142 lines
3.9 KiB
C
142 lines
3.9 KiB
C
#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/errno.h>
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#include <linux/miscdevice.h>
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#include <linux/kernel.h>
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#include <linux/major.h>
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#include <linux/mutex.h>
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#include <linux/proc_fs.h>
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#include <linux/seq_file.h>
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#include <linux/stat.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/tty.h>
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#include <linux/kmod.h>
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#include <linux/gfp.h>
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#include <asm/pgtable.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/mman.h>
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#include <linux/memblock.h>
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#include <linux/memblock.h>
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#include <linux/pagemap.h>
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#define WEIGHT_ADDR 0x4307F000 // 权重加载的内存地址处
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#define MEM_ACCESS_RELEASE_PHYS_ADDR _IOR('M', 0, unsigned int) // 自定义ioctl命令，用于释放预留内存
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static int major = 0;
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static struct class *mem_operation_class;
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static int check_page_reserved(unsigned long addr)
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{
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struct page *page;
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page = pfn_to_page(addr >> PAGE_SHIFT); // 将虚拟地址转换为页面索引，然后得到页面结构
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if (PageReserved(page)) {
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printk(KERN_INFO "Page at address 0x%lx is reserved.\n", addr);
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return 0;
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} else {
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printk(KERN_INFO "Page at address 0x%lx is not reserved.\n", addr);
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return -1;
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}
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}
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static int mem_operation_drv_open (struct inode *node, struct file *file)
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{
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printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
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return 0;
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}
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static int mem_operation_drv_close (struct inode *node, struct file *file)
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{
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printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
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return 0;
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}
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static int mem_operation_drv_mmap(struct file *file, struct vm_area_struct *vma)
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{
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unsigned long phy = WEIGHT_ADDR;
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if(check_page_reserved(WEIGHT_ADDR) < 0)
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return -EINVAL;
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/* 设置属性: cache, buffer */
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vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
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/* map */
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if (remap_pfn_range(vma, vma->vm_start, phy >> PAGE_SHIFT,
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vma->vm_end - vma->vm_start, vma->vm_page_prot)) {
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printk("mmap remap_pfn_range failed\n");
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return -ENOBUFS;
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}
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return 0;
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}
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static long mem_operation_drv_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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int ret = 0;
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switch (cmd) {
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case MEM_ACCESS_RELEASE_PHYS_ADDR: {
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unsigned int mem_size;
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if (get_user(mem_size, (unsigned long __user *)arg))
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return -EFAULT;
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if(check_page_reserved(WEIGHT_ADDR) < 0)
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return -EINVAL;
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memblock_free(WEIGHT_ADDR, mem_size);
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free_reserved_area(__va(WEIGHT_ADDR), __va(WEIGHT_ADDR + mem_size), -1, "wakeup_source");
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printk("release phy addr: 0x%x, size: %d\n", WEIGHT_ADDR, mem_size);
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break;
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}
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static struct file_operations mem_operation_drv = {
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.owner = THIS_MODULE,
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.open = mem_operation_drv_open,
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.release = mem_operation_drv_close,
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.mmap = mem_operation_drv_mmap,
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.unlocked_ioctl = mem_operation_drv_ioctl,
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};
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static int __init mem_operation_init(void)
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{
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int err;
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printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
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major = register_chrdev(0, "mem_operation", &mem_operation_drv); /* /dev/mem_operation */
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mem_operation_class = class_create(THIS_MODULE, "mem_operation_class");
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err = PTR_ERR(mem_operation_class);
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if (IS_ERR(mem_operation_class)) {
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printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
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unregister_chrdev(major, "mem_operation");
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return -1;
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}
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device_create(mem_operation_class, NULL, MKDEV(major, 0), NULL, "mem_operation"); /* 设备节点： /dev/mem_operation */
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return 0;
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}
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static void __exit mem_operation_exit(void)
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{
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printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);
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device_destroy(mem_operation_class, MKDEV(major, 0));
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class_destroy(mem_operation_class);
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unregister_chrdev(major, "mem_operation");
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}
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module_init(mem_operation_init);
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module_exit(mem_operation_exit);
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MODULE_LICENSE("GPL");
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