acsi.c

讲述linux的初始化过程

/*
 * acsi.c -- Device driver for Atari ACSI hard disks
 *
 * Copyright 1994 Roman Hodek <[e-mail]>
 *
 * Some parts are based on hd.c by Linus Torvalds
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 *
 */

/*
 * Still to in this file:
 *  - If a command ends with an error status (!= 0), the following
 *    REQUEST SENSE commands (4 to fill the ST-DMA FIFO) are done by
 *    polling the _IRQ signal (not interrupt-driven). This should be
 *    avoided in future because it takes up a non-neglectible time in
 *    the interrupt service routine while interrupts are disabled.
 *    Maybe a timer interrupt will get lost :-(
 */

/*
 * General notes:
 *
 *  - All ACSI devices (disks, CD-ROMs, ...) use major number 28.
 *    Minors are organized like it is with SCSI: The upper 4 bits
 *    identify the device, the lower 4 bits the partition.
 *    The device numbers (the upper 4 bits) are given in the same
 *    order as the devices are found on the bus.
 *  - Up to 8 LUNs are supported for each target (if CONFIG_ACSI_MULTI_LUN
 *    is defined), but only a total of 16 devices (due to minor
 *    numbers...). Note that Atari allows only a maximum of 4 targets
 *    (i.e. controllers, not devices) on the ACSI bus!
 *  - A optimizing scheme similar to SCSI scatter-gather is implemented.
 *  - Removable media are supported. After a medium change to device
 *    is reinitialized (partition check etc.). Also, if the device
 *    knows the PREVENT/ALLOW MEDIUM REMOVAL command, the door should
 *    be locked and unlocked when mounting the first or unmounting the
 *    last filesystem on the device. The code is untested, because I
 *    don't have a removable hard disk.
 *
 */

#define MAJOR_NR ACSI_MAJOR

#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/genhd.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/major.h>
#include <linux/blk.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <scsi/scsi.h> /* for SCSI_IOCTL_GET_IDLUN */
typedef void Scsi_Device; /* hack to avoid including scsi.h */
#include <scsi/scsi_ioctl.h>
#include <linux/hdreg.h> /* for HDIO_GETGEO */
#include <linux/blkpg.h>

#include <asm/setup.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/atarihw.h>
#include <asm/atariints.h>
#include <asm/atari_acsi.h>
#include <asm/atari_stdma.h>
#include <asm/atari_stram.h>


#define DEBUG
#undef DEBUG_DETECT
#undef NO_WRITE

#define MAX_ERRORS     		8	/* Max read/write errors/sector */
#define MAX_LUN				8	/* Max LUNs per target */
#define MAX_DEV		   		16

#define ACSI_BUFFER_SIZE			(16*1024) /* "normal" ACSI buffer size */
#define ACSI_BUFFER_MINSIZE			(2048) 	  /* min. buf size if ext. DMA */
#define ACSI_BUFFER_SIZE_ORDER	 	2		  /* order size for above */
#define ACSI_BUFFER_MINSIZE_ORDER	0 	  	  /* order size for above */
#define ACSI_BUFFER_SECTORS	(ACSI_BUFFER_SIZE/512)

#define ACSI_BUFFER_ORDER \
	(ATARIHW_PRESENT(EXTD_DMA) ? \
	 ACSI_BUFFER_MINSIZE_ORDER : \
	 ACSI_BUFFER_SIZE_ORDER)

#define ACSI_TIMEOUT		(4*HZ)

/* minimum delay between two commands */

#define COMMAND_DELAY 500

typedef enum {
	NONE, HARDDISK, CDROM
} ACSI_TYPE;

struct acsi_info_struct {
	ACSI_TYPE		type;			/* type of device */
	unsigned		target;			/* target number */
	unsigned		lun;			/* LUN in target controller */
	unsigned		removable : 1;	/* Flag for removable media */
	unsigned		read_only : 1;	/* Flag for read only devices */
	unsigned		old_atari_disk : 1; /* Is an old Atari disk       */
	unsigned		changed : 1;	/* Medium has been changed */
	unsigned long 	size;			/* #blocks */
} acsi_info[MAX_DEV];

/*
 *	SENSE KEYS
 */

#define NO_SENSE		0x00
#define RECOVERED_ERROR 	0x01
#define NOT_READY		0x02
#define MEDIUM_ERROR		0x03
#define HARDWARE_ERROR		0x04
#define ILLEGAL_REQUEST 	0x05
#define UNIT_ATTENTION		0x06
#define DATA_PROTECT		0x07
#define BLANK_CHECK		0x08
#define COPY_ABORTED		0x0a
#define ABORTED_COMMAND 	0x0b
#define VOLUME_OVERFLOW 	0x0d
#define MISCOMPARE		0x0e


/*
 *	DEVICE TYPES
 */

#define TYPE_DISK	0x00
#define TYPE_TAPE	0x01
#define TYPE_WORM	0x04
#define TYPE_ROM	0x05
#define TYPE_MOD	0x07
#define TYPE_NO_LUN	0x7f

/* The data returned by MODE SENSE differ between the old Atari
 * hard disks and SCSI disks connected to ACSI. In the following, both
 * formats are defined and some macros to operate on them potably.
 */

typedef struct {
	unsigned long	dummy[2];
	unsigned long	sector_size;
	unsigned char	format_code;
#define ATARI_SENSE_FORMAT_FIX	1	
#define ATARI_SENSE_FORMAT_CHNG	2
	unsigned char	cylinders_h;
	unsigned char	cylinders_l;
	unsigned char	heads;
	unsigned char	reduced_h;
	unsigned char	reduced_l;
	unsigned char	precomp_h;
	unsigned char	precomp_l;
	unsigned char	landing_zone;
	unsigned char	steprate;
	unsigned char	type;
#define ATARI_SENSE_TYPE_FIXCHNG_MASK		4
#define ATARI_SENSE_TYPE_SOFTHARD_MASK		8
#define ATARI_SENSE_TYPE_FIX				4
#define ATARI_SENSE_TYPE_CHNG				0
#define ATARI_SENSE_TYPE_SOFT				0
#define ATARI_SENSE_TYPE_HARD				8
	unsigned char	sectors;
} ATARI_SENSE_DATA;

#define ATARI_CAPACITY(sd) \
	(((int)((sd).cylinders_h<<8)|(sd).cylinders_l) * \
	 (sd).heads * (sd).sectors)


typedef struct {
	unsigned char   dummy1;
	unsigned char   medium_type;
	unsigned char   dummy2;
	unsigned char   descriptor_size;
	unsigned long   block_count;
	unsigned long   sector_size;
	/* Page 0 data */
	unsigned char	page_code;
	unsigned char	page_size;
	unsigned char	page_flags;
	unsigned char	qualifier;
} SCSI_SENSE_DATA;

#define SCSI_CAPACITY(sd) 	((sd).block_count & 0xffffff)


typedef union {
	ATARI_SENSE_DATA	atari;
	SCSI_SENSE_DATA		scsi;
} SENSE_DATA;

#define SENSE_TYPE_UNKNOWN	0
#define SENSE_TYPE_ATARI	1
#define SENSE_TYPE_SCSI		2

#define SENSE_TYPE(sd)										\
	(((sd).atari.dummy[0] == 8 &&							\
	  ((sd).atari.format_code == 1 ||						\
	   (sd).atari.format_code == 2)) ? SENSE_TYPE_ATARI :	\
	 ((sd).scsi.dummy1 >= 11) ? SENSE_TYPE_SCSI :			\
	 SENSE_TYPE_UNKNOWN)
	 
#define CAPACITY(sd)							\
	(SENSE_TYPE(sd) == SENSE_TYPE_ATARI ?		\
	 ATARI_CAPACITY((sd).atari) :				\
	 SCSI_CAPACITY((sd).scsi))

#define SECTOR_SIZE(sd)							\
	(SENSE_TYPE(sd) == SENSE_TYPE_ATARI ?		\
	 (sd).atari.sector_size :					\
	 (sd).scsi.sector_size & 0xffffff)

/* Default size if capacity cannot be determined (1 GByte) */
#define	DEFAULT_SIZE	0x1fffff

#define CARTRCH_STAT(dev,buf)					\
	(acsi_info[(dev)].old_atari_disk ?			\
	 (((buf)[0] & 0x7f) == 0x28) :					\
	 ((((buf)[0] & 0x70) == 0x70) ?					\
	  (((buf)[2] & 0x0f) == 0x06) :					\
	  (((buf)[0] & 0x0f) == 0x06)))					\

/* These two are also exported to other drivers that work on the ACSI bus and
 * need an ST-RAM buffer. */
char 			*acsi_buffer;
unsigned long 	phys_acsi_buffer;

static int				NDevices = 0;
static int				acsi_sizes[MAX_DEV<<4] = { 0, };
static int				acsi_blocksizes[MAX_DEV<<4] = { 0, };
static struct hd_struct	acsi_part[MAX_DEV<<4] = { {0,0}, };
static int 				access_count[MAX_DEV] = { 0, };
static char 			busy[MAX_DEV] = { 0, };
static DECLARE_WAIT_QUEUE_HEAD(busy_wait);

static int				CurrentNReq;
static int				CurrentNSect;
static char				*CurrentBuffer;


#define SET_TIMER()	mod_timer(&acsi_timer, jiffies + ACSI_TIMEOUT)
#define CLEAR_TIMER()	del_timer(&acsi_timer)

static unsigned long	STramMask;
#define STRAM_ADDR(a)	(((a) & STramMask) == 0)



/* ACSI commands */

static char tur_cmd[6]        = { 0x00, 0, 0, 0, 0, 0 };
static char modesense_cmd[6]  = { 0x1a, 0, 0, 0, 24, 0 };
static char modeselect_cmd[6] = { 0x15, 0, 0, 0, 12, 0 };
static char inquiry_cmd[6]    = { 0x12, 0, 0, 0,255, 0 };
static char reqsense_cmd[6]   = { 0x03, 0, 0, 0, 4, 0 };
static char read_cmd[6]       = { 0x08, 0, 0, 0, 0, 0 };
static char write_cmd[6]      = { 0x0a, 0, 0, 0, 0, 0 };
static char pa_med_rem_cmd[6] = { 0x1e, 0, 0, 0, 0, 0 };

#define CMDSET_TARG_LUN(cmd,targ,lun)			\
    do {						\
		cmd[0] = (cmd[0] & ~0xe0) | (targ)<<5;	\
		cmd[1] = (cmd[1] & ~0xe0) | (lun)<<5;	\
	} while(0)

#define CMDSET_BLOCK(cmd,blk)						\
    do {											\
		unsigned long __blk = (blk);				\
		cmd[3] = __blk; __blk >>= 8;				\
		cmd[2] = __blk; __blk >>= 8;				\
		cmd[1] = (cmd[1] & 0xe0) | (__blk & 0x1f);	\
	} while(0)

#define CMDSET_LEN(cmd,len)						\
	do {										\
		cmd[4] = (len);							\
	} while(0)

#define min(a,b)	(((a)<(b))?(a):(b))


/* ACSI errors (from REQUEST SENSE); There are two tables, one for the
 * old Atari disks and one for SCSI on ACSI disks.
 */

struct acsi_error {
	unsigned char	code;
	const char		*text;
} atari_acsi_errors[] = {
	{ 0x00, "No error (??)" },
	{ 0x01, "No index pulses" },
	{ 0x02, "Seek not complete" },
	{ 0x03, "Write fault" },
	{ 0x04, "Drive not ready" },
	{ 0x06, "No Track 00 signal" },
	{ 0x10, "ECC error in ID field" },
	{ 0x11, "Uncorrectable data error" },
	{ 0x12, "ID field address mark not found" },
	{ 0x13, "Data field address mark not found" },
	{ 0x14, "Record not found" },
	{ 0x15, "Seek error" },
	{ 0x18, "Data check in no retry mode" },
	{ 0x19, "ECC error during verify" },
	{ 0x1a, "Access to bad block" },
	{ 0x1c, "Unformatted or bad format" },
	{ 0x20, "Invalid command" },
	{ 0x21, "Invalid block address" },
	{ 0x23, "Volume overflow" },
	{ 0x24, "Invalid argument" },
	{ 0x25, "Invalid drive number" },
	{ 0x26, "Byte zero parity check" },
	{ 0x28, "Cartride changed" },
	{ 0x2c, "Error count overflow" },
	{ 0x30, "Controller selftest failed" }
},

	scsi_acsi_errors[] = {
	{ 0x00, "No error (??)" },
	{ 0x01, "Recovered error" },
	{ 0x02, "Drive not ready" },
	{ 0x03, "Uncorrectable medium error" },
	{ 0x04, "Hardware error" },
	{ 0x05, "Illegal request" },
	{ 0x06, "Unit attention (Reset or cartridge changed)" },
	{ 0x07, "Data protection" },
	{ 0x08, "Blank check" },
	{ 0x0b, "Aborted Command" },
	{ 0x0d, "Volume overflow" }
};



/***************************** Prototypes *****************************/

static int acsicmd_dma( const char *cmd, char *buffer, int blocks, int
                        rwflag, int enable);
static int acsi_reqsense( char *buffer, int targ, int lun);
static void acsi_print_error( const unsigned char *errblk, int dev );
static void acsi_interrupt (int irq, void *data, struct pt_regs *fp);
static void unexpected_acsi_interrupt( void );
static void bad_rw_intr( void );
static void read_intr( void );
static void write_intr( void);
static void acsi_times_out( unsigned long dummy );
static void copy_to_acsibuffer( void );
static void copy_from_acsibuffer( void );
static void do_end_requests( void );
static void do_acsi_request( request_queue_t * );
static void redo_acsi_request( void );
static int acsi_ioctl( struct inode *inode, struct file *file, unsigned int
                       cmd, unsigned long arg );
static int acsi_open( struct inode * inode, struct file * filp );
static int acsi_release( struct inode * inode, struct file * file );
static void acsi_prevent_removal( int target, int flag );
static int acsi_change_blk_size( int target, int lun);
static int acsi_mode_sense( int target, int lun, SENSE_DATA *sd );
static void acsi_geninit(void);
static int revalidate_acsidisk( int dev, int maxusage );
static int acsi_revalidate (dev_t);

/************************* End of Prototypes **************************/


struct timer_list acsi_timer = { NULL, NULL, 0, 0, acsi_times_out };


#ifdef CONFIG_ATARI_SLM

extern int attach_slm( int target, int lun );
extern int slm_init( void );

#endif



/***********************************************************************
 *
 *   ACSI primitives
 *
 **********************************************************************/


/*
 * The following two functions wait for _IRQ to become Low or High,
 * resp., with a timeout. The 'timeout' parameter is in jiffies
 * (10ms).
 * If the functions are called with timer interrupts on (int level <
 * 6), the timeout is based on the 'jiffies' variable to provide exact
 * timeouts for device probing etc.
 * If interrupts are disabled, the number of tries is based on the
 * 'loops_per_jiffy' variable. A rough estimation is sufficient here...
 */

#define INT_LEVEL													\
	({	unsigned __sr;												\
		__asm__ __volatile__ ( "movew	%/sr,%0" : "=dm" (__sr) );	\
		(__sr >> 8) & 7;											\
	})

int acsi_wait_for_IRQ( unsigned timeout )

{
	if (INT_LEVEL < 6) {
		unsigned long maxjif = jiffies + timeout;
		while (time_before(jiffies, maxjif))
			if (!(mfp.par_dt_reg & 0x20)) return( 1 );
	}
	else {
		long tries = loops_per_jiffy / 8 * timeout;
		while( --tries >= 0 )
			if (!(mfp.par_dt_reg & 0x20)) return( 1 );
	}		
	return( 0 ); /* timeout! */
}


int acsi_wait_for_noIRQ( unsigned timeout )

{
	if (INT_LEVEL < 6) {
		unsigned long maxjif = jiffies + timeout;
		while (time_before(jiffies, maxjif))
			if (mfp.par_dt_reg & 0x20) return( 1 );
	}
	else {
		long tries = loops_per_jiffy * timeout / 8;
		while( tries-- >= 0 )
			if (mfp.par_dt_reg & 0x20) return( 1 );
	}		
	return( 0 ); /* timeout! */
}

static struct timeval start_time;

void
acsi_delay_start(void)
{
	do_gettimeofday(&start_time);
}

/* wait from acsi_delay_start to now usec (<1E6) usec */

void
acsi_delay_end(long usec)
{
	struct timeval end_time;
	long deltau,deltas;
	do_gettimeofday(&end_time);
	deltau=end_time.tv_usec - start_time.tv_usec;
	deltas=end_time.tv_sec - start_time.tv_sec;
	if (deltas > 1 || deltas < 0)
		return;
	if (deltas > 0)
		deltau += 1000*1000;
	if (deltau >= usec)
		return;
	udelay(usec-deltau);
}

/* acsicmd_dma() sends an ACSI command and sets up the DMA to transfer
 * 'blocks' blocks of 512 bytes from/to 'buffer'.
 * Because the _IRQ signal is used for handshaking the command bytes,
 * the ACSI interrupt has to be disabled in this function. If the end
 * of the operation should be signalled by a real interrupt, it has to be
 * reenabled afterwards.
 */