From 1bc4ccfff8675adc3d96f91245eb7e2dc0043ca9 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
Date: Mon, 9 Jan 2006 17:18:14 +0000
Subject: [PATCH] [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>
---
drivers/scsi/libata-core.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/libata.h | 2 ++
2 files changed, 36 insertions(+)
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index bc48d88fef5a3..b42acbe0e9a5e 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -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);
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a43c95f8f968b..af6624450f653 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -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 *,
--
2.30.2