[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>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index bc48d88..b42acbe0 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1169,6 +1169,39 @@
}
/**
+ * 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_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);