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