Mark Jackson | 5b50c16 | 2008-10-13 13:14:50 +0000 | [diff] [blame] | 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> |
Paul Gortmaker | 5745d6a | 2014-01-10 09:29:39 -0500 | [diff] [blame] | 14 | #include <linux/module.h> |
Mark Jackson | 5b50c16 | 2008-10-13 13:14:50 +0000 | [diff] [blame] | 15 | #include <linux/proc_fs.h> |
| 16 | #include <linux/mm.h> |
| 17 | #include <linux/io.h> |
| 18 | |
| 19 | #define FRAM_BASE 0xac000000 |
| 20 | #define FRAM_SIZE 0x20000 |
| 21 | |
| 22 | /* |
| 23 | * The are the file operation function for user access to /dev/fram |
| 24 | */ |
| 25 | |
| 26 | static int fram_mmap(struct file *filp, struct vm_area_struct *vma) |
| 27 | { |
| 28 | int ret; |
| 29 | |
| 30 | ret = remap_pfn_range(vma, |
| 31 | vma->vm_start, |
| 32 | virt_to_phys((void *)((unsigned long)FRAM_BASE)) >> PAGE_SHIFT, |
| 33 | vma->vm_end-vma->vm_start, |
| 34 | PAGE_SHARED); |
| 35 | |
| 36 | if (ret != 0) |
| 37 | return -EAGAIN; |
| 38 | |
| 39 | return 0; |
| 40 | } |
| 41 | |
| 42 | static const struct file_operations fram_fops = { |
| 43 | .owner = THIS_MODULE, |
| 44 | .mmap = fram_mmap, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 45 | .llseek = noop_llseek, |
Mark Jackson | 5b50c16 | 2008-10-13 13:14:50 +0000 | [diff] [blame] | 46 | }; |
| 47 | |
| 48 | #define FRAM_MINOR 0 |
| 49 | |
| 50 | static struct miscdevice fram_dev = { |
| 51 | FRAM_MINOR, |
| 52 | "fram", |
| 53 | &fram_fops |
| 54 | }; |
| 55 | |
| 56 | static int __init |
| 57 | fram_init(void) |
| 58 | { |
| 59 | int ret; |
| 60 | |
| 61 | ret = misc_register(&fram_dev); |
| 62 | if (ret) { |
| 63 | printk(KERN_ERR "fram: can't misc_register on minor=%d\n", |
| 64 | FRAM_MINOR); |
| 65 | return ret; |
| 66 | } |
| 67 | printk(KERN_INFO "FRAM memory driver v" FRAM_VERSION "\n"); |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | static void __exit |
| 72 | fram_cleanup_module(void) |
| 73 | { |
| 74 | misc_deregister(&fram_dev); |
| 75 | } |
| 76 | |
| 77 | module_init(fram_init); |
| 78 | module_exit(fram_cleanup_module); |
| 79 | |
| 80 | MODULE_LICENSE("GPL"); |
| 81 | |
| 82 | MODULE_ALIAS_MISCDEV(FRAM_MINOR); |