ata: add ata_id_pio_need_iordy() helper (v2)

v2:
Minor fixes per Sergei's review.

Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/ata.h b/include/linux/ata.h
index 915da43edee1..9c75921f0c16 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -800,6 +800,20 @@ static inline int ata_id_is_ssd(const u16 *id)
         return id[ATA_ID_ROT_SPEED] == 0x01;
 }
 
+static inline int ata_id_pio_need_iordy(const u16 *id, const u8 pio)
+{
+        /* CF spec. r4.1 Table 22 says no IORDY on PIO5 and PIO6. */
+        if (pio > 4 && ata_id_is_cfa(id))
+                return 0;
+        /* For PIO3 and higher it is mandatory. */
+        if (pio > 2)
+                return 1;
+        /* Turn it on when possible. */
+        if (ata_id_has_iordy(id))
+                return 1;
+        return 0;
+}
+
 static inline int ata_drive_40wire(const u16 *dev_id)
 {
         if (ata_id_is_sata(dev_id))