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path: root/drivers/ide/ide-timings.c
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Diffstat (limited to 'drivers/ide/ide-timings.c')
-rw-r--r--drivers/ide/ide-timings.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/ide/ide-timings.c b/drivers/ide/ide-timings.c
index ebef6d4e3f63..8c2f8327f487 100644
--- a/drivers/ide/ide-timings.c
+++ b/drivers/ide/ide-timings.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 1999-2001 Vojtech Pavlik
+ * Copyright (c) 2007-2008 Bartlomiej Zolnierkiewicz
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -75,6 +76,27 @@ struct ide_timing *ide_timing_find_mode(u8 speed)
}
EXPORT_SYMBOL_GPL(ide_timing_find_mode);
+u16 ide_pio_cycle_time(ide_drive_t *drive, u8 pio)
+{
+ struct hd_driveid *id = drive->id;
+ struct ide_timing *t = ide_timing_find_mode(XFER_PIO_0 + pio);
+ u16 cycle = 0;
+
+ if (id->field_valid & 2) {
+ if (id->capability & 8)
+ cycle = id->eide_pio_iordy;
+ else
+ cycle = id->eide_pio;
+
+ /* conservative "downgrade" for all pre-ATA2 drives */
+ if (pio < 3 && cycle < t->cycle)
+ cycle = 0; /* use standard timing */
+ }
+
+ return cycle ? cycle : t->cycle;
+}
+EXPORT_SYMBOL_GPL(ide_pio_cycle_time);
+
#define ENOUGH(v, unit) (((v) - 1) / (unit) + 1)
#define EZ(v, unit) ((v) ? ENOUGH(v, unit) : 0)