Release 4.7 drivers/usb/gadget/function/u_fs.h

/*
 * 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>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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>

#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 {
	
const char *name;
	
bool name_allocated;
	
bool mounted;
	
bool desc_ready;
	
bool single;
	
struct ffs_data *ffs_data;
	
struct f_fs_opts *opts;
	
struct list_head entry;

	
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);
}

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static inline void ffs_dev_unlock(void)
{
	mutex_unlock(&ffs_lock);
}

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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 */
	
atomic_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

	/* 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;

	
u8				eps_addrmap[15];

	
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;
	
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);
}

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#endif /* U_FFS_H */
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Directory: drivers/usb/gadget/function

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