mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Dominique van den Broeck](/assets/img/avatar_default.png)
Coding-style-only modifications to remove every warning saying:
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
Compiled against revision "next-20160327".
(checkpatch.pl was updated to treat "UNSPECIFIED_INT" warnings
as of commit a1ce18e4f9
)
Signed-off-by: Dominique van den Broeck <domdevlin@free.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
303 lines
7.9 KiB
C
303 lines
7.9 KiB
C
/*
|
|
* DMA-able FIFO implementation
|
|
*
|
|
* Copyright (C) 2012 Peter Hurley <peter@hurleysoftware.com>
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/list.h>
|
|
#include <linux/bug.h>
|
|
|
|
#include "dma_fifo.h"
|
|
|
|
#ifdef DEBUG_TRACING
|
|
#define df_trace(s, args...) pr_debug(s, ##args)
|
|
#else
|
|
#define df_trace(s, args...)
|
|
#endif
|
|
|
|
#define FAIL(fifo, condition, format...) ({ \
|
|
fifo->corrupt = !!(condition); \
|
|
WARN(fifo->corrupt, format); \
|
|
})
|
|
|
|
/*
|
|
* private helper fn to determine if check is in open interval (lo,hi)
|
|
*/
|
|
static bool addr_check(unsigned int check, unsigned int lo, unsigned int hi)
|
|
{
|
|
return check - (lo + 1) < (hi - 1) - lo;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_init: initialize the fifo to a valid but inoperative state
|
|
* @fifo: address of in-place "struct dma_fifo" object
|
|
*/
|
|
void dma_fifo_init(struct dma_fifo *fifo)
|
|
{
|
|
memset(fifo, 0, sizeof(*fifo));
|
|
INIT_LIST_HEAD(&fifo->pending);
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_alloc - initialize and allocate dma_fifo
|
|
* @fifo: address of in-place "struct dma_fifo" object
|
|
* @size: 'apparent' size, in bytes, of fifo
|
|
* @align: dma alignment to maintain (should be at least cpu cache alignment),
|
|
* must be power of 2
|
|
* @tx_limit: maximum # of bytes transmissible per dma (rounded down to
|
|
* multiple of alignment, but at least align size)
|
|
* @open_limit: maximum # of outstanding dma transactions allowed
|
|
* @gfp_mask: get_free_pages mask, passed to kmalloc()
|
|
*
|
|
* The 'apparent' size will be rounded up to next greater aligned size.
|
|
* Returns 0 if no error, otherwise an error code
|
|
*/
|
|
int dma_fifo_alloc(struct dma_fifo *fifo, int size, unsigned int align,
|
|
int tx_limit, int open_limit, gfp_t gfp_mask)
|
|
{
|
|
int capacity;
|
|
|
|
if (!is_power_of_2(align) || size < 0)
|
|
return -EINVAL;
|
|
|
|
size = round_up(size, align);
|
|
capacity = size + align * open_limit + align * DMA_FIFO_GUARD;
|
|
fifo->data = kmalloc(capacity, gfp_mask);
|
|
if (!fifo->data)
|
|
return -ENOMEM;
|
|
|
|
fifo->in = 0;
|
|
fifo->out = 0;
|
|
fifo->done = 0;
|
|
fifo->size = size;
|
|
fifo->avail = size;
|
|
fifo->align = align;
|
|
fifo->tx_limit = max_t(int, round_down(tx_limit, align), align);
|
|
fifo->open = 0;
|
|
fifo->open_limit = open_limit;
|
|
fifo->guard = size + align * open_limit;
|
|
fifo->capacity = capacity;
|
|
fifo->corrupt = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_free - frees the fifo
|
|
* @fifo: address of in-place "struct dma_fifo" to free
|
|
*
|
|
* Also reinits the fifo to a valid but inoperative state. This
|
|
* allows the fifo to be reused with a different target requiring
|
|
* different fifo parameters.
|
|
*/
|
|
void dma_fifo_free(struct dma_fifo *fifo)
|
|
{
|
|
struct dma_pending *pending, *next;
|
|
|
|
if (!fifo->data)
|
|
return;
|
|
|
|
list_for_each_entry_safe(pending, next, &fifo->pending, link)
|
|
list_del_init(&pending->link);
|
|
kfree(fifo->data);
|
|
fifo->data = NULL;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_reset - dumps the fifo contents and reinits for reuse
|
|
* @fifo: address of in-place "struct dma_fifo" to reset
|
|
*/
|
|
void dma_fifo_reset(struct dma_fifo *fifo)
|
|
{
|
|
struct dma_pending *pending, *next;
|
|
|
|
if (!fifo->data)
|
|
return;
|
|
|
|
list_for_each_entry_safe(pending, next, &fifo->pending, link)
|
|
list_del_init(&pending->link);
|
|
fifo->in = 0;
|
|
fifo->out = 0;
|
|
fifo->done = 0;
|
|
fifo->avail = fifo->size;
|
|
fifo->open = 0;
|
|
fifo->corrupt = 0;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_in - copies data into the fifo
|
|
* @fifo: address of in-place "struct dma_fifo" to write to
|
|
* @src: buffer to copy from
|
|
* @n: # of bytes to copy
|
|
*
|
|
* Returns the # of bytes actually copied, which can be less than requested if
|
|
* the fifo becomes full. If < 0, return is error code.
|
|
*/
|
|
int dma_fifo_in(struct dma_fifo *fifo, const void *src, int n)
|
|
{
|
|
int ofs, l;
|
|
|
|
if (!fifo->data)
|
|
return -ENOENT;
|
|
if (fifo->corrupt)
|
|
return -ENXIO;
|
|
|
|
if (n > fifo->avail)
|
|
n = fifo->avail;
|
|
if (n <= 0)
|
|
return 0;
|
|
|
|
ofs = fifo->in % fifo->capacity;
|
|
l = min(n, fifo->capacity - ofs);
|
|
memcpy(fifo->data + ofs, src, l);
|
|
memcpy(fifo->data, src + l, n - l);
|
|
|
|
if (FAIL(fifo, addr_check(fifo->done, fifo->in, fifo->in + n) ||
|
|
fifo->avail < n,
|
|
"fifo corrupt: in:%u out:%u done:%u n:%d avail:%d",
|
|
fifo->in, fifo->out, fifo->done, n, fifo->avail))
|
|
return -ENXIO;
|
|
|
|
fifo->in += n;
|
|
fifo->avail -= n;
|
|
|
|
df_trace("in:%u out:%u done:%u n:%d avail:%d", fifo->in, fifo->out,
|
|
fifo->done, n, fifo->avail);
|
|
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_out_pend - gets address/len of next avail read and marks as pended
|
|
* @fifo: address of in-place "struct dma_fifo" to read from
|
|
* @pended: address of structure to fill with read address/len
|
|
* The data/len fields will be NULL/0 if no dma is pended.
|
|
*
|
|
* Returns the # of used bytes remaining in fifo (ie, if > 0, more data
|
|
* remains in the fifo that was not pended). If < 0, return is error code.
|
|
*/
|
|
int dma_fifo_out_pend(struct dma_fifo *fifo, struct dma_pending *pended)
|
|
{
|
|
unsigned int len, n, ofs, l, limit;
|
|
|
|
if (!fifo->data)
|
|
return -ENOENT;
|
|
if (fifo->corrupt)
|
|
return -ENXIO;
|
|
|
|
pended->len = 0;
|
|
pended->data = NULL;
|
|
pended->out = fifo->out;
|
|
|
|
len = fifo->in - fifo->out;
|
|
if (!len)
|
|
return -ENODATA;
|
|
if (fifo->open == fifo->open_limit)
|
|
return -EAGAIN;
|
|
|
|
n = len;
|
|
ofs = fifo->out % fifo->capacity;
|
|
l = fifo->capacity - ofs;
|
|
limit = min_t(unsigned int, l, fifo->tx_limit);
|
|
if (n > limit) {
|
|
n = limit;
|
|
fifo->out += limit;
|
|
} else if (ofs + n > fifo->guard) {
|
|
fifo->out += l;
|
|
fifo->in = fifo->out;
|
|
} else {
|
|
fifo->out += round_up(n, fifo->align);
|
|
fifo->in = fifo->out;
|
|
}
|
|
|
|
df_trace("in: %u out: %u done: %u n: %d len: %u avail: %d", fifo->in,
|
|
fifo->out, fifo->done, n, len, fifo->avail);
|
|
|
|
pended->len = n;
|
|
pended->data = fifo->data + ofs;
|
|
pended->next = fifo->out;
|
|
list_add_tail(&pended->link, &fifo->pending);
|
|
++fifo->open;
|
|
|
|
if (FAIL(fifo, fifo->open > fifo->open_limit,
|
|
"past open limit:%d (limit:%d)",
|
|
fifo->open, fifo->open_limit))
|
|
return -ENXIO;
|
|
if (FAIL(fifo, fifo->out & (fifo->align - 1),
|
|
"fifo out unaligned:%u (align:%u)",
|
|
fifo->out, fifo->align))
|
|
return -ENXIO;
|
|
|
|
return len - n;
|
|
}
|
|
|
|
/**
|
|
* dma_fifo_out_complete - marks pended dma as completed
|
|
* @fifo: address of in-place "struct dma_fifo" which was read from
|
|
* @complete: address of structure for previously pended dma to mark completed
|
|
*/
|
|
int dma_fifo_out_complete(struct dma_fifo *fifo, struct dma_pending *complete)
|
|
{
|
|
struct dma_pending *pending, *next, *tmp;
|
|
|
|
if (!fifo->data)
|
|
return -ENOENT;
|
|
if (fifo->corrupt)
|
|
return -ENXIO;
|
|
if (list_empty(&fifo->pending) && fifo->open == 0)
|
|
return -EINVAL;
|
|
|
|
if (FAIL(fifo, list_empty(&fifo->pending) != (fifo->open == 0),
|
|
"pending list disagrees with open count:%d",
|
|
fifo->open))
|
|
return -ENXIO;
|
|
|
|
tmp = complete->data;
|
|
*tmp = *complete;
|
|
list_replace(&complete->link, &tmp->link);
|
|
dp_mark_completed(tmp);
|
|
|
|
/* Only update the fifo in the original pended order */
|
|
list_for_each_entry_safe(pending, next, &fifo->pending, link) {
|
|
if (!dp_is_completed(pending)) {
|
|
df_trace("still pending: saved out: %u len: %d",
|
|
pending->out, pending->len);
|
|
break;
|
|
}
|
|
|
|
if (FAIL(fifo, pending->out != fifo->done ||
|
|
addr_check(fifo->in, fifo->done, pending->next),
|
|
"in:%u out:%u done:%u saved:%u next:%u",
|
|
fifo->in, fifo->out, fifo->done, pending->out,
|
|
pending->next))
|
|
return -ENXIO;
|
|
|
|
list_del_init(&pending->link);
|
|
fifo->done = pending->next;
|
|
fifo->avail += pending->len;
|
|
--fifo->open;
|
|
|
|
df_trace("in: %u out: %u done: %u len: %u avail: %d", fifo->in,
|
|
fifo->out, fifo->done, pending->len, fifo->avail);
|
|
}
|
|
|
|
if (FAIL(fifo, fifo->open < 0, "open dma:%d < 0", fifo->open))
|
|
return -ENXIO;
|
|
if (FAIL(fifo, fifo->avail > fifo->size, "fifo avail:%d > size:%d",
|
|
fifo->avail, fifo->size))
|
|
return -ENXIO;
|
|
|
|
return 0;
|
|
}
|