/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * A generic kernel FIFO implementation * * Copyright (C) 2013 Stefani Seibold <[email protected]> */ #ifndef _LINUX_KFIFO_H #define _LINUX_KFIFO_H /* * How to 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_spinlocked and kfifo_get * into kfifo_out_spinlocked * Note: the spinlock pointer formerly passed to kfifo_init/kfifo_alloc * must be passed now to the kfifo_in_spinlocked and kfifo_out_spinlocked * as the last parameter * - The formerly __kfifo_* functions are renamed into kfifo_* */ /* * Note about locking: There is no locking required until only one reader * and one writer is using the fifo and no kfifo_reset() will be called. * kfifo_reset_out() can be safely used, until it will be only called * in the reader thread. * For multiple writer and one reader there is only a need to lock the writer. * And vice versa for only one writer and multiple reader there is only a need * to lock the reader. */ #include <linux/array_size.h> #include <linux/dma-mapping.h> #include <linux/spinlock.h> #include <linux/stddef.h> #include <linux/types.h> #include <asm/barrier.h> #include <asm/errno.h> struct scatterlist; struct __kfifo { … }; #define __STRUCT_KFIFO_COMMON(datatype, recsize, ptrtype) … #define __STRUCT_KFIFO(type, size, recsize, ptrtype) … #define STRUCT_KFIFO(type, size) … #define __STRUCT_KFIFO_PTR(type, recsize, ptrtype) … #define STRUCT_KFIFO_PTR(type) … /* * define compatibility "struct kfifo" for dynamic allocated fifos */ struct kfifo __STRUCT_KFIFO_PTR( … } ; #define STRUCT_KFIFO_REC_1(size) … #define STRUCT_KFIFO_REC_2(size) … /* * define kfifo_rec types */ struct kfifo_rec_ptr_1 __STRUCT_KFIFO_PTR( … } ; struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR( … } ; /* * helper macro to distinguish between real in place fifo where the fifo * array is a part of the structure and the fifo type where the array is * outside of the fifo structure. */ #define __is_kfifo_ptr(fifo) … /** * DECLARE_KFIFO_PTR - macro to declare a fifo pointer object * @fifo: name of the declared fifo * @type: type of the fifo elements */ #define DECLARE_KFIFO_PTR(fifo, type) … /** * DECLARE_KFIFO - macro to declare a fifo object * @fifo: name of the declared fifo * @type: type of the fifo elements * @size: the number of elements in the fifo, this must be a power of 2 */ #define DECLARE_KFIFO(fifo, type, size) … /** * INIT_KFIFO - Initialize a fifo declared by DECLARE_KFIFO * @fifo: name of the declared fifo datatype */ #define INIT_KFIFO(fifo) … /** * DEFINE_KFIFO - macro to define and initialize a fifo * @fifo: name of the declared fifo datatype * @type: type of the fifo elements * @size: the number of elements in the fifo, this must be a power of 2 * * Note: the macro can be used for global and local fifo data type variables. */ #define DEFINE_KFIFO(fifo, type, size) … static inline unsigned int __must_check __kfifo_uint_must_check_helper(unsigned int val) { … } static inline int __must_check __kfifo_int_must_check_helper(int val) { … } /** * kfifo_initialized - Check if the fifo is initialized * @fifo: address of the fifo to check * * Return %true if fifo is initialized, otherwise %false. * Assumes the fifo was 0 before. */ #define kfifo_initialized(fifo) … /** * kfifo_esize - returns the size of the element managed by the fifo * @fifo: address of the fifo to be used */ #define kfifo_esize(fifo) … /** * kfifo_recsize - returns the size of the record length field * @fifo: address of the fifo to be used */ #define kfifo_recsize(fifo) … /** * kfifo_size - returns the size of the fifo in elements * @fifo: address of the fifo to be used */ #define kfifo_size(fifo) … /** * kfifo_reset - removes the entire fifo content * @fifo: address of the fifo to be used * * Note: usage of kfifo_reset() is dangerous. It should be only called when the * fifo is exclusived locked or when it is secured that no other thread is * accessing the fifo. */ #define kfifo_reset(fifo) … /** * kfifo_reset_out - skip fifo content * @fifo: address of the fifo to be used * * Note: The usage of kfifo_reset_out() is safe until it will be only called * from the reader thread and there is only one concurrent reader. Otherwise * it is dangerous and must be handled in the same way as kfifo_reset(). */ #define kfifo_reset_out(fifo) … /** * kfifo_len - returns the number of used elements in the fifo * @fifo: address of the fifo to be used */ #define kfifo_len(fifo) … /** * kfifo_is_empty - returns true if the fifo is empty * @fifo: address of the fifo to be used */ #define kfifo_is_empty(fifo) … /** * kfifo_is_empty_spinlocked - returns true if the fifo is empty using * a spinlock for locking * @fifo: address of the fifo to be used * @lock: spinlock to be used for locking */ #define kfifo_is_empty_spinlocked(fifo, lock) … /** * kfifo_is_empty_spinlocked_noirqsave - returns true if the fifo is empty * using a spinlock for locking, doesn't disable interrupts * @fifo: address of the fifo to be used * @lock: spinlock to be used for locking */ #define kfifo_is_empty_spinlocked_noirqsave(fifo, lock) … /** * kfifo_is_full - returns true if the fifo is full * @fifo: address of the fifo to be used */ #define kfifo_is_full(fifo) … /** * kfifo_avail - returns the number of unused elements in the fifo * @fifo: address of the fifo to be used */ #define kfifo_avail(fifo) … /** * kfifo_skip_count - skip output data * @fifo: address of the fifo to be used * @count: count of data to skip */ #define kfifo_skip_count(fifo, count) … /** * kfifo_skip - skip output data * @fifo: address of the fifo to be used */ #define kfifo_skip(fifo) … /** * kfifo_peek_len - gets the size of the next fifo record * @fifo: address of the fifo to be used * * This function returns the size of the next fifo record in number of bytes. */ #define kfifo_peek_len(fifo) … /** * kfifo_alloc - dynamically allocates a new fifo buffer * @fifo: pointer to the fifo * @size: the number of elements in the fifo, this must be a power of 2 * @gfp_mask: get_free_pages mask, passed to kmalloc() * * This macro dynamically allocates a new fifo buffer. * * The number of elements will be rounded-up to a power of 2. * The fifo will be release with kfifo_free(). * Return 0 if no error, otherwise an error code. */ #define kfifo_alloc(fifo, size, gfp_mask) … /** * kfifo_free - frees the fifo * @fifo: the fifo to be freed */ #define kfifo_free(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 have to be a power of 2 * * This macro initializes a fifo using a preallocated buffer. * * The number of elements will be rounded-up to a power of 2. * Return 0 if no error, otherwise an error code. */ #define kfifo_init(fifo, buffer, size) … /** * kfifo_put - put data into the fifo * @fifo: address of the fifo to be used * @val: the data to be added * * This macro copies the given value into the fifo. * It returns 0 if the fifo was full. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_put(fifo, val) … /** * kfifo_get - get data from the fifo * @fifo: address of the fifo to be used * @val: address where to store the data * * This macro reads the data from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_get(fifo, val) … /** * kfifo_peek - get data from the fifo without removing * @fifo: address of the fifo to be used * @val: address where to store the data * * This reads the data from the fifo without removing it from the fifo. * It returns 0 if the fifo was empty. Otherwise it returns the number * processed elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_peek(fifo, val) … /** * kfifo_in - put data into the fifo * @fifo: address of the fifo to be used * @buf: the data to be added * @n: number of elements to be added * * This macro copies the given buffer into the fifo and returns the * number of copied elements. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_in(fifo, buf, n) … /** * kfifo_in_spinlocked - put data into the fifo using a spinlock for locking * @fifo: address of the fifo to be used * @buf: the data to be added * @n: number of elements to be added * @lock: pointer to the spinlock to use for locking * * This macro copies the given values buffer into the fifo and returns the * number of copied elements. */ #define kfifo_in_spinlocked(fifo, buf, n, lock) … /** * kfifo_in_spinlocked_noirqsave - put data into fifo using a spinlock for * locking, don't disable interrupts * @fifo: address of the fifo to be used * @buf: the data to be added * @n: number of elements to be added * @lock: pointer to the spinlock to use for locking * * This is a variant of kfifo_in_spinlocked() but uses spin_lock/unlock() * for locking and doesn't disable interrupts. */ #define kfifo_in_spinlocked_noirqsave(fifo, buf, n, lock) … /* alias for kfifo_in_spinlocked, will be removed in a future release */ #define kfifo_in_locked(fifo, buf, n, lock) … /** * kfifo_out - get data from the fifo * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * * This macro gets some data from the fifo and returns the numbers of elements * copied. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out(fifo, buf, n) … /** * kfifo_out_spinlocked - get data from the fifo using a spinlock for locking * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * @lock: pointer to the spinlock to use for locking * * This macro gets the data from the fifo and returns the numbers of elements * copied. */ #define kfifo_out_spinlocked(fifo, buf, n, lock) … /** * kfifo_out_spinlocked_noirqsave - get data from the fifo using a spinlock * for locking, don't disable interrupts * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * @lock: pointer to the spinlock to use for locking * * This is a variant of kfifo_out_spinlocked() which uses spin_lock/unlock() * for locking and doesn't disable interrupts. */ #define kfifo_out_spinlocked_noirqsave(fifo, buf, n, lock) … /* alias for kfifo_out_spinlocked, will be removed in a future release */ #define kfifo_out_locked(fifo, buf, n, lock) … /** * kfifo_from_user - puts some data from user space into the fifo * @fifo: address of the fifo to be used * @from: pointer to the data to be added * @len: the length of the data to be added * @copied: pointer to output variable to store the number of copied bytes * * This macro copies at most @len bytes from the @from into the * fifo, depending of the available space and returns -EFAULT/0. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_from_user(fifo, from, len, copied) … /** * kfifo_to_user - copies data from the fifo into user space * @fifo: address of the fifo to be used * @to: where the data must be copied * @len: the size of the destination buffer * @copied: pointer to output variable to store the number of copied bytes * * This macro copies at most @len bytes from the fifo into the * @to buffer and returns -EFAULT/0. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_to_user(fifo, to, len, copied) … /** * kfifo_dma_in_prepare_mapped - setup a scatterlist for DMA input * @fifo: address of the fifo to be used * @sgl: pointer to the scatterlist array * @nents: number of entries in the scatterlist array * @len: number of elements to transfer * @dma: mapped dma address to fill into @sgl * * This macro fills a scatterlist for DMA input. * It returns the number entries in the scatterlist array. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_in_prepare_mapped(fifo, sgl, nents, len, dma) … #define kfifo_dma_in_prepare(fifo, sgl, nents, len) … /** * kfifo_dma_in_finish - finish a DMA IN operation * @fifo: address of the fifo to be used * @len: number of bytes to received * * This macro finishes a DMA IN operation. The in counter will be updated by * the len parameter. No error checking will be done. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_in_finish(fifo, len) … /** * kfifo_dma_out_prepare_mapped - setup a scatterlist for DMA output * @fifo: address of the fifo to be used * @sgl: pointer to the scatterlist array * @nents: number of entries in the scatterlist array * @len: number of elements to transfer * @dma: mapped dma address to fill into @sgl * * This macro fills a scatterlist for DMA output which at most @len bytes * to transfer. * It returns the number entries in the scatterlist array. * A zero means there is no space available and the scatterlist is not filled. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_out_prepare_mapped(fifo, sgl, nents, len, dma) … #define kfifo_dma_out_prepare(fifo, sgl, nents, len) … /** * kfifo_dma_out_finish - finish a DMA OUT operation * @fifo: address of the fifo to be used * @len: number of bytes transferred * * This macro finishes a DMA OUT operation. The out counter will be updated by * the len parameter. No error checking will be done. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macros. */ #define kfifo_dma_out_finish(fifo, len) … /** * kfifo_out_peek - gets some data from the fifo * @fifo: address of the fifo to be used * @buf: pointer to the storage buffer * @n: max. number of elements to get * * This macro gets the data from the fifo and returns the numbers of elements * copied. The data is not removed from the fifo. * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out_peek(fifo, buf, n) … /** * kfifo_out_linear - gets a tail of/offset to available data * @fifo: address of the fifo to be used * @tail: pointer to an unsigned int to store the value of tail * @n: max. number of elements to point at * * This macro obtains the offset (tail) to the available data in the fifo * buffer and returns the * numbers of elements available. It returns the available count till the end * of data or till the end of the buffer. So that it can be used for linear * data processing (like memcpy() of (@fifo->data + @tail) with count * returned). * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out_linear(fifo, tail, n) … /** * kfifo_out_linear_ptr - gets a pointer to the available data * @fifo: address of the fifo to be used * @ptr: pointer to data to store the pointer to tail * @n: max. number of elements to point at * * Similarly to kfifo_out_linear(), this macro obtains the pointer to the * available data in the fifo buffer and returns the numbers of elements * available. It returns the available count till the end of available data or * till the end of the buffer. So that it can be used for linear data * processing (like memcpy() of @ptr with count returned). * * Note that with only one concurrent reader and one concurrent * writer, you don't need extra locking to use these macro. */ #define kfifo_out_linear_ptr(fifo, ptr, n) … extern int __kfifo_alloc(struct __kfifo *fifo, unsigned int size, size_t esize, gfp_t gfp_mask); extern void __kfifo_free(struct __kfifo *fifo); extern int __kfifo_init(struct __kfifo *fifo, void *buffer, unsigned int size, size_t esize); extern unsigned int __kfifo_in(struct __kfifo *fifo, const void *buf, unsigned int len); extern unsigned int __kfifo_out(struct __kfifo *fifo, void *buf, unsigned int len); extern int __kfifo_from_user(struct __kfifo *fifo, const void __user *from, unsigned long len, unsigned int *copied); extern int __kfifo_to_user(struct __kfifo *fifo, void __user *to, unsigned long len, unsigned int *copied); extern unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma); extern unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, dma_addr_t dma); extern unsigned int __kfifo_out_peek(struct __kfifo *fifo, void *buf, unsigned int len); extern unsigned int __kfifo_out_linear(struct __kfifo *fifo, unsigned int *tail, unsigned int n); extern unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf, unsigned int len, size_t recsize); extern unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf, unsigned int len, size_t recsize); extern int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from, unsigned long len, unsigned int *copied, size_t recsize); extern int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to, unsigned long len, unsigned int *copied, size_t recsize); extern unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, size_t recsize, dma_addr_t dma); extern void __kfifo_dma_in_finish_r(struct __kfifo *fifo, unsigned int len, size_t recsize); extern unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo, struct scatterlist *sgl, int nents, unsigned int len, size_t recsize, dma_addr_t dma); extern unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize); extern void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize); extern unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf, unsigned int len, size_t recsize); extern unsigned int __kfifo_out_linear_r(struct __kfifo *fifo, unsigned int *tail, unsigned int n, size_t recsize); extern unsigned int __kfifo_max_r(unsigned int len, size_t recsize); #endif
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