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| author | Alan Cox <alan@lxorguk.ukuu.org.uk> | 2006-01-09 17:18:14 +0000 |
|---|---|---|
| committer | Jeff Garzik <jgarzik@pobox.com> | 2006-01-17 08:25:39 -0500 |
| commit | 1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9 (patch) | |
| tree | 03bd5a2d64c52dff3c68a66e37f43b4109854170 /drivers/scsi | |
| parent | ffa29456cd316a5394cdd489de5af3bf87d3c485 (diff) | |
| download | linux-1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9.tar.gz linux-1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9.tar.bz2 linux-1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9.zip | |
[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: Jeff Garzik <jgarzik@pobox.com>
Diffstat (limited to 'drivers/scsi')
| -rw-r--r-- | drivers/scsi/libata-core.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index bc48d88fef5a..b42acbe0e9a5 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -1169,6 +1169,39 @@ ata_exec_internal(struct ata_port *ap, struct ata_device *dev, } /** + * 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 * @device: device bus address, starting at zero @@ -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); |