Sometimes one needs to be able not only to catch PPS signals but to produce them also. For example, running a distributed simulation, which requires computers' clock to be synchronized very tightly. This patch adds PPS generators class in order to have a well-defined interface for these devices. Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx> --- drivers/pps/Makefile | 3 +- drivers/pps/generators/Kconfig | 19 +- drivers/pps/generators/Makefile | 4 + drivers/pps/generators/pps_gen-dummy.c | 83 ++++++++ drivers/pps/generators/pps_gen.c | 283 +++++++++++++++++++++++++ drivers/pps/generators/sysfs.c | 89 ++++++++ include/linux/pps_gen_kernel.h | 57 +++++ include/uapi/linux/pps_gen.h | 35 +++ 8 files changed, 571 insertions(+), 2 deletions(-) create mode 100644 drivers/pps/generators/pps_gen-dummy.c create mode 100644 drivers/pps/generators/pps_gen.c create mode 100644 drivers/pps/generators/sysfs.c create mode 100644 include/linux/pps_gen_kernel.h create mode 100644 include/uapi/linux/pps_gen.h diff --git a/drivers/pps/Makefile b/drivers/pps/Makefile index ceaf65cc1f1d..0aea394d4e4d 100644 --- a/drivers/pps/Makefile +++ b/drivers/pps/Makefile @@ -6,6 +6,7 @@ pps_core-y := pps.o kapi.o sysfs.o pps_core-$(CONFIG_NTP_PPS) += kc.o obj-$(CONFIG_PPS) := pps_core.o -obj-y += clients/ generators/ +obj-y += clients/ +obj-$(CONFIG_PPS_GENERATOR) += generators/ ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG diff --git a/drivers/pps/generators/Kconfig b/drivers/pps/generators/Kconfig index d615e640fcad..e3dfe31609ba 100644 --- a/drivers/pps/generators/Kconfig +++ b/drivers/pps/generators/Kconfig @@ -3,7 +3,22 @@ # PPS generators configuration # -comment "PPS generators support" +menuconfig PPS_GENERATOR + tristate "PPS generators support" + help + PPS generators are special hardware which are able to produce PPS + (Pulse Per Second) signals. + +if PPS_GENERATOR + +config PPS_GENERATOR_DUMMY + tristate "Dummy PPS generator (Testing generator, use for debug)" + help + If you say yes here you get support for a PPS debugging generator + (which actual generates no PPS signal at all). + + This driver can also be built as a module. If so, the module + will be called pps_gen-dummy. config PPS_GENERATOR_PARPORT tristate "Parallel port PPS signal generator" @@ -12,3 +27,5 @@ config PPS_GENERATOR_PARPORT If you say yes here you get support for a PPS signal generator which utilizes STROBE pin of a parallel port to send PPS signals. It uses parport abstraction layer and hrtimers to precisely control the signal. + +endif # PPS_GENERATOR diff --git a/drivers/pps/generators/Makefile b/drivers/pps/generators/Makefile index 2589fd0f2481..dc1aa5a4688b 100644 --- a/drivers/pps/generators/Makefile +++ b/drivers/pps/generators/Makefile @@ -3,6 +3,10 @@ # Makefile for PPS generators. # +pps_gen_core-y := pps_gen.o sysfs.o +obj-$(CONFIG_PPS_GENERATOR) := pps_gen_core.o + +obj-$(CONFIG_PPS_GENERATOR_DUMMY) += pps_gen-dummy.o obj-$(CONFIG_PPS_GENERATOR_PARPORT) += pps_gen_parport.o ccflags-$(CONFIG_PPS_DEBUG) := -DDEBUG diff --git a/drivers/pps/generators/pps_gen-dummy.c b/drivers/pps/generators/pps_gen-dummy.c new file mode 100644 index 000000000000..2d257f3f9bf9 --- /dev/null +++ b/drivers/pps/generators/pps_gen-dummy.c @@ -0,0 +1,83 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * PPS dummy generator + * + * Copyright (C) 2024 Rodolfo Giometti <giometti@xxxxxxxxxxxx> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/pps_gen_kernel.h> + +/* + * Global variables + */ + +static struct pps_gen_device *pps_gen; + +/* + * PPS Generator methods + */ + +static int pps_gen_dummy_get_time(struct pps_gen_device *pps_gen, + struct timespec64 *time) +{ + struct system_time_snapshot snap; + + ktime_get_snapshot(&snap); + *time = ktime_to_timespec64(snap.real); + + return 0; +} + +static int pps_gen_dummy_enable(struct pps_gen_device *pps_gen, bool enable) +{ + /* always enabled */ + return 0; +} + +/* + * The PPS info struct + */ + +static struct pps_gen_source_info pps_gen_dummy_info = { + .name = "dummy", + .use_system_clock = true, + .get_time = pps_gen_dummy_get_time, + .enable = pps_gen_dummy_enable, +}; + +/* + * Module staff + */ + +static void __exit pps_gen_dummy_exit(void) +{ + dev_info(pps_gen->dev, "dummy PPS generator unregistered\n"); + + pps_gen_unregister_source(pps_gen); +} + +static int __init pps_gen_dummy_init(void) +{ + pps_gen = pps_gen_register_source(&pps_gen_dummy_info); + if (IS_ERR(pps_gen)) { + pr_err("cannot register PPS generator\n"); + return PTR_ERR(pps_gen); + } + + dev_info(pps_gen->dev, "dummy PPS generator registered\n"); + + return 0; +} + +module_init(pps_gen_dummy_init); +module_exit(pps_gen_dummy_exit); + +MODULE_AUTHOR("Rodolfo Giometti <giometti@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("LinuxPPS dummy generator"); +MODULE_LICENSE("GPL"); diff --git a/drivers/pps/generators/pps_gen.c b/drivers/pps/generators/pps_gen.c new file mode 100644 index 000000000000..40b05087b4b4 --- /dev/null +++ b/drivers/pps/generators/pps_gen.c @@ -0,0 +1,283 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * PPS generators core file + * + * Copyright (C) 2024 Rodolfo Giometti <giometti@xxxxxxxxxxxx> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/time.h> +#include <linux/timex.h> +#include <linux/uaccess.h> +#include <linux/idr.h> +#include <linux/mutex.h> +#include <linux/cdev.h> +#include <linux/fs.h> +#include <linux/pps_gen_kernel.h> +#include <linux/slab.h> + +/* + * Local variables + */ + +static int pps_gen_major; +static struct class *pps_gen_class; + +static DEFINE_MUTEX(pps_gen_idr_lock); +static DEFINE_IDR(pps_gen_idr); + +/* + * Char device methods + */ + +static long pps_gen_cdev_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct pps_gen_device *pps_gen = file->private_data; + unsigned int __user *uiuarg = (unsigned int __user *) arg; + unsigned int status; + int ret; + + switch (cmd) { + case PPS_GEN_SETENABLE: + dev_dbg(pps_gen->dev, "PPS_GEN_SETENABLE\n"); + + ret = get_user(status, uiuarg); + if (ret) + return -EFAULT; + + ret = pps_gen->info.enable(pps_gen, status); + if (ret) + return ret; + pps_gen->enabled = status; + + break; + + default: + return -ENOTTY; + } + + return 0; +} + +#ifdef CONFIG_COMPAT +static long pps_gen_cdev_compat_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + cmd = _IOC(_IOC_DIR(cmd), _IOC_TYPE(cmd), _IOC_NR(cmd), sizeof(void *)); + return pps_gen_cdev_ioctl(file, cmd, arg); +} +#else +#define pps_gen_cdev_compat_ioctl NULL +#endif + +static struct pps_gen_device *pps_gen_idr_get(unsigned long id) +{ + struct pps_gen_device *pps_gen; + + mutex_lock(&pps_gen_idr_lock); + pps_gen = idr_find(&pps_gen_idr, id); + if (pps_gen) + kobject_get(&pps_gen->dev->kobj); + + mutex_unlock(&pps_gen_idr_lock); + return pps_gen; +} + +static int pps_gen_cdev_open(struct inode *inode, struct file *file) +{ + struct pps_gen_device *pps_gen = pps_gen_idr_get(iminor(inode)); + + if (!pps_gen) + return -ENODEV; + + file->private_data = pps_gen; + return 0; +} + +static int pps_gen_cdev_release(struct inode *inode, struct file *file) +{ + struct pps_gen_device *pps_gen = file->private_data; + + WARN_ON(pps_gen->id != iminor(inode)); + kobject_put(&pps_gen->dev->kobj); + return 0; +} + +/* + * Char device stuff + */ + +static const struct file_operations pps_gen_cdev_fops = { + .owner = THIS_MODULE, + .compat_ioctl = pps_gen_cdev_compat_ioctl, + .unlocked_ioctl = pps_gen_cdev_ioctl, + .open = pps_gen_cdev_open, + .release = pps_gen_cdev_release, +}; + +static void pps_gen_device_destruct(struct device *dev) +{ + struct pps_gen_device *pps_gen = dev_get_drvdata(dev); + + pr_debug("deallocating pps-gen%d\n", pps_gen->id); + kfree(dev); + kfree(pps_gen); +} + +static int pps_gen_register_cdev(struct pps_gen_device *pps_gen) +{ + int err; + dev_t devt; + + mutex_lock(&pps_gen_idr_lock); + + err = idr_alloc(&pps_gen_idr, pps_gen, 0, PPS_GEN_MAX_SOURCES, + GFP_KERNEL); + if (err < 0) { + if (err == -ENOSPC) { + pr_err("%s: too many PPS sources in the system\n", + pps_gen->info.name); + err = -EBUSY; + } + goto out_unlock; + } + pps_gen->id = err; + + devt = MKDEV(pps_gen_major, pps_gen->id); + pps_gen->dev = device_create(pps_gen_class, pps_gen->info.parent, devt, + pps_gen, "pps-gen%d", pps_gen->id); + if (IS_ERR(pps_gen->dev)) { + err = PTR_ERR(pps_gen->dev); + goto free_idr; + } + + /* Override the release function with our own */ + pps_gen->dev->release = pps_gen_device_destruct; + + pr_debug("generator %s got cdev (%d:%d)\n", + pps_gen->info.name, pps_gen_major, pps_gen->id); + + kobject_get(&pps_gen->dev->kobj); + mutex_unlock(&pps_gen_idr_lock); + return 0; + +free_idr: + idr_remove(&pps_gen_idr, pps_gen->id); +out_unlock: + mutex_unlock(&pps_gen_idr_lock); + return err; +} + +static void pps_gen_unregister_cdev(struct pps_gen_device *pps_gen) +{ + pr_debug("unregistering pps-gen%d\n", pps_gen->id); + device_destroy(pps_gen_class, pps_gen->dev->devt); + + /* Now we can release the ID for re-use */ + mutex_lock(&pps_gen_idr_lock); + idr_remove(&pps_gen_idr, pps_gen->id); + kobject_put(&pps_gen->dev->kobj); + mutex_unlock(&pps_gen_idr_lock); +} + +/* + * Exported functions + */ + +/* pps_gen_register_source - add a PPS generator in the system + * @info: the PPS generator info struct + * + * The function returns, in case of success, the PPS generaor device. Otherwise + * ERR_PTR(errno). + */ + +struct pps_gen_device *pps_gen_register_source(struct pps_gen_source_info *info) +{ + struct pps_gen_device *pps_gen; + int err; + + pps_gen = kzalloc(sizeof(struct pps_gen_device), GFP_KERNEL); + if (pps_gen == NULL) { + err = -ENOMEM; + goto pps_gen_register_source_exit; + } + pps_gen->info = *info; + pps_gen->enabled = false; + + /* Create the char device */ + err = pps_gen_register_cdev(pps_gen); + if (err < 0) { + pr_err("%s: unable to create char device\n", + info->name); + goto kfree_pps_gen; + } + + dev_info(pps_gen->dev, "new PPS generator %s\n", info->name); + + return pps_gen; + +kfree_pps_gen: + kfree(pps_gen); + +pps_gen_register_source_exit: + pr_err("%s: unable to register generaor\n", info->name); + + return ERR_PTR(err); +} +EXPORT_SYMBOL(pps_gen_register_source); + +/* pps_gen_unregister_source - remove a PPS generator from the system + * @pps_gen: the PPS generator + */ + +void pps_gen_unregister_source(struct pps_gen_device *pps_gen) +{ + pps_gen_unregister_cdev(pps_gen); +} +EXPORT_SYMBOL(pps_gen_unregister_source); + +/* + * Module stuff + */ + +static void __exit pps_gen_exit(void) +{ + class_destroy(pps_gen_class); + __unregister_chrdev(pps_gen_major, 0, PPS_GEN_MAX_SOURCES, "pps-gen"); +} + +static int __init pps_gen_init(void) +{ + pps_gen_class = class_create("pps-gen"); + if (IS_ERR(pps_gen_class)) { + pr_err("failed to allocate class\n"); + return PTR_ERR(pps_gen_class); + } + pps_gen_class->dev_groups = pps_gen_groups; + + pps_gen_major = __register_chrdev(0, 0, PPS_GEN_MAX_SOURCES, "pps-gen", + &pps_gen_cdev_fops); + if (pps_gen_major < 0) { + pr_err("failed to allocate char device region\n"); + goto remove_class; + } + + return 0; + +remove_class: + class_destroy(pps_gen_class); + return pps_gen_major; +} + +subsys_initcall(pps_gen_init); +module_exit(pps_gen_exit); + +MODULE_AUTHOR("Rodolfo Giometti <giometti@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("LinuxPPS generators support"); +MODULE_LICENSE("GPL"); diff --git a/drivers/pps/generators/sysfs.c b/drivers/pps/generators/sysfs.c new file mode 100644 index 000000000000..247030d138e1 --- /dev/null +++ b/drivers/pps/generators/sysfs.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * PPS generators sysfs support + * + * Copyright (C) 2024 Rodolfo Giometti <giometti@xxxxxxxxxxxx> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/device.h> +#include <linux/module.h> +#include <linux/string.h> +#include <linux/pps_gen_kernel.h> + +/* + * Attribute functions + */ + +static ssize_t system_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_gen_device *pps_gen = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%d\n", pps_gen->info.use_system_clock); +} +static DEVICE_ATTR_RO(system); + +static ssize_t time_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_gen_device *pps_gen = dev_get_drvdata(dev); + struct timespec64 time; + int ret; + + ret = pps_gen->info.get_time(pps_gen, &time); + if (ret) + return ret; + + return sysfs_emit(buf, "%llu %09lu\n", time.tv_sec, time.tv_nsec); +} +static DEVICE_ATTR_RO(time); + +static ssize_t enable_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pps_gen_device *pps_gen = dev_get_drvdata(dev); + bool status; + unsigned int enable; + int ret; + + ret = sscanf(buf, "%u", &enable); + if (ret != 1) + return -EINVAL; + status = !!enable; + + ret = pps_gen->info.enable(pps_gen, status); + if (ret) + return ret; + pps_gen->enabled = status; + + return count; +} +static DEVICE_ATTR_WO(enable); + +static ssize_t name_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct pps_gen_device *pps_gen = dev_get_drvdata(dev); + + return sysfs_emit(buf, "%s\n", pps_gen->info.name); +} +static DEVICE_ATTR_RO(name); + +static struct attribute *pps_gen_attrs[] = { + &dev_attr_enable.attr, + &dev_attr_name.attr, + &dev_attr_time.attr, + &dev_attr_system.attr, + NULL, +}; + +static const struct attribute_group pps_gen_group = { + .attrs = pps_gen_attrs, +}; + +const struct attribute_group *pps_gen_groups[] = { + &pps_gen_group, + NULL, +}; diff --git a/include/linux/pps_gen_kernel.h b/include/linux/pps_gen_kernel.h new file mode 100644 index 000000000000..5513415b53ec --- /dev/null +++ b/include/linux/pps_gen_kernel.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * PPS generator API kernel header + * + * Copyright (C) 2024 Rodolfo Giometti <giometti@xxxxxxxxxxxx> + */ + +#ifndef LINUX_PPS_GEN_KERNEL_H +#define LINUX_PPS_GEN_KERNEL_H + +#include <linux/pps_gen.h> +#include <linux/cdev.h> +#include <linux/device.h> + +/* + * Global defines + */ + +struct pps_gen_device; + +/* The specific PPS source info */ +struct pps_gen_source_info { + char name[PPS_GEN_MAX_NAME_LEN]; /* symbolic name */ + bool use_system_clock; + + int (*get_time)(struct pps_gen_device *pps_gen, + struct timespec64 *time); + int (*enable)(struct pps_gen_device *pps_gen, bool enable); + + struct module *owner; + struct device *parent; /* for device_create */ +}; + +/* The main struct */ +struct pps_gen_device { + struct pps_gen_source_info info; /* PSS generator info */ + bool enabled; /* PSS generator status */ + + unsigned int id; /* PPS generator unique ID */ + struct device *dev; +}; + +/* + * Global variables + */ + +extern const struct attribute_group *pps_gen_groups[]; + +/* + * Exported functions + */ + +extern struct pps_gen_device *pps_gen_register_source( + struct pps_gen_source_info *info); +extern void pps_gen_unregister_source(struct pps_gen_device *pps_gen); + +#endif /* LINUX_PPS_GEN_KERNEL_H */ diff --git a/include/uapi/linux/pps_gen.h b/include/uapi/linux/pps_gen.h new file mode 100644 index 000000000000..7b6f50fcab8c --- /dev/null +++ b/include/uapi/linux/pps_gen.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */ +/* + * PPS generator API header + * + * Copyright (C) 2024 Rodolfo Giometti <giometti@xxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + + +#ifndef _PPS_GEN_H_ +#define _PPS_GEN_H_ + +#include <linux/types.h> + +#define PPS_GEN_MAX_SOURCES 16 /* should be enough... */ +#define PPS_GEN_MAX_NAME_LEN 32 + +#include <linux/ioctl.h> + +#define PPS_GEN_SETENABLE _IOW('g', 0xa1, unsigned int *) + +#endif /* _PPS_GEN_H_ */ -- 2.34.1