00001 
00015 #include <linux/init.h>
00016 #include <linux/kernel.h>
00017 #include <linux/module.h>
00018 #include <linux/sched.h>
00019 #include <linux/wait.h>
00020 #include <asm/uaccess.h>
00021 #include <asm/io.h>
00022 #include <linux/slab.h>
00023 
00024 #include <opl_hw_ops.h>
00025 #include <opl_reg_mmap.h>
00026 
00030 /*--------------------------Macro definition------------------------- */
00031 #define OPL_REG_MAJOR    110
00032 #define OPL_REG_DEVICE  "opl_reg"
00033 
00034 
00040 /*--------------------------type definition------------------------- */
00041 
00047 /*-----------------global varible/function declaration--------------- */
00048 
00060 /*--------------local  function declaration------------- */
00061 static int opl_reg_open(struct inode *inode, struct file *filp);         
00062 static ssize_t opl_reg_read(struct file *filp, char  *buffer, size_t length, loff_t *offset);
00063 static ssize_t opl_reg_write(struct file *filp, const char *buffer, size_t length, loff_t *offset);
00064 static int opl_reg_mmap(struct file * file, struct vm_area_struct * vma);
00065 static int opl_reg_release(struct inode *inode, struct file *filp);
00066 
00072 /*--------------local  varible declaration and definition------------- */
00073 static u32 opl_reg_open_count = 0;
00074 static u32 opl_reg_is_open = 0;
00075 struct file_operations opl_reg_fops = {
00076   .read = opl_reg_read,
00077   .write = opl_reg_write,
00078   .mmap = opl_reg_mmap,
00079   .open = opl_reg_open,
00080   .release = opl_reg_release, 
00081 };
00082 
00088 /*------------local  function declaration and definition-------------- */
00089 
00102 static ssize_t opl_reg_read(struct file *filp, char  *buffer, size_t length, loff_t *offset)
00103 {
00104   return 0;
00105 }
00106 
00107 static ssize_t opl_reg_write(struct file *filp, const char *buffer, size_t length, loff_t *offset)
00108 {
00109   return 0;
00110 }
00111 
00124 static int opl_reg_mmap(struct file * file, struct vm_area_struct * vma)
00125 {
00126   unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
00127   /*
00128    * Accessing memory above the top the kernel knows about or
00129    * through a file pointer that was marked O_SYNC will be
00130    * done non-cached.
00131    */
00132   offset += 0x1f000000;
00133   if ((offset>__pa(high_memory)) || (file->f_flags & O_SYNC)) {
00134     vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
00135   }
00136 
00137   /* Don't try to swap out physical pages.. */
00138   vma->vm_flags |= VM_RESERVED;
00139   
00140   /* Don't dump addresses that are not real memory to a core file.*/
00141   if (offset >= __pa(high_memory) || (file->f_flags & O_SYNC))
00142     vma->vm_flags |= VM_IO;
00143   if (remap_page_range(vma->vm_start, offset, vma->vm_end-vma->vm_start,
00144                        vma->vm_page_prot)){
00145     return -EAGAIN;
00146   }
00147   return 0;
00148 }
00149 
00150 static int opl_reg_open(struct inode *inode, struct file *filp)         
00151 {
00152   if (test_and_set_bit(0, &opl_reg_is_open))
00153     printk(KERN_DEBUG "the /dev/opl_reg is already opened\n");
00154   opl_reg_open_count ++;
00155   MOD_INC_USE_COUNT;
00156   return 0;
00157 }
00158 
00159 static int opl_reg_release(struct inode *inode, struct file *filp)
00160 {
00161   opl_reg_open_count ++;
00162   if(!opl_reg_open_count)
00163     clear_bit(0, &opl_reg_is_open);
00164   MOD_DEC_USE_COUNT;
00165   return 0;
00166 }
00176 static int __init opl_reg_init(void)
00177 {
00178   int ret;
00179   ret = register_chrdev(OPL_REG_MAJOR,OPL_REG_DEVICE,&opl_reg_fops);
00180   if(ret<0){
00181     /* TBD add debug message */
00182   }
00183   return ret;
00184 }
00193 static void __exit opl_reg_exit(void)
00194 {
00195   int ret;
00196   ret = unregister_chrdev(OPL_REG_MAJOR,OPL_REG_DEVICE);
00197   if(ret < 0){
00198     /*TBD:add debug message  */
00199   }
00200   return;
00201 }
00202 
00203 module_init(opl_reg_init);
00204 module_exit(opl_reg_exit);
00205 MODULE_LICENSE("GPL2");
00206 MODULE_AUTHOR("stephanxu <[email protected]>");
00207 MODULE_DESCRIPTION("dedicated the module for mmap the opulan switch chip register.");