73 lines
1.7 KiB
C
73 lines
1.7 KiB
C
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/**
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* Tiny FIFO implemenation - simplest FIFO only for handling 1-dimensional
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* single unstructured unsigned integer data array in circular manner.
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**/
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#include <linux/slab.h>
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struct __tfifo {
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unsigned int *data;
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unsigned int length;
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unsigned int in;
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unsigned int out;
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};
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/**
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* For now, we only consider of 'unsigned integer' use case.
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**/
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#define __entity_size (sizeof(unsigned int))
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#define tfifo_init(fifo) \
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({ \
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typeof((fifo) + 1) __tmp = (fifo); \
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*__tmp = (struct __tfifo) { \
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.data = NULL, \
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.length = 0, \
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.in = 0, \
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.out = 0 }; \
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})
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#define tfifo_alloc(fifo, len) \
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({ \
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bool __ret = true; \
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typeof((fifo) + 1) __tmp = (fifo); \
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__tmp->data = kmalloc(__entity_size * (len + 1), GFP_KERNEL); \
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if (__tmp->data) \
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__tmp->length = (len + 1); \
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else \
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__ret = false; \
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__ret; \
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})
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#define is_tfifo_empty(fifo) \
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({ \
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typeof((fifo) + 1) __tmp = (fifo); \
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bool __ret = (__tmp->in == __tmp->out) ? true : false; \
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__ret; \
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})
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#define tfifo_free(fifo) \
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({ \
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typeof((fifo) + 1) __tmp = (fifo); \
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if (__tmp->data) kfree(__tmp->data); \
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__tmp->length = 0; \
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__tmp->in = 0; \
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__tmp->out = 0; \
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})
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#define tfifo_in(fifo, val) \
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({ \
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typeof((fifo) + 1) __tmp = (fifo); \
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__tmp->data[__tmp->in] = (val); \
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__tmp->in = (__tmp->in + 1) % __tmp->length; \
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})
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#define tfifo_out(fifo) \
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({ \
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unsigned int __ret; \
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typeof((fifo) + 1) __tmp = (fifo); \
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__ret = __tmp->data[__tmp->out]; \
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__tmp->out = (__tmp->out + 1) % __tmp->length; \
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__ret; \
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})
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