1/* 2 * FRAM driver for MIMC200 board 3 * 4 * Copyright 2008 Mark Jackson <mpfj@mimc.co.uk> 5 * 6 * This module adds *very* simply support for the system's FRAM device. 7 * At the moment, this is hard-coded to the MIMC200 platform, and only 8 * supports mmap(). 9 */ 10 11#define FRAM_VERSION "1.0" 12 13#include <linux/miscdevice.h> 14#include <linux/proc_fs.h> 15#include <linux/mm.h> 16#include <linux/io.h> 17 18#define FRAM_BASE 0xac000000 19#define FRAM_SIZE 0x20000 20 21/* 22 * The are the file operation function for user access to /dev/fram 23 */ 24 25static int fram_mmap(struct file *filp, struct vm_area_struct *vma) 26{ 27 int ret; 28 29 ret = remap_pfn_range(vma, 30 vma->vm_start, 31 virt_to_phys((void *)((unsigned long)FRAM_BASE)) >> PAGE_SHIFT, 32 vma->vm_end-vma->vm_start, 33 PAGE_SHARED); 34 35 if (ret != 0) 36 return -EAGAIN; 37 38 return 0; 39} 40 41static const struct file_operations fram_fops = { 42 .owner = THIS_MODULE, 43 .mmap = fram_mmap, 44}; 45 46#define FRAM_MINOR 0 47 48static struct miscdevice fram_dev = { 49 FRAM_MINOR, 50 "fram", 51 &fram_fops 52}; 53 54static int __init 55fram_init(void) 56{ 57 int ret; 58 59 ret = misc_register(&fram_dev); 60 if (ret) { 61 printk(KERN_ERR "fram: can't misc_register on minor=%d\n", 62 FRAM_MINOR); 63 return ret; 64 } 65 printk(KERN_INFO "FRAM memory driver v" FRAM_VERSION "\n"); 66 return 0; 67} 68 69static void __exit 70fram_cleanup_module(void) 71{ 72 misc_deregister(&fram_dev); 73} 74 75module_init(fram_init); 76module_exit(fram_cleanup_module); 77 78MODULE_LICENSE("GPL"); 79 80MODULE_ALIAS_MISCDEV(FRAM_MINOR); 81