[RFC,5/5] i3c: add i3cdev module to expose i3c dev in /dev

Message ID	f9f20eaf900ed5629dd3d824bc1e90c7e6b4a371.1575977795.git.vitor.soares@synopsys.com (mailing list archive)
State	Changes Requested
Headers	show Return-Path: <SRS0=Y+vv=2A=lists.infradead.org=linux-i3c-bounces+linux-i3c=patchwork.kernel.org@kernel.org> DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54B80207FF From: Vitor Soares <Vitor.Soares@synopsys.com> To: linux-kernel@vger.kernel.org, linux-i3c@lists.infradead.org Subject: [RFC 5/5] i3c: add i3cdev module to expose i3c dev in /dev Date: Tue, 10 Dec 2019 16:37:33 +0100 Message-Id: <f9f20eaf900ed5629dd3d824bc1e90c7e6b4a371.1575977795.git.vitor.soares@synopsys.com> In-Reply-To: <cover.1575977795.git.vitor.soares@synopsys.com> References: <cover.1575977795.git.vitor.soares@synopsys.com> In-Reply-To: <cover.1575977795.git.vitor.soares@synopsys.com> References: <cover.1575977795.git.vitor.soares@synopsys.com> summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain Precedence: list Cc: Joao.Pinto@synopsys.com, arnd@arndb.de, wsa@the-dreams.de, gregkh@linuxfoundation.org, bbrezillon@kernel.org, Vitor Soares <Vitor.Soares@synopsys.com>, broonie@kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-i3c" <linux-i3c-bounces@lists.infradead.org> Errors-To: linux-i3c-bounces+linux-i3c=patchwork.kernel.org@lists.infradead.org
Series	Introduce i3c device userspace interface \| expand [RFC,0/5] Introduce i3c device userspace interface [RFC,1/5] i3c: master: export i3c_masterdev_type [RFC,2/5] i3c: master: export i3c_bus_type symbol [RFC,3/5] i3c: device: expose transfer strutures to uapi [RFC,4/5] i3c: master: add i3c_for_each_dev helper [RFC,5/5] i3c: add i3cdev module to expose i3c dev in /dev

diff --git a/drivers/i3c/Kconfig b/drivers/i3c/Kconfig index 30a4415..0164276 100644 --- a/drivers/i3c/Kconfig +++ b/drivers/i3c/Kconfig @@ -20,5 +20,20 @@ menuconfig I3C will be called i3c. if I3C + +config I3CDEV + tristate "I3C device interface" + depends on I3C + help + Say Y here to use i3c-* device files, usually found in the /dev + directory on your system. They make it possible to have user-space + programs use the I3C devices. + + This support is also available as a module. If so, the module + will be called i3cdev. + + Note that this application programming interface is EXPERIMENTAL + and hence SUBJECT TO CHANGE WITHOUT NOTICE while it stabilizes. + source "drivers/i3c/master/Kconfig" endif # I3C diff --git a/drivers/i3c/Makefile b/drivers/i3c/Makefile index 11982ef..606d422 100644 --- a/drivers/i3c/Makefile +++ b/drivers/i3c/Makefile @@ -1,4 +1,5 @@ # SPDX-License-Identifier: GPL-2.0 i3c-y := device.o master.o obj-$(CONFIG_I3C) += i3c.o +obj-$(CONFIG_I3CDEV) += i3cdev.o obj-$(CONFIG_I3C) += master/ diff --git a/drivers/i3c/i3cdev.c b/drivers/i3c/i3cdev.c new file mode 100644 index 0000000..4d4b83c --- /dev/null +++ b/drivers/i3c/i3cdev.c @@ -0,0 +1,438 @@ +// 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" + +#define I3C_MINORS MINORMASK +#define N_I3C_MINORS 16 /* For now */ + +static DECLARE_BITMAP(minors, N_I3C_MINORS); + +struct i3cdev_data { + struct list_head list; + struct i3c_device *i3c; + struct cdev cdev; + struct device *dev; + dev_t devt; +}; + +static dev_t i3cdev_number; /* Alloted device number */ + +static LIST_HEAD(i3cdev_list); +static DEFINE_SPINLOCK(i3cdev_list_lock); + +static struct i3cdev_data *i3cdev_get_by_minor(unsigned int minor) +{ + struct i3cdev_data *i3cdev; + + spin_lock(&i3cdev_list_lock); + list_for_each_entry(i3cdev, &i3cdev_list, list) { + if (MINOR(i3cdev->devt) == minor) + goto found; + } + + i3cdev = NULL; + +found: + spin_unlock(&i3cdev_list_lock); + return i3cdev; +} + +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; + unsigned long minor; + + minor = find_first_zero_bit(minors, N_I3C_MINORS); + if (minor >= N_I3C_MINORS) { + pr_err("i3cdev: no minor number available!\n"); + return ERR_PTR(-ENODEV); + } + + i3cdev = kzalloc(sizeof(*i3cdev), GFP_KERNEL); + if (!i3cdev) + return ERR_PTR(-ENOMEM); + + i3cdev->i3c = i3c; + i3cdev->devt = MKDEV(MAJOR(i3cdev_number), minor); + set_bit(minor, minors); + + 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_priv_xfer *xfers, + unsigned int nxfers) +{ + void __user **data_ptrs; + unsigned int i; + int ret = 0; + + data_ptrs = kmalloc_array(nxfers, sizeof(*data_ptrs), GFP_KERNEL); + if (!data_ptrs) + return -ENOMEM; + + for (i = 0; i < nxfers; i++) { + if (xfers[i].rnw) { + data_ptrs[i] = (void __user *)xfers[i].data.in; + xfers[i].data.in = memdup_user(data_ptrs[i], + xfers[i].len); + if (IS_ERR(xfers[i].data.in)) { + ret = PTR_ERR(xfers[i].data.in); + break; + } + } else { + data_ptrs[i] = (void __user *)xfers[i].data.out; + xfers[i].data.out = memdup_user(data_ptrs[i], + xfers[i].len); + if (IS_ERR(xfers[i].data.out)) { + ret = PTR_ERR(xfers[i].data.out); + break; + } + } + } + + if (ret < 0) { + unsigned int j; + + for (j = 0; j < i; ++j) { + if (xfers[i].rnw) + kfree(xfers[i].data.in); + else + kfree(xfers[i].data.out); + } + + kfree(data_ptrs); + return ret; + } + + ret = i3c_device_do_priv_xfers(dev, xfers, nxfers); + while (i-- > 0) { + if (ret >= 0 && xfers[i].rnw) { + if (copy_to_user(data_ptrs[i], xfers[i].data.in, + xfers[i].len)) + ret = -EFAULT; + } + + if (xfers[i].rnw) + kfree(xfers[i].data.in); + else + kfree(xfers[i].data.out); + } + + kfree(data_ptrs); + return ret; +} + +static int +i3cdev_ioc_priv_xfer(struct i3c_device *i3c, + struct i3c_ioc_priv_xfer __user *u_ioc_xfers) +{ + struct i3c_ioc_priv_xfer k_ioc_xfer; + struct i3c_priv_xfer *xfers; + int ret; + + if (copy_from_user(&k_ioc_xfer, u_ioc_xfers, sizeof(k_ioc_xfer))) + return -EFAULT; + + xfers = memdup_user(k_ioc_xfer.xfers, + k_ioc_xfer.nxfers * sizeof(struct i3c_priv_xfer)); + if (IS_ERR(xfers)) + return PTR_ERR(xfers); + + ret = i3cdev_do_priv_xfer(i3c, xfers, k_ioc_xfer.nxfers); + kfree(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; + + if (cmd == I3C_IOC_PRIV_XFER) + return i3cdev_ioc_priv_xfer(i3c, + (struct i3c_ioc_priv_xfer __user *)arg); + + return 0; +} + +static int i3cdev_open(struct inode *inode, struct file *file) +{ + unsigned int minor = iminor(inode); + struct i3cdev_data *i3cdev; + + i3cdev = i3cdev_get_by_minor(minor); + if (!i3cdev) + return -ENODEV; + + 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 i3c_device *i3c; + struct i3cdev_data *i3cdev; + 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, i3cdev->devt, 1); + if (res) + goto error_cdev; + + /* register this i3c device with the driver core */ + i3cdev->dev = device_create(i3cdev_class, &i3c->dev, + i3cdev->devt, NULL, + "i3c-%s", dev_name(&i3c->dev)); + if (IS_ERR(i3cdev->dev)) { + res = PTR_ERR(i3cdev->dev); + goto error; + } + pr_debug("i3c-cdev: I3C device [%s] registered as minor %d\n", + dev_name(&i3c->dev), MINOR(i3cdev->devt)); + return 0; + +error: + cdev_del(&i3cdev->cdev); +error_cdev: + put_i3cdev(i3cdev); + return res; +} + +static int i3cdev_detach(struct device *dev, void *dummy) +{ + struct i3c_device *i3c; + struct i3cdev_data *i3cdev; + + if (dev->type == &i3c_masterdev_type) + return 0; + + i3c = dev_to_i3cdev(dev); + + i3cdev = i3cdev_get_by_i3c(i3c); + if (!i3cdev) + return 0; + + clear_bit(MINOR(i3cdev->devt), minors); + cdev_del(&i3cdev->cdev); + device_destroy(i3cdev_class, i3cdev->devt); + put_i3cdev(i3cdev); + + pr_debug("i3c-busdev: bus [%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; + + pr_info("i3c /dev entries driver\n"); + + /* Dynamically request unused major number */ + res = alloc_chrdev_region(&i3cdev_number, 0, N_I3C_MINORS, "i3c"); + if (res) + goto out; + + /* Create a classe to populate sysfs entries*/ + i3cdev_class = class_create(THIS_MODULE, "i3c-dev"); + 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); diff --git a/include/uapi/linux/i3c/i3cdev.h b/include/uapi/linux/i3c/i3cdev.h new file mode 100644 index 0000000..4030043 --- /dev/null +++ b/include/uapi/linux/i3c/i3cdev.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (c) 2019 Synopsys, Inc. and/or its affiliates. + * + * Author: Vitor Soares <vitor.soares@synopsys.com> + */ + +#ifndef _UAPI_I3C_DEV_H_ +#define _UAPI_I3C_DEV_H_ + +#include <linux/types.h> +#include <linux/ioctl.h> + +/* IOCTL commands */ +#define I3C_DEV_IOC_MAGIC 0x07 + +struct i3c_ioc_priv_xfer { + struct i3c_priv_xfer __user *xfers; /* pointers to i3c_priv_xfer */ + __u32 nxfers; /* number of i3c_priv_xfer */ +}; + +#define I3C_IOC_PRIV_XFER \ + _IOW(I3C_DEV_IOC_MAGIC, 30, struct i3c_ioc_priv_xfer) + +#define I3C_IOC_PRIV_XFER_MAX_MSGS 42 + +#endif

[RFC,5/5] i3c: add i3cdev module to expose i3c dev in /dev

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