drivers/usb/gadget/function/u_fs.h

   1 /*
   2  * u_fs.h
   3  *
   4  * Utility definitions for the FunctionFS
   5  *
   6  * Copyright (c) 2013 Samsung Electronics Co., Ltd.
   7  *              http://www.samsung.com
   8  *
   9  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  */
  15
  16 #ifndef U_FFS_H
  17 #define U_FFS_H
  18
  19 #include <linux/usb/composite.h>
  20 #include <linux/list.h>
  21 #include <linux/mutex.h>
  22 #include <linux/workqueue.h>
  23
  24 #ifdef VERBOSE_DEBUG
  25 #ifndef pr_vdebug
  26 #  define pr_vdebug pr_debug
  27 #endif /* pr_vdebug */
  28 #  define ffs_dump_mem(prefix, ptr, len) \
  29         print_hex_dump_bytes(pr_fmt(prefix ": "), DUMP_PREFIX_NONE, ptr, len)
  30 #else
  31 #ifndef pr_vdebug
  32 #  define pr_vdebug(...)                 do { } while (0)
  33 #endif /* pr_vdebug */
  34 #  define ffs_dump_mem(prefix, ptr, len) do { } while (0)
  35 #endif /* VERBOSE_DEBUG */
  36
  37 #define ENTER()    pr_vdebug("%s()\n", __func__)
  38
  39 struct f_fs_opts;
  40
  41 struct ffs_dev {
  42         const char *name;
  43         bool name_allocated;
  44         bool mounted;
  45         bool desc_ready;
  46         bool single;
  47         struct ffs_data *ffs_data;
  48         struct f_fs_opts *opts;
  49         struct list_head entry;
  50
  51         int (*ffs_ready_callback)(struct ffs_data *ffs);
  52         void (*ffs_closed_callback)(struct ffs_data *ffs);
  53         void *(*ffs_acquire_dev_callback)(struct ffs_dev *dev);
  54         void (*ffs_release_dev_callback)(struct ffs_dev *dev);
  55 };
  56
  57 extern struct mutex ffs_lock;
  58
  59 static inline void ffs_dev_lock(void)
  60 {
  61         mutex_lock(&ffs_lock);
  62 }
  63
  64 static inline void ffs_dev_unlock(void)
  65 {
  66         mutex_unlock(&ffs_lock);
  67 }
  68
  69 int ffs_name_dev(struct ffs_dev *dev, const char *name);
  70 int ffs_single_dev(struct ffs_dev *dev);
  71
  72 struct ffs_epfile;
  73 struct ffs_function;
  74
  75 enum ffs_state {
  76         /*
  77          * Waiting for descriptors and strings.
  78          *
  79          * In this state no open(2), read(2) or write(2) on epfiles
  80          * may succeed (which should not be the problem as there
  81          * should be no such files opened in the first place).
  82          */
  83         FFS_READ_DESCRIPTORS,
  84         FFS_READ_STRINGS,
  85
  86         /*
  87          * We've got descriptors and strings.  We are or have called
  88          * functionfs_ready_callback().  functionfs_bind() may have
  89          * been called but we don't know.
  90          *
  91          * This is the only state in which operations on epfiles may
  92          * succeed.
  93          */
  94         FFS_ACTIVE,
  95
  96         /*
  97          * Function is visible to host, but it's not functional. All
  98          * setup requests are stalled and transfers on another endpoints
  99          * are refused. All epfiles, except ep0, are deleted so there
 100          * is no way to perform any operations on them.
 101          *
 102          * This state is set after closing all functionfs files, when
 103          * mount parameter "no_disconnect=1" has been set. Function will
 104          * remain in deactivated state until filesystem is umounted or
 105          * ep0 is opened again. In the second case functionfs state will
 106          * be reset, and it will be ready for descriptors and strings
 107          * writing.
 108          *
 109          * This is useful only when functionfs is composed to gadget
 110          * with another function which can perform some critical
 111          * operations, and it's strongly desired to have this operations
 112          * completed, even after functionfs files closure.
 113          */
 114         FFS_DEACTIVATED,
 115
 116         /*
 117          * All endpoints have been closed.  This state is also set if
 118          * we encounter an unrecoverable error.  The only
 119          * unrecoverable error is situation when after reading strings
 120          * from user space we fail to initialise epfiles or
 121          * functionfs_ready_callback() returns with error (<0).
 122          *
 123          * In this state no open(2), read(2) or write(2) (both on ep0
 124          * as well as epfile) may succeed (at this point epfiles are
 125          * unlinked and all closed so this is not a problem; ep0 is
 126          * also closed but ep0 file exists and so open(2) on ep0 must
 127          * fail).
 128          */
 129         FFS_CLOSING
 130 };
 131
 132 enum ffs_setup_state {
 133         /* There is no setup request pending. */
 134         FFS_NO_SETUP,
 135         /*
 136          * User has read events and there was a setup request event
 137          * there.  The next read/write on ep0 will handle the
 138          * request.
 139          */
 140         FFS_SETUP_PENDING,
 141         /*
 142          * There was event pending but before user space handled it
 143          * some other event was introduced which canceled existing
 144          * setup.  If this state is set read/write on ep0 return
 145          * -EIDRM.  This state is only set when adding event.
 146          */
 147         FFS_SETUP_CANCELLED
 148 };
 149
 150 struct ffs_data {
 151         struct usb_gadget               *gadget;
 152
 153         /*
 154          * Protect access read/write operations, only one read/write
 155          * at a time.  As a consequence protects ep0req and company.
 156          * While setup request is being processed (queued) this is
 157          * held.
 158          */
 159         struct mutex                    mutex;
 160
 161         /*
 162          * Protect access to endpoint related structures (basically
 163          * usb_ep_queue(), usb_ep_dequeue(), etc. calls) except for
 164          * endpoint zero.
 165          */
 166         spinlock_t                      eps_lock;
 167
 168         /*
 169          * XXX REVISIT do we need our own request? Since we are not
 170          * handling setup requests immediately user space may be so
 171          * slow that another setup will be sent to the gadget but this
 172          * time not to us but another function and then there could be
 173          * a race.  Is that the case? Or maybe we can use cdev->req
 174          * after all, maybe we just need some spinlock for that?
 175          */
 176         struct usb_request              *ep0req;                /* P: mutex */
 177         struct completion               ep0req_completion;      /* P: mutex */
 178
 179         /* reference counter */
 180         atomic_t                        ref;
 181         /* how many files are opened (EP0 and others) */
 182         atomic_t                        opened;
 183
 184         /* EP0 state */
 185         enum ffs_state                  state;
 186
 187         /*
 188          * Possible transitions:
 189          * + FFS_NO_SETUP        -> FFS_SETUP_PENDING  -- P: ev.waitq.lock
 190          *               happens only in ep0 read which is P: mutex
 191          * + FFS_SETUP_PENDING   -> FFS_NO_SETUP       -- P: ev.waitq.lock
 192          *               happens only in ep0 i/o  which is P: mutex
 193          * + FFS_SETUP_PENDING   -> FFS_SETUP_CANCELLED -- P: ev.waitq.lock
 194          * + FFS_SETUP_CANCELLED -> FFS_NO_SETUP        -- cmpxchg
 195          *
 196          * This field should never be accessed directly and instead
 197          * ffs_setup_state_clear_cancelled function should be used.
 198          */
 199         enum ffs_setup_state            setup_state;
 200
 201         /* Events & such. */
 202         struct {
 203                 u8                              types[4];
 204                 unsigned short                  count;
 205                 /* XXX REVISIT need to update it in some places, or do we? */
 206                 unsigned short                  can_stall;
 207                 struct usb_ctrlrequest          setup;
 208
 209                 wait_queue_head_t               waitq;
 210         } ev; /* the whole structure, P: ev.waitq.lock */
 211
 212         /* Flags */
 213         unsigned long                   flags;
 214 #define FFS_FL_CALL_CLOSED_CALLBACK 0
 215 #define FFS_FL_BOUND                1
 216
 217         /* Active function */
 218         struct ffs_function             *func;
 219
 220         /*
 221          * Device name, write once when file system is mounted.
 222          * Intended for user to read if she wants.
 223          */
 224         const char                      *dev_name;
 225         /* Private data for our user (ie. gadget).  Managed by user. */
 226         void                            *private_data;
 227
 228         /* filled by __ffs_data_got_descs() */
 229         /*
 230          * raw_descs is what you kfree, real_descs points inside of raw_descs,
 231          * where full speed, high speed and super speed descriptors start.
 232          * real_descs_length is the length of all those descriptors.
 233          */
 234         const void                      *raw_descs_data;
 235         const void                      *raw_descs;
 236         unsigned                        raw_descs_length;
 237         unsigned                        fs_descs_count;
 238         unsigned                        hs_descs_count;
 239         unsigned                        ss_descs_count;
 240         unsigned                        ms_os_descs_count;
 241         unsigned                        ms_os_descs_ext_prop_count;
 242         unsigned                        ms_os_descs_ext_prop_name_len;
 243         unsigned                        ms_os_descs_ext_prop_data_len;
 244         void                            *ms_os_descs_ext_prop_avail;
 245         void                            *ms_os_descs_ext_prop_name_avail;
 246         void                            *ms_os_descs_ext_prop_data_avail;
 247
 248         unsigned                        user_flags;
 249
 250         u8                              eps_addrmap[15];
 251
 252         unsigned short                  strings_count;
 253         unsigned short                  interfaces_count;
 254         unsigned short                  eps_count;
 255         unsigned short                  _pad1;
 256
 257         /* filled by __ffs_data_got_strings() */
 258         /* ids in stringtabs are set in functionfs_bind() */
 259         const void                      *raw_strings;
 260         struct usb_gadget_strings       **stringtabs;
 261
 262         /*
 263          * File system's super block, write once when file system is
 264          * mounted.
 265          */
 266         struct super_block              *sb;
 267
 268         /* File permissions, written once when fs is mounted */
 269         struct ffs_file_perms {
 270                 umode_t                         mode;
 271                 kuid_t                          uid;
 272                 kgid_t                          gid;
 273         }                               file_perms;
 274
 275         struct eventfd_ctx *ffs_eventfd;
 276         bool no_disconnect;
 277         struct work_struct reset_work;
 278
 279         /*
 280          * The endpoint files, filled by ffs_epfiles_create(),
 281          * destroyed by ffs_epfiles_destroy().
 282          */
 283         struct ffs_epfile               *epfiles;
 284 };
 285
 286
 287 struct f_fs_opts {
 288         struct usb_function_instance    func_inst;
 289         struct ffs_dev                  *dev;
 290         unsigned                        refcnt;
 291         bool                            no_configfs;
 292 };
 293
 294 static inline struct f_fs_opts *to_f_fs_opts(struct usb_function_instance *fi)
 295 {
 296         return container_of(fi, struct f_fs_opts, func_inst);
 297 }
 298
 299 #endif /* U_FFS_H */