Linux0.96c/kernel/blk_drv/scsi/scsi_ioctl.c

#include <linux/config.h>
#ifdef CONFIG_SCSI 

#include <errno.h>
#include <asm/io.h>
#include <asm/segment.h>
#include <asm/system.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>

#include "scsi.h"
#include "hosts.h"
#include "scsi_ioctl.h"

#define MAX_RETRIES 5	
#define MAX_TIMEOUT 200
#define MAX_BUF 1024  	

#define max(a,b) (((a) > (b)) ? (a) : (b))

/*
 * If we are told to probe a host, we will return 0 if  the host is not
 * present, 1 if the host is present, and will return an identifying
 * string at *arg, if arg is non null, filling to the length stored at
 * (int *) arg
 */

static int ioctl_probe(int dev, void *buffer)
{
	int temp;
	int len;
	
	if ((temp = scsi_hosts[dev].present) && buffer) {
		len = get_fs_long ((int *) buffer);
		memcpy_tofs (buffer, scsi_hosts[dev].info(), len);
	}
	return temp;
}

/*
 * 
 * The SCSI_IOCTL_SEND_COMMAND ioctl sends a command out to the SCSI host.
 * The MAX_TIMEOUT and MAX_RETRIES  variables are used.  
 * 
 * dev is the SCSI device number, *(int *) arg the length of the input
 * data, *((int *)arg + 1) the output buffer.
 * 
 * *(char *) ((int *) arg)[1] the actual command.   
 * 
 * Note that no more than MAX_BUF bytes will be transfered.  Since
 * SCSI block device size is 512 bytes, I figured 1K was good.
 * 
 * This size * does  * include  the initial lengths that were passed.
 * 
 * The SCSI command is read from  the memory location immediately after the
 * length words, and the out data after the command.  The SCSI routines know the
 * command size based on the length byte.  
 * 
 * The area is then filled in from the byte at offset 0. 
 */

static int the_result[MAX_SCSI_HOSTS];

static void scsi_ioctl_done (int host, int result)
{
	the_result[host] = result;	
}	
	
static int ioctl_command(Scsi_Device *dev, void *buffer)
{
	char buf[MAX_BUF];
	char cmd[10];
	char * cmd_in;
	unsigned char opcode;
	int inlen, outlen, cmdlen, temp, host;

	if (!buffer)
		return -EINVAL;
	
	inlen = get_fs_long((int *) buffer);
	outlen = get_fs_long(((int *) buffer) + 1);

	cmd_in = (char *) ( ((int *)buffer) + 2);
	opcode = get_fs_byte(cmd_in); 

	memcpy_fromfs ((void *) cmd,  cmd_in, cmdlen = COMMAND_SIZE (opcode));
	memcpy_fromfs ((void *) buf,  (void *) (cmd_in + cmdlen), inlen);
	host = dev->host_no;

#ifndef DEBUG_NO_CMD
	do {
		cli();
		if (the_result[host]) {
			sti();
			while(the_result[host])
				/* nothing */;
		} else {
			the_result[host]=-1;
			sti();
			break;
		}
	} while (1);
	
	scsi_do_cmd(host,  dev->id, cmd, buf, ((outlen > MAX_BUF) ? 
			MAX_BUF : outlen),  scsi_ioctl_done, MAX_TIMEOUT, 
			buf, MAX_RETRIES);

	while (the_result[host] == -1)
		/* nothing */;
	temp = the_result[host];
	the_result[host]=0;
	memcpy_tofs (buffer, buf, (outlen > MAX_BUF) ? MAX_BUF  : outlen);
	return temp;
#else
	{
	int i;
	printk("scsi_ioctl : device %d.  command = ", dev);
	for (i = 0; i < 10; ++i)
		printk("%02x ", cmd[i]);
	printk("\r\nbuffer =");
	for (i = 0; i < 20; ++i)
		printk("%02x ", buf[i]);
	printk("\r\n");
	}
	return 0;
#endif
}

	
/*
	the scsi_ioctl() function differs from most ioctls in that it does
	not take a major/minor number as the dev filed.  Rather, it takes
	an index in scsi_devices[] 
*/
int scsi_ioctl (int dev, int cmd, void *arg)
{
	if ((cmd != 0 && dev > NR_SCSI_DEVICES) || dev < 0)
		return -ENODEV;
	if ((cmd == 0 && dev > MAX_SCSI_HOSTS))
		return -ENODEV;
	
	switch (cmd) {
		case SCSI_IOCTL_PROBE_HOST:
			return ioctl_probe(dev, arg);
		case SCSI_IOCTL_SEND_COMMAND:
			return ioctl_command((Scsi_Device *) dev, arg);
		default :			
			return -EINVAL;
	}
}
#endif