diff options
Diffstat (limited to 'drivers/i3c/i3cdev.c')
-rw-r--r-- | drivers/i3c/i3cdev.c | 428 |
1 files changed, 428 insertions, 0 deletions
diff --git a/drivers/i3c/i3cdev.c b/drivers/i3c/i3cdev.c new file mode 100644 index 000000000000..07f5641a902d --- /dev/null +++ b/drivers/i3c/i3cdev.c @@ -0,0 +1,428 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019 Synopsys, Inc. and/or its affiliates. + * + * Author: Vitor Soares <soares@synopsys.com> + */ + +#include <linux/cdev.h> +#include <linux/compat.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/notifier.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +#include <linux/i3c/i3cdev.h> + +#include "internals.h" + +struct i3cdev_data { + struct list_head list; + struct i3c_device *i3c; + struct cdev cdev; + struct device *dev; + int id; +}; + +static DEFINE_IDA(i3cdev_ida); +static dev_t i3cdev_number; +#define I3C_MINORS 16 /* 16 I3C devices supported for now */ + +static LIST_HEAD(i3cdev_list); +static DEFINE_SPINLOCK(i3cdev_list_lock); + +static struct i3cdev_data *i3cdev_get_by_i3c(struct i3c_device *i3c) +{ + struct i3cdev_data *i3cdev; + + spin_lock(&i3cdev_list_lock); + list_for_each_entry(i3cdev, &i3cdev_list, list) { + if (i3cdev->i3c == i3c) + goto found; + } + + i3cdev = NULL; + +found: + spin_unlock(&i3cdev_list_lock); + return i3cdev; +} + +static struct i3cdev_data *get_free_i3cdev(struct i3c_device *i3c) +{ + struct i3cdev_data *i3cdev; + int id; + + id = ida_simple_get(&i3cdev_ida, 0, I3C_MINORS, GFP_KERNEL); + if (id < 0) { + pr_err("i3cdev: no minor number available!\n"); + return ERR_PTR(id); + } + + i3cdev = kzalloc(sizeof(*i3cdev), GFP_KERNEL); + if (!i3cdev) { + ida_simple_remove(&i3cdev_ida, id); + return ERR_PTR(-ENOMEM); + } + + i3cdev->i3c = i3c; + i3cdev->id = id; + + spin_lock(&i3cdev_list_lock); + list_add_tail(&i3cdev->list, &i3cdev_list); + spin_unlock(&i3cdev_list_lock); + + return i3cdev; +} + +static void put_i3cdev(struct i3cdev_data *i3cdev) +{ + spin_lock(&i3cdev_list_lock); + list_del(&i3cdev->list); + spin_unlock(&i3cdev_list_lock); + kfree(i3cdev); +} + +static ssize_t +i3cdev_read(struct file *file, char __user *buf, size_t count, loff_t *f_pos) +{ + struct i3c_device *i3c = file->private_data; + struct i3c_priv_xfer xfers = { + .rnw = true, + .len = count, + }; + char *tmp; + int ret; + + tmp = kzalloc(count, GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + xfers.data.in = tmp; + + dev_dbg(&i3c->dev, "Reading %zu bytes.\n", count); + + ret = i3c_device_do_priv_xfers(i3c, &xfers, 1); + if (!ret) + ret = copy_to_user(buf, tmp, count) ? -EFAULT : ret; + + kfree(tmp); + return ret; +} + +static ssize_t +i3cdev_write(struct file *file, const char __user *buf, size_t count, + loff_t *f_pos) +{ + struct i3c_device *i3c = file->private_data; + struct i3c_priv_xfer xfers = { + .rnw = false, + .len = count, + }; + char *tmp; + int ret; + + tmp = memdup_user(buf, count); + if (IS_ERR(tmp)) + return PTR_ERR(tmp); + + xfers.data.out = tmp; + + dev_dbg(&i3c->dev, "Writing %zu bytes.\n", count); + + ret = i3c_device_do_priv_xfers(i3c, &xfers, 1); + kfree(tmp); + return (!ret) ? count : ret; +} + +static int +i3cdev_do_priv_xfer(struct i3c_device *dev, struct i3c_ioc_priv_xfer *xfers, + unsigned int nxfers) +{ + struct i3c_priv_xfer *k_xfers; + u8 **data_ptrs; + int i, ret = 0; + + k_xfers = kcalloc(nxfers, sizeof(*k_xfers), GFP_KERNEL); + if (!k_xfers) + return -ENOMEM; + + data_ptrs = kcalloc(nxfers, sizeof(*data_ptrs), GFP_KERNEL); + if (!data_ptrs) { + ret = -ENOMEM; + goto err_free_k_xfer; + } + + for (i = 0; i < nxfers; i++) { + data_ptrs[i] = memdup_user((const u8 __user *) + (uintptr_t)xfers[i].data, + xfers[i].len); + if (IS_ERR(data_ptrs[i])) { + ret = PTR_ERR(data_ptrs[i]); + break; + } + + k_xfers[i].len = xfers[i].len; + if (xfers[i].rnw) { + k_xfers[i].rnw = true; + k_xfers[i].data.in = data_ptrs[i]; + } else { + k_xfers[i].rnw = false; + k_xfers[i].data.out = data_ptrs[i]; + } + } + + if (ret < 0) { + i--; + goto err_free_mem; + } + + ret = i3c_device_do_priv_xfers(dev, k_xfers, nxfers); + if (ret) + goto err_free_mem; + + for (i = 0; i < nxfers; i++) { + if (xfers[i].rnw) { + if (copy_to_user((void __user *)(uintptr_t)xfers[i].data, + data_ptrs[i], xfers[i].len)) + ret = -EFAULT; + } + } + +err_free_mem: + for (; i >= 0; i--) + kfree(data_ptrs[i]); + kfree(data_ptrs); +err_free_k_xfer: + kfree(k_xfers); + return ret; +} + +static struct i3c_ioc_priv_xfer * +i3cdev_get_ioc_priv_xfer(unsigned int cmd, struct i3c_ioc_priv_xfer *u_xfers, + unsigned int *nxfers) +{ + u32 tmp = _IOC_SIZE(cmd); + + if ((tmp % sizeof(struct i3c_ioc_priv_xfer)) != 0) + return ERR_PTR(-EINVAL); + + *nxfers = tmp / sizeof(struct i3c_ioc_priv_xfer); + if (*nxfers == 0) + return NULL; + + return memdup_user(u_xfers, tmp); +} + +static int +i3cdev_ioc_priv_xfer(struct i3c_device *i3c, unsigned int cmd, + struct i3c_ioc_priv_xfer *u_xfers) +{ + struct i3c_ioc_priv_xfer *k_xfers; + unsigned int nxfers; + int ret; + + k_xfers = i3cdev_get_ioc_priv_xfer(cmd, u_xfers, &nxfers); + if (IS_ERR_OR_NULL(k_xfers)) + return PTR_ERR(k_xfers); + + ret = i3cdev_do_priv_xfer(i3c, k_xfers, nxfers); + + kfree(k_xfers); + + return ret; +} + +static long +i3cdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct i3c_device *i3c = file->private_data; + + dev_dbg(&i3c->dev, "ioctl, cmd=0x%02x, arg=0x%02lx\n", cmd, arg); + + if (_IOC_TYPE(cmd) != I3C_DEV_IOC_MAGIC) + return -ENOTTY; + + /* Check command number and direction */ + if (_IOC_NR(cmd) == _IOC_NR(I3C_IOC_PRIV_XFER(0)) && + _IOC_DIR(cmd) == (_IOC_READ | _IOC_WRITE)) + return i3cdev_ioc_priv_xfer(i3c, cmd, + (struct i3c_ioc_priv_xfer __user *)arg); + + return 0; +} + +static int i3cdev_open(struct inode *inode, struct file *file) +{ + struct i3cdev_data *i3cdev = container_of(inode->i_cdev, + struct i3cdev_data, + cdev); + + file->private_data = i3cdev->i3c; + + return 0; +} + +static int i3cdev_release(struct inode *inode, struct file *file) +{ + file->private_data = NULL; + + return 0; +} + +static const struct file_operations i3cdev_fops = { + .owner = THIS_MODULE, + .read = i3cdev_read, + .write = i3cdev_write, + .unlocked_ioctl = i3cdev_ioctl, + .open = i3cdev_open, + .release = i3cdev_release, +}; + +/* ------------------------------------------------------------------------- */ + +static struct class *i3cdev_class; + +static int i3cdev_attach(struct device *dev, void *dummy) +{ + struct i3cdev_data *i3cdev; + struct i3c_device *i3c; + int res; + + if (dev->type == &i3c_masterdev_type || dev->driver) + return 0; + + i3c = dev_to_i3cdev(dev); + + /* Get a device */ + i3cdev = get_free_i3cdev(i3c); + if (IS_ERR(i3cdev)) + return PTR_ERR(i3cdev); + + cdev_init(&i3cdev->cdev, &i3cdev_fops); + i3cdev->cdev.owner = THIS_MODULE; + res = cdev_add(&i3cdev->cdev, + MKDEV(MAJOR(i3cdev_number), i3cdev->id), 1); + if (res) + goto error_cdev; + + /* register this i3c device with the driver core */ + i3cdev->dev = device_create(i3cdev_class, &i3c->dev, + MKDEV(MAJOR(i3cdev_number), i3cdev->id), + NULL, "i3c-%s", dev_name(&i3c->dev)); + if (IS_ERR(i3cdev->dev)) { + res = PTR_ERR(i3cdev->dev); + goto error; + } + pr_debug("i3cdev: I3C device [%s] registered as minor %d\n", + dev_name(&i3c->dev), i3cdev->id); + return 0; + +error: + cdev_del(&i3cdev->cdev); +error_cdev: + put_i3cdev(i3cdev); + return res; +} + +static int i3cdev_detach(struct device *dev, void *dummy) +{ + struct i3cdev_data *i3cdev; + struct i3c_device *i3c; + + if (dev->type == &i3c_masterdev_type) + return 0; + + i3c = dev_to_i3cdev(dev); + + i3cdev = i3cdev_get_by_i3c(i3c); + if (!i3cdev) + return 0; + + cdev_del(&i3cdev->cdev); + device_destroy(i3cdev_class, MKDEV(MAJOR(i3cdev_number), i3cdev->id)); + ida_simple_remove(&i3cdev_ida, i3cdev->id); + put_i3cdev(i3cdev); + + pr_debug("i3cdev: device [%s] unregistered\n", dev_name(&i3c->dev)); + + return 0; +} + +static int i3cdev_notifier_call(struct notifier_block *nb, + unsigned long action, + void *data) +{ + struct device *dev = data; + + switch (action) { + case BUS_NOTIFY_ADD_DEVICE: + case BUS_NOTIFY_UNBOUND_DRIVER: + return i3cdev_attach(dev, NULL); + case BUS_NOTIFY_DEL_DEVICE: + case BUS_NOTIFY_BOUND_DRIVER: + return i3cdev_detach(dev, NULL); + } + + return 0; +} + +static struct notifier_block i3c_notifier = { + .notifier_call = i3cdev_notifier_call, +}; + +static int __init i3cdev_init(void) +{ + int res; + + /* Dynamically request unused major number */ + res = alloc_chrdev_region(&i3cdev_number, 0, I3C_MINORS, "i3c"); + if (res) + goto out; + + /* Create a classe to populate sysfs entries*/ + i3cdev_class = class_create(THIS_MODULE, "i3cdev"); + if (IS_ERR(i3cdev_class)) { + res = PTR_ERR(i3cdev_class); + goto out_unreg_chrdev; + } + + /* Keep track of busses which have devices to add or remove later */ + res = bus_register_notifier(&i3c_bus_type, &i3c_notifier); + if (res) + goto out_unreg_class; + + /* Bind to already existing device without driver right away */ + i3c_for_each_dev(NULL, i3cdev_attach); + + return 0; + +out_unreg_class: + class_destroy(i3cdev_class); +out_unreg_chrdev: + unregister_chrdev_region(i3cdev_number, I3C_MINORS); +out: + pr_err("%s: Driver Initialisation failed\n", __FILE__); + return res; +} + +static void __exit i3cdev_exit(void) +{ + bus_unregister_notifier(&i3c_bus_type, &i3c_notifier); + i3c_for_each_dev(NULL, i3cdev_detach); + class_destroy(i3cdev_class); + unregister_chrdev_region(i3cdev_number, I3C_MINORS); +} + +MODULE_AUTHOR("Vitor Soares <soares@synopsys.com>"); +MODULE_DESCRIPTION("I3C /dev entries driver"); +MODULE_LICENSE("GPL"); + +module_init(i3cdev_init); +module_exit(i3cdev_exit); |