ch.c

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/*
 * SCSI Media Changer device driver for Linux 2.6
 *
 *     (c) 1996-2003 Gerd Knorr <[e-mail]>
 *
 */

#define VERSION "0.25"

#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/completion.h>
#include <linux/compat.h>
#include <linux/chio.h>			/* here are all the ioctls */
#include <linux/mutex.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_driver.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dbg.h>

#define CH_DT_MAX       16
#define CH_TYPES        8

MODULE_DESCRIPTION("device driver for scsi media changer devices");
MODULE_AUTHOR("Gerd Knorr <[e-mail]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(SCSI_CHANGER_MAJOR);

static int init = 1;
module_param(init, int, 0444);
MODULE_PARM_DESC(init, \
    "initialize element status on driver load (default: on)");

static int timeout_move = 300;
module_param(timeout_move, int, 0644);
MODULE_PARM_DESC(timeout_move,"timeout for move commands "
		 "(default: 300 seconds)");

static int timeout_init = 3600;
module_param(timeout_init, int, 0644);
MODULE_PARM_DESC(timeout_init,"timeout for INITIALIZE ELEMENT STATUS "
		 "(default: 3600 seconds)");

static int verbose = 1;
module_param(verbose, int, 0644);
MODULE_PARM_DESC(verbose,"be verbose (default: on)");

static int debug = 0;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug,"enable/disable debug messages, also prints more "
		 "detailed sense codes on scsi errors (default: off)");

static int dt_id[CH_DT_MAX] = { [ 0 ... (CH_DT_MAX-1) ] = -1 };
static int dt_lun[CH_DT_MAX];
module_param_array(dt_id,  int, NULL, 0444);
module_param_array(dt_lun, int, NULL, 0444);

/* tell the driver about vendor-specific slots */
static int vendor_firsts[CH_TYPES-4];
static int vendor_counts[CH_TYPES-4];
module_param_array(vendor_firsts, int, NULL, 0444);
module_param_array(vendor_counts, int, NULL, 0444);

static const char * vendor_labels[CH_TYPES-4] = {
	"v0", "v1", "v2", "v3"
};
// module_param_string_array(vendor_labels, NULL, 0444);

#define dprintk(fmt, arg...)    if (debug) \
        printk(KERN_DEBUG "%s: " fmt, ch->name , ## arg)
#define vprintk(fmt, arg...)    if (verbose) \
        printk(KERN_INFO "%s: " fmt, ch->name , ## arg)

/* ------------------------------------------------------------------- */

#define MAX_RETRIES   1

static int  ch_probe(struct device *);
static int  ch_remove(struct device *);
static int  ch_open(struct inode * inode, struct file * filp);
static int  ch_release(struct inode * inode, struct file * filp);
static int  ch_ioctl(struct inode * inode, struct file * filp,
		     unsigned int cmd, unsigned long arg);
#ifdef CONFIG_COMPAT
static long ch_ioctl_compat(struct file * filp,
			    unsigned int cmd, unsigned long arg);
#endif

static struct class * ch_sysfs_class;

typedef struct {
	struct list_head    list;
	int                 minor;
	char                name[8];
	struct scsi_device  *device;
	struct scsi_device  **dt;        /* ptrs to data transfer elements */
	u_int               firsts[CH_TYPES];
	u_int               counts[CH_TYPES];
	u_int               unit_attention;
	u_int		    voltags;
	struct mutex	    lock;
} scsi_changer;

static LIST_HEAD(ch_devlist);
static DEFINE_SPINLOCK(ch_devlist_lock);
static int ch_devcount;

static struct scsi_driver ch_template =
{
	.owner     	= THIS_MODULE,
	.gendrv     	= {
		.name	= "ch",
		.probe  = ch_probe,
		.remove = ch_remove,
	},
};

static const struct file_operations changer_fops =
{
	.owner        = THIS_MODULE,
	.open         = ch_open,
	.release      = ch_release,
	.ioctl        = ch_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl = ch_ioctl_compat,
#endif
};

static const struct {
	unsigned char  sense;
	unsigned char  asc;
	unsigned char  ascq;
	int	       errno;
} err[] = {
/* Just filled in what looks right. Hav'nt checked any standard paper for
   these errno assignments, so they may be wrong... */
	{
		.sense  = ILLEGAL_REQUEST,
		.asc    = 0x21,
		.ascq   = 0x01,
		.errno  = EBADSLT, /* Invalid element address */
	},{
		.sense  = ILLEGAL_REQUEST,
		.asc    = 0x28,
		.ascq   = 0x01,
		.errno  = EBADE,   /* Import or export element accessed */
	},{
		.sense  = ILLEGAL_REQUEST,
		.asc    = 0x3B,
		.ascq   = 0x0D,
		.errno  = EXFULL,  /* Medium destination element full */
	},{
		.sense  = ILLEGAL_REQUEST,
		.asc    = 0x3B,
		.ascq   = 0x0E,
		.errno  = EBADE,   /* Medium source element empty */
	},{
		.sense  = ILLEGAL_REQUEST,
		.asc    = 0x20,
		.ascq   = 0x00,
		.errno  = EBADRQC, /* Invalid command operation code */
	},{
	        /* end of list */
	}
};

/* ------------------------------------------------------------------- */

static int ch_find_errno(struct scsi_sense_hdr *sshdr)
{
	int i,errno = 0;

	/* Check to see if additional sense information is available */
	if (scsi_sense_valid(sshdr) &&
	    sshdr->asc != 0) {
		for (i = 0; err[i].errno != 0; i++) {
			if (err[i].sense == sshdr->sense_key &&
			    err[i].asc   == sshdr->asc &&
			    err[i].ascq  == sshdr->ascq) {
				errno = -err[i].errno;
				break;
			}
		}
	}
	if (errno == 0)
		errno = -EIO;
	return errno;
}

static int
ch_do_scsi(scsi_changer *ch, unsigned char *cmd,
	   void *buffer, unsigned buflength,
	   enum dma_data_direction direction)
{
	int errno, retries = 0, timeout, result;
	struct scsi_sense_hdr sshdr;
	
	timeout = (cmd[0] == INITIALIZE_ELEMENT_STATUS)
		? timeout_init : timeout_move;

 retry:
	errno = 0;
	if (debug) {
		dprintk("command: ");
		__scsi_print_command(cmd);
	}

        result = scsi_execute_req(ch->device, cmd, direction, buffer,
				  buflength, &sshdr, timeout * HZ,
				  MAX_RETRIES);

	dprintk("result: 0x%x\n",result);
	if (driver_byte(result) & DRIVER_SENSE) {
		if (debug)
			scsi_print_sense_hdr(ch->name, &sshdr);
		errno = ch_find_errno(&sshdr);

		switch(sshdr.sense_key) {
		case UNIT_ATTENTION:
			ch->unit_attention = 1;
			if (retries++ < 3)
				goto retry;
			break;
		}
	}
	return errno;
}

/* ------------------------------------------------------------------------ */

static int
ch_elem_to_typecode(scsi_changer *ch, u_int elem)
{
	int i;
	
	for (i = 0; i < CH_TYPES; i++) {
		if (elem >= ch->firsts[i]  &&
		    elem <  ch->firsts[i] +
	            ch->counts[i])
			return i+1;
	}
	return 0;
}

static int
ch_read_element_status(scsi_changer *ch, u_int elem, char *data)
{
	u_char  cmd[12];
	u_char  *buffer;
	int     result;
	
	buffer = kmalloc(512, GFP_KERNEL | GFP_DMA);
	if(!buffer)
		return -ENOMEM;
	
 retry:
	memset(cmd,0,sizeof(cmd));
	cmd[0] = READ_ELEMENT_STATUS;
	cmd[1] = (ch->device->lun << 5) | 
		(ch->voltags ? 0x10 : 0) |
		ch_elem_to_typecode(ch,elem);
	cmd[2] = (elem >> 8) & 0xff;
	cmd[3] = elem        & 0xff;
	cmd[5] = 1;
	cmd[9] = 255;
	if (0 == (result = ch_do_scsi(ch, cmd, buffer, 256, DMA_FROM_DEVICE))) {
		if (((buffer[16] << 8) | buffer[17]) != elem) {
			dprintk("asked for element 0x%02x, got 0x%02x\n",
				elem,(buffer[16] << 8) | buffer[17]);
			kfree(buffer);
			return -EIO;
		}
		memcpy(data,buffer+16,16);
	} else {
		if (ch->voltags) {
			ch->voltags = 0;
			vprintk("device has no volume tag support\n");
			goto retry;
		}
		dprintk("READ ELEMENT STATUS for element 0x%x failed\n",elem);
	}
	kfree(buffer);
	return result;
}

static int 
ch_init_elem(scsi_changer *ch)
{
	int err;
	u_char cmd[6];

	vprintk("INITIALIZE ELEMENT STATUS, may take some time ...\n");
	memset(cmd,0,sizeof(cmd));
	cmd[0] = INITIALIZE_ELEMENT_STATUS;
	cmd[1] = ch->device->lun << 5;
	err = ch_do_scsi(ch, cmd, NULL, 0, DMA_NONE);
	vprintk("... finished\n");
	return err;
}

static int
ch_readconfig(scsi_changer *ch)
{
	u_char  cmd[10], data[16];
	u_char  *buffer;
	int     result,id,lun,i;
	u_int   elem;

	buffer = kzalloc(512, GFP_KERNEL | GFP_DMA);
	if (!buffer)
		return -ENOMEM;
	
	memset(cmd,0,sizeof(cmd));
	cmd[0] = MODE_SENSE;
	cmd[1] = ch->device->lun << 5;
	cmd[2] = 0x1d;
	cmd[4] = 255;
	result = ch_do_scsi(ch, cmd, buffer, 255, DMA_FROM_DEVICE);
	if (0 != result) {
		cmd[1] |= (1<<3);
		result  = ch_do_scsi(ch, cmd, buffer, 255, DMA_FROM_DEVICE);
	}
	if (0 == result) {
		ch->firsts[CHET_MT] =
			(buffer[buffer[3]+ 6] << 8) | buffer[buffer[3]+ 7];
		ch->counts[CHET_MT] =
			(buffer[buffer[3]+ 8] << 8) | buffer[buffer[3]+ 9];
		ch->firsts[CHET_ST] =
			(buffer[buffer[3]+10] << 8) | buffer[buffer[3]+11];
		ch->counts[CHET_ST] =
			(buffer[buffer[3]+12] << 8) | buffer[buffer[3]+13];
		ch->firsts[CHET_IE] =
			(buffer[buffer[3]+14] << 8) | buffer[buffer[3]+15];
		ch->counts[CHET_IE] =
			(buffer[buffer[3]+16] << 8) | buffer[buffer[3]+17];
		ch->firsts[CHET_DT] =
			(buffer[buffer[3]+18] << 8) | buffer[buffer[3]+19];
		ch->counts[CHET_DT] =
			(buffer[buffer[3]+20] << 8) | buffer[buffer[3]+21];
		vprintk("type #1 (mt): 0x%x+%d [medium transport]\n",
			ch->firsts[CHET_MT],
			ch->counts[CHET_MT]);
		vprintk("type #2 (st): 0x%x+%d [storage]\n",
			ch->firsts[CHET_ST],
			ch->counts[CHET_ST]);
		vprintk("type #3 (ie): 0x%x+%d [import/export]\n",
			ch->firsts[CHET_IE],
			ch->counts[CHET_IE]);
		vprintk("type #4 (dt): 0x%x+%d [data transfer]\n",
			ch->firsts[CHET_DT],
			ch->counts[CHET_DT]);
	} else {
		vprintk("reading element address assigment page failed!\n");
	}
	
	/* vendor specific element types */
	for (i = 0; i < 4; i++) {
		if (0 == vendor_counts[i])
			continue;
		if (NULL == vendor_labels[i])
			continue;
		ch->firsts[CHET_V1+i] = vendor_firsts[i];
		ch->counts[CHET_V1+i] = vendor_counts[i];
		vprintk("type #%d (v%d): 0x%x+%d [%s, vendor specific]\n",
			i+5,i+1,vendor_firsts[i],vendor_counts[i],
			vendor_labels[i]);
	}

	/* look up the devices of the data transfer elements */
	ch->dt = kmalloc(ch->counts[CHET_DT]*sizeof(struct scsi_device),
			 GFP_KERNEL);
	for (elem = 0; elem < ch->counts[CHET_DT]; elem++) {
		id  = -1;
		lun = 0;
		if (elem < CH_DT_MAX  &&  -1 != dt_id[elem]) {
			id  = dt_id[elem];
			lun = dt_lun[elem];
			vprintk("dt 0x%x: [insmod option] ",
				elem+ch->firsts[CHET_DT]);
		} else if (0 != ch_read_element_status
			   (ch,elem+ch->firsts[CHET_DT],data)) {
			vprintk("dt 0x%x: READ ELEMENT STATUS failed\n",
				elem+ch->firsts[CHET_DT]);
		} else {
			vprintk("dt 0x%x: ",elem+ch->firsts[CHET_DT]);
			if (data[6] & 0x80) {
				if (verbose)
					printk("not this SCSI bus\n");
				ch->dt[elem] = NULL;
			} else if (0 == (data[6] & 0x30)) {
				if (verbose)
					printk("ID/LUN unknown\n");
				ch->dt[elem] = NULL;
			} else {
				id  = ch->device->id;
				lun = 0;
				if (data[6] & 0x20) id  = data[7];
				if (data[6] & 0x10) lun = data[6] & 7;
			}
		}
		if (-1 != id) {
			if (verbose)
				printk("ID %i, LUN %i, ",id,lun);
			ch->dt[elem] =
				scsi_device_lookup(ch->device->host,
						   ch->device->channel,
						   id,lun);
			if (!ch->dt[elem]) {
				/* should not happen */
				if (verbose)
					printk("Huh? device not found!\n");
			} else {
				if (verbose)
					printk("name: %8.8s %16.16s %4.4s\n",
					       ch->dt[elem]->vendor,
					       ch->dt[elem]->model,
					       ch->dt[elem]->rev);
			}
		}
	}
	ch->voltags = 1;
	kfree(buffer);

	return 0;
}

/* ------------------------------------------------------------------------ */

static int
ch_position(scsi_changer *ch, u_int trans, u_int elem, int rotate)
{
	u_char  cmd[10];
	
	dprintk("position: 0x%x\n",elem);
	if (0 == trans)
		trans = ch->firsts[CHET_MT];
	memset(cmd,0,sizeof(cmd));
	cmd[0]  = POSITION_TO_ELEMENT;
	cmd[1]  = ch->device->lun << 5;
	cmd[2]  = (trans >> 8) & 0xff;
	cmd[3]  =  trans       & 0xff;
	cmd[4]  = (elem  >> 8) & 0xff;
	cmd[5]  =  elem        & 0xff;
	cmd[8]  = rotate ? 1 : 0;
	return ch_do_scsi(ch, cmd, NULL, 0, DMA_NONE);
}

static int
ch_move(scsi_changer *ch, u_int trans, u_int src, u_int dest, int rotate)
{
	u_char  cmd[12];
	
	dprintk("move: 0x%x => 0x%x\n",src,dest);
	if (0 == trans)
		trans = ch->firsts[CHET_MT];
	memset(cmd,0,sizeof(cmd));
	cmd[0]  = MOVE_MEDIUM;
	cmd[1]  = ch->device->lun << 5;
	cmd[2]  = (trans >> 8) & 0xff;
	cmd[3]  =  trans       & 0xff;
	cmd[4]  = (src   >> 8) & 0xff;
	cmd[5]  =  src         & 0xff;
	cmd[6]  = (dest  >> 8) & 0xff;
	cmd[7]  =  dest        & 0xff;
	cmd[10] = rotate ? 1 : 0;
	return ch_do_scsi(ch, cmd, NULL,0, DMA_NONE);
}

static int
ch_exchange(scsi_changer *ch, u_int trans, u_int src,
	    u_int dest1, u_int dest2, int rotate1, int rotate2)
{
	u_char  cmd[12];
	
	dprintk("exchange: 0x%x => 0x%x => 0x%x\n",
		src,dest1,dest2);
	if (0 == trans)
		trans = ch->firsts[CHET_MT];
	memset(cmd,0,sizeof(cmd));
	cmd[0]  = EXCHANGE_MEDIUM;
	cmd[1]  = ch->device->lun << 5;
	cmd[2]  = (trans >> 8) & 0xff;
	cmd[3]  =  trans       & 0xff;
	cmd[4]  = (src   >> 8) & 0xff;
	cmd[5]  =  src         & 0xff;
	cmd[6]  = (dest1 >> 8) & 0xff;
	cmd[7]  =  dest1       & 0xff;
	cmd[8]  = (dest2 >> 8) & 0xff;
	cmd[9]  =  dest2       & 0xff;
	cmd[10] = (rotate1 ? 1 : 0) | (rotate2 ? 2 : 0);
	
	return ch_do_scsi(ch, cmd, NULL,0, DMA_NONE);
}