1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * arch/um/drivers/mmapper_kern.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * BRIEF MODULE DESCRIPTION
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Copyright (C) 2000 RidgeRun, Inc.
8*4882a593Smuzhiyun * Author: RidgeRun, Inc.
9*4882a593Smuzhiyun * Greg Lonnon glonnon@ridgerun.com or info@ridgerun.com
10*4882a593Smuzhiyun *
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include <linux/stddef.h>
14*4882a593Smuzhiyun #include <linux/types.h>
15*4882a593Smuzhiyun #include <linux/fs.h>
16*4882a593Smuzhiyun #include <linux/init.h>
17*4882a593Smuzhiyun #include <linux/miscdevice.h>
18*4882a593Smuzhiyun #include <linux/module.h>
19*4882a593Smuzhiyun #include <linux/mm.h>
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun #include <linux/uaccess.h>
22*4882a593Smuzhiyun #include <mem_user.h>
23*4882a593Smuzhiyun
24*4882a593Smuzhiyun /* These are set in mmapper_init, which is called at boot time */
25*4882a593Smuzhiyun static unsigned long mmapper_size;
26*4882a593Smuzhiyun static unsigned long p_buf;
27*4882a593Smuzhiyun static char *v_buf;
28*4882a593Smuzhiyun
mmapper_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)29*4882a593Smuzhiyun static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count,
30*4882a593Smuzhiyun loff_t *ppos)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size);
33*4882a593Smuzhiyun }
34*4882a593Smuzhiyun
mmapper_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)35*4882a593Smuzhiyun static ssize_t mmapper_write(struct file *file, const char __user *buf,
36*4882a593Smuzhiyun size_t count, loff_t *ppos)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun if (*ppos > mmapper_size)
39*4882a593Smuzhiyun return -EINVAL;
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun return simple_write_to_buffer(v_buf, mmapper_size, ppos, buf, count);
42*4882a593Smuzhiyun }
43*4882a593Smuzhiyun
mmapper_ioctl(struct file * file,unsigned int cmd,unsigned long arg)44*4882a593Smuzhiyun static long mmapper_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun return -ENOIOCTLCMD;
47*4882a593Smuzhiyun }
48*4882a593Smuzhiyun
mmapper_mmap(struct file * file,struct vm_area_struct * vma)49*4882a593Smuzhiyun static int mmapper_mmap(struct file *file, struct vm_area_struct *vma)
50*4882a593Smuzhiyun {
51*4882a593Smuzhiyun int ret = -EINVAL;
52*4882a593Smuzhiyun int size;
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun if (vma->vm_pgoff != 0)
55*4882a593Smuzhiyun goto out;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun size = vma->vm_end - vma->vm_start;
58*4882a593Smuzhiyun if (size > mmapper_size)
59*4882a593Smuzhiyun return -EFAULT;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun /*
62*4882a593Smuzhiyun * XXX A comment above remap_pfn_range says it should only be
63*4882a593Smuzhiyun * called when the mm semaphore is held
64*4882a593Smuzhiyun */
65*4882a593Smuzhiyun if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size,
66*4882a593Smuzhiyun vma->vm_page_prot))
67*4882a593Smuzhiyun goto out;
68*4882a593Smuzhiyun ret = 0;
69*4882a593Smuzhiyun out:
70*4882a593Smuzhiyun return ret;
71*4882a593Smuzhiyun }
72*4882a593Smuzhiyun
mmapper_open(struct inode * inode,struct file * file)73*4882a593Smuzhiyun static int mmapper_open(struct inode *inode, struct file *file)
74*4882a593Smuzhiyun {
75*4882a593Smuzhiyun return 0;
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
mmapper_release(struct inode * inode,struct file * file)78*4882a593Smuzhiyun static int mmapper_release(struct inode *inode, struct file *file)
79*4882a593Smuzhiyun {
80*4882a593Smuzhiyun return 0;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun static const struct file_operations mmapper_fops = {
84*4882a593Smuzhiyun .owner = THIS_MODULE,
85*4882a593Smuzhiyun .read = mmapper_read,
86*4882a593Smuzhiyun .write = mmapper_write,
87*4882a593Smuzhiyun .unlocked_ioctl = mmapper_ioctl,
88*4882a593Smuzhiyun .mmap = mmapper_mmap,
89*4882a593Smuzhiyun .open = mmapper_open,
90*4882a593Smuzhiyun .release = mmapper_release,
91*4882a593Smuzhiyun .llseek = default_llseek,
92*4882a593Smuzhiyun };
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun /*
95*4882a593Smuzhiyun * No locking needed - only used (and modified) by below initcall and exitcall.
96*4882a593Smuzhiyun */
97*4882a593Smuzhiyun static struct miscdevice mmapper_dev = {
98*4882a593Smuzhiyun .minor = MISC_DYNAMIC_MINOR,
99*4882a593Smuzhiyun .name = "mmapper",
100*4882a593Smuzhiyun .fops = &mmapper_fops
101*4882a593Smuzhiyun };
102*4882a593Smuzhiyun
mmapper_init(void)103*4882a593Smuzhiyun static int __init mmapper_init(void)
104*4882a593Smuzhiyun {
105*4882a593Smuzhiyun int err;
106*4882a593Smuzhiyun
107*4882a593Smuzhiyun printk(KERN_INFO "Mapper v0.1\n");
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun v_buf = (char *) find_iomem("mmapper", &mmapper_size);
110*4882a593Smuzhiyun if (mmapper_size == 0) {
111*4882a593Smuzhiyun printk(KERN_ERR "mmapper_init - find_iomem failed\n");
112*4882a593Smuzhiyun return -ENODEV;
113*4882a593Smuzhiyun }
114*4882a593Smuzhiyun p_buf = __pa(v_buf);
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun err = misc_register(&mmapper_dev);
117*4882a593Smuzhiyun if (err) {
118*4882a593Smuzhiyun printk(KERN_ERR "mmapper - misc_register failed, err = %d\n",
119*4882a593Smuzhiyun err);
120*4882a593Smuzhiyun return err;
121*4882a593Smuzhiyun }
122*4882a593Smuzhiyun return 0;
123*4882a593Smuzhiyun }
124*4882a593Smuzhiyun
mmapper_exit(void)125*4882a593Smuzhiyun static void mmapper_exit(void)
126*4882a593Smuzhiyun {
127*4882a593Smuzhiyun misc_deregister(&mmapper_dev);
128*4882a593Smuzhiyun }
129*4882a593Smuzhiyun
130*4882a593Smuzhiyun module_init(mmapper_init);
131*4882a593Smuzhiyun module_exit(mmapper_exit);
132*4882a593Smuzhiyun
133*4882a593Smuzhiyun MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>");
134*4882a593Smuzhiyun MODULE_DESCRIPTION("DSPLinux simulator mmapper driver");
135*4882a593Smuzhiyun MODULE_LICENSE("GPL");
136