2 * Copyright (C) 1997 Claus-Justus Heine
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; see the file COPYING. If not, write to
16 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
19 * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-buffer.c,v $
21 * $Date: 1997/10/16 23:33:11 $
23 * This file contains the allocator/dealloctor for ftape's dynamic dma
27 #include <asm/segment.h>
28 #include <linux/malloc.h>
30 #include <linux/mman.h>
31 #include <linux/wrapper.h>
34 #include <linux/ftape.h>
35 #include "../lowlevel/ftape-rw.h"
36 #include "../lowlevel/ftape-read.h"
37 #include "../lowlevel/ftape-tracing.h"
39 /* DMA'able memory allocation stuff.
42 static inline void *dmaalloc(size_t size)
49 addr = __get_dma_pages(GFP_KERNEL, get_order(size));
53 for (page = virt_to_page(addr); page < virt_to_page(addr+size); page++)
54 mem_map_reserve(page);
59 static inline void dmafree(void *addr, size_t size)
64 for (page = virt_to_page((unsigned long)addr);
65 page < virt_to_page((unsigned long)addr+size); page++)
66 mem_map_unreserve(page);
67 free_pages((unsigned long) addr, get_order(size));
71 static int add_one_buffer(void)
75 if (ft_nr_buffers >= FT_MAX_NR_BUFFERS) {
78 ft_buffer[ft_nr_buffers] = kmalloc(sizeof(buffer_struct), GFP_KERNEL);
79 if (ft_buffer[ft_nr_buffers] == NULL) {
82 memset(ft_buffer[ft_nr_buffers], 0, sizeof(buffer_struct));
83 ft_buffer[ft_nr_buffers]->address = dmaalloc(FT_BUFF_SIZE);
84 if (ft_buffer[ft_nr_buffers]->address == NULL) {
85 kfree(ft_buffer[ft_nr_buffers]);
86 ft_buffer[ft_nr_buffers] = NULL;
90 TRACE(ft_t_info, "buffer nr #%d @ %p, dma area @ %p",
92 ft_buffer[ft_nr_buffers-1],
93 ft_buffer[ft_nr_buffers-1]->address);
97 static void del_one_buffer(void)
100 if (ft_nr_buffers > 0) {
101 TRACE(ft_t_info, "releasing buffer nr #%d @ %p, dma area @ %p",
103 ft_buffer[ft_nr_buffers-1],
104 ft_buffer[ft_nr_buffers-1]->address);
106 dmafree(ft_buffer[ft_nr_buffers]->address, FT_BUFF_SIZE);
107 kfree(ft_buffer[ft_nr_buffers]);
108 ft_buffer[ft_nr_buffers] = NULL;
113 int ftape_set_nr_buffers(int cnt)
115 int delta = cnt - ft_nr_buffers;
116 TRACE_FUN(ft_t_flow);
120 if (add_one_buffer() < 0) {
124 } else if (delta < 0) {
129 ftape_zap_read_buffers();