82 lines
1.5 KiB
C
82 lines
1.5 KiB
C
/*
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* FRAM driver for MIMC200 board
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*
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* Copyright 2008 Mark Jackson <mpfj@mimc.co.uk>
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*
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* This module adds *very* simply support for the system's FRAM device.
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* At the moment, this is hard-coded to the MIMC200 platform, and only
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* supports mmap().
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*/
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#define FRAM_VERSION "1.0"
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#include <linux/miscdevice.h>
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#include <linux/proc_fs.h>
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#include <linux/mm.h>
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#include <linux/io.h>
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#define FRAM_BASE 0xac000000
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#define FRAM_SIZE 0x20000
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/*
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* The are the file operation function for user access to /dev/fram
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*/
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static int fram_mmap(struct file *filp, struct vm_area_struct *vma)
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{
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int ret;
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ret = remap_pfn_range(vma,
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vma->vm_start,
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virt_to_phys((void *)((unsigned long)FRAM_BASE)) >> PAGE_SHIFT,
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vma->vm_end-vma->vm_start,
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PAGE_SHARED);
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if (ret != 0)
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return -EAGAIN;
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return 0;
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}
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static const struct file_operations fram_fops = {
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.owner = THIS_MODULE,
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.mmap = fram_mmap,
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.llseek = noop_llseek,
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};
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#define FRAM_MINOR 0
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static struct miscdevice fram_dev = {
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FRAM_MINOR,
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"fram",
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&fram_fops
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};
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static int __init
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fram_init(void)
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{
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int ret;
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ret = misc_register(&fram_dev);
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if (ret) {
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printk(KERN_ERR "fram: can't misc_register on minor=%d\n",
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FRAM_MINOR);
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return ret;
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}
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printk(KERN_INFO "FRAM memory driver v" FRAM_VERSION "\n");
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return 0;
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}
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static void __exit
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fram_cleanup_module(void)
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{
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misc_deregister(&fram_dev);
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}
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module_init(fram_init);
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module_exit(fram_cleanup_module);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(FRAM_MINOR);
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