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Commit 1bc4ccff authored by Alan Cox's avatar Alan Cox Committed by Jeff Garzik
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[PATCH] libata: add a function to decide if we need iordy 



This ought to be simple but for PIO2 we have to poke around the drive
data to get it 100% correct.

Signed-off-by: default avatarJeff Garzik <jgarzik@pobox.com>
parent ffa29456

drivers/scsi/libata-core.c

+34 −0
Original line number Diff line number Diff line
@@ -1168,6 +1168,39 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev, 
	return AC_ERR_OTHER;

}



/**

 *	ata_pio_need_iordy	-	check if iordy needed

 *	@adev: ATA device

 *

 *	Check if the current speed of the device requires IORDY. Used

 *	by various controllers for chip configuration.

 */



unsigned int ata_pio_need_iordy(const struct ata_device *adev)

{

	int pio;

	int speed = adev->pio_mode - XFER_PIO_0;



	if (speed < 2)

		return 0;

	if (speed > 2)

		return 1;

		

	/* If we have no drive specific rule, then PIO 2 is non IORDY */



	if (adev->id[ATA_ID_FIELD_VALID] & 2) {	/* EIDE */

		pio = adev->id[ATA_ID_EIDE_PIO];

		/* Is the speed faster than the drive allows non IORDY ? */

		if (pio) {

			/* This is cycle times not frequency - watch the logic! */

			if (pio > 240)	/* PIO2 is 240nS per cycle */

				return 1;

			return 0;

		}

	}

	return 0;

}



/**

 *	ata_dev_identify - obtain IDENTIFY x DEVICE page

 *	@ap: port on which device we wish to probe resides
@@ -5126,6 +5159,7 @@ EXPORT_SYMBOL_GPL(ata_dev_id_string); 
EXPORT_SYMBOL_GPL(ata_dev_config);

EXPORT_SYMBOL_GPL(ata_scsi_simulate);



EXPORT_SYMBOL_GPL(ata_pio_need_iordy);

EXPORT_SYMBOL_GPL(ata_timing_compute);

EXPORT_SYMBOL_GPL(ata_timing_merge);

include/linux/libata.h

+2 −0
Original line number Diff line number Diff line
@@ -499,6 +499,8 @@ extern int ata_scsi_slave_config(struct scsi_device *sdev); 
/*

 * Timing helpers

 */



extern unsigned int ata_pio_need_iordy(const struct ata_device *);

extern int ata_timing_compute(struct ata_device *, unsigned short,

			      struct ata_timing *, int, int);

extern void ata_timing_merge(const struct ata_timing *,