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 #include <asm/uaccess.h> 20 #include "mem_user.h" 21 22 /* These are set in mmapper_init, which is called at boot time */ 23 static unsigned long mmapper_size; 24 static unsigned long p_buf; 25 static char *v_buf; 26 27 static ssize_t mmapper_read(struct file *file, char __user *buf, size_t count, 28 loff_t *ppos) 29 { 30 return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size); 31 } 32 33 static ssize_t mmapper_write(struct file *file, const char __user *buf, 34 size_t count, loff_t *ppos) 35 { 36 if (*ppos > mmapper_size) 37 return -EINVAL; 38 39 if (count > mmapper_size - *ppos) 40 count = mmapper_size - *ppos; 41 42 if (copy_from_user(&v_buf[*ppos], buf, count)) 43 return -EFAULT; 44 45 return count; 46 } 47 48 static int mmapper_ioctl(struct inode *inode, struct file *file, 49 unsigned int cmd, unsigned long arg) 50 { 51 return -ENOIOCTLCMD; 52 } 53 54 static int mmapper_mmap(struct file *file, struct vm_area_struct *vma) 55 { 56 int ret = -EINVAL; 57 int size; 58 59 if (vma->vm_pgoff != 0) 60 goto out; 61 62 size = vma->vm_end - vma->vm_start; 63 if (size > mmapper_size) 64 return -EFAULT; 65 66 /* 67 * XXX A comment above remap_pfn_range says it should only be 68 * called when the mm semaphore is held 69 */ 70 if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size, 71 vma->vm_page_prot)) 72 goto out; 73 ret = 0; 74 out: 75 return ret; 76 } 77 78 static int mmapper_open(struct inode *inode, struct file *file) 79 { 80 return 0; 81 } 82 83 static int mmapper_release(struct inode *inode, struct file *file) 84 { 85 return 0; 86 } 87 88 static const struct file_operations mmapper_fops = { 89 .owner = THIS_MODULE, 90 .read = mmapper_read, 91 .write = mmapper_write, 92 .ioctl = mmapper_ioctl, 93 .mmap = mmapper_mmap, 94 .open = mmapper_open, 95 .release = mmapper_release, 96 }; 97 98 /* 99 * No locking needed - only used (and modified) by below initcall and exitcall. 100 */ 101 static struct miscdevice mmapper_dev = { 102 .minor = MISC_DYNAMIC_MINOR, 103 .name = "mmapper", 104 .fops = &mmapper_fops 105 }; 106 107 static int __init mmapper_init(void) 108 { 109 int err; 110 111 printk(KERN_INFO "Mapper v0.1\n"); 112 113 v_buf = (char *) find_iomem("mmapper", &mmapper_size); 114 if (mmapper_size == 0) { 115 printk(KERN_ERR "mmapper_init - find_iomem failed\n"); 116 goto out; 117 } 118 119 err = misc_register(&mmapper_dev); 120 if (err) { 121 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n", 122 err); 123 goto out; 124 } 125 126 p_buf = __pa(v_buf); 127 out: 128 return 0; 129 } 130 131 static void mmapper_exit(void) 132 { 133 misc_deregister(&mmapper_dev); 134 } 135 136 module_init(mmapper_init); 137 module_exit(mmapper_exit); 138 139 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>"); 140 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver"); 141