| /* |
| * linux/kernel/chr_drv/mem.c |
| * |
| * (C) 1991 Linus Torvalds |
| */ |
| |
| #include <errno.h> |
| #include <sys/types.h> |
| |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/tty.h> |
| |
| #include <asm/segment.h> |
| #include <asm/io.h> |
| |
| static int read_ram(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| return -EIO; |
| } |
| |
| static int write_ram(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| return -EIO; |
| } |
| |
| static int read_mem(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| unsigned long addr; |
| char *tmp; |
| unsigned long pde, pte, page; |
| int i; |
| |
| if (count < 0) |
| return -EINVAL; |
| addr = file->f_pos; |
| tmp = buf; |
| while (count > 0) { |
| pde = (unsigned long) pg_dir + (addr >> 20 & 0xffc); |
| if (!((pte = *((unsigned long *) pde)) & 1)) |
| break; |
| pte &= 0xfffff000; |
| pte += (addr >> 10) & 0xffc; |
| if (((page = *((unsigned long *) pte)) & 1) == 0) |
| break; |
| /* |
| if ((page & 2) == 0) |
| un_wp_page((unsigned long *) pte); |
| */ |
| page &= 0xfffff000; |
| page += addr & 0xfff; |
| i = 4096-(addr & 0xfff); |
| if (i > count) |
| i = count; |
| memcpy_tofs(tmp,(void *) page,i); |
| addr += i; |
| tmp += i; |
| count -= i; |
| } |
| file->f_pos = addr; |
| return tmp-buf; |
| } |
| |
| static int write_mem(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| unsigned long addr; |
| char *tmp; |
| unsigned long pde, pte, page; |
| int i; |
| |
| if (count < 0) |
| return -EINVAL; |
| addr = file->f_pos; |
| tmp = buf; |
| while (count > 0) { |
| pde = (unsigned long) pg_dir + (addr >> 20 & 0xffc); |
| if (!((pte = *((unsigned long *) pde)) & 1)) |
| break; |
| pte &= 0xfffff000; |
| pte += (addr >> 10) & 0xffc; |
| if (((page = *((unsigned long *) pte)) & 1) == 0) |
| break; |
| if ((page & 2) == 0) |
| un_wp_page((unsigned long *) pte); |
| page &= 0xfffff000; |
| page += addr & 0xfff; |
| i = 4096-(addr & 0xfff); |
| if (i > count) |
| i = count; |
| memcpy_fromfs((void *) page,tmp,i); |
| addr += i; |
| tmp += i; |
| count -= i; |
| } |
| file->f_pos = addr; |
| return tmp-buf; |
| } |
| |
| static int read_kmem(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| unsigned long p = file->f_pos; |
| |
| if (count < 0) |
| return -EINVAL; |
| if (p >= HIGH_MEMORY) |
| return 0; |
| if (count > HIGH_MEMORY - p) |
| count = HIGH_MEMORY - p; |
| memcpy_tofs(buf,(void *) p,count); |
| file->f_pos += count; |
| return count; |
| } |
| |
| static int write_kmem(struct inode * inode, struct file * file,char * buf, int count) |
| { |
| unsigned long p = file->f_pos; |
| |
| if (count < 0) |
| return -EINVAL; |
| if (p >= HIGH_MEMORY) |
| return 0; |
| if (count > HIGH_MEMORY - p) |
| count = HIGH_MEMORY - p; |
| memcpy_fromfs((void *) p,buf,count); |
| file->f_pos += count; |
| return count; |
| } |
| |
| static int read_port(struct inode * inode,struct file * file,char * buf, int count) |
| { |
| unsigned int i = file->f_pos; |
| char * tmp = buf; |
| |
| while (count-- > 0 && i < 65536) { |
| put_fs_byte(inb(i),tmp); |
| i++; |
| tmp++; |
| } |
| file->f_pos = i; |
| return tmp-buf; |
| } |
| |
| static int write_port(struct inode * inode,struct file * file,char * buf, int count) |
| { |
| unsigned int i = file->f_pos; |
| char * tmp = buf; |
| |
| while (count-- > 0 && i < 65536) { |
| outb(get_fs_byte(tmp),i); |
| i++; |
| tmp++; |
| } |
| file->f_pos = i; |
| return tmp-buf; |
| } |
| |
| static int read_zero(struct inode *node,struct file *file,char *buf,int count) |
| { |
| int left; |
| |
| for (left = count; left > 0; left--) { |
| put_fs_byte(0,buf); |
| buf++; |
| } |
| return count; |
| } |
| |
| /* |
| * The memory devices use the full 32 bits of the offset, and so we cannot |
| * check against negative addresses: they are ok. The return value is weird, |
| * though, in that case (0). |
| * |
| * also note that seeking relative to the "end of file" isn't supported: |
| * it has no meaning, so it returns -EINVAL. |
| */ |
| static int mem_lseek(struct inode * inode, struct file * file, off_t offset, int orig) |
| { |
| switch (orig) { |
| case 0: |
| file->f_pos = offset; |
| return file->f_pos; |
| case 1: |
| file->f_pos += offset; |
| return file->f_pos; |
| default: |
| return -EINVAL; |
| } |
| if (file->f_pos < 0) |
| return 0; |
| return file->f_pos; |
| } |
| |
| static int mem_read(struct inode * inode, struct file * file, char * buf, int count) |
| { |
| switch (MINOR(inode->i_rdev)) { |
| case 0: |
| return read_ram(inode,file,buf,count); |
| case 1: |
| return read_mem(inode,file,buf,count); |
| case 2: |
| return read_kmem(inode,file,buf,count); |
| case 3: |
| return 0; /* /dev/null */ |
| case 4: |
| return read_port(inode,file,buf,count); |
| case 5: |
| return read_zero(inode,file,buf,count); |
| default: |
| return -ENODEV; |
| } |
| } |
| |
| static int mem_write(struct inode * inode, struct file * file, char * buf, int count) |
| { |
| switch (MINOR(inode->i_rdev)) { |
| case 0: |
| return write_ram(inode,file,buf,count); |
| case 1: |
| return write_mem(inode,file,buf,count); |
| case 2: |
| return write_kmem(inode,file,buf,count); |
| case 3: |
| return count; /* /dev/null */ |
| case 4: |
| return write_port(inode,file,buf,count); |
| case 5: |
| return count; /* /dev/zero */ |
| default: |
| return -ENODEV; |
| } |
| } |
| |
| static struct file_operations mem_fops = { |
| mem_lseek, |
| mem_read, |
| mem_write, |
| NULL, /* mem_readdir */ |
| NULL, /* mem_select */ |
| NULL, /* mem_ioctl */ |
| NULL, /* no special open code */ |
| NULL /* no special release code */ |
| }; |
| |
| long chr_dev_init(long mem_start, long mem_end) |
| { |
| chrdev_fops[1] = &mem_fops; |
| mem_start = tty_init(mem_start); |
| mem_start = lp_init(mem_start); |
| return mem_start; |
| } |