iLiad How to compile new driver for Iliad

[illiad_fan]

Hi all,
I'm learning to write driver for Linux, and then install it to Iliad.
parlelport.c

/* Necessary includes for drivers */
#include <linux/init.h>
//#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h> /* printk() */
#include <linux/slab.h> /* kmalloc() */
#include <linux/fs.h> /* everything... */
#include <linux/errno.h> /* error codes */
#include <linux/types.h> /* size_t */
#include <linux/proc_fs.h>
#include <linux/fcntl.h> /* O_ACCMODE */
#include <linux/ioport.h>
#include <asm/system.h> /* cli(), *_flags */
#include <asm/uaccess.h> /* copy_from/to_user */
#include <asm/io.h> /* inb, outb */
MODULE_LICENSE("Dual BSD/GPL");
/* Function declaration of parlelport.c */
int port_number = 0x0165;
const char* port_name = "parlelport";

int parlelport_open(struct inode *inode, struct file *filp);
int parlelport_release(struct inode *inode, struct file *filp);
ssize_t parlelport_read(struct file *filp, char *buf,
                       size_t count, loff_t *f_pos);
ssize_t parlelport_write(struct file *filp, char *buf,
                       size_t count, loff_t *f_pos);
void parlelport_exit(void);
int parlelport_init(void);
/* Structure that declares the common */
/* file access fcuntions */
struct file_operations parlelport_fops = {
  read: parlelport_read,
  write: parlelport_write,
  open: parlelport_open,
  release: parlelport_release
};
/* Driver global variables */
/* Major number */
int parlelport_major = 61;
/* Control variable for memory */
/* reservation of the parallel port*/
int port;
module_init(parlelport_init);
module_exit(parlelport_exit);

int parlelport_init(void) {
  int result;
  /* Registering device */
  result = register_chrdev(parlelport_major, port_name,
      &parlelport_fops);
  if (result < 0) {
    printk(
      "<1>parlelport: cannot obtain major number %d\n",
      parlelport_major);
    return result;
  }

  /* Registering port */
/*
  port = check_region(port_number, 1);
  if (port) {
    printk("<1>parlelport: cannot reserve 0x378\n");
    result = port;
    goto fail;
  }
  request_region(port_number, 1, port_name);
*/

  printk("<1>Inserting parlelport module\n");
  return 0;
  fail:
    parlelport_exit();
    return result;
}

void parlelport_exit(void) {
  /* Make major number free! */
  unregister_chrdev(parlelport_major, port_name);

  /* Make port free! */
  if (!port) {
    //release_region(port_number,1);
  }

  printk("<1>Removing parlelport module\n");
}

int parlelport_open(struct inode *inode, struct file *filp) {
  /* Success */
  return 0;
}

int parlelport_release(struct inode *inode, struct file *filp) {
  /* Success */
  return 0;
}

ssize_t parlelport_read(struct file *filp, char *buf,
  size_t count, loff_t *f_pos) {
  /* Buffer to read the device */
  char parlelport_buffer;
  
  /* Reading port */
  parlelport_buffer = inb(port_number);

  /* We transfer data to user space */
  copy_to_user(buf,&parlelport_buffer,1);
  /* We change the reading position as best suits */
  if (*f_pos == 0) {
    *f_pos+=1;
    return 1;
  } else {
    return 0;
  }
}

ssize_t parlelport_write( struct file *filp, char *buf,
  size_t count, loff_t *f_pos) {
  char *tmp;
  /* Buffer writing to the device */
  char parlelport_buffer;
  tmp=buf+count-1;
  copy_from_user(&parlelport_buffer,tmp,1);

  /* Writing to the port */
  outb(parlelport_buffer,port_number);

  return 1;
}

Makefile

obj-m += parlelport.o

all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean

I use command make to compile and insmod to install this driver on Ubuntu 8 ok. But now I don't know how to compile this driver for Iliad because when I install the ko file to Iliad, I got error different architecture.
After that I try to compile this driver on crosstool for Iliad, but not sucessful. Is there any one know how to do this? Please help me!
Thank you very much.

[Antartica]

Originally Posted by illiad_fan

After that I try to compile this driver on crosstool for Iliad, but not sucessful. Is there any one know how to do this? Please help me!
Thank you very much.

When you say "crosstool", you mean the unofficial toolchain? As I understand it, crosstool is used to produce a toolchain, but then you use the toolchain for compiling (not crosstool).

Anyway, you are right in that you have to compile the driver using an arm toolchain.

You must take care of the following:
1. Use the same kernel sources that iRex used (same patches; if that is not possible, then you can just "fake" the version string with a reasonably similar kernel source tree)
2. Use the same ".config" in the kernel sources tree, and do a "make oldconfig dep" to prepare the sources.
3. Use a Makefile prepared for out-of-tree drivers. I have used in the past one ripped from the bttv modules. Mine is as follows:

# Makefile for this module
#
# Sanely ripped from bttv driver ;-)
#
# Modified for kernel 2.4.x
#################################################
# config

# currently running kernel
#CURRENT=$(shell uname -r)
CURRENT=2.4.18

# where the kernel sources are located
KERNEL_LOCATION=/usr/src/linux-$(CURRENT)

#################################################
# some magic for using linux kernel settings
# when compiling module(s)


# Independent modules
M_OBJS       = mydriver.o
# Modules on whom other relay to work
MX_OBJS      = 
# Flags, defines (-Dname) and other usefull stuff
EXTRA_CFLAGS = -I/usr/src/extra_headers -DLINUX

here:
        DIR=`pwd`; (cd $(KERNEL_LOCATION); make SUBDIRS=$$DIR modules)

install:
        su -c "cp -v $(M_OBJS) $(MX_OBJS) /lib/modules/$(CURRENT)/misc"

modules: mydriver.o


clean:
        -rm -f $(M_OBJS) $(MX_OBJS) .*.o.flags *~

include $(KERNEL_LOCATION)/Rules.make

This one is for compiling a driver with source file "mydriver.c" and generate a kernel module for kernel 2.4.x named "mydriver.o" (".ko" is how kernel modules are named in kernel 2.6, but for earlier kernels they were ".o").

Hope that helps.

P.S: In the wiki page for compiling a toolchain for the iliad there are instruction on where to download the kernel sources for the iliad. See
https://wiki.mobileread.com/wiki/Note...sing_crosstool

[illiad_fan]

Thank you very much, it works.