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authorAlan Cox <alan@lxorguk.ukuu.org.uk>2006-01-09 17:18:14 +0000
committerJeff Garzik <jgarzik@pobox.com>2006-01-17 08:25:39 -0500
commit1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9 (patch)
tree03bd5a2d64c52dff3c68a66e37f43b4109854170 /drivers
parentffa29456cd316a5394cdd489de5af3bf87d3c485 (diff)
[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')
-rw-r--r--drivers/scsi/libata-core.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index bc48d88fef5..b42acbe0e9a 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);