609 lines
13 KiB
C
609 lines
13 KiB
C
/*
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* A generic kernel FIFO implementation
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*
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* Copyright (C) 2009/2010 Stefani Seibold <stefani@seibold.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/log2.h>
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#include <linux/uaccess.h>
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#include <linux/kfifo.h>
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/*
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* internal helper to calculate the unused elements in a fifo
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*/
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static inline unsigned int kfifo_unused(struct __kfifo *fifo)
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{
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return (fifo->mask + 1) - (fifo->in - fifo->out);
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}
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int __kfifo_alloc(struct __kfifo *fifo, unsigned int size,
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size_t esize, gfp_t gfp_mask)
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{
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/*
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* round down to the next power of 2, since our 'let the indices
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* wrap' technique works only in this case.
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*/
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if (!is_power_of_2(size))
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size = rounddown_pow_of_two(size);
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fifo->in = 0;
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fifo->out = 0;
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fifo->esize = esize;
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if (size < 2) {
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fifo->data = NULL;
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fifo->mask = 0;
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return -EINVAL;
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}
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fifo->data = kmalloc(size * esize, gfp_mask);
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if (!fifo->data) {
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fifo->mask = 0;
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return -ENOMEM;
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}
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fifo->mask = size - 1;
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return 0;
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}
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EXPORT_SYMBOL(__kfifo_alloc);
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void __kfifo_free(struct __kfifo *fifo)
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{
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kfree(fifo->data);
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fifo->in = 0;
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fifo->out = 0;
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fifo->esize = 0;
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fifo->data = NULL;
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fifo->mask = 0;
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}
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EXPORT_SYMBOL(__kfifo_free);
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int __kfifo_init(struct __kfifo *fifo, void *buffer,
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unsigned int size, size_t esize)
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{
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size /= esize;
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if (!is_power_of_2(size))
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size = rounddown_pow_of_two(size);
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fifo->in = 0;
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fifo->out = 0;
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fifo->esize = esize;
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fifo->data = buffer;
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if (size < 2) {
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fifo->mask = 0;
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return -EINVAL;
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}
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fifo->mask = size - 1;
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return 0;
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}
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EXPORT_SYMBOL(__kfifo_init);
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static void kfifo_copy_in(struct __kfifo *fifo, const void *src,
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unsigned int len, unsigned int off)
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{
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unsigned int size = fifo->mask + 1;
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unsigned int esize = fifo->esize;
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unsigned int l;
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off &= fifo->mask;
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if (esize != 1) {
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off *= esize;
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size *= esize;
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len *= esize;
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}
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l = min(len, size - off);
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memcpy(fifo->data + off, src, l);
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memcpy(fifo->data, src + l, len - l);
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/*
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* make sure that the data in the fifo is up to date before
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* incrementing the fifo->in index counter
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*/
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smp_wmb();
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}
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unsigned int __kfifo_in(struct __kfifo *fifo,
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const void *buf, unsigned int len)
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{
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unsigned int l;
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l = kfifo_unused(fifo);
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if (len > l)
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len = l;
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kfifo_copy_in(fifo, buf, len, fifo->in);
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fifo->in += len;
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return len;
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}
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EXPORT_SYMBOL(__kfifo_in);
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static void kfifo_copy_out(struct __kfifo *fifo, void *dst,
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unsigned int len, unsigned int off)
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{
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unsigned int size = fifo->mask + 1;
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unsigned int esize = fifo->esize;
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unsigned int l;
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off &= fifo->mask;
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if (esize != 1) {
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off *= esize;
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size *= esize;
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len *= esize;
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}
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l = min(len, size - off);
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memcpy(dst, fifo->data + off, l);
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memcpy(dst + l, fifo->data, len - l);
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/*
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* make sure that the data is copied before
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* incrementing the fifo->out index counter
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*/
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smp_wmb();
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}
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unsigned int __kfifo_out_peek(struct __kfifo *fifo,
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void *buf, unsigned int len)
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{
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unsigned int l;
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l = fifo->in - fifo->out;
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if (len > l)
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len = l;
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kfifo_copy_out(fifo, buf, len, fifo->out);
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return len;
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}
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EXPORT_SYMBOL(__kfifo_out_peek);
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unsigned int __kfifo_out(struct __kfifo *fifo,
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void *buf, unsigned int len)
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{
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len = __kfifo_out_peek(fifo, buf, len);
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fifo->out += len;
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return len;
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}
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EXPORT_SYMBOL(__kfifo_out);
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static unsigned long kfifo_copy_from_user(struct __kfifo *fifo,
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const void __user *from, unsigned int len, unsigned int off,
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unsigned int *copied)
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{
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unsigned int size = fifo->mask + 1;
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unsigned int esize = fifo->esize;
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unsigned int l;
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unsigned long ret;
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off &= fifo->mask;
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if (esize != 1) {
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off *= esize;
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size *= esize;
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len *= esize;
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}
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l = min(len, size - off);
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ret = copy_from_user(fifo->data + off, from, l);
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if (unlikely(ret))
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ret = DIV_ROUND_UP(ret + len - l, esize);
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else {
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ret = copy_from_user(fifo->data, from + l, len - l);
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if (unlikely(ret))
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ret = DIV_ROUND_UP(ret, esize);
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}
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/*
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* make sure that the data in the fifo is up to date before
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* incrementing the fifo->in index counter
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*/
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smp_wmb();
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*copied = len - ret;
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/* return the number of elements which are not copied */
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return ret;
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}
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int __kfifo_from_user(struct __kfifo *fifo, const void __user *from,
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unsigned long len, unsigned int *copied)
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{
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unsigned int l;
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unsigned long ret;
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unsigned int esize = fifo->esize;
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int err;
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if (esize != 1)
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len /= esize;
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l = kfifo_unused(fifo);
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if (len > l)
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len = l;
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ret = kfifo_copy_from_user(fifo, from, len, fifo->in, copied);
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if (unlikely(ret)) {
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len -= ret;
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err = -EFAULT;
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} else
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err = 0;
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fifo->in += len;
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return err;
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}
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EXPORT_SYMBOL(__kfifo_from_user);
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static unsigned long kfifo_copy_to_user(struct __kfifo *fifo, void __user *to,
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unsigned int len, unsigned int off, unsigned int *copied)
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{
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unsigned int l;
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unsigned long ret;
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unsigned int size = fifo->mask + 1;
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unsigned int esize = fifo->esize;
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off &= fifo->mask;
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if (esize != 1) {
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off *= esize;
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size *= esize;
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len *= esize;
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}
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l = min(len, size - off);
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ret = copy_to_user(to, fifo->data + off, l);
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if (unlikely(ret))
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ret = DIV_ROUND_UP(ret + len - l, esize);
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else {
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ret = copy_to_user(to + l, fifo->data, len - l);
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if (unlikely(ret))
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ret = DIV_ROUND_UP(ret, esize);
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}
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/*
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* make sure that the data is copied before
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* incrementing the fifo->out index counter
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*/
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smp_wmb();
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*copied = len - ret;
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/* return the number of elements which are not copied */
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return ret;
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}
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int __kfifo_to_user(struct __kfifo *fifo, void __user *to,
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unsigned long len, unsigned int *copied)
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{
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unsigned int l;
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unsigned long ret;
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unsigned int esize = fifo->esize;
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int err;
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if (esize != 1)
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len /= esize;
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l = fifo->in - fifo->out;
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if (len > l)
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len = l;
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ret = kfifo_copy_to_user(fifo, to, len, fifo->out, copied);
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if (unlikely(ret)) {
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len -= ret;
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err = -EFAULT;
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} else
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err = 0;
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fifo->out += len;
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return err;
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}
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EXPORT_SYMBOL(__kfifo_to_user);
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static int setup_sgl_buf(struct scatterlist *sgl, void *buf,
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int nents, unsigned int len)
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{
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int n;
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unsigned int l;
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unsigned int off;
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struct page *page;
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if (!nents)
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return 0;
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if (!len)
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return 0;
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n = 0;
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page = virt_to_page(buf);
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off = offset_in_page(buf);
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l = 0;
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while (len >= l + PAGE_SIZE - off) {
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struct page *npage;
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l += PAGE_SIZE;
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buf += PAGE_SIZE;
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npage = virt_to_page(buf);
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if (page_to_phys(page) != page_to_phys(npage) - l) {
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sg_set_page(sgl, page, l - off, off);
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sgl = sg_next(sgl);
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if (++n == nents || sgl == NULL)
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return n;
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page = npage;
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len -= l - off;
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l = off = 0;
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}
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}
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sg_set_page(sgl, page, len, off);
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return n + 1;
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}
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static unsigned int setup_sgl(struct __kfifo *fifo, struct scatterlist *sgl,
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int nents, unsigned int len, unsigned int off)
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{
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unsigned int size = fifo->mask + 1;
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unsigned int esize = fifo->esize;
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unsigned int l;
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unsigned int n;
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off &= fifo->mask;
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if (esize != 1) {
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off *= esize;
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size *= esize;
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len *= esize;
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}
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l = min(len, size - off);
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n = setup_sgl_buf(sgl, fifo->data + off, nents, l);
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n += setup_sgl_buf(sgl + n, fifo->data, nents - n, len - l);
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return n;
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}
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unsigned int __kfifo_dma_in_prepare(struct __kfifo *fifo,
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struct scatterlist *sgl, int nents, unsigned int len)
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{
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unsigned int l;
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l = kfifo_unused(fifo);
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if (len > l)
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len = l;
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return setup_sgl(fifo, sgl, nents, len, fifo->in);
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}
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EXPORT_SYMBOL(__kfifo_dma_in_prepare);
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unsigned int __kfifo_dma_out_prepare(struct __kfifo *fifo,
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struct scatterlist *sgl, int nents, unsigned int len)
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{
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unsigned int l;
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l = fifo->in - fifo->out;
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if (len > l)
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len = l;
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return setup_sgl(fifo, sgl, nents, len, fifo->out);
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}
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EXPORT_SYMBOL(__kfifo_dma_out_prepare);
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unsigned int __kfifo_max_r(unsigned int len, size_t recsize)
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{
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unsigned int max = (1 << (recsize << 3)) - 1;
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if (len > max)
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return max;
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return len;
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}
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#define __KFIFO_PEEK(data, out, mask) \
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((data)[(out) & (mask)])
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/*
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* __kfifo_peek_n internal helper function for determinate the length of
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* the next record in the fifo
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*/
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static unsigned int __kfifo_peek_n(struct __kfifo *fifo, size_t recsize)
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{
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unsigned int l;
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unsigned int mask = fifo->mask;
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unsigned char *data = fifo->data;
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l = __KFIFO_PEEK(data, fifo->out, mask);
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if (--recsize)
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l |= __KFIFO_PEEK(data, fifo->out + 1, mask) << 8;
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return l;
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}
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#define __KFIFO_POKE(data, in, mask, val) \
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( \
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(data)[(in) & (mask)] = (unsigned char)(val) \
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)
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/*
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* __kfifo_poke_n internal helper function for storeing the length of
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* the record into the fifo
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*/
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static void __kfifo_poke_n(struct __kfifo *fifo, unsigned int n, size_t recsize)
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{
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unsigned int mask = fifo->mask;
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unsigned char *data = fifo->data;
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__KFIFO_POKE(data, fifo->in, mask, n);
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if (recsize > 1)
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__KFIFO_POKE(data, fifo->in + 1, mask, n >> 8);
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}
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unsigned int __kfifo_len_r(struct __kfifo *fifo, size_t recsize)
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{
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return __kfifo_peek_n(fifo, recsize);
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}
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EXPORT_SYMBOL(__kfifo_len_r);
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unsigned int __kfifo_in_r(struct __kfifo *fifo, const void *buf,
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unsigned int len, size_t recsize)
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{
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if (len + recsize > kfifo_unused(fifo))
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return 0;
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__kfifo_poke_n(fifo, len, recsize);
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kfifo_copy_in(fifo, buf, len, fifo->in + recsize);
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fifo->in += len + recsize;
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return len;
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}
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EXPORT_SYMBOL(__kfifo_in_r);
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static unsigned int kfifo_out_copy_r(struct __kfifo *fifo,
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void *buf, unsigned int len, size_t recsize, unsigned int *n)
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{
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*n = __kfifo_peek_n(fifo, recsize);
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if (len > *n)
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len = *n;
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kfifo_copy_out(fifo, buf, len, fifo->out + recsize);
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return len;
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}
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unsigned int __kfifo_out_peek_r(struct __kfifo *fifo, void *buf,
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unsigned int len, size_t recsize)
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{
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unsigned int n;
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if (fifo->in == fifo->out)
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return 0;
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return kfifo_out_copy_r(fifo, buf, len, recsize, &n);
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}
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EXPORT_SYMBOL(__kfifo_out_peek_r);
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unsigned int __kfifo_out_r(struct __kfifo *fifo, void *buf,
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unsigned int len, size_t recsize)
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{
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unsigned int n;
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if (fifo->in == fifo->out)
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return 0;
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len = kfifo_out_copy_r(fifo, buf, len, recsize, &n);
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fifo->out += n + recsize;
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return len;
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}
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EXPORT_SYMBOL(__kfifo_out_r);
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void __kfifo_skip_r(struct __kfifo *fifo, size_t recsize)
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{
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unsigned int n;
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n = __kfifo_peek_n(fifo, recsize);
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fifo->out += n + recsize;
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}
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EXPORT_SYMBOL(__kfifo_skip_r);
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int __kfifo_from_user_r(struct __kfifo *fifo, const void __user *from,
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unsigned long len, unsigned int *copied, size_t recsize)
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{
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unsigned long ret;
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len = __kfifo_max_r(len, recsize);
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if (len + recsize > kfifo_unused(fifo)) {
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*copied = 0;
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return 0;
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}
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__kfifo_poke_n(fifo, len, recsize);
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ret = kfifo_copy_from_user(fifo, from, len, fifo->in + recsize, copied);
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if (unlikely(ret)) {
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*copied = 0;
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return -EFAULT;
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}
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fifo->in += len + recsize;
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return 0;
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}
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EXPORT_SYMBOL(__kfifo_from_user_r);
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int __kfifo_to_user_r(struct __kfifo *fifo, void __user *to,
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unsigned long len, unsigned int *copied, size_t recsize)
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{
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unsigned long ret;
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unsigned int n;
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if (fifo->in == fifo->out) {
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*copied = 0;
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return 0;
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}
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n = __kfifo_peek_n(fifo, recsize);
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if (len > n)
|
|
len = n;
|
|
|
|
ret = kfifo_copy_to_user(fifo, to, len, fifo->out + recsize, copied);
|
|
if (unlikely(ret)) {
|
|
*copied = 0;
|
|
return -EFAULT;
|
|
}
|
|
fifo->out += n + recsize;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(__kfifo_to_user_r);
|
|
|
|
unsigned int __kfifo_dma_in_prepare_r(struct __kfifo *fifo,
|
|
struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
|
|
{
|
|
if (!nents)
|
|
BUG();
|
|
|
|
len = __kfifo_max_r(len, recsize);
|
|
|
|
if (len + recsize > kfifo_unused(fifo))
|
|
return 0;
|
|
|
|
return setup_sgl(fifo, sgl, nents, len, fifo->in + recsize);
|
|
}
|
|
EXPORT_SYMBOL(__kfifo_dma_in_prepare_r);
|
|
|
|
void __kfifo_dma_in_finish_r(struct __kfifo *fifo,
|
|
unsigned int len, size_t recsize)
|
|
{
|
|
len = __kfifo_max_r(len, recsize);
|
|
__kfifo_poke_n(fifo, len, recsize);
|
|
fifo->in += len + recsize;
|
|
}
|
|
EXPORT_SYMBOL(__kfifo_dma_in_finish_r);
|
|
|
|
unsigned int __kfifo_dma_out_prepare_r(struct __kfifo *fifo,
|
|
struct scatterlist *sgl, int nents, unsigned int len, size_t recsize)
|
|
{
|
|
if (!nents)
|
|
BUG();
|
|
|
|
len = __kfifo_max_r(len, recsize);
|
|
|
|
if (len + recsize > fifo->in - fifo->out)
|
|
return 0;
|
|
|
|
return setup_sgl(fifo, sgl, nents, len, fifo->out + recsize);
|
|
}
|
|
EXPORT_SYMBOL(__kfifo_dma_out_prepare_r);
|
|
|
|
void __kfifo_dma_out_finish_r(struct __kfifo *fifo, size_t recsize)
|
|
{
|
|
unsigned int len;
|
|
|
|
len = __kfifo_peek_n(fifo, recsize);
|
|
fifo->out += len + recsize;
|
|
}
|
|
EXPORT_SYMBOL(__kfifo_dma_out_finish_r);
|