xref: /kernel/liteos_a/drivers/char/mem/src/mem.c (revision 0d163575) 
1/*
2 * Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
3 * Copyright (c) 2020-2021 Huawei Device Co., Ltd. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without modification,
6 * are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice, this list of
9 *    conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
12 *    of conditions and the following disclaimer in the documentation and/or other materials
13 *    provided with the distribution.
14 *
15 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
16 *    to endorse or promote products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
21 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
26 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
28 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
29 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include "fcntl.h"
33#include "linux/kernel.h"
34#include "fs/driver.h"
35
36static int MemOpen(struct file *filep)
37{
38    return 0;
39}
40
41static int MemClose(struct file *filep)
42{
43    return 0;
44}
45
46static ssize_t MemRead(struct file *filep, char *buffer, size_t buflen)
47{
48    return 0;
49}
50
51static ssize_t MemWrite(struct file *filep, const char *buffer, size_t buflen)
52{
53    return 0;
54}
55
56static ssize_t MemMap(struct file *filep, LosVmMapRegion *region)
57{
58#ifdef LOSCFG_KERNEL_VM
59    size_t size = region->range.size;
60    PADDR_T paddr = region->pgOff << PAGE_SHIFT;
61    VADDR_T vaddr = region->range.base;
62    LosVmSpace *space = LOS_SpaceGet(vaddr);
63
64    if (((paddr + size) >= SYS_MEM_BASE) && (paddr < SYS_MEM_END)) {
65        return -EINVAL;
66    }
67
68    /* Peripheral register memory adds strongly ordered attributes */
69    region->regionFlags |= VM_MAP_REGION_FLAG_STRONGLY_ORDERED;
70
71    if (space == NULL) {
72        return -EAGAIN;
73    }
74    if (LOS_ArchMmuMap(&space->archMmu, vaddr, paddr, size >> PAGE_SHIFT, region->regionFlags) <= 0) {
75        return -EAGAIN;
76    }
77#else
78    UNUSED(filep);
79    UNUSED(region);
80#endif
81    return 0;
82}
83
84static const struct file_operations_vfs g_memDevOps = {
85    MemOpen,  /* open */
86    MemClose, /* close */
87    MemRead,  /* read */
88    MemWrite, /* write */
89    NULL,      /* seek */
90    NULL,      /* ioctl */
91    MemMap,   /* mmap */
92#ifndef CONFIG_DISABLE_POLL
93    NULL,      /* poll */
94#endif
95    NULL,      /* unlink */
96};
97
98int DevMemRegister(void)
99{
100    return register_driver("/dev/mem", &g_memDevOps, 0644, 0); /* 0644: file mode */
101}
102