#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>

const char* dev = "/dev/secbulk0";

int main(int argc, char* argv[])
{
    unsigned char* file_buffer = NULL;
    
    long int addr  =  0;
    
    if( 3 != argc )    {
        printf("Usage: dwn <filename> address\n");
        return 1;
    }
    

    int fd = open(argv[1], O_RDONLY);
    if(-1 == fd) {
        printf("Can not open file - %s\n", argv[1]);
        return 1;
    }
    addr = strtol((char *) argv[2] ,NULL, 16);
    
    printf("addr = %lx \n", addr);
    

    // get file size 
    struct stat file_stat;
    if( -1 == fstat(fd, &file_stat) ) {
        printf("Get file size filed!\n");
        return 1;
    }    

    file_buffer = (unsigned char*)malloc(file_stat.st_size+10);
    if(NULL == file_buffer) {
        printf("malloc failed!\n");
        goto error;
    }
    //memset(file_buffer, ‘\0‘, sizeof(file_buffer)); // bad code ! corrected by Qulory
    memset(file_buffer, ‘\0‘, sizeof(char)*(file_stat.st_size+10));

    // the first 8 bytes in the file_buffer is reserved, the last 2 bytes also;
    if( file_stat.st_size !=  read(fd, file_buffer+8, file_stat.st_size))    {
        printf("Read file failed!\n");
        goto error;
    }

    printf("File name : %s\n", argv[1]);
    printf("File size : %ld bytes\n", file_stat.st_size);// off_t is long int 

    int fd_dev = open(dev, O_WRONLY);
    if( -1 == fd_dev)    {
        printf("Can not open %s\n", dev);
        goto error;
    }

    /*
     * Note: the first 4 bytes store the dest addr ;
     * the following 4 bytes store the file size ;
     * and the last 2 bytes store the sum of each bytes of the file ;
     */
    *((unsigned long*)file_buffer) = addr;     //load address
    *((unsigned long*)file_buffer+1) = file_stat.st_size+10;    //file size
    unsigned short sum = 0;
    int i;
    for(i=8; i<file_stat.st_size+8; i++)    {
        sum += file_buffer[i];
    }

    *((unsigned short*)(file_buffer+8+file_stat.st_size)) = sum;

    printf("Start Sending data...\n");
    size_t remain_size = file_stat.st_size+10;
    size_t block_size = 512;
    size_t written = 0;
    while(remain_size > 0)    {
        size_t to_write = remain_size > block_size ? block_size:remain_size;
        size_t real_write = write(fd_dev, file_buffer+written, to_write);
        if( to_write != real_write)    {
            printf(" write  /dev/secbulk0 failed!");
            return 1;
        }
        remain_size -= to_write;
        written += to_write;
        printf("\rSent %lu%% \t %lu bytes !", written*100/(file_stat.st_size+10),  written);
        fflush(stdout);

    }    

    printf("OK\n");
    return 0;

error:
    if(-1 != fd_dev) {
        close(fd_dev);
    }
    if(fd != -1)  {
        close(fd);
    }
    if( NULL != file_buffer ) {
        free(file_buffer);
    }
    return -1;
}

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/slab.h>

#define BULKOUT_BUFFER_SIZE 512
char *bulkout_buffer;
struct usb_device *udev;
__u8 bulk_out_endaddr;

static struct usb_device_id dnw_id_table [] = {
    { USB_DEVICE(0x5345, 0x1234) },
    { }        
};

static int dnw_open(struct inode* inode, struct file *file)
{
     bulkout_buffer = kmalloc(BULKOUT_BUFFER_SIZE,GFP_KERNEL);
     return 0;
}

static int dnw_release (struct inode* inode, struct file *file)
{
    kfree(bulkout_buffer);
    return 0;    
}

static ssize_t dnw_write(struct file *file, const char __user *buf, size_t len, loff_t *pos)
{
    size_t to_write;
    size_t total_write = 0;
    size_t act_len;
    
    while(len>0)    
    {
        to_write = min(len,(size_t)BULKOUT_BUFFER_SIZE);
            
    copy_from_user(bulkout_buffer,buf+total_write,to_write);
    
    usb_bulk_msg(udev,usb_sndbulkpipe(udev,bulk_out_endaddr),bulkout_buffer,to_write,&act_len,3*HZ);
    
    len -= to_write;
    total_write += to_write;
    }
    
    return total_write;
}

static struct file_operations dnw_ops =
{
    .owner =    THIS_MODULE,
    .write =    dnw_write,
    .open =        dnw_open,
    .release =    dnw_release,
};

static struct usb_class_driver dnw_class = {
    .name =        "secbulk%d",
    .fops =        &dnw_ops,
    .minor_base =    100,
};


static int dnw_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
    /* ?ó?úéè???èê? */
    struct usb_host_interface *interface;
    struct usb_endpoint_descriptor *endpoint;    
    int i;
    
    interface = intf->cur_altsetting;
    
    
    
    for(i=0;i<interface->desc.bNumEndpoints;i++)
    {
        endpoint = &interface->endpoint[i].desc;
        if(usb_endpoint_is_bulk_out(endpoint))
        {
            bulk_out_endaddr =     endpoint->bEndpointAddress;
            break;
        }
        
    }
    
    usb_register_dev(intf,&dnw_class);
    
    udev = usb_get_dev(interface_to_usbdev(intf));
    
}

static void dnw_disconnect(struct usb_interface *intf)
{
    usb_deregister_dev(intf,&dnw_class);
}

struct usb_driver dnw_driver = {
    .name        = "dnw",   /* ?y?ˉ?? */
    .probe        = dnw_probe, /* 2???oˉêy */
    .disconnect    = dnw_disconnect, /* D???oˉêy */
    .id_table    = dnw_id_table, /* éè±?áD±í */
};



int dnw_init( void )
{
    usb_register( &dnw_driver );
    return 0;    
}

void dnw_exit( void )
{
    usb_deregister(&dnw_driver);    
}


module_init(dnw_init);
module_exit(dnw_exit);
MODULE_LICENSE("GPL");

obj-m := secbulk.o

KDIR := /lib/modules/`uname -r`/build
PWD := $(shell pwd)

all:
    make -C $(KDIR) M=$(PWD) modules

clean:
    rm *.o* *.s* *.ko* *.mod.* *.k*