ide-tape.c

讲述linux的初始化过程

/*
 * 	IDETAPE_PC_RQ is used to queue a packet command in the request queue.
 */
#define IDETAPE_PC_RQ1			90
#define IDETAPE_PC_RQ2			91

/*
 *	IDETAPE_READ_RQ and IDETAPE_WRITE_RQ are used by our
 *	character device interface to request read/write operations from
 *	our block device interface.
 */
#define IDETAPE_READ_RQ			92
#define IDETAPE_WRITE_RQ		93
#define IDETAPE_ABORTED_WRITE_RQ	94
#define IDETAPE_ABORTED_READ_RQ		95
#define IDETAPE_READ_BUFFER_RQ		96

#define IDETAPE_LAST_RQ			96

/*
 *	A macro which can be used to check if a we support a given
 *	request command.
 */
#define IDETAPE_RQ_CMD(cmd) 		((cmd >= IDETAPE_FIRST_RQ) && (cmd <= IDETAPE_LAST_RQ))

/*
 *	Error codes which are returned in rq->errors to the higher part
 *	of the driver.
 */
#define	IDETAPE_ERROR_GENERAL		101
#define	IDETAPE_ERROR_FILEMARK		102
#define	IDETAPE_ERROR_EOD		103

/*
 *	The ATAPI Status Register.
 */
typedef union {
	unsigned all			:8;
	struct {
		unsigned check		:1;	/* Error occurred */
		unsigned idx		:1;	/* Reserved */
		unsigned corr		:1;	/* Correctable error occurred */
		unsigned drq		:1;	/* Data is request by the device */
		unsigned dsc		:1;	/* Buffer availability / Media access command finished */
		unsigned reserved5	:1;	/* Reserved */
		unsigned drdy		:1;	/* Ignored for ATAPI commands (ready to accept ATA command) */
		unsigned bsy		:1;	/* The device has access to the command block */
	} b;
} idetape_status_reg_t;

/*
 *	The ATAPI error register.
 */
typedef union {
	unsigned all			:8;
	struct {
		unsigned ili		:1;	/* Illegal Length Indication */
		unsigned eom		:1;	/* End Of Media Detected */
		unsigned abrt		:1;	/* Aborted command - As defined by ATA */
		unsigned mcr		:1;	/* Media Change Requested - As defined by ATA */
		unsigned sense_key	:4;	/* Sense key of the last failed packet command */
	} b;
} idetape_error_reg_t;

/*
 *	ATAPI Feature Register
 */
typedef union {
	unsigned all			:8;
	struct {
		unsigned dma		:1;	/* Using DMA of PIO */
		unsigned reserved321	:3;	/* Reserved */
		unsigned reserved654	:3;	/* Reserved (Tag Type) */
		unsigned reserved7	:1;	/* Reserved */
	} b;
} idetape_feature_reg_t;

/*
 *	ATAPI Byte Count Register.
 */
typedef union {
	unsigned all			:16;
	struct {
		unsigned low		:8;	/* LSB */
		unsigned high		:8;	/* MSB */
	} b;
} idetape_bcount_reg_t;

/*
 *	ATAPI Interrupt Reason Register.
 */
typedef union {
	unsigned all			:8;
	struct {
		unsigned cod		:1;	/* Information transferred is command (1) or data (0) */
		unsigned io		:1;	/* The device requests us to read (1) or write (0) */
		unsigned reserved	:6;	/* Reserved */
	} b;
} idetape_ireason_reg_t;

/*
 *	ATAPI Drive Select Register
 */
typedef union {	
	unsigned all			:8;
	struct {
		unsigned sam_lun	:4;	/* Should be zero with ATAPI (not used) */
		unsigned drv		:1;	/* The responding drive will be drive 0 (0) or drive 1 (1) */
		unsigned one5		:1;	/* Should be set to 1 */
		unsigned reserved6	:1;	/* Reserved */
		unsigned one7		:1;	/* Should be set to 1 */
	} b;
} idetape_drivesel_reg_t;

/*
 *	ATAPI Device Control Register
 */
typedef union {			
	unsigned all			:8;
	struct {
		unsigned zero0		:1;	/* Should be set to zero */
		unsigned nien		:1;	/* Device interrupt is disabled (1) or enabled (0) */
		unsigned srst		:1;	/* ATA software reset. ATAPI devices should use the new ATAPI srst. */
		unsigned one3		:1;	/* Should be set to 1 */
		unsigned reserved4567	:4;	/* Reserved */
	} b;
} idetape_control_reg_t;

/*
 *	idetape_chrdev_t provides the link between out character device
 *	interface and our block device interface and the corresponding
 *	ide_drive_t structure.
 */
typedef struct {
	ide_drive_t *drive;
} idetape_chrdev_t;

/*
 *	The following is used to format the general configuration word of
 *	the ATAPI IDENTIFY DEVICE command.
 */
struct idetape_id_gcw {	
	unsigned packet_size		:2;	/* Packet Size */
	unsigned reserved234		:3;	/* Reserved */
	unsigned drq_type		:2;	/* Command packet DRQ type */
	unsigned removable		:1;	/* Removable media */
	unsigned device_type		:5;	/* Device type */
	unsigned reserved13		:1;	/* Reserved */
	unsigned protocol		:2;	/* Protocol type */
};

/*
 *	INQUIRY packet command - Data Format (From Table 6-8 of QIC-157C)
 */
typedef struct {
	unsigned	device_type	:5;	/* Peripheral Device Type */
	unsigned	reserved0_765	:3;	/* Peripheral Qualifier - Reserved */
	unsigned	reserved1_6t0	:7;	/* Reserved */
	unsigned	rmb		:1;	/* Removable Medium Bit */
	unsigned	ansi_version	:3;	/* ANSI Version */
	unsigned	ecma_version	:3;	/* ECMA Version */
	unsigned	iso_version	:2;	/* ISO Version */
	unsigned	response_format :4;	/* Response Data Format */
	unsigned	reserved3_45	:2;	/* Reserved */
	unsigned	reserved3_6	:1;	/* TrmIOP - Reserved */
	unsigned	reserved3_7	:1;	/* AENC - Reserved */
	__u8		additional_length;	/* Additional Length (total_length-4) */
	__u8		rsv5, rsv6, rsv7;	/* Reserved */
	__u8		vendor_id[8];		/* Vendor Identification */
	__u8		product_id[16];		/* Product Identification */
	__u8		revision_level[4];	/* Revision Level */
	__u8		vendor_specific[20];	/* Vendor Specific - Optional */
	__u8		reserved56t95[40];	/* Reserved - Optional */
						/* Additional information may be returned */
} idetape_inquiry_result_t;

/*
 *	READ POSITION packet command - Data Format (From Table 6-57)
 */
typedef struct {
	unsigned	reserved0_10	:2;	/* Reserved */
	unsigned	bpu		:1;	/* Block Position Unknown */	
	unsigned	reserved0_543	:3;	/* Reserved */
	unsigned	eop		:1;	/* End Of Partition */
	unsigned	bop		:1;	/* Beginning Of Partition */
	u8		partition;		/* Partition Number */
	u8		reserved2, reserved3;	/* Reserved */
	u32		first_block;		/* First Block Location */
	u32		last_block;		/* Last Block Location (Optional) */
	u8		reserved12;		/* Reserved */
	u8		blocks_in_buffer[3];	/* Blocks In Buffer - (Optional) */
	u32		bytes_in_buffer;	/* Bytes In Buffer (Optional) */
} idetape_read_position_result_t;

/*
 *	Follows structures which are related to the SELECT SENSE / MODE SENSE
 *	packet commands. Those packet commands are still not supported
 *	by ide-tape.
 */
#define	IDETAPE_CAPABILITIES_PAGE	0x2a
#define IDETAPE_BLOCK_SIZE_PAGE		0x30

/*
 *	Mode Parameter Header for the MODE SENSE packet command
 */
typedef struct {
	__u8	mode_data_length;	/* Length of the following data transfer */
	__u8	medium_type;		/* Medium Type */
	__u8	dsp;			/* Device Specific Parameter */
	__u8	bdl;			/* Block Descriptor Length */
#if 0
	/* data transfer page */
	__u8	page_code	:6;
	__u8	reserved0_6	:1;
	__u8	ps		:1;	/* parameters saveable */
	__u8	page_length;		/* page Length == 0x02 */
	__u8	reserved2;
	__u8	read32k		:1;	/* 32k blk size (data only) */
	__u8	read32k5	:1;	/* 32.5k blk size (data&AUX) */
	__u8	reserved3_23	:2;
	__u8	write32k	:1;	/* 32k blk size (data only) */
	__u8	write32k5	:1;	/* 32.5k blk size (data&AUX) */
	__u8	reserved3_6	:1;
	__u8	streaming	:1;	/* streaming mode enable */
#endif
} idetape_mode_parameter_header_t;

/*
 *	Mode Parameter Block Descriptor the MODE SENSE packet command
 *
 *	Support for block descriptors is optional.
 */
typedef struct {
	__u8		density_code;		/* Medium density code */
	__u8		blocks[3];		/* Number of blocks */
	__u8		reserved4;		/* Reserved */
	__u8		length[3];		/* Block Length */
} idetape_parameter_block_descriptor_t;

/*
 *	The Data Compression Page, as returned by the MODE SENSE packet command.
 */
typedef struct {
	unsigned	page_code	:6;	/* Page Code - Should be 0xf */
	unsigned	reserved0	:1;	/* Reserved */
	unsigned	ps		:1;
	__u8		page_length;		/* Page Length - Should be 14 */
	unsigned	reserved2	:6;	/* Reserved */
	unsigned	dcc		:1;	/* Data Compression Capable */
	unsigned	dce		:1;	/* Data Compression Enable */
	unsigned	reserved3	:5;	/* Reserved */
	unsigned	red		:2;	/* Report Exception on Decompression */
	unsigned	dde		:1;	/* Data Decompression Enable */
	__u32		ca;			/* Compression Algorithm */
	__u32		da;			/* Decompression Algorithm */
	__u8		reserved[4];		/* Reserved */
} idetape_data_compression_page_t;

/*
 *	The Medium Partition Page, as returned by the MODE SENSE packet command.
 */
typedef struct {
	unsigned	page_code	:6;	/* Page Code - Should be 0x11 */
	unsigned	reserved1_6	:1;	/* Reserved */
	unsigned	ps		:1;
	__u8		page_length;		/* Page Length - Should be 6 */
	__u8		map;			/* Maximum Additional Partitions - Should be 0 */
	__u8		apd;			/* Additional Partitions Defined - Should be 0 */
	unsigned	reserved4_012	:3;	/* Reserved */
	unsigned	psum		:2;	/* Should be 0 */
	unsigned	idp		:1;	/* Should be 0 */
	unsigned	sdp		:1;	/* Should be 0 */
	unsigned	fdp		:1;	/* Fixed Data Partitions */
	__u8		mfr;			/* Medium Format Recognition */
	__u8		reserved[2];		/* Reserved */
} idetape_medium_partition_page_t;

/*
 *	Run time configurable parameters.
 */
typedef struct {
	int	dsc_rw_frequency;
	int	dsc_media_access_frequency;
	int	nr_stages;
} idetape_config_t;

/*
 *	The variables below are used for the character device interface.
 *	Additional state variables are defined in our ide_drive_t structure.
 */
static idetape_chrdev_t idetape_chrdevs[MAX_HWIFS * MAX_DRIVES];
static int idetape_chrdev_present = 0;

#if IDETAPE_DEBUG_LOG_VERBOSE

/*
 * DO NOT REMOVE, BUILDING A VERBOSE DEBUG SCHEME FOR ATAPI
 */

char *idetape_sense_key_verbose (byte idetape_sense_key)
{
	switch (idetape_sense_key) {
		default: {
			char buf[22];
			sprintf(buf, "IDETAPE_SENSE (0x%02x)", idetape_sense_key);
			return(buf);
		}

	}
}

char *idetape_command_key_verbose (byte idetape_command_key)
{
	switch (idetape_command_key) {
		case IDETAPE_TEST_UNIT_READY_CMD:	return("TEST_UNIT_READY_CMD");
		case IDETAPE_REWIND_CMD:		return("REWIND_CMD");
		case IDETAPE_REQUEST_SENSE_CMD:		return("REQUEST_SENSE_CMD");
		case IDETAPE_READ_CMD:			return("READ_CMD");
		case IDETAPE_WRITE_CMD:			return("WRITE_CMD");
		case IDETAPE_WRITE_FILEMARK_CMD:	return("WRITE_FILEMARK_CMD");
		case IDETAPE_SPACE_CMD:			return("SPACE_CMD");
		case IDETAPE_INQUIRY_CMD:		return("INQUIRY_CMD");
		case IDETAPE_ERASE_CMD:			return("ERASE_CMD")
		case IDETAPE_MODE_SENSE_CMD:		return("MODE_SENSE_CMD");
		case IDETAPE_MODE_SELECT_CMD:		return("MODE_SELECT_CMD");
		case IDETAPE_LOAD_UNLOAD_CMD:		return("LOAD_UNLOAD_CMD");
		case IDETAPE_PREVENT_CMD:		return("PREVENT_CMD");
		case IDETAPE_LOCATE_CMD:		return("LOCATE_CMD");
		case IDETAPE_READ_POSITION_CMD:		return("READ_POSITION_CMD");
		case IDETAPE_READ_BUFFER_CMD:		return("READ_BUFFER_CMD");
		case IDETAPE_SET_SPEED_CMD:		return("SET_SPEED_CMD");
		default: {
				char buf[20];
				sprintf(buf, "CMD (0x%02x)", idetape_command_key);
				return(buf);
			}
	}
}
#endif /* IDETAPE_DEBUG_LOG_VERBOSE */

/*
 *	Too bad. The drive wants to send us data which we are not ready to accept.
 *	Just throw it away.
 */
static void idetape_discard_data (ide_drive_t *drive, unsigned int bcount)
{
	while (bcount--)
		IN_BYTE (IDE_DATA_REG);
}

static void idetape_input_buffers (ide_drive_t *drive, idetape_pc_t *pc, unsigned int bcount)
{
	struct buffer_head *bh = pc->bh;
	int count;

	while (bcount) {
#if IDETAPE_DEBUG_BUGS
		if (bh == NULL) {
			printk (KERN_ERR "ide-tape: bh == NULL in idetape_input_buffers\n");
			idetape_discard_data (drive, bcount);
			return;
		}
#endif /* IDETAPE_DEBUG_BUGS */