBOL(…); /** * drm_dev_put - Drop reference of a DRM device * @dev: device to drop reference of or NULL * * This decreases the ref-count of @dev by one. The device is destroyed if the * ref-count drops to zero. */ void drm_dev_put(struct drm_device *dev) { … } EXPORT_SYMBOL(…); static int create_compat_control_link(struct drm_device *dev) { … } static void remove_compat_control_link(struct drm_device *dev) { … } /** * drm_dev_register - Register DRM device * @dev: Device to register * @flags: Flags passed to the driver's .load() function * * Register the DRM device @dev with the system, advertise device to user-space * and start normal device operation. @dev must be initialized via drm_dev_init() * previously. * * Never call this twice on any device! * * NOTE: To ensure backward compatibility with existing drivers method this * function calls the &drm_driver.load method after registering the device * nodes, creating race conditions. Usage of the &drm_driver.load methods is * therefore deprecated, drivers must perform all initialization before calling * drm_dev_register(). * * RETURNS: * 0 on success, negative error code on failure. */ int drm_dev_register(struct drm_device *dev, unsigned long flags) { … } EXPORT_SYMBOL(…); /** * drm_dev_unregister - Unregister DRM device * @dev: Device to unregister * * Unregister the DRM device from the system. This does the reverse of * drm_dev_register() but does not deallocate the device. The caller must call * drm_dev_put() to drop their final reference, unless it is managed with devres * (as devices allocated with devm_drm_dev_alloc() are), in which case there is * already an unwind action registered. * * A special form of unregistering for hotpluggable devices is drm_dev_unplug(), * which can be called while there are still open users of @dev. * * This should be called first in the device teardown code to make sure * userspace can't access the device instance any more. */ void drm_dev_unregister(struct drm_device *dev) { … } EXPORT_SYMBOL(…); /* * DRM Core * The DRM core module initializes all global DRM objects and makes them * available to drivers. Once setup, drivers can probe their respective * devices. * Currently, core management includes: * - The "DRM-Global" key/value database * - Global ID management for connectors * - DRM major number allocation * - DRM minor management * - DRM sysfs class * - DRM debugfs root * * Furthermore, the DRM core provides dynamic char-dev lookups. For each * interface registered on a DRM device, you can request minor numbers from DRM * core. DRM core takes care of major-number management and char-dev * registration. A stub ->open() callback forwards any open() requests to the * registered minor. */ static int drm_stub_open(struct inode *inode, struct file *filp) { … } static const struct file_operations drm_stub_fops = …; static void drm_core_exit(void) { … } static int __init drm_core_init(void) { … } module_init(…) …; module_exit(drm_core_exit);
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