ide-floppy.c

讲述linux的初始化过程

#ifdef CONFIG_BLK_DEV_IDEDMA
	if (test_bit (PC_DMA_IN_PROGRESS, &pc->flags)) {
		if (HWIF(drive)->dmaproc(ide_dma_end, drive)) {
			set_bit (PC_DMA_ERROR, &pc->flags);
		} else {
			pc->actually_transferred=pc->request_transfer;
			idefloppy_update_buffers (drive, pc);
		}
#if IDEFLOPPY_DEBUG_LOG
		printk (KERN_INFO "ide-floppy: DMA finished\n");
#endif /* IDEFLOPPY_DEBUG_LOG */
	}
#endif /* CONFIG_BLK_DEV_IDEDMA */

	status.all = GET_STAT();					/* Clear the interrupt */

	if (!status.b.drq) {						/* No more interrupts */
#if IDEFLOPPY_DEBUG_LOG
		printk (KERN_INFO "Packet command completed, %d bytes transferred\n", pc->actually_transferred);
#endif /* IDEFLOPPY_DEBUG_LOG */
		clear_bit (PC_DMA_IN_PROGRESS, &pc->flags);

		ide__sti();	/* local CPU only */

		if (status.b.check || test_bit (PC_DMA_ERROR, &pc->flags)) {	/* Error detected */
#if IDEFLOPPY_DEBUG_LOG
			printk (KERN_INFO "ide-floppy: %s: I/O error\n",drive->name);
#endif /* IDEFLOPPY_DEBUG_LOG */
			rq->errors++;
			if (pc->c[0] == IDEFLOPPY_REQUEST_SENSE_CMD) {
				printk (KERN_ERR "ide-floppy: I/O error in request sense command\n");
				return ide_do_reset (drive);
			}
			idefloppy_retry_pc (drive);				/* Retry operation */
			return ide_stopped; /* queued, but not started */
		}
		pc->error = 0;
		if (floppy->failed_pc == pc)
			floppy->failed_pc=NULL;
		pc->callback(drive);			/* Command finished - Call the callback function */
		return ide_stopped;
	}
#ifdef CONFIG_BLK_DEV_IDEDMA
	if (test_and_clear_bit (PC_DMA_IN_PROGRESS, &pc->flags)) {
		printk (KERN_ERR "ide-floppy: The floppy wants to issue more interrupts in DMA mode\n");
		(void) HWIF(drive)->dmaproc(ide_dma_off, drive);
		return ide_do_reset (drive);
	}
#endif /* CONFIG_BLK_DEV_IDEDMA */
	bcount.b.high=IN_BYTE (IDE_BCOUNTH_REG);			/* Get the number of bytes to transfer */
	bcount.b.low=IN_BYTE (IDE_BCOUNTL_REG);			/* on this interrupt */
	ireason.all=IN_BYTE (IDE_IREASON_REG);

	if (ireason.b.cod) {
		printk (KERN_ERR "ide-floppy: CoD != 0 in idefloppy_pc_intr\n");
		return ide_do_reset (drive);
	}
	if (ireason.b.io == test_bit (PC_WRITING, &pc->flags)) {	/* Hopefully, we will never get here */
		printk (KERN_ERR "ide-floppy: We wanted to %s, ", ireason.b.io ? "Write":"Read");
		printk (KERN_ERR "but the floppy wants us to %s !\n",ireason.b.io ? "Read":"Write");
		return ide_do_reset (drive);
	}
	if (!test_bit (PC_WRITING, &pc->flags)) {			/* Reading - Check that we have enough space */
		temp = pc->actually_transferred + bcount.all;
		if ( temp > pc->request_transfer) {
			if (temp > pc->buffer_size) {
				printk (KERN_ERR "ide-floppy: The floppy wants to send us more data than expected - discarding data\n");
				idefloppy_discard_data (drive,bcount.all);
				ide_set_handler (drive,&idefloppy_pc_intr,IDEFLOPPY_WAIT_CMD, NULL);
				return ide_started;
			}
#if IDEFLOPPY_DEBUG_LOG
			printk (KERN_NOTICE "ide-floppy: The floppy wants to send us more data than expected - allowing transfer\n");
#endif /* IDEFLOPPY_DEBUG_LOG */
		}
	}
	if (test_bit (PC_WRITING, &pc->flags)) {
		if (pc->buffer != NULL)
			atapi_output_bytes (drive,pc->current_position,bcount.all);	/* Write the current buffer */
		else
			idefloppy_output_buffers (drive, pc, bcount.all);
	} else {
		if (pc->buffer != NULL)
			atapi_input_bytes (drive,pc->current_position,bcount.all);	/* Read the current buffer */
		else
			idefloppy_input_buffers (drive, pc, bcount.all);
	}
	pc->actually_transferred+=bcount.all;				/* Update the current position */
	pc->current_position+=bcount.all;

	ide_set_handler (drive,&idefloppy_pc_intr,IDEFLOPPY_WAIT_CMD, NULL);		/* And set the interrupt handler again */
	return ide_started;
}

static ide_startstop_t idefloppy_transfer_pc (ide_drive_t *drive)
{
	ide_startstop_t startstop;
	idefloppy_floppy_t *floppy = drive->driver_data;
	idefloppy_ireason_reg_t ireason;

	if (ide_wait_stat (&startstop,drive,DRQ_STAT,BUSY_STAT,WAIT_READY)) {
		printk (KERN_ERR "ide-floppy: Strange, packet command initiated yet DRQ isn't asserted\n");
		return startstop;
	}
	ireason.all=IN_BYTE (IDE_IREASON_REG);
	if (!ireason.b.cod || ireason.b.io) {
		printk (KERN_ERR "ide-floppy: (IO,CoD) != (0,1) while issuing a packet command\n");
		return ide_do_reset (drive);
	}
	ide_set_handler (drive, &idefloppy_pc_intr, IDEFLOPPY_WAIT_CMD, NULL);	/* Set the interrupt routine */
	atapi_output_bytes (drive, floppy->pc->c, 12);		/* Send the actual packet */
	return ide_started;
}

/*
 *	Issue a packet command
 */
static ide_startstop_t idefloppy_issue_pc (ide_drive_t *drive, idefloppy_pc_t *pc)
{
	idefloppy_floppy_t *floppy = drive->driver_data;
	idefloppy_bcount_reg_t bcount;
	int dma_ok = 0;

#if IDEFLOPPY_DEBUG_BUGS
	if (floppy->pc->c[0] == IDEFLOPPY_REQUEST_SENSE_CMD && pc->c[0] == IDEFLOPPY_REQUEST_SENSE_CMD) {
		printk (KERN_ERR "ide-floppy: possible ide-floppy.c bug - Two request sense in serial were issued\n");
	}
#endif /* IDEFLOPPY_DEBUG_BUGS */

	if (floppy->failed_pc == NULL && pc->c[0] != IDEFLOPPY_REQUEST_SENSE_CMD)
		floppy->failed_pc=pc;
	floppy->pc=pc;							/* Set the current packet command */

	if (pc->retries > IDEFLOPPY_MAX_PC_RETRIES || test_bit (PC_ABORT, &pc->flags)) {
		/*
		 *	We will "abort" retrying a packet command in case
		 *	a legitimate error code was received.
		 */
		if (!test_bit (PC_ABORT, &pc->flags)) {
			printk (KERN_ERR "ide-floppy: %s: I/O error, pc = %2x, key = %2x, asc = %2x, ascq = %2x\n",
				drive->name, pc->c[0], floppy->sense_key, floppy->asc, floppy->ascq);
			pc->error = IDEFLOPPY_ERROR_GENERAL;		/* Giving up */
		}
		floppy->failed_pc=NULL;
		pc->callback(drive);
		return ide_stopped;
	}
#if IDEFLOPPY_DEBUG_LOG
	printk (KERN_INFO "Retry number - %d\n",pc->retries);
#endif /* IDEFLOPPY_DEBUG_LOG */

	pc->retries++;
	pc->actually_transferred=0;					/* We haven't transferred any data yet */
	pc->current_position=pc->buffer;
	bcount.all = IDE_MIN(pc->request_transfer, 63 * 1024);

#ifdef CONFIG_BLK_DEV_IDEDMA
	if (test_and_clear_bit (PC_DMA_ERROR, &pc->flags)) {
		(void) HWIF(drive)->dmaproc(ide_dma_off, drive);
	}
	if (test_bit (PC_DMA_RECOMMENDED, &pc->flags) && drive->using_dma)
		dma_ok=!HWIF(drive)->dmaproc(test_bit (PC_WRITING, &pc->flags) ? ide_dma_write : ide_dma_read, drive);
#endif /* CONFIG_BLK_DEV_IDEDMA */

	if (IDE_CONTROL_REG)
		OUT_BYTE (drive->ctl,IDE_CONTROL_REG);
	OUT_BYTE (dma_ok ? 1:0,IDE_FEATURE_REG);			/* Use PIO/DMA */
	OUT_BYTE (bcount.b.high,IDE_BCOUNTH_REG);
	OUT_BYTE (bcount.b.low,IDE_BCOUNTL_REG);
	OUT_BYTE (drive->select.all,IDE_SELECT_REG);

#ifdef CONFIG_BLK_DEV_IDEDMA
	if (dma_ok) {							/* Begin DMA, if necessary */
		set_bit (PC_DMA_IN_PROGRESS, &pc->flags);
		(void) (HWIF(drive)->dmaproc(ide_dma_begin, drive));
	}
#endif /* CONFIG_BLK_DEV_IDEDMA */

	if (test_bit (IDEFLOPPY_DRQ_INTERRUPT, &floppy->flags)) {
		ide_set_handler (drive, &idefloppy_transfer_pc, IDEFLOPPY_WAIT_CMD, NULL);
		OUT_BYTE (WIN_PACKETCMD, IDE_COMMAND_REG);		/* Issue the packet command */
		return ide_started;
	} else {
		OUT_BYTE (WIN_PACKETCMD, IDE_COMMAND_REG);
		return idefloppy_transfer_pc (drive);
	}
}

static void idefloppy_rw_callback (ide_drive_t *drive)
{
#if IDEFLOPPY_DEBUG_LOG	
	printk (KERN_INFO "ide-floppy: Reached idefloppy_rw_callback\n");
#endif /* IDEFLOPPY_DEBUG_LOG */

	idefloppy_end_request(1, HWGROUP(drive));
	return;
}

static void idefloppy_create_prevent_cmd (idefloppy_pc_t *pc, int prevent)
{
#if IDEFLOPPY_DEBUG_LOG
	printk (KERN_INFO "ide-floppy: creating prevent removal command, prevent = %d\n", prevent);
#endif /* IDEFLOPPY_DEBUG_LOG */

	idefloppy_init_pc (pc);
	pc->c[0] = IDEFLOPPY_PREVENT_REMOVAL_CMD;
	pc->c[4] = prevent;
}

static void idefloppy_create_read_capacity_cmd (idefloppy_pc_t *pc)
{
	idefloppy_init_pc (pc);
	pc->c[0] = IDEFLOPPY_READ_CAPACITY_CMD;
	pc->c[7] = 255;
	pc->c[8] = 255;
	pc->request_transfer = 255;
}

/*
 *	A mode sense command is used to "sense" floppy parameters.
 */
static void idefloppy_create_mode_sense_cmd (idefloppy_pc_t *pc, byte page_code, byte type)
{
	unsigned short length = sizeof (idefloppy_mode_parameter_header_t);
	
	idefloppy_init_pc (pc);
	pc->c[0] = IDEFLOPPY_MODE_SENSE_CMD;
	pc->c[1] = 0;
	pc->c[2] = page_code + (type << 6);

	switch (page_code) {
		case IDEFLOPPY_CAPABILITIES_PAGE:
			length += 12;
			break;
		case IDEFLOPPY_FLEXIBLE_DISK_PAGE:
			length += 32;
			break;
		default:
			printk (KERN_ERR "ide-floppy: unsupported page code in create_mode_sense_cmd\n");
	}
	put_unaligned (htons (length), (unsigned short *) &pc->c[7]);
	pc->request_transfer = length;
}

static void idefloppy_create_start_stop_cmd (idefloppy_pc_t *pc, int start)
{
	idefloppy_init_pc (pc);
	pc->c[0] = IDEFLOPPY_START_STOP_CMD;
	pc->c[4] = start;
}

static void idefloppy_create_test_unit_ready_cmd(idefloppy_pc_t *pc)
{
	idefloppy_init_pc(pc);
	pc->c[0] = IDEFLOPPY_TEST_UNIT_READY_CMD;
}

static void idefloppy_create_rw_cmd (idefloppy_floppy_t *floppy, idefloppy_pc_t *pc, struct request *rq, unsigned long sector)
{
	int block = sector / floppy->bs_factor;
	int blocks = rq->nr_sectors / floppy->bs_factor;
	
#if IDEFLOPPY_DEBUG_LOG
	printk ("create_rw1%d_cmd: block == %d, blocks == %d\n",
		2 * test_bit (IDEFLOPPY_USE_READ12, &floppy->flags), block, blocks);
#endif /* IDEFLOPPY_DEBUG_LOG */

	idefloppy_init_pc (pc);
	if (test_bit (IDEFLOPPY_USE_READ12, &floppy->flags)) {
		pc->c[0] = rq->cmd == READ ? IDEFLOPPY_READ12_CMD : IDEFLOPPY_WRITE12_CMD;
		put_unaligned (htonl (blocks), (unsigned int *) &pc->c[6]);
	} else {
		pc->c[0] = rq->cmd == READ ? IDEFLOPPY_READ10_CMD : IDEFLOPPY_WRITE10_CMD;
		put_unaligned (htons (blocks), (unsigned short *) &pc->c[7]);
	}
	put_unaligned (htonl (block), (unsigned int *) &pc->c[2]);
	pc->callback = &idefloppy_rw_callback;
	pc->rq = rq;
	pc->b_data = rq->buffer;
	pc->b_count = rq->cmd == READ ? 0 : rq->bh->b_size;
	if (rq->cmd == WRITE)
		set_bit (PC_WRITING, &pc->flags);
	pc->buffer = NULL;
	pc->request_transfer = pc->buffer_size = blocks * floppy->block_size;
	set_bit (PC_DMA_RECOMMENDED, &pc->flags);
}

/*
 *	idefloppy_do_request is our request handling function.	
 */
static ide_startstop_t idefloppy_do_request (ide_drive_t *drive, struct request *rq, unsigned long block)
{
	idefloppy_floppy_t *floppy = drive->driver_data;
	idefloppy_pc_t *pc;

#if IDEFLOPPY_DEBUG_LOG
	printk (KERN_INFO "rq_status: %d, rq_dev: %u, cmd: %d, errors: %d\n",rq->rq_status,(unsigned int) rq->rq_dev,rq->cmd,rq->errors);
	printk (KERN_INFO "sector: %ld, nr_sectors: %ld, current_nr_sectors: %ld\n",rq->sector,rq->nr_sectors,rq->current_nr_sectors);
#endif /* IDEFLOPPY_DEBUG_LOG */

	if (rq->errors >= ERROR_MAX) {
		if (floppy->failed_pc != NULL)
			printk (KERN_ERR "ide-floppy: %s: I/O error, pc = %2x, key = %2x, asc = %2x, ascq = %2x\n",
				drive->name, floppy->failed_pc->c[0], floppy->sense_key, floppy->asc, floppy->ascq);
		else
			printk (KERN_ERR "ide-floppy: %s: I/O error\n", drive->name);
		idefloppy_end_request (0, HWGROUP(drive));
		return ide_stopped;
	}
	switch (rq->cmd) {
		case READ:
		case WRITE:
			if (rq->sector % floppy->bs_factor || rq->nr_sectors % floppy->bs_factor) {
				printk ("%s: unsupported r/w request size\n", drive->name);
				idefloppy_end_request (0, HWGROUP(drive));
				return ide_stopped;
			}
			pc = idefloppy_next_pc_storage (drive);
			idefloppy_create_rw_cmd (floppy, pc, rq, block);
			break;
		case IDEFLOPPY_PC_RQ:
			pc = (idefloppy_pc_t *) rq->buffer;
			break;
		default:
			printk (KERN_ERR "ide-floppy: unsupported command %x in request queue\n", rq->cmd);
			idefloppy_end_request (0,HWGROUP (drive));
			return ide_stopped;
	}
	pc->rq = rq;
	return idefloppy_issue_pc (drive, pc);
}

/*
 *	idefloppy_queue_pc_tail adds a special packet command request to the
 *	tail of the request queue, and waits for it to be serviced.
 */
static int idefloppy_queue_pc_tail (ide_drive_t *drive,idefloppy_pc_t *pc)
{
	struct request rq;

	ide_init_drive_cmd (&rq);
	rq.buffer = (char *) pc;
	rq.cmd = IDEFLOPPY_PC_RQ;
	return ide_do_drive_cmd (drive, &rq, ide_wait);
}

/*
 *	Look at the flexible disk page parameters. We will ignore the CHS
 *	capacity parameters and use the LBA parameters instead.
 */
static int idefloppy_get_flexible_disk_page (ide_drive_t *drive)
{
	idefloppy_floppy_t *floppy = drive->driver_data;
	idefloppy_pc_t pc;
	idefloppy_mode_parameter_header_t *header;
	idefloppy_flexible_disk_page_t *page;
	int capacity, lba_capacity;

	idefloppy_create_mode_sense_cmd (&pc, IDEFLOPPY_FLEXIBLE_DISK_PAGE, MODE_SENSE_CURRENT);
	if (idefloppy_queue_pc_tail (drive,&pc)) {
		printk (KERN_ERR "ide-floppy: Can't get flexible disk page parameters\n");
		return 1;
	}
	header = (idefloppy_mode_parameter_header_t *) pc.buffer;
	floppy->wp = header->wp;
	page = (idefloppy_flexible_disk_page_t *) (header + 1);

	page->transfer_rate = ntohs (page->transfer_rate);
	page->sector_size = ntohs (page->sector_size);
	page->cyls = ntohs (page->cyls);
	page->rpm = ntohs (page->rpm);
	capacity = page->cyls * page->heads * page->sectors * page->sector_size;
	if (memcmp (page, &floppy->flexible_disk_page, sizeof (idefloppy_flexible_disk_page_t)))
		printk (KERN_INFO "%s: %dkB, %d/%d/%d CHS, %d kBps, %d sector size, %d rpm\n",
			drive->name, capacity / 1024, page->cyls, page->heads, page->sectors,
			page->transfer_rate / 8, page->sector_size, page->rpm);

	floppy->flexible_disk_page = *page;
	drive->bios_cyl = page->cyls;
	drive->bios_head = page->heads;
	drive->bios_sect = page->sectors;
	lba_capacity = floppy->blocks * floppy->block_size;
	if (capacity < lba_capacity) {
		printk (KERN_NOTICE "%s: The disk reports a capacity of %d bytes, "
			"but the drive only handles %d\n",
			drive->name, lba_capacity, capacity);
		floppy->blocks = floppy->block_size ? capacity / floppy->block_size : 0;
	}
	return 0;
}

/*
 *	Determine if a media is present in the floppy drive, and if so,
 *	its LBA capacity.
 */
static int idefloppy_get_capacity (ide_drive_t *drive)
{
	idefloppy_floppy_t *floppy = drive->driver_data;
	idefloppy_pc_t pc;
	idefloppy_capacity_header_t *header;
	idefloppy_capacity_descriptor_t *descriptor;
	int i, descriptors, rc = 1, blocks, length;
	
	drive->bios_cyl = 0;
	drive->bios_head = drive->bios_sect = 0;
	floppy->blocks = floppy->bs_factor = 0;
	drive->part[0].nr_sects = 0;

	idefloppy_create_read_capacity_cmd (&pc);
	if (idefloppy_queue_pc_tail (drive, &pc)) {
		printk (KERN_ERR "ide-floppy: Can't get floppy parameters\n");
		return 1;
	}
	header = (idefloppy_capacity_header_t *) pc.buffer;
	descriptors = header->length / sizeof (idefloppy_capacity_descriptor_t);
	descriptor = (idefloppy_capacity_descriptor_t *) (header + 1);
	for (i = 0; i < descriptors; i++, descriptor++) {
		blocks = descriptor->blocks = ntohl (descriptor->blocks);
		length = descriptor->length = ntohs (descriptor->length);
		if (!i && descriptor->dc == CAPACITY_CURRENT) {
			if (memcmp (descriptor, &floppy->capacity, sizeof (idefloppy_capacity_descriptor_t))) {
				printk (KERN_INFO "%s: %dkB, %d blocks, %d sector size, %s \n",
					drive->name, blocks * length / 1024, blocks, length,