1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * arch/um/drivers/mmapper_kern.c |
4 | * |
5 | * BRIEF MODULE DESCRIPTION |
6 | * |
7 | * Copyright (C) 2000 RidgeRun, Inc. |
8 | * Author: RidgeRun, Inc. |
9 | * Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com |
10 | * |
11 | */ |
12 | |
13 | #include <linux/stddef.h> |
14 | #include <linux/types.h> |
15 | #include <linux/fs.h> |
16 | #include <linux/init.h> |
17 | #include <linux/miscdevice.h> |
18 | #include <linux/module.h> |
19 | #include <linux/mm.h> |
20 | |
21 | #include <linux/uaccess.h> |
22 | #include <mem_user.h> |
23 | |
24 | /* These are set in mmapper_init, which is called at boot time */ |
25 | static unsigned long mmapper_size; |
26 | static unsigned long p_buf; |
27 | static char *v_buf; |
28 | |
29 | static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count, |
30 | loff_t *ppos) |
31 | { |
32 | return simple_read_from_buffer(to: buf, count, ppos, from: v_buf, available: mmapper_size); |
33 | } |
34 | |
35 | static ssize_t mmapper_write(struct file *file, const char __user *buf, |
36 | size_t count, loff_t *ppos) |
37 | { |
38 | if (*ppos > mmapper_size) |
39 | return -EINVAL; |
40 | |
41 | return simple_write_to_buffer(to: v_buf, available: mmapper_size, ppos, from: buf, count); |
42 | } |
43 | |
44 | static long mmapper_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
45 | { |
46 | return -ENOIOCTLCMD; |
47 | } |
48 | |
49 | static int mmapper_mmap(struct file *file, struct vm_area_struct *vma) |
50 | { |
51 | int ret = -EINVAL; |
52 | int size; |
53 | |
54 | if (vma->vm_pgoff != 0) |
55 | goto out; |
56 | |
57 | size = vma->vm_end - vma->vm_start; |
58 | if (size > mmapper_size) |
59 | return -EFAULT; |
60 | |
61 | /* |
62 | * XXX A comment above remap_pfn_range says it should only be |
63 | * called when the mm semaphore is held |
64 | */ |
65 | if (remap_pfn_range(vma, addr: vma->vm_start, pfn: p_buf >> PAGE_SHIFT, size, |
66 | vma->vm_page_prot)) |
67 | goto out; |
68 | ret = 0; |
69 | out: |
70 | return ret; |
71 | } |
72 | |
73 | static int mmapper_open(struct inode *inode, struct file *file) |
74 | { |
75 | return 0; |
76 | } |
77 | |
78 | static int mmapper_release(struct inode *inode, struct file *file) |
79 | { |
80 | return 0; |
81 | } |
82 | |
83 | static const struct file_operations mmapper_fops = { |
84 | .owner = THIS_MODULE, |
85 | .read = mmapper_read, |
86 | .write = mmapper_write, |
87 | .unlocked_ioctl = mmapper_ioctl, |
88 | .mmap = mmapper_mmap, |
89 | .open = mmapper_open, |
90 | .release = mmapper_release, |
91 | .llseek = default_llseek, |
92 | }; |
93 | |
94 | /* |
95 | * No locking needed - only used (and modified) by below initcall and exitcall. |
96 | */ |
97 | static struct miscdevice mmapper_dev = { |
98 | .minor = MISC_DYNAMIC_MINOR, |
99 | .name = "mmapper" , |
100 | .fops = &mmapper_fops |
101 | }; |
102 | |
103 | static int __init mmapper_init(void) |
104 | { |
105 | int err; |
106 | |
107 | printk(KERN_INFO "Mapper v0.1\n" ); |
108 | |
109 | v_buf = (char *) find_iomem("mmapper" , &mmapper_size); |
110 | if (mmapper_size == 0) { |
111 | printk(KERN_ERR "mmapper_init - find_iomem failed\n" ); |
112 | return -ENODEV; |
113 | } |
114 | p_buf = __pa(v_buf); |
115 | |
116 | err = misc_register(misc: &mmapper_dev); |
117 | if (err) { |
118 | printk(KERN_ERR "mmapper - misc_register failed, err = %d\n" , |
119 | err); |
120 | return err; |
121 | } |
122 | return 0; |
123 | } |
124 | |
125 | static void __exit mmapper_exit(void) |
126 | { |
127 | misc_deregister(misc: &mmapper_dev); |
128 | } |
129 | |
130 | module_init(mmapper_init); |
131 | module_exit(mmapper_exit); |
132 | |
133 | MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>" ); |
134 | MODULE_DESCRIPTION("DSPLinux simulator mmapper driver" ); |
135 | MODULE_LICENSE("GPL" ); |
136 | |