linux/drivers/accel/drm_accel.c
Ricardo B. Marliere 576d7cc5a9 accel: constify the struct device_type usage
Since commit aed65af1cc ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
accel_sysfs_device_minor variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
2024-02-26 09:59:18 +02:00

321 lines
7.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright 2022 HabanaLabs, Ltd.
* All Rights Reserved.
*
*/
#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/idr.h>
#include <drm/drm_accel.h>
#include <drm/drm_auth.h>
#include <drm/drm_debugfs.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_ioctl.h>
#include <drm/drm_print.h>
static DEFINE_SPINLOCK(accel_minor_lock);
static struct idr accel_minors_idr;
static struct dentry *accel_debugfs_root;
static const struct device_type accel_sysfs_device_minor = {
.name = "accel_minor"
};
static char *accel_devnode(const struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "accel/%s", dev_name(dev));
}
static const struct class accel_class = {
.name = "accel",
.devnode = accel_devnode,
};
static int accel_sysfs_init(void)
{
return class_register(&accel_class);
}
static void accel_sysfs_destroy(void)
{
class_unregister(&accel_class);
}
static int accel_name_info(struct seq_file *m, void *data)
{
struct drm_info_node *node = (struct drm_info_node *) m->private;
struct drm_minor *minor = node->minor;
struct drm_device *dev = minor->dev;
struct drm_master *master;
mutex_lock(&dev->master_mutex);
master = dev->master;
seq_printf(m, "%s", dev->driver->name);
if (dev->dev)
seq_printf(m, " dev=%s", dev_name(dev->dev));
if (master && master->unique)
seq_printf(m, " master=%s", master->unique);
if (dev->unique)
seq_printf(m, " unique=%s", dev->unique);
seq_puts(m, "\n");
mutex_unlock(&dev->master_mutex);
return 0;
}
static const struct drm_info_list accel_debugfs_list[] = {
{"name", accel_name_info, 0}
};
#define ACCEL_DEBUGFS_ENTRIES ARRAY_SIZE(accel_debugfs_list)
/**
* accel_debugfs_init() - Initialize debugfs for device
* @dev: Pointer to the device instance.
*
* This function creates a root directory for the device in debugfs.
*/
void accel_debugfs_init(struct drm_device *dev)
{
drm_debugfs_dev_init(dev, accel_debugfs_root);
}
/**
* accel_debugfs_register() - Register debugfs for device
* @dev: Pointer to the device instance.
*
* Creates common files for accelerators.
*/
void accel_debugfs_register(struct drm_device *dev)
{
struct drm_minor *minor = dev->accel;
minor->debugfs_root = dev->debugfs_root;
drm_debugfs_create_files(accel_debugfs_list, ACCEL_DEBUGFS_ENTRIES,
dev->debugfs_root, minor);
}
/**
* 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 idr and allocates from it
* a new id to represent a new accel minor
*
* Return: A new id on success or error code in case idr_alloc failed
*/
int accel_minor_alloc(void)
{
unsigned long flags;
int r;
spin_lock_irqsave(&accel_minor_lock, flags);
r = idr_alloc(&accel_minors_idr, NULL, 0, ACCEL_MAX_MINORS, GFP_NOWAIT);
spin_unlock_irqrestore(&accel_minor_lock, flags);
return r;
}
/**
* accel_minor_remove() - Remove an accel minor
* @index: The minor id to remove.
*
* This function access the accel minors idr and removes from
* it the member with the id that is passed to this function.
*/
void accel_minor_remove(int index)
{
unsigned long flags;
spin_lock_irqsave(&accel_minor_lock, flags);
idr_remove(&accel_minors_idr, index);
spin_unlock_irqrestore(&accel_minor_lock, flags);
}
/**
* accel_minor_replace() - Replace minor pointer in accel minors idr.
* @minor: Pointer to the new minor.
* @index: The minor id to replace.
*
* This function access the accel minors idr 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
*/
void accel_minor_replace(struct drm_minor *minor, int index)
{
unsigned long flags;
spin_lock_irqsave(&accel_minor_lock, flags);
idr_replace(&accel_minors_idr, minor, index);
spin_unlock_irqrestore(&accel_minor_lock, flags);
}
/*
* 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;
unsigned long flags;
spin_lock_irqsave(&accel_minor_lock, flags);
minor = idr_find(&accel_minors_idr, minor_id);
if (minor)
drm_dev_get(minor->dev);
spin_unlock_irqrestore(&accel_minor_lock, flags);
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)
{
const struct file_operations *new_fops;
struct drm_minor *minor;
int err;
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 err;
}
static const struct file_operations accel_stub_fops = {
.owner = THIS_MODULE,
.open = accel_stub_open,
.llseek = noop_llseek,
};
void accel_core_exit(void)
{
unregister_chrdev(ACCEL_MAJOR, "accel");
debugfs_remove(accel_debugfs_root);
accel_sysfs_destroy();
idr_destroy(&accel_minors_idr);
}
int __init accel_core_init(void)
{
int ret;
idr_init(&accel_minors_idr);
ret = accel_sysfs_init();
if (ret < 0) {
DRM_ERROR("Cannot create ACCEL class: %d\n", ret);
goto error;
}
accel_debugfs_root = debugfs_create_dir("accel", NULL);
ret = register_chrdev(ACCEL_MAJOR, "accel", &accel_stub_fops);
if (ret < 0)
DRM_ERROR("Cannot register ACCEL major: %d\n", ret);
error:
/*
* Any cleanup due to errors will be done in drm_core_exit() that
* will call accel_core_exit()
*/
return ret;
}