From 2e4986cf2d525eed3a240b7821f89ca45cf36d78 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 27 Feb 2025 20:26:29 -0400 Subject: fwctl: Add basic structure for a class subsystem with a cdev Create the class, character device and functions for a fwctl driver to un/register to the subsystem. A typical fwctl driver has a sysfs presence like: $ ls -l /dev/fwctl/fwctl0 crw------- 1 root root 250, 0 Apr 25 19:16 /dev/fwctl/fwctl0 $ ls /sys/class/fwctl/fwctl0 dev device power subsystem uevent $ ls /sys/class/fwctl/fwctl0/device/infiniband/ ibp0s10f0 $ ls /sys/class/infiniband/ibp0s10f0/device/fwctl/ fwctl0/ $ ls /sys/devices/pci0000:00/0000:00:0a.0/fwctl/fwctl0 dev device power subsystem uevent Which allows userspace to link all the multi-subsystem driver components together and learn the subsystem specific names for the device's components. Link: https://patch.msgid.link/r/1-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com Reviewed-by: Jonathan Cameron Reviewed-by: Dan Williams Reviewed-by: Dave Jiang Reviewed-by: Shannon Nelson Tested-by: Dave Jiang Tested-by: Shannon Nelson Signed-off-by: Jason Gunthorpe --- include/linux/fwctl.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 include/linux/fwctl.h (limited to 'include/linux') diff --git a/include/linux/fwctl.h b/include/linux/fwctl.h new file mode 100644 index 000000000000..39d5059c9e59 --- /dev/null +++ b/include/linux/fwctl.h @@ -0,0 +1,69 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (c) 2024-2025, NVIDIA CORPORATION & AFFILIATES + */ +#ifndef __LINUX_FWCTL_H +#define __LINUX_FWCTL_H +#include +#include +#include + +struct fwctl_device; +struct fwctl_uctx; + +struct fwctl_ops { +}; + +/** + * struct fwctl_device - Per-driver registration struct + * @dev: The sysfs (class/fwctl/fwctlXX) device + * + * Each driver instance will have one of these structs with the driver private + * data following immediately after. This struct is refcounted, it is freed by + * calling fwctl_put(). + */ +struct fwctl_device { + struct device dev; + /* private: */ + struct cdev cdev; + const struct fwctl_ops *ops; +}; + +struct fwctl_device *_fwctl_alloc_device(struct device *parent, + const struct fwctl_ops *ops, + size_t size); +/** + * fwctl_alloc_device - Allocate a fwctl + * @parent: Physical device that provides the FW interface + * @ops: Driver ops to register + * @drv_struct: 'struct driver_fwctl' that holds the struct fwctl_device + * @member: Name of the struct fwctl_device in @drv_struct + * + * This allocates and initializes the fwctl_device embedded in the drv_struct. + * Upon success the pointer must be freed via fwctl_put(). Returns a 'drv_struct + * \*' on success, NULL on error. + */ +#define fwctl_alloc_device(parent, ops, drv_struct, member) \ + ({ \ + static_assert(__same_type(struct fwctl_device, \ + ((drv_struct *)NULL)->member)); \ + static_assert(offsetof(drv_struct, member) == 0); \ + (drv_struct *)_fwctl_alloc_device(parent, ops, \ + sizeof(drv_struct)); \ + }) + +static inline struct fwctl_device *fwctl_get(struct fwctl_device *fwctl) +{ + get_device(&fwctl->dev); + return fwctl; +} +static inline void fwctl_put(struct fwctl_device *fwctl) +{ + put_device(&fwctl->dev); +} +DEFINE_FREE(fwctl, struct fwctl_device *, if (_T) fwctl_put(_T)); + +int fwctl_register(struct fwctl_device *fwctl); +void fwctl_unregister(struct fwctl_device *fwctl); + +#endif -- cgit v1.2.3