drivers/rpmsg/rpmsg_ctrl.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * Copyright (C) 2022, STMicroelectronics
0004  * Copyright (c) 2016, Linaro Ltd.
0005  * Copyright (c) 2012, Michal Simek <monstr@monstr.eu>
0006  * Copyright (c) 2012, PetaLogix
0007  * Copyright (c) 2011, Texas Instruments, Inc.
0008  * Copyright (c) 2011, Google, Inc.
0009  *
0010  * Based on rpmsg performance statistics driver by Michal Simek, which in turn
0011  * was based on TI & Google OMX rpmsg driver.
0012  */
0013
0014 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
0015
0016 #include <linux/cdev.h>
0017 #include <linux/device.h>
0018 #include <linux/fs.h>
0019 #include <linux/idr.h>
0020 #include <linux/kernel.h>
0021 #include <linux/module.h>
0022 #include <linux/rpmsg.h>
0023 #include <linux/skbuff.h>
0024 #include <linux/slab.h>
0025 #include <linux/uaccess.h>
0026 #include <uapi/linux/rpmsg.h>
0027
0028 #include "rpmsg_char.h"
0029 #include "rpmsg_internal.h"
0030
0031 #define RPMSG_DEV_MAX   (MINORMASK + 1)
0032
0033 static dev_t rpmsg_major;
0034
0035 static DEFINE_IDA(rpmsg_ctrl_ida);
0036 static DEFINE_IDA(rpmsg_minor_ida);
0037
0038 #define dev_to_ctrldev(dev) container_of(dev, struct rpmsg_ctrldev, dev)
0039 #define cdev_to_ctrldev(i_cdev) container_of(i_cdev, struct rpmsg_ctrldev, cdev)
0040
0041 /**
0042  * struct rpmsg_ctrldev - control device for instantiating endpoint devices
0043  * @rpdev:  underlaying rpmsg device
0044  * @cdev:   cdev for the ctrl device
0045  * @dev:    device for the ctrl device
0046  * @ctrl_lock:  serialize the ioctrls.
0047  */
0048 struct rpmsg_ctrldev {
0049     struct rpmsg_device *rpdev;
0050     struct cdev cdev;
0051     struct device dev;
0052     struct mutex ctrl_lock;
0053 };
0054
0055 static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp)
0056 {
0057     struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
0058
0059     get_device(&ctrldev->dev);
0060     filp->private_data = ctrldev;
0061
0062     return 0;
0063 }
0064
0065 static int rpmsg_ctrldev_release(struct inode *inode, struct file *filp)
0066 {
0067     struct rpmsg_ctrldev *ctrldev = cdev_to_ctrldev(inode->i_cdev);
0068
0069     put_device(&ctrldev->dev);
0070
0071     return 0;
0072 }
0073
0074 static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd,
0075                 unsigned long arg)
0076 {
0077     struct rpmsg_ctrldev *ctrldev = fp->private_data;
0078     void __user *argp = (void __user *)arg;
0079     struct rpmsg_endpoint_info eptinfo;
0080     struct rpmsg_channel_info chinfo;
0081     struct rpmsg_device *rpdev;
0082     int ret = 0;
0083
0084     if (copy_from_user(&eptinfo, argp, sizeof(eptinfo)))
0085         return -EFAULT;
0086
0087     memcpy(chinfo.name, eptinfo.name, RPMSG_NAME_SIZE);
0088     chinfo.name[RPMSG_NAME_SIZE - 1] = '\0';
0089     chinfo.src = eptinfo.src;
0090     chinfo.dst = eptinfo.dst;
0091
0092     mutex_lock(&ctrldev->ctrl_lock);
0093     switch (cmd) {
0094     case RPMSG_CREATE_EPT_IOCTL:
0095         ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo);
0096         break;
0097
0098     case RPMSG_CREATE_DEV_IOCTL:
0099         rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo);
0100         if (!rpdev) {
0101             dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name);
0102             ret = -ENXIO;
0103         }
0104         break;
0105
0106     case RPMSG_RELEASE_DEV_IOCTL:
0107         ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo);
0108         if (ret)
0109             dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n",
0110                 chinfo.name, ret);
0111         break;
0112
0113     default:
0114         ret = -EINVAL;
0115     }
0116     mutex_unlock(&ctrldev->ctrl_lock);
0117
0118     return ret;
0119 };
0120
0121 static const struct file_operations rpmsg_ctrldev_fops = {
0122     .owner = THIS_MODULE,
0123     .open = rpmsg_ctrldev_open,
0124     .release = rpmsg_ctrldev_release,
0125     .unlocked_ioctl = rpmsg_ctrldev_ioctl,
0126     .compat_ioctl = compat_ptr_ioctl,
0127 };
0128
0129 static void rpmsg_ctrldev_release_device(struct device *dev)
0130 {
0131     struct rpmsg_ctrldev *ctrldev = dev_to_ctrldev(dev);
0132
0133     ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
0134     ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
0135     kfree(ctrldev);
0136 }
0137
0138 static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev)
0139 {
0140     struct rpmsg_ctrldev *ctrldev;
0141     struct device *dev;
0142     int ret;
0143
0144     ctrldev = kzalloc(sizeof(*ctrldev), GFP_KERNEL);
0145     if (!ctrldev)
0146         return -ENOMEM;
0147
0148     ctrldev->rpdev = rpdev;
0149
0150     dev = &ctrldev->dev;
0151     device_initialize(dev);
0152     dev->parent = &rpdev->dev;
0153     dev->class = rpmsg_class;
0154
0155     mutex_init(&ctrldev->ctrl_lock);
0156     cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops);
0157     ctrldev->cdev.owner = THIS_MODULE;
0158
0159     ret = ida_simple_get(&rpmsg_minor_ida, 0, RPMSG_DEV_MAX, GFP_KERNEL);
0160     if (ret < 0)
0161         goto free_ctrldev;
0162     dev->devt = MKDEV(MAJOR(rpmsg_major), ret);
0163
0164     ret = ida_simple_get(&rpmsg_ctrl_ida, 0, 0, GFP_KERNEL);
0165     if (ret < 0)
0166         goto free_minor_ida;
0167     dev->id = ret;
0168     dev_set_name(&ctrldev->dev, "rpmsg_ctrl%d", ret);
0169
0170     ret = cdev_device_add(&ctrldev->cdev, &ctrldev->dev);
0171     if (ret)
0172         goto free_ctrl_ida;
0173
0174     /* We can now rely on the release function for cleanup */
0175     dev->release = rpmsg_ctrldev_release_device;
0176
0177     dev_set_drvdata(&rpdev->dev, ctrldev);
0178
0179     return ret;
0180
0181 free_ctrl_ida:
0182     ida_simple_remove(&rpmsg_ctrl_ida, dev->id);
0183 free_minor_ida:
0184     ida_simple_remove(&rpmsg_minor_ida, MINOR(dev->devt));
0185 free_ctrldev:
0186     put_device(dev);
0187     kfree(ctrldev);
0188
0189     return ret;
0190 }
0191
0192 static void rpmsg_ctrldev_remove(struct rpmsg_device *rpdev)
0193 {
0194     struct rpmsg_ctrldev *ctrldev = dev_get_drvdata(&rpdev->dev);
0195     int ret;
0196
0197     /* Destroy all endpoints */
0198     ret = device_for_each_child(&ctrldev->dev, NULL, rpmsg_chrdev_eptdev_destroy);
0199     if (ret)
0200         dev_warn(&rpdev->dev, "failed to nuke endpoints: %d\n", ret);
0201
0202     cdev_device_del(&ctrldev->cdev, &ctrldev->dev);
0203     put_device(&ctrldev->dev);
0204 }
0205
0206 static struct rpmsg_driver rpmsg_ctrldev_driver = {
0207     .probe = rpmsg_ctrldev_probe,
0208     .remove = rpmsg_ctrldev_remove,
0209     .drv = {
0210         .name = "rpmsg_ctrl",
0211     },
0212 };
0213
0214 static int rpmsg_ctrldev_init(void)
0215 {
0216     int ret;
0217
0218     ret = alloc_chrdev_region(&rpmsg_major, 0, RPMSG_DEV_MAX, "rpmsg_ctrl");
0219     if (ret < 0) {
0220         pr_err("failed to allocate char dev region\n");
0221         return ret;
0222     }
0223
0224     ret = register_rpmsg_driver(&rpmsg_ctrldev_driver);
0225     if (ret < 0) {
0226         pr_err("failed to register rpmsg driver\n");
0227         unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
0228     }
0229
0230     return ret;
0231 }
0232 postcore_initcall(rpmsg_ctrldev_init);
0233
0234 static void rpmsg_ctrldev_exit(void)
0235 {
0236     unregister_rpmsg_driver(&rpmsg_ctrldev_driver);
0237     unregister_chrdev_region(rpmsg_major, RPMSG_DEV_MAX);
0238 }
0239 module_exit(rpmsg_ctrldev_exit);
0240
0241 MODULE_DESCRIPTION("rpmsg control interface");
0242 MODULE_ALIAS("rpmsg:" KBUILD_MODNAME);
0243 MODULE_LICENSE("GPL v2");