diff options
Diffstat (limited to 'drivers/usb/gadget/function/u_fs.h')
| -rw-r--r-- | drivers/usb/gadget/function/u_fs.h | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/u_fs.h b/drivers/usb/gadget/function/u_fs.h new file mode 100644 index 000000000..c3aba4dfa --- /dev/null +++ b/drivers/usb/gadget/function/u_fs.h @@ -0,0 +1,303 @@ +// 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 <andrzej.p@samsung.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 */ + +#define ENTER() pr_vdebug("%s()\n", __func__) + +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 */ |