/* $Id: scsi_debug.c,v 1.2 2005/06/16 13:46:39 cgoh Exp $
 *  linux/kernel/scsi_debug.c
 *
 *  Copyright (C) 1992  Eric Youngdale
 *  Simulate a host adapter with 2 disks attached.  Do a lot of checking
 *  to make sure that we are not getting blocks mixed up, and panic if
 *  anything out of the ordinary is seen.
 */

#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/string.h>
#include <linux/genhd.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>

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

#ifdef MODULE
#include <linux/module.h>
#endif

#include <linux/blk.h>
#include "scsi.h"
#include "hosts.h"

#include "sd.h"

#include<linux/stat.h>

struct proc_dir_entry proc_scsi_scsi_debug = {
    PROC_SCSI_SCSI_DEBUG, 10, "scsi_debug",
    S_IFDIR | S_IRUGO | S_IXUGO, 2
};


/* A few options that we want selected */

#define NR_HOSTS_PRESENT 20
#define NR_FAKE_DISKS   6
#define N_HEAD          32
#define N_SECTOR        64
#define DISK_READONLY(TGT)      (1)
#define DISK_REMOVEABLE(TGT)    (1)

/* Do not attempt to use a timer to simulate a real disk with latency */
/* Only use this in the actual kernel, not in the simulator. */
/* #define IMMEDIATE */

/* Skip some consistency checking.  Good for benchmarking */
#define SPEEDY
/* Read return zeros. Undefine for benchmarking */
#define CLEAR

/* Number of real scsi disks that will be detected ahead of time */
static int NR_REAL=-1;

#define NR_BLK_DEV  12
#ifndef MAJOR_NR
#define MAJOR_NR 8
#endif
#define START_PARTITION 4

/* Number of jiffies to wait before completing a command */
#define DISK_SPEED     10
#define CAPACITY (0x80000)

static int starts[] = {N_HEAD, N_HEAD * N_SECTOR, 50000, CAPACITY, 0};
static int npart = 0;

#include "scsi_debug.h"
#ifdef DEBUG
#define DEB(x) x
#else
#define DEB(x)
#endif

#ifdef SPEEDY
#define VERIFY1_DEBUG(RW) 
#define VERIFY_DEBUG(RW) 
#else

#define VERIFY1_DEBUG(RW)                           \
    if (bufflen != 1024) {printk("%d", bufflen); panic("(1)Bad bufflen");};         \
    start = 0;                          \
    if ((MINOR(SCpnt->request.rq_dev) & 0xf) != 0) start = starts[(MINOR(SCpnt->request.rq_dev) & 0xf) - 1];        \
    if (bh){                            \
	if (bh->b_size != 1024) panic ("Wrong bh size");    \
	if ((bh->b_blocknr << 1) + start != block)          \
	{   printk("Wrong bh block# %d %d ",bh->b_blocknr, block);  \
	    panic ("Wrong bh block#"); \
	};  \
	if (bh->b_dev != SCpnt->request.rq_dev)  \
	    panic ("Bad bh target"); \
    };

#define VERIFY_DEBUG(RW)                            \
    if (bufflen != 1024 && (!SCpnt->use_sg)) {printk("%x %d\n ",bufflen, SCpnt->use_sg); panic("Bad bufflen");};    \
    start = 0;                          \
    if ((MINOR(SCpnt->request.rq_dev) & 0xf) > npart) panic ("Bad partition");    \
    if ((MINOR(SCpnt->request.rq_dev) & 0xf) != 0) start = starts[(MINOR(SCpnt->request.rq_dev) & 0xf) - 1];        \
    if (SCpnt->request.cmd != RW) panic ("Wrong  operation");       \
    if (SCpnt->request.sector + start != block) panic("Wrong block.");  \
    if (SCpnt->request.current_nr_sectors != 2 && (!SCpnt->use_sg)) panic ("Wrong # blocks");   \
    if (SCpnt->request.bh){                         \
	if (SCpnt->request.bh->b_size != 1024) panic ("Wrong bh size"); \
	if ((SCpnt->request.bh->b_blocknr << 1) + start != block)           \
	{   printk("Wrong bh block# %d %d ",SCpnt->request.bh->b_blocknr, block);  \
	    panic ("Wrong bh block#"); \
	};  \
	if (SCpnt->request.bh->b_dev != SCpnt->request.rq_dev) \
	    panic ("Bad bh target");\
    };
#endif

typedef void (*done_fct_t)(Scsi_Cmnd *);

static volatile done_fct_t do_done[SCSI_DEBUG_MAILBOXES] = {NULL, };

static void scsi_debug_intr_handle(unsigned long);

static struct timer_list timeout[SCSI_DEBUG_MAILBOXES];

Scsi_Cmnd * SCint[SCSI_DEBUG_MAILBOXES] = {NULL,};
static char SCrst[SCSI_DEBUG_MAILBOXES] = {0,};

/*
 * Semaphore used to simulate bus lockups.
 */
static int scsi_debug_lockup = 0;

static char sense_buffer[128] = {0,};

static void scsi_dump(Scsi_Cmnd * SCpnt, int flag){
    int i;
#if 0
    unsigned char * pnt;
#endif
    unsigned int * lpnt;
    struct scatterlist * sgpnt = NULL;
    printk("use_sg: %d",SCpnt->use_sg);
    if (SCpnt->use_sg){
	sgpnt = (struct scatterlist *) SCpnt->buffer;
	for(i=0; i<SCpnt->use_sg; i++) {
	    lpnt = (int *) sgpnt[i].alt_address;
	    printk(":%p %p %d\n",sgpnt[i].alt_address, sgpnt[i].address, sgpnt[i].length);
	    if (lpnt) printk(" (Alt %x) ",lpnt[15]);
	};
    } else {
	printk("nosg: %p %p %d\n",SCpnt->request.buffer, SCpnt->buffer,
	       SCpnt->bufflen);
	lpnt = (int *) SCpnt->request.buffer;
	if (lpnt) printk(" (Alt %x) ",lpnt[15]);
    };
    lpnt = (unsigned int *) SCpnt;
    for (i=0;i<sizeof(Scsi_Cmnd)/4+1; i++) {
	if ((i & 7) == 0) printk("\n");
	printk("%x ",*lpnt++);
    };
    printk("\n");
    if (flag == 0) return;
    lpnt = (unsigned int *) sgpnt[0].alt_address;
    for (i=0;i<sizeof(Scsi_Cmnd)/4+1; i++) {
	if ((i & 7) == 0) printk("\n");
	printk("%x ",*lpnt++);
    };
#if 0
    printk("\n");
    lpnt = (unsigned int *) sgpnt[0].address;
    for (i=0;i<sizeof(Scsi_Cmnd)/4+1; i++) {
	if ((i & 7) == 0) printk("\n");
	printk("%x ",*lpnt++);
    };
    printk("\n");
#endif
    printk("DMA free %d sectors.\n", scsi_dma_free_sectors);
}

int scsi_debug_queuecommand(Scsi_Cmnd * SCpnt, void (*done)(Scsi_Cmnd *))
{
    unchar *cmd = (unchar *) SCpnt->cmnd;
    struct partition * p;
    int block;
    struct buffer_head * bh = NULL;
    unsigned char * buff;
    int nbytes, sgcount;
    int scsi_debug_errsts;
    struct scatterlist * sgpnt;
    int target = SCpnt->target;
    int bufflen = SCpnt->request_bufflen;
    unsigned long flags;
    int i;
    sgcount = 0;
    sgpnt = NULL;
    
    /*
     * If we are being notified of the mid-level reposessing a command due to timeout,
     * just return.
     */
    if( done == NULL )
    {
        return 0;
    }

    DEB(if (target >= NR_FAKE_DISKS) 
        { 
            SCpnt->result = DID_TIME_OUT << 16;done(SCpnt);return 0;
        });
    
    buff = (unsigned char *) SCpnt->request_buffer;
    
    if(target>=NR_FAKE_DISKS || SCpnt->lun != 0) 
    {
	SCpnt->result =  DID_NO_CONNECT << 16;
	done(SCpnt);
	return 0;
    }
    
    if( SCrst[target] != 0 && !scsi_debug_lockup )
    {
        SCrst[target] = 0;
        memset(SCpnt->sense_buffer, 0, sizeof(SCpnt->sense_buffer));
        SCpnt->sense_buffer[0] = 0x70;
        SCpnt->sense_buffer[2] = UNIT_ATTENTION;
	SCpnt->result = (CHECK_CONDITION << 1);
	done(SCpnt);         
    }
    switch(*cmd){
    case REQUEST_SENSE:
	SCSI_LOG_LLQUEUE(3,printk("Request sense...\n"));
#ifndef DEBUG
	{ 
	    int i;
	    printk("scsi_debug: Requesting sense buffer (%p %p %p %d):", SCpnt, buff, done, bufflen);
	    for(i=0;i<12;i++) printk("%d ",sense_buffer[i]);
	    printk("\n");
	};
#endif
	memset(buff, 0, bufflen);
	memcpy(buff, sense_buffer, bufflen);
	memset(sense_buffer, 0, sizeof(sense_buffer));
	SCpnt->result = 0;
	done(SCpnt); 
	return 0;
    case ALLOW_MEDIUM_REMOVAL:
	if(cmd[4]) 
        {
            SCSI_LOG_LLQUEUE(2,printk("Medium removal inhibited..."));
        }
	else
        {
            SCSI_LOG_LLQUEUE(2,printk("Medium removal enabled..."));
        }
	scsi_debug_errsts = 0;
	break;
    case INQUIRY:
	SCSI_LOG_LLQUEUE(3,printk("Inquiry...(%p %d)\n", buff, bufflen));
	memset(buff, 0, bufflen);
	buff[0] = TYPE_DISK;
	buff[1] = DISK_REMOVEABLE(target) ? 0x80 : 0;  /* Removable disk */
	buff[2] = 1;
	buff[4] = 33 - 5;
	memcpy(&buff[8],"Foo Inc",7);
	memcpy(&buff[16],"XYZZY",5);
	memcpy(&buff[32],"1",1);
	scsi_debug_errsts = 0;
	break;
    case TEST_UNIT_READY:
	SCSI_LOG_LLQUEUE(3,printk("Test unit ready(%p %d)\n", buff, bufflen));
	if (buff)
	    memset(buff, 0, bufflen);
	scsi_debug_errsts = 0;
	break;
    case READ_CAPACITY:
	SCSI_LOG_LLQUEUE(3,printk("Read Capacity\n"));
	if(NR_REAL < 0) NR_REAL = (MINOR(SCpnt->request.rq_dev) >> 4) & 0x0f;
	memset(buff, 0, bufflen);
	buff[0] = (CAPACITY >> 24);
	buff[1] = (CAPACITY >> 16) & 0xff;
	buff[2] = (CAPACITY >> 8) & 0xff;
	buff[3] = CAPACITY & 0xff;
	buff[6] = 2; /* 512 byte sectors */
	scsi_debug_errsts = 0;
	break;
    case READ_10:
    case READ_6:
#ifdef DEBUG
	printk("Read...");
#endif
	if ((*cmd) == READ_10)
	    block = cmd[5] + (cmd[4] << 8) + (cmd[3] << 16) + (cmd[2] << 24); 
	else 
	    block = cmd[3] + (cmd[2] << 8) + ((cmd[1] & 0x1f) << 16);
	VERIFY_DEBUG(READ);
#if defined(SCSI_SETUP_LATENCY) || defined(SCSI_DATARATE)
    {
	int delay = SCSI_SETUP_LATENCY;
	
	delay += SCpnt->request.nr_sectors * SCSI_DATARATE;
	if(delay) usleep(delay);
    };
#endif
	
#ifdef DEBUG
	printk("(r%d)",SCpnt->request.nr_sectors);
#endif
	nbytes = bufflen;
	if(SCpnt->use_sg){
	    sgcount = 0;
	    sgpnt = (struct scatterlist *) buff;
	    buff = sgpnt[sgcount].address;
	    bufflen = sgpnt[sgcount].length;
	    bh = SCpnt->request.bh;
	};
	scsi_debug_errsts = 0;
	do{
	    VERIFY1_DEBUG(READ);
	    /* For the speedy test, we do not even want to fill the buffer with anything */
#ifdef CLEAR
	    memset(buff, 0, bufflen);
#endif
	    /* If this is block 0, then we want to read the partition table for this
	     * device.  Let's make one up */
	    if(block == 0) {
	    	int i;
                memset(buff, 0, bufflen);
		*((unsigned short *) (buff+510)) = 0xAA55;
		p = (struct partition* ) (buff + 0x1be);
		i = 0;
		while(starts[i+1]){
		    p->start_sect = starts[i];
		    p->nr_sects = starts[i+1] - starts [i];
		    p->sys_ind = 0x81;  /* Linux partition */
                    p->head       = (i == 0 ? 1 : 0);
                    p->sector     = 1;
                    p->cyl        = starts[i] / N_HEAD / N_SECTOR;
                    p->end_head   = N_HEAD - 1;
                    p->end_sector = N_SECTOR;
                    p->end_cyl    = starts[i + 1] / N_HEAD / N_SECTOR;
		    p++;
		    i++;
		};
		if (!npart) npart = i;
		scsi_debug_errsts = 0;
		break;
	    };
#ifdef DEBUG
	    if (SCpnt->use_sg) printk("Block %x (%d %d)\n",block, SCpnt->request.nr_sectors,
				      SCpnt->request.current_nr_sectors);
#endif
	    
#if 0
	    /* Simulate a disk change */
	    if(block == 0xfff0) {
		sense_buffer[0] = 0x70;
		sense_buffer[2] = UNIT_ATTENTION;
		starts[0] += 10;
		starts[1] += 10;
		starts[2] += 10;
		
#ifdef DEBUG
		{ 
		    int i;
		    printk("scsi_debug: Filling sense buffer:");
		    for(i=0;i<12;i++) printk("%d ",sense_buffer[i]);
		    printk("\n");
		};
#endif
		scsi_debug_errsts = (COMMAND_COMPLETE << 8) | (CHECK_CONDITION << 1);
		break;
	    } /* End phony disk change code */
#endif
	    
#ifdef CLEAR
	    memcpy(buff, &target, sizeof(target));
	    memcpy(buff+sizeof(target), cmd, 24);
	    memcpy(buff+60, &block, sizeof(block));
	    memcpy(buff+64, SCpnt, sizeof(Scsi_Cmnd));
#endif
	    nbytes -= bufflen;
	    if(SCpnt->use_sg){
#ifdef CLEAR
		memcpy(buff+128, bh, sizeof(struct buffer_head));
#endif
		block += bufflen >> 9;
		bh = bh->b_reqnext;
		sgcount++;
		if (nbytes) {
		    if(!bh) panic("Too few blocks for linked request.");
		    buff = sgpnt[sgcount].address;
		    bufflen = sgpnt[sgcount].length;
		};
	    }
	} while(nbytes);
	
	SCpnt->result = 0;
	(done)(SCpnt);
	return 0;
	
	if (SCpnt->use_sg && !scsi_debug_errsts)
	    if(bh) scsi_dump(SCpnt, 0);
	break;
    case WRITE_10:
    case WRITE_6:
#ifdef DEBUG
	printk("Write\n");
#endif
	if ((*cmd) == WRITE_10)
	    block = cmd[5] + (cmd[4] << 8) + (cmd[3] << 16) + (cmd[2] << 24); 
	else 
	    block = cmd[3] + (cmd[2] << 8) + ((cmd[1] & 0x1f) << 16);
	VERIFY_DEBUG(WRITE);
	/*      printk("(w%d)",SCpnt->request.nr_sectors); */
	if (SCpnt->use_sg){
	    if ((bufflen >> 9) != SCpnt->request.nr_sectors)
		panic ("Trying to write wrong number of blocks\n");
	    sgpnt = (struct scatterlist *) buff;
	    buff = sgpnt[sgcount].address;
	};
#if 0
	if (block != *((unsigned long *) (buff+60))) {
	    printk("%x %x :",block,  *((unsigned long *) (buff+60)));
	    scsi_dump(SCpnt,1);
	    panic("Bad block written.\n");
	};
#endif
	scsi_debug_errsts = 0;
	break;
    case MODE_SENSE:
        /*
         * Used to detect write protected status.
         */
	scsi_debug_errsts = 0;
        memset(buff, 0, 6);
        break;
    default:
	SCSI_LOG_LLQUEUE(3,printk("Unknown command %d\n",*cmd));
	SCpnt->result =  DID_NO_CONNECT << 16;
	done(SCpnt);
	return 0;
    };
    
    save_flags(flags); 
    cli();
    for(i=0;i<SCSI_DEBUG_MAILBOXES; i++){
        if( timeout[i].function == NULL ) break;
    };
    
    /*
     * If all of the slots are full, just return 1.  The new error handling scheme
     * allows this, and the mid-level should queue things.
     */
    if (i >= SCSI_DEBUG_MAILBOXES ||  timeout[i].function != 0)
    {
        SCSI_LOG_LLQUEUE(1,printk("Command rejected - host busy\n"));
        restore_flags(flags);
        return 1;
    }

    SCSI_LOG_LLQUEUE(1,printk("Command accepted - slot %d\n", i));
    
#ifdef IMMEDIATE
    if( !scsi_debug_lockup )
    {
        SCpnt->result = scsi_debug_errsts;
        scsi_debug_intr_handle(i);  /* No timer - do this one right away */
    }
    restore_flags(flags);
#else
        
    SCpnt->result = scsi_debug_errsts;
    timeout[i].function = scsi_debug_intr_handle;
    timeout[i].data     = i;
    timeout[i].expires  = jiffies + DISK_SPEED;
    SCint[i]   = SCpnt;
    do_done[i] = done;
    
    restore_flags(flags);
    add_timer(&timeout[i]);
    if (!done)
	panic("scsi_debug_queuecommand: done can't be NULL\n");
    
#if 0
    printk("Sending command (%d %x %d %d)...", i, done, timeout[i].expires,jiffies);
#endif
#endif
    
    return 0;
}

volatile static int internal_done_flag = 0;
volatile static int internal_done_errcode = 0;
static void internal_done(Scsi_Cmnd * SCpnt)
{
    internal_done_errcode = SCpnt->result;
    ++internal_done_flag;
}

int scsi_debug_command(Scsi_Cmnd * SCpnt)
{
    DEB(printk("scsi_debug_command: ..calling scsi_debug_queuecommand\n"));
    scsi_debug_queuecommand(SCpnt, internal_done);
    
    while (!internal_done_flag);
    internal_done_flag = 0;
    return internal_done_errcode;
}

/* A "high" level interrupt handler.  This should be called once per jiffy
 * to simulate a regular scsi disk.  We use a timer to do this. */

static void scsi_debug_intr_handle(unsigned long indx)
{
    Scsi_Cmnd * SCtmp;
    void (*my_done)(Scsi_Cmnd *); 
#ifdef DEBUG
    int to;
#endif
    
#if 0
    del_timer(&timeout[indx]);
#endif
    
    SCtmp                  = (Scsi_Cmnd *) SCint[indx];
    my_done                = do_done[indx];
    do_done[indx]          = NULL;
    timeout[indx].function = NULL;
    SCint[indx]            = NULL;
    
    if (!my_done) {
      printk("scsi_debug_intr_handle: Unexpected interrupt\n"); 
      return;
    }
    
#ifdef DEBUG
    printk("In intr_handle...");
    printk("...done %d %x %d %d\n",i , my_done, to, jiffies);
    printk("In intr_handle: %d %x %x\n",i, SCtmp, my_done);
#endif
    
    my_done(SCtmp);
#ifdef DEBUG
    printk("Called done.\n");
#endif
}


int scsi_debug_detect(Scsi_Host_Template * tpnt)
{
    int i;

    for(i=0; i < NR_HOSTS_PRESENT; i++)
    {
        tpnt->proc_dir = &proc_scsi_scsi_debug;
        scsi_register(tpnt,0);
    }
    return NR_HOSTS_PRESENT;
}

int scsi_debug_abort(Scsi_Cmnd * SCpnt)
{
#if 0
    int j;
    void (*my_done)(Scsi_Cmnd *);
    unsigned long flags;
#endif
    
    DEB(printk("scsi_debug_abort\n"));
#if 0
    SCpnt->result = SCpnt->abort_reason << 16;
    for(j=0;j<SCSI_DEBUG_MAILBOXES; j++) {
	if(SCpnt == SCint[j]) {
	    my_done = do_done[j];
	    my_done(SCpnt);
	    save_flags(flags);
	    cli();
	    timeout[j] = 0;
	    SCint[j] = NULL;
	    do_done[j] = NULL;
	    restore_flags(flags);
	};
    };
#endif
    return SCSI_ABORT_SNOOZE;
}

int scsi_debug_biosparam(Disk * disk, kdev_t dev, int* info){
    int size = disk->capacity;
    info[0] = N_HEAD;
    info[1] = N_SECTOR;
    info[2] = (size + 2047) >> 11;
    if (info[2] >= 1024) info[2] = 1024;
    return 0;
}

int scsi_debug_reset(Scsi_Cmnd * SCpnt, unsigned int why)
{
    int i;
    unsigned long flags;
    
    void (*my_done)(Scsi_Cmnd *);
    printk("Bus unlocked by reset - %d\n", why);
    scsi_debug_lockup = 0;
    DEB(printk("scsi_debug_reset called\n"));
    for(i=0;i<SCSI_DEBUG_MAILBOXES; i++) {
        if (SCint[i] == NULL) continue;
        SCint[i]->result = DID_RESET << 16;
        my_done = do_done[i];
        my_done(SCint[i]);
        save_flags(flags);
        cli();
        SCint[i]            = NULL;
        do_done[i]          = NULL;
        timeout[i].function = NULL;
        restore_flags(flags);
    }
    return SCSI_RESET_SUCCESS;
}

const char *scsi_debug_info(void)
{
    static char buffer[] = " ";         /* looks nicer without anything here */
    return buffer;
}

/* scsi_debug_proc_info
 * Used if the driver currently has no own support for /proc/scsi
 */
int scsi_debug_proc_info(char *buffer, char **start, off_t offset, 
		     int length, int inode, int inout)
{
    int len, pos, begin;
    int orig_length;

    orig_length = length;

    if(inout == 1)
    {
        /* First check for the Signature */
        if (length >= 10 && strncmp(buffer, "scsi_debug", 10) == 0) {
            buffer += 11;
            length -= 11;

            if( buffer[length - 1] == '\n' )
            {
                buffer[length-1] = '\0';
                length--;
            }

            /*
             * OK, we are getting some kind of command.  Figure out
             * what we are supposed to do here.  Simulate bus lockups
             * to test our reset capability.
             */
            if( length == 6 && strncmp(buffer, "lockup", length) == 0 )
            {
                scsi_debug_lockup = 1;
                return orig_length;
            } 
            
            if( length == 6 && strncmp(buffer, "unlock", length) == 0 )
            {
                scsi_debug_lockup = 0;
                return orig_length;
            } 
            
            printk("Unknown command:%s (%d)\n", buffer, length);
        } else 
            printk("Wrong Signature:%10s\n", (char *) buffer);

        return -EINVAL;
        
    }
    
    begin = 0;
    pos = len = sprintf(buffer, 
			"This driver is not a real scsi driver, but it plays one on TV.\n"
                        "It is very handy for debugging specific problems because you\n"
                        "can simulate a variety of error conditions\n");
    if(pos < offset)
    {
	len = 0;
	begin = pos;
    }
    
    *start = buffer + (offset - begin);   /* Start of wanted data */
    len -= (offset - begin);
    if(len > length)
	len = length;
    
    return(len);
}

#ifdef MODULE
/* Eventually this will go into an include file, but this will be later */
Scsi_Host_Template driver_template = SCSI_DEBUG;

#include "scsi_module.c"
#endif
 
/*
 * Overrides for Emacs so that we almost follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-indent-level: 4
 * c-brace-imaginary-offset: 0
 * c-brace-offset: -4
 * c-argdecl-indent: 4
 * c-label-offset: -4
 * c-continued-statement-offset: 4
 * c-continued-brace-offset: 0
 * indent-tabs-mode: nil
 * tab-width: 8
 * End:
 */
