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/*
* Copyright (C) 1997 Claus-Justus Heine
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, 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; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-buffer.c,v $
* $Revision: 1.3 $
* $Date: 1997/10/16 23:33:11 $
*
* This file contains the allocator/dealloctor for ftape's dynamic dma
* buffer.
*/
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <asm/dma.h>
#include <linux/ftape.h>
#include "../lowlevel/ftape-rw.h"
#include "../lowlevel/ftape-read.h"
#include "../lowlevel/ftape-tracing.h"
#include "../lowlevel/ftape-buffer.h"
/* DMA'able memory allocation stuff.
*/
static inline void *dmaalloc(size_t size)
{
unsigned long addr;
if (size == 0) {
return NULL;
}
addr = __get_dma_pages(GFP_KERNEL, get_order(size));
if (addr) {
struct page *page;
for (page = virt_to_page(addr); page < virt_to_page(addr+size); page++)
SetPageReserved(page);
}
return (void *)addr;
}
static inline void dmafree(void *addr, size_t size)
{
if (size > 0) {
struct page *page;
for (page = virt_to_page((unsigned long)addr);
page < virt_to_page((unsigned long)addr+size); page++)
ClearPageReserved(page);
free_pages((unsigned long) addr, get_order(size));
}
}
static int add_one_buffer(void)
{
TRACE_FUN(ft_t_flow);
if (ft_nr_buffers >= FT_MAX_NR_BUFFERS) {
TRACE_EXIT -ENOMEM;
}
ft_buffer[ft_nr_buffers] = kmalloc(sizeof(buffer_struct), GFP_KERNEL);
if (ft_buffer[ft_nr_buffers] == NULL) {
TRACE_EXIT -ENOMEM;
}
memset(ft_buffer[ft_nr_buffers], 0, sizeof(buffer_struct));
ft_buffer[ft_nr_buffers]->address = dmaalloc(FT_BUFF_SIZE);
if (ft_buffer[ft_nr_buffers]->address == NULL) {
kfree(ft_buffer[ft_nr_buffers]);
ft_buffer[ft_nr_buffers] = NULL;
TRACE_EXIT -ENOMEM;
}
ft_nr_buffers ++;
TRACE(ft_t_info, "buffer nr #%d @ %p, dma area @ %p",
ft_nr_buffers,
ft_buffer[ft_nr_buffers-1],
ft_buffer[ft_nr_buffers-1]->address);
TRACE_EXIT 0;
}
static void del_one_buffer(void)
{
TRACE_FUN(ft_t_flow);
if (ft_nr_buffers > 0) {
TRACE(ft_t_info, "releasing buffer nr #%d @ %p, dma area @ %p",
ft_nr_buffers,
ft_buffer[ft_nr_buffers-1],
ft_buffer[ft_nr_buffers-1]->address);
ft_nr_buffers --;
dmafree(ft_buffer[ft_nr_buffers]->address, FT_BUFF_SIZE);
kfree(ft_buffer[ft_nr_buffers]);
ft_buffer[ft_nr_buffers] = NULL;
}
TRACE_EXIT;
}
int ftape_set_nr_buffers(int cnt)
{
int delta = cnt - ft_nr_buffers;
TRACE_FUN(ft_t_flow);
if (delta > 0) {
while (delta--) {
if (add_one_buffer() < 0) {
TRACE_EXIT -ENOMEM;
}
}
} else if (delta < 0) {
while (delta++) {
del_one_buffer();
}
}
ftape_zap_read_buffers();
TRACE_EXIT 0;
}
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