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