/* * A generic kernel FIFO implementation. * * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net> * Copyright (C) 2004 Stelian Pop <stelian@popies.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ /* * Howto porting drivers to the new generic fifo API: * * - Modify the declaration of the "struct kfifo *" object into a * in-place "struct kfifo" object * - Init the in-place object with kfifo_alloc() or kfifo_init() * Note: The address of the in-place "struct kfifo" object must be * passed as the first argument to this functions * - Replace the use of __kfifo_put into kfifo_in and __kfifo_get * into kfifo_out * - Replace the use of kfifo_put into kfifo_in_locked and kfifo_get * into kfifo_out_locked * Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc * must be passed now to the kfifo_in_locked and kfifo_out_locked * as the last parameter. * - All formerly name __kfifo_* functions has been renamed into kfifo_* */ #ifndef _LINUX_KFIFO_H #define _LINUX_KFIFO_H #include "stdint.h" #include "stdlib.h" #include "string.h" #include "os_config.h" extern struct kfifo fifo; #define FIFO_BUFFER_SIZE 8 * 128 struct kfifo { unsigned char *buffer; /* the buffer holding the data */ unsigned int size; /* the size of the allocated buffer */ unsigned int in; /* data is added at offset (in % size) */ unsigned int out; /* data is extracted from off. (out % size) */ }; /* * Macros for declaration and initialization of the kfifo datatype */ /* helper macro */ #define __kfifo_initializer(s, b) (struct kfifo) { .size = s, .in = 0, .out = 0, .buffer = b } /** * DECLARE_KFIFO - macro to declare a kfifo and the associated buffer * @name: name of the declared kfifo datatype * @size: size of the fifo buffer. Must be a power of two. * * Note1: the macro can be used inside struct or union declaration * Note2: the macro creates two objects: * A kfifo object with the given name and a buffer for the kfifo * object named name##kfifo_buffer */ #define DECLARE_KFIFO(name, size) union { struct kfifo name; unsigned char name##kfifo_buffer[size + sizeof(struct kfifo)]; } /** * INIT_KFIFO - Initialize a kfifo declared by DECLARE_KFIFO * @name: name of the declared kfifo datatype */ #define INIT_KFIFO(name) name = __kfifo_initializer(sizeof(name##kfifo_buffer) - sizeof(struct kfifo), name##kfifo_buffer) /** * DEFINE_KFIFO - macro to define and initialize a kfifo * @name: name of the declared kfifo datatype * @size: size of the fifo buffer. Must be a power of two. * * Note1: the macro can be used for global and local kfifo data type variables * Note2: the macro creates two objects: * A kfifo object with the given name and a buffer for the kfifo * object named name##kfifo_buffer */ #define DEFINE_KFIFO(name, size) unsigned char name##kfifo_buffer[size]; struct kfifo name = __kfifo_initializer(size, name##kfifo_buffer) #undef __kfifo_initializer extern void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size); extern int kfifo_alloc(struct kfifo *fifo, unsigned int size); extern void kfifo_free(struct kfifo *fifo); extern unsigned int kfifo_in(struct kfifo *fifo, const void *from, unsigned int len); extern unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len); extern unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len, unsigned offset); /** * kfifo_initialized - Check if kfifo is initialized. * @fifo: fifo to check * Return %true if FIFO is initialized, otherwise %false. * Assumes the fifo was 0 before. */ static inline uint8_t kfifo_initialized(struct kfifo *fifo) { return fifo->buffer != NULL; } /** * kfifo_reset - removes the entire FIFO contents * @fifo: the fifo to be emptied. */ static inline void kfifo_reset(struct kfifo *fifo) { fifo->in = fifo->out = 0; } /** * kfifo_reset_out - skip FIFO contents * @fifo: the fifo to be emptied. */ static inline void kfifo_reset_out(struct kfifo *fifo) { fifo->out = fifo->in; } /** * kfifo_size - returns the size of the fifo in bytes * @fifo: the fifo to be used. */ static inline unsigned int kfifo_size(struct kfifo *fifo) { return fifo->size; } /** * kfifo_len - returns the number of used bytes in the FIFO * @fifo: the fifo to be used. */ static inline unsigned int kfifo_len(struct kfifo *fifo) { register unsigned int out; out = fifo->out; return fifo->in - out; } /** * kfifo_is_empty - returns true if the fifo is empty * @fifo: the fifo to be used. */ static inline int kfifo_is_empty(struct kfifo *fifo) { return fifo->in == fifo->out; } /** * kfifo_is_full - returns true if the fifo is full * @fifo: the fifo to be used. */ static inline int kfifo_is_full(struct kfifo *fifo) { return kfifo_len(fifo) == kfifo_size(fifo); } /** * kfifo_avail - returns the number of bytes available in the FIFO * @fifo: the fifo to be used. */ static inline unsigned int kfifo_avail(struct kfifo *fifo) { return kfifo_size(fifo) - kfifo_len(fifo); } extern void kfifo_skip(struct kfifo *fifo, unsigned int len); extern int kfifo_from_user(struct kfifo *fifo, const void *from, unsigned int n, unsigned *lenout); extern int kfifo_to_user(struct kfifo *fifo, void *to, unsigned int n, unsigned *lenout); /* * __kfifo_add_out internal helper function for updating the out offset */ static inline void __kfifo_add_out(struct kfifo *fifo, unsigned int off) { fifo->out += off; } /* * __kfifo_add_in internal helper function for updating the in offset */ static inline void __kfifo_add_in(struct kfifo *fifo, unsigned int off) { fifo->in += off; } /* * __kfifo_off internal helper function for calculating the index of a * given offeset */ static inline unsigned int __kfifo_off(struct kfifo *fifo, unsigned int off) { // size-1 0111111... return off & (fifo->size - 1); } /* * __kfifo_peek_n internal helper function for determinate the length of * the next record in the fifo */ static inline unsigned int __kfifo_peek_n(struct kfifo *fifo, unsigned int recsize) { #define __KFIFO_GET(fifo, off, shift) ((fifo)->buffer[__kfifo_off((fifo), (fifo)->out+(off))] << (shift)) unsigned int l; l = __KFIFO_GET(fifo, 0, 0); if (--recsize) l |= __KFIFO_GET(fifo, 1, 8); return l; #undef __KFIFO_GET } /* * __kfifo_poke_n internal helper function for storing the length of * the next record into the fifo */ static inline void __kfifo_poke_n(struct kfifo *fifo, unsigned int recsize, unsigned int n) { #define __KFIFO_PUT(fifo, off, val, shift) ( (fifo)->buffer[__kfifo_off((fifo), (fifo)->in+(off))] = (unsigned char)((val) >> (shift)) ) __KFIFO_PUT(fifo, 0, n, 0); if (--recsize) __KFIFO_PUT(fifo, 1, n, 8); #undef __KFIFO_PUT } /* * __kfifo_in_... internal functions for put date into the fifo * do not call it directly, use kfifo_in_rec() instead */ extern unsigned int __kfifo_in_n(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize); extern unsigned int __kfifo_in_generic(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize); static inline unsigned int __kfifo_in_rec(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize) { unsigned int ret; ret = __kfifo_in_n(fifo, from, n, recsize); if (ret == 0) { if (recsize) __kfifo_poke_n(fifo, recsize, n); __kfifo_add_in(fifo, n + recsize); } return ret; } /** * kfifo_in_rec - puts some record data into the FIFO * @fifo: the fifo to be used. * @from: the data to be added. * @n: the length of the data to be added. * @recsize: size of record field * * This function copies @n bytes from the @from into the FIFO and returns * the number of bytes which cannot be copied. * A returned value greater than the @n value means that the record doesn't * fit into the buffer. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ static inline unsigned int kfifo_in_rec(struct kfifo *fifo, void *from, unsigned int n, unsigned int recsize) { if (!recsize) return __kfifo_in_generic(fifo, from, n, recsize); return __kfifo_in_rec(fifo, from, n, recsize); } /* * __kfifo_out_... internal functions for get date from the fifo * do not call it directly, use kfifo_out_rec() instead */ extern unsigned int __kfifo_out_n(struct kfifo *fifo, void *to, unsigned int reclen, unsigned int recsize); extern unsigned int __kfifo_out_generic(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total); static inline unsigned int __kfifo_out_rec(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total) { unsigned int l; if (!recsize) { l = n; if (total) *total = l; } else { l = __kfifo_peek_n(fifo, recsize); if (total) *total = l; if (n < l) return l; } return __kfifo_out_n(fifo, to, l, recsize); } /** * kfifo_out_rec - gets some record data from the FIFO * @fifo: the fifo to be used. * @to: where the data must be copied. * @n: the size of the destination buffer. * @recsize: size of record field * @total: pointer where the total number of to copied bytes should stored * * This function copies at most @n bytes from the FIFO to @to and returns the * number of bytes which cannot be copied. * A returned value greater than the @n value means that the record doesn't * fit into the @to buffer. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ static inline unsigned int kfifo_out_rec(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total) { if (!recsize) return __kfifo_out_generic(fifo, to, n, recsize, total); return __kfifo_out_rec(fifo, to, n, recsize, total); } /* * __kfifo_from_user_... internal functions for transfer from user space into * the fifo. do not call it directly, use kfifo_from_user_rec() instead */ extern unsigned int __kfifo_from_user_n(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize); extern unsigned int __kfifo_from_user_generic(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize); static inline unsigned int __kfifo_from_user_rec(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize) { unsigned int ret; ret = __kfifo_from_user_n(fifo, from, n, recsize); if (ret == 0) { if (recsize) __kfifo_poke_n(fifo, recsize, n); __kfifo_add_in(fifo, n + recsize); } return ret; } /** * kfifo_from_user_rec - puts some data from user space into the FIFO * @fifo: the fifo to be used. * @from: pointer to the data to be added. * @n: the length of the data to be added. * @recsize: size of record field * * This function copies @n bytes from the @from into the * FIFO and returns the number of bytes which cannot be copied. * * If the returned value is equal or less the @n value, the copy_from_user() * functions has failed. Otherwise the record doesn't fit into the buffer. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ static inline unsigned int kfifo_from_user_rec(struct kfifo *fifo, const void *from, unsigned int n, unsigned int recsize) { if (!recsize) return __kfifo_from_user_generic(fifo, from, n, recsize); return __kfifo_from_user_rec(fifo, from, n, recsize); } /* * __kfifo_to_user_... internal functions for transfer fifo data into user space * do not call it directly, use kfifo_to_user_rec() instead */ extern unsigned int __kfifo_to_user_n(struct kfifo *fifo, void *to, unsigned int n, unsigned int reclen, unsigned int recsize); extern unsigned int __kfifo_to_user_generic(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total); static inline unsigned int __kfifo_to_user_rec(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total) { unsigned int l; if (!recsize) { l = n; if (total) *total = l; } else { l = __kfifo_peek_n(fifo, recsize); if (total) *total = l; if (n < l) return l; } return __kfifo_to_user_n(fifo, to, n, l, recsize); } /** * kfifo_to_user_rec - gets data from the FIFO and write it to user space * @fifo: the fifo to be used. * @to: where the data must be copied. * @n: the size of the destination buffer. * @recsize: size of record field * @total: pointer where the total number of to copied bytes should stored * * This function copies at most @n bytes from the FIFO to the @to. * In case of an error, the function returns the number of bytes which cannot * be copied. * If the returned value is equal or less the @n value, the copy_to_user() * functions has failed. Otherwise the record doesn't fit into the @to buffer. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ static inline unsigned int kfifo_to_user_rec(struct kfifo *fifo, void *to, unsigned int n, unsigned int recsize, unsigned int *total) { if (!recsize) return __kfifo_to_user_generic(fifo, to, n, recsize, total); return __kfifo_to_user_rec(fifo, to, n, recsize, total); } /* * __kfifo_peek_... internal functions for peek into the next fifo record * do not call it directly, use kfifo_peek_rec() instead */ extern unsigned int __kfifo_peek_generic(struct kfifo *fifo, unsigned int recsize); /** * kfifo_peek_rec - gets the size of the next FIFO record data * @fifo: the fifo to be used. * @recsize: size of record field * * This function returns the size of the next FIFO record in number of bytes */ static inline unsigned int kfifo_peek_rec(struct kfifo *fifo, unsigned int recsize) { if (!recsize) return __kfifo_peek_generic(fifo, recsize); if (!recsize) return kfifo_len(fifo); return __kfifo_peek_n(fifo, recsize); } /* * __kfifo_skip_... internal functions for skip the next fifo record * do not call it directly, use kfifo_skip_rec() instead */ extern void __kfifo_skip_generic(struct kfifo *fifo, unsigned int recsize); static inline void __kfifo_skip_rec(struct kfifo *fifo, unsigned int recsize) { unsigned int l; if (recsize) { l = __kfifo_peek_n(fifo, recsize); if (l + recsize <= kfifo_len(fifo)) { __kfifo_add_out(fifo, l + recsize); return; } } kfifo_reset_out(fifo); } /** * kfifo_skip_rec - skip the next fifo out record * @fifo: the fifo to be used. * @recsize: size of record field * * This function skips the next FIFO record */ static inline void kfifo_skip_rec(struct kfifo *fifo, unsigned int recsize) { if (!recsize) __kfifo_skip_generic(fifo, recsize); else __kfifo_skip_rec(fifo, recsize); } /** * kfifo_avail_rec - returns the number of bytes available in a record FIFO * @fifo: the fifo to be used. * @recsize: size of record field */ static inline unsigned int kfifo_avail_rec(struct kfifo *fifo, unsigned int recsize) { unsigned int l = kfifo_size(fifo) - kfifo_len(fifo); return (l > recsize) ? l - recsize : 0; } #endif
/* * A generic kernel FIFO implementation. * * Copyright (C) 2009 Stefani Seibold <stefani@seibold.net> * Copyright (C) 2004 Stelian Pop <stelian@popies.net> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. * */ #include "fifo.h" struct kfifo fifo; /* struct kfifo fifo; unsigned int val; int ret; ret = kfifo_alloc(&fifo, FIFO_BUFFER_SIZE); unsigned int i; for (i = 0; i < 31; i++) { kfifo_in(&fifo, &i, sizeof(i)); } // 查看队尾 ret = kfifo_out_peek(&fifo, &val, sizeof(val), 0); printf("%d ", val); // 队列满时，返回0 while (kfifo_avail(&fifo)) { int ret; ret = kfifo_out(&fifo, &val, sizeof(val)); if (ret != sizeof(val)) return -1; printf("%d ", val); } */ static unsigned int min(unsigned int a, unsigned int b) { if (a < b) return a; else return b; } //static unsigned int max(unsigned int a, unsigned int b) //{ // if (a < b) // return b; // else // return a; //} unsigned char fifo_buffer[FIFO_BUFFER_SIZE]; static void _kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size) { fifo->buffer = buffer; fifo->size = size; kfifo_reset(fifo); } /** * kfifo_init - initialize a FIFO using a preallocated buffer * @fifo: the fifo to assign the buffer * @buffer: the preallocated buffer to be used. * @size: the size of the internal buffer, this has to be a power of 2. * */ void kfifo_init(struct kfifo *fifo, void *buffer, unsigned int size) { /* size must be a power of 2 */ _kfifo_init(fifo, buffer, size); } /** * kfifo_alloc - allocates a new FIFO internal buffer * @fifo: the fifo to assign then new buffer * @size: the size of the buffer to be allocated, this have to be a power of 2. * @gfp_mask: get_free_pages mask, passed to kmalloc() * * This function dynamically allocates a new fifo internal buffer * * The size will be rounded-up to a power of 2. * The buffer will be release with kfifo_free(). * Return 0 if no error, otherwise the an error code */ int kfifo_alloc(struct kfifo *fifo, unsigned int size) { _kfifo_init(fifo, fifo_buffer, size); return 0; } /** * kfifo_free - frees the FIFO internal buffer * @fifo: the fifo to be freed. */ void kfifo_free(struct kfifo *fifo) { _kfifo_init(fifo, NULL, 0); } /** * kfifo_skip - skip output data * @fifo: the fifo to be used. * @len: number of bytes to skip */ void kfifo_skip(struct kfifo *fifo, unsigned int len) { if (len < kfifo_len(fifo)) { __kfifo_add_out(fifo, len); return; } kfifo_reset_out(fifo); } static inline void __kfifo_in_data(struct kfifo *fifo, const uint8_t *from, unsigned int len, unsigned int off) { unsigned int l; /* * Ensure that we sample the fifo->out index -before- we * start putting bytes into the kfifo. */ off = __kfifo_off(fifo, fifo->in + off); /* first put the data starting from fifo->in to buffer end */ // 先拷贝一部分数据在缓冲区尾部 l = min(len, fifo->size - off); memcpy(fifo->buffer + off, from, l); // 剩余部分拷贝到缓冲区前 /* then put the rest (if any) at the beginning of the buffer */ memcpy(fifo->buffer, from + l, len - l); } static inline void __kfifo_out_data(struct kfifo *fifo, uint8_t *to, unsigned int len, unsigned int off) { unsigned int l; /* * Ensure that we sample the fifo->in index -before- we * start removing bytes from the kfifo. */ off = __kfifo_off(fifo, fifo->out + off); /* first get the data from fifo->out until the end of the buffer */ l = min(len, fifo->size - off); memcpy(to, fifo->buffer + off, l); /* then get the rest (if any) from the beginning of the buffer */ memcpy(to + l, fifo->buffer, len - l); } unsigned int __kfifo_in_n(struct kfifo *fifo, const void *from, unsigned int len, unsigned int recsize) { if (kfifo_avail(fifo) < len + recsize) return len + 1; __kfifo_in_data(fifo, from, len, recsize); return 0; } /** * kfifo_in - puts some data into the FIFO * @fifo: the fifo to be used. * @from: the data to be added. * @len: the length of the data to be added. * * This function copies at most @len bytes from the @from buffer into * the FIFO depending on the free space, and returns the number of * bytes copied. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ unsigned int kfifo_in(struct kfifo *fifo, const void *from, unsigned int len) { if (kfifo_avail(fifo) < len) { // 若队列已满，不进行操作，打印错误信息 #ifdef OS_TEST printf("fifo is full "); #endif return 0; } len = min(kfifo_avail(fifo), len); __kfifo_in_data(fifo, from, len, 0); __kfifo_add_in(fifo, len); return len; } unsigned int __kfifo_in_generic(struct kfifo *fifo, const void *from, unsigned int len, unsigned int recsize) { return __kfifo_in_rec(fifo, from, len, recsize); } unsigned int __kfifo_out_n(struct kfifo *fifo, void *to, unsigned int len, unsigned int recsize) { if (kfifo_len(fifo) < len + recsize) return len; __kfifo_out_data(fifo, to, len, recsize); __kfifo_add_out(fifo, len + recsize); return 0; } /** * kfifo_out - gets some data from the FIFO * @fifo: the fifo to be used. * @to: where the data must be copied. * @len: the size of the destination buffer. * * This function copies at most @len bytes from the FIFO into the * @to buffer and returns the number of copied bytes. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these functions. */ unsigned int kfifo_out(struct kfifo *fifo, void *to, unsigned int len) { len = min(kfifo_len(fifo), len); __kfifo_out_data(fifo, to, len, 0); __kfifo_add_out(fifo, len); return len; } /** * kfifo_out_peek - copy some data from the FIFO, but do not remove it * @fifo: the fifo to be used. * @to: where the data must be copied. * @len: the size of the destination buffer. * @offset: offset into the fifo * * This function copies at most @len bytes at @offset from the FIFO * into the @to buffer and returns the number of copied bytes. * The data is not removed from the FIFO. */ unsigned int kfifo_out_peek(struct kfifo *fifo, void *to, unsigned int len, unsigned offset) { len = min(kfifo_len(fifo), len + offset); __kfifo_out_data(fifo, to, len, offset); return len; }