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[PATCH] libata: add a function to decide if we need iordy

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

Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
This commit is contained in:
Alan Cox
2006-01-09 17:18:14 +00:00
committed by Jeff Garzik
parent ffa29456cd
commit 1bc4ccfff8
2 changed files with 36 additions and 0 deletions
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34
drivers/scsi/libata-core.c
View File

@ -1168,6 +1168,39 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev,
return AC_ERR_OTHER; 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 * ata_dev_identify - obtain IDENTIFY x DEVICE page
* @ap: port on which device we wish to probe resides * @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_dev_config);
EXPORT_SYMBOL_GPL(ata_scsi_simulate); EXPORT_SYMBOL_GPL(ata_scsi_simulate);
EXPORT_SYMBOL_GPL(ata_pio_need_iordy);
EXPORT_SYMBOL_GPL(ata_timing_compute); EXPORT_SYMBOL_GPL(ata_timing_compute);
EXPORT_SYMBOL_GPL(ata_timing_merge); EXPORT_SYMBOL_GPL(ata_timing_merge);

2
include/linux/libata.h
View File

@ -499,6 +499,8 @@ extern int ata_scsi_slave_config(struct scsi_device *sdev);
/* /*
* Timing helpers * Timing helpers
*/ */
extern unsigned int ata_pio_need_iordy(const struct ata_device *);
extern int ata_timing_compute(struct ata_device *, unsigned short, extern int ata_timing_compute(struct ata_device *, unsigned short,
struct ata_timing *, int, int); struct ata_timing *, int, int);
extern void ata_timing_merge(const struct ata_timing *, extern void ata_timing_merge(const struct ata_timing *,