tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 1997 Claus-Justus Heine
3
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)
7 any later version.
8
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.
13
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.
17
18 *
19 * $Source: /homes/cvs/ftape-stacked/ftape/lowlevel/ftape-buffer.c,v $
20 * $Revision: 1.3 $
21 * $Date: 1997/10/16 23:33:11 $
22 *
23 * This file contains the allocator/dealloctor for ftape's dynamic dma
24 * buffer.
25 */
26
27#include <linux/slab.h>
28#include <linux/mm.h>
29#include <linux/mman.h>
30#include <asm/dma.h>
31
32#include <linux/ftape.h>
33#include "../lowlevel/ftape-rw.h"
34#include "../lowlevel/ftape-read.h"
35#include "../lowlevel/ftape-tracing.h"
36#include "../lowlevel/ftape-buffer.h"
37
38/* DMA'able memory allocation stuff.
39 */
40
41static inline void *dmaalloc(size_t size)
42{
43 unsigned long addr;
44
45 if (size == 0) {
46 return NULL;
47 }
48 addr = __get_dma_pages(GFP_KERNEL, get_order(size));
49 if (addr) {
50 struct page *page;
51
52 for (page = virt_to_page(addr); page < virt_to_page(addr+size); page++)
53 SetPageReserved(page);
54 }
55 return (void *)addr;
56}
57
58static inline void dmafree(void *addr, size_t size)
59{
60 if (size > 0) {
61 struct page *page;
62
63 for (page = virt_to_page((unsigned long)addr);
64 page < virt_to_page((unsigned long)addr+size); page++)
65 ClearPageReserved(page);
66 free_pages((unsigned long) addr, get_order(size));
67 }
68}
69
70static int add_one_buffer(void)
71{
72 TRACE_FUN(ft_t_flow);
73
74 if (ft_nr_buffers >= FT_MAX_NR_BUFFERS) {
75 TRACE_EXIT -ENOMEM;
76 }
77 ft_buffer[ft_nr_buffers] = kmalloc(sizeof(buffer_struct), GFP_KERNEL);
78 if (ft_buffer[ft_nr_buffers] == NULL) {
79 TRACE_EXIT -ENOMEM;
80 }
81 memset(ft_buffer[ft_nr_buffers], 0, sizeof(buffer_struct));
82 ft_buffer[ft_nr_buffers]->address = dmaalloc(FT_BUFF_SIZE);
83 if (ft_buffer[ft_nr_buffers]->address == NULL) {
84 kfree(ft_buffer[ft_nr_buffers]);
85 ft_buffer[ft_nr_buffers] = NULL;
86 TRACE_EXIT -ENOMEM;
87 }
88 ft_nr_buffers ++;
89 TRACE(ft_t_info, "buffer nr #%d @ %p, dma area @ %p",
90 ft_nr_buffers,
91 ft_buffer[ft_nr_buffers-1],
92 ft_buffer[ft_nr_buffers-1]->address);
93 TRACE_EXIT 0;
94}
95
96static void del_one_buffer(void)
97{
98 TRACE_FUN(ft_t_flow);
99 if (ft_nr_buffers > 0) {
100 TRACE(ft_t_info, "releasing buffer nr #%d @ %p, dma area @ %p",
101 ft_nr_buffers,
102 ft_buffer[ft_nr_buffers-1],
103 ft_buffer[ft_nr_buffers-1]->address);
104 ft_nr_buffers --;
105 dmafree(ft_buffer[ft_nr_buffers]->address, FT_BUFF_SIZE);
106 kfree(ft_buffer[ft_nr_buffers]);
107 ft_buffer[ft_nr_buffers] = NULL;
108 }
109 TRACE_EXIT;
110}
111
112int ftape_set_nr_buffers(int cnt)
113{
114 int delta = cnt - ft_nr_buffers;
115 TRACE_FUN(ft_t_flow);
116
117 if (delta > 0) {
118 while (delta--) {
119 if (add_one_buffer() < 0) {
120 TRACE_EXIT -ENOMEM;
121 }
122 }
123 } else if (delta < 0) {
124 while (delta++) {
125 del_one_buffer();
126 }
127 }
128 ftape_zap_read_buffers();
129 TRACE_EXIT 0;
130}