/* SPDX-License-Identifier: GPL-2.0 */ /* * u_fs.h * * Utility definitions for the FunctionFS * * Copyright (c) 2013 Samsung Electronics Co., Ltd. * http://www.samsung.com * * Author: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com> */ #ifndef U_FFS_H #define U_FFS_H #include <linux/usb/composite.h> #include <linux/list.h> #include <linux/mutex.h> #include <linux/workqueue.h> #include <linux/refcount.h> #ifdef VERBOSE_DEBUG #ifndef pr_vdebug # define pr_vdebug pr_debug #endif /* pr_vdebug */ # define ffs_dump_mem(prefix, ptr, len) \ print_hex_dump_bytes(pr_fmt(prefix ": "), DUMP_PREFIX_NONE, ptr, len) #else #ifndef pr_vdebug # define pr_vdebug(...) do { } while (0) #endif /* pr_vdebug */ # define ffs_dump_mem(prefix, ptr, len) do { } while (0) #endif /* VERBOSE_DEBUG */ struct f_fs_opts; struct ffs_dev { struct ffs_data *ffs_data; struct f_fs_opts *opts; struct list_head entry; char name[41]; bool mounted; bool desc_ready; bool single; int (*ffs_ready_callback)(struct ffs_data *ffs); void (*ffs_closed_callback)(struct ffs_data *ffs); void *(*ffs_acquire_dev_callback)(struct ffs_dev *dev); void (*ffs_release_dev_callback)(struct ffs_dev *dev); }; extern struct mutex ffs_lock; static inline void ffs_dev_lock(void) { mutex_lock(&ffs_lock); } static inline void ffs_dev_unlock(void) { mutex_unlock(&ffs_lock); } int ffs_name_dev(struct ffs_dev *dev, const char *name); int ffs_single_dev(struct ffs_dev *dev); struct ffs_epfile; struct ffs_function; enum ffs_state { /* * Waiting for descriptors and strings. * * In this state no open(2), read(2) or write(2) on epfiles * may succeed (which should not be the problem as there * should be no such files opened in the first place). */ FFS_READ_DESCRIPTORS, FFS_READ_STRINGS, /* * We've got descriptors and strings. We are or have called * functionfs_ready_callback(). functionfs_bind() may have * been called but we don't know. * * This is the only state in which operations on epfiles may * succeed. */ FFS_ACTIVE, /* * Function is visible to host, but it's not functional. All * setup requests are stalled and transfers on another endpoints * are refused. All epfiles, except ep0, are deleted so there * is no way to perform any operations on them. * * This state is set after closing all functionfs files, when * mount parameter "no_disconnect=1" has been set. Function will * remain in deactivated state until filesystem is umounted or * ep0 is opened again. In the second case functionfs state will * be reset, and it will be ready for descriptors and strings * writing. * * This is useful only when functionfs is composed to gadget * with another function which can perform some critical * operations, and it's strongly desired to have this operations * completed, even after functionfs files closure. */ FFS_DEACTIVATED, /* * All endpoints have been closed. This state is also set if * we encounter an unrecoverable error. The only * unrecoverable error is situation when after reading strings * from user space we fail to initialise epfiles or * functionfs_ready_callback() returns with error (<0). * * In this state no open(2), read(2) or write(2) (both on ep0 * as well as epfile) may succeed (at this point epfiles are * unlinked and all closed so this is not a problem; ep0 is * also closed but ep0 file exists and so open(2) on ep0 must * fail). */ FFS_CLOSING }; enum ffs_setup_state { /* There is no setup request pending. */ FFS_NO_SETUP, /* * User has read events and there was a setup request event * there. The next read/write on ep0 will handle the * request. */ FFS_SETUP_PENDING, /* * There was event pending but before user space handled it * some other event was introduced which canceled existing * setup. If this state is set read/write on ep0 return * -EIDRM. This state is only set when adding event. */ FFS_SETUP_CANCELLED }; struct ffs_data { struct usb_gadget *gadget; /* * Protect access read/write operations, only one read/write * at a time. As a consequence protects ep0req and company. * While setup request is being processed (queued) this is * held. */ struct mutex mutex; /* * Protect access to endpoint related structures (basically * usb_ep_queue(), usb_ep_dequeue(), etc. calls) except for * endpoint zero. */ spinlock_t eps_lock; /* * XXX REVISIT do we need our own request? Since we are not * handling setup requests immediately user space may be so * slow that another setup will be sent to the gadget but this * time not to us but another function and then there could be * a race. Is that the case? Or maybe we can use cdev->req * after all, maybe we just need some spinlock for that? */ struct usb_request *ep0req; /* P: mutex */ struct completion ep0req_completion; /* P: mutex */ /* reference counter */ refcount_t ref; /* how many files are opened (EP0 and others) */ atomic_t opened; /* EP0 state */ enum ffs_state state; /* * Possible transitions: * + FFS_NO_SETUP -> FFS_SETUP_PENDING -- P: ev.waitq.lock * happens only in ep0 read which is P: mutex * + FFS_SETUP_PENDING -> FFS_NO_SETUP -- P: ev.waitq.lock * happens only in ep0 i/o which is P: mutex * + FFS_SETUP_PENDING -> FFS_SETUP_CANCELLED -- P: ev.waitq.lock * + FFS_SETUP_CANCELLED -> FFS_NO_SETUP -- cmpxchg * * This field should never be accessed directly and instead * ffs_setup_state_clear_cancelled function should be used. */ enum ffs_setup_state setup_state; /* Events & such. */ struct { u8 types[4]; unsigned short count; /* XXX REVISIT need to update it in some places, or do we? */ unsigned short can_stall; struct usb_ctrlrequest setup; wait_queue_head_t waitq; } ev; /* the whole structure, P: ev.waitq.lock */ /* Flags */ unsigned long flags; #define FFS_FL_CALL_CLOSED_CALLBACK 0 #define FFS_FL_BOUND 1 /* For waking up blocked threads when function is enabled. */ wait_queue_head_t wait; /* Active function */ struct ffs_function *func; /* * Device name, write once when file system is mounted. * Intended for user to read if she wants. */ const char *dev_name; /* Private data for our user (ie. gadget). Managed by user. */ void *private_data; /* filled by __ffs_data_got_descs() */ /* * raw_descs is what you kfree, real_descs points inside of raw_descs, * where full speed, high speed and super speed descriptors start. * real_descs_length is the length of all those descriptors. */ const void *raw_descs_data; const void *raw_descs; unsigned raw_descs_length; unsigned fs_descs_count; unsigned hs_descs_count; unsigned ss_descs_count; unsigned ms_os_descs_count; unsigned ms_os_descs_ext_prop_count; unsigned ms_os_descs_ext_prop_name_len; unsigned ms_os_descs_ext_prop_data_len; void *ms_os_descs_ext_prop_avail; void *ms_os_descs_ext_prop_name_avail; void *ms_os_descs_ext_prop_data_avail; unsigned user_flags; #define FFS_MAX_EPS_COUNT 31 u8 eps_addrmap[FFS_MAX_EPS_COUNT]; unsigned short strings_count; unsigned short interfaces_count; unsigned short eps_count; unsigned short _pad1; /* filled by __ffs_data_got_strings() */ /* ids in stringtabs are set in functionfs_bind() */ const void *raw_strings; struct usb_gadget_strings **stringtabs; /* * File system's super block, write once when file system is * mounted. */ struct super_block *sb; /* File permissions, written once when fs is mounted */ struct ffs_file_perms { umode_t mode; kuid_t uid; kgid_t gid; } file_perms; struct eventfd_ctx *ffs_eventfd; struct workqueue_struct *io_completion_wq; bool no_disconnect; struct work_struct reset_work; /* * The endpoint files, filled by ffs_epfiles_create(), * destroyed by ffs_epfiles_destroy(). */ struct ffs_epfile *epfiles; }; struct f_fs_opts { struct usb_function_instance func_inst; struct ffs_dev *dev; unsigned refcnt; bool no_configfs; }; static inline struct f_fs_opts *to_f_fs_opts(struct usb_function_instance *fi) { return container_of(fi, struct f_fs_opts, func_inst); } #endif /* U_FFS_H */