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/init.h> 13 #include <linux/module.h> 14 #include <linux/mm.h> 15 #include <linux/miscdevice.h> 16 #include <asm/uaccess.h> 17 #include "mem_user.h" 18 #include "user_util.h" 19 20 /* These are set in mmapper_init, which is called at boot time */ 21 static unsigned long mmapper_size; 22 static unsigned long p_buf = 0; 23 static char *v_buf = NULL; 24 25 static ssize_t 26 mmapper_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 27 { 28 return simple_read_from_buffer(buf, count, ppos, v_buf, mmapper_size); 29 } 30 31 static ssize_t 32 mmapper_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 33 { 34 if (*ppos > mmapper_size) 35 return -EINVAL; 36 37 if (count > mmapper_size - *ppos) 38 count = mmapper_size - *ppos; 39 40 if (copy_from_user(&v_buf[*ppos], buf, count)) 41 return -EFAULT; 42 43 return count; 44 } 45 46 static int 47 mmapper_ioctl(struct inode *inode, struct file *file, unsigned int cmd, 48 unsigned long arg) 49 { 50 return(-ENOIOCTLCMD); 51 } 52 53 static int 54 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) return(-EFAULT); 64 65 /* XXX A comment above remap_pfn_range says it should only be 66 * called when the mm semaphore is held 67 */ 68 if (remap_pfn_range(vma, vma->vm_start, p_buf >> PAGE_SHIFT, size, 69 vma->vm_page_prot)) 70 goto out; 71 ret = 0; 72 out: 73 return ret; 74 } 75 76 static int 77 mmapper_open(struct inode *inode, struct file *file) 78 { 79 return 0; 80 } 81 82 static int 83 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 /* No locking needed - only used (and modified) by below initcall and exitcall. */ 99 static struct miscdevice mmapper_dev = { 100 .minor = MISC_DYNAMIC_MINOR, 101 .name = "mmapper", 102 .fops = &mmapper_fops 103 }; 104 105 static int __init mmapper_init(void) 106 { 107 int err; 108 109 printk(KERN_INFO "Mapper v0.1\n"); 110 111 v_buf = (char *) find_iomem("mmapper", &mmapper_size); 112 if(mmapper_size == 0){ 113 printk(KERN_ERR "mmapper_init - find_iomem failed\n"); 114 goto out; 115 } 116 117 err = misc_register(&mmapper_dev); 118 if(err){ 119 printk(KERN_ERR "mmapper - misc_register failed, err = %d\n", 120 err); 121 goto out; 122 } 123 124 p_buf = __pa(v_buf); 125 out: 126 return 0; 127 } 128 129 static void mmapper_exit(void) 130 { 131 misc_deregister(&mmapper_dev); 132 } 133 134 module_init(mmapper_init); 135 module_exit(mmapper_exit); 136 137 MODULE_AUTHOR("Greg Lonnon <glonnon@ridgerun.com>"); 138 MODULE_DESCRIPTION("DSPLinux simulator mmapper driver"); 139 /* 140 * --------------------------------------------------------------------------- 141 * Local variables: 142 * c-file-style: "linux" 143 * End: 144 */ 145