Add a function to check an ATA device's id for head unload support as
specified in ATA-7.
Signed-off-by: Elias Oltmanns <eo@xxxxxxxxxxxxxx>
---
include/linux/ata.h | 15 +++++++++++++++
1 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/include/linux/ata.h b/include/linux/ata.h
index cf4ef6d..c92ac10 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -530,6 +530,21 @@ static inline bool ata_id_has_dipm(const u16 *id)
}
+static inline int ata_id_has_unload(const u16 *id)
+{
+ /*
+ * ATA-7 specifies two places to indicate unload feature support.
+ * Since I don't really understand the difference, I'll just check
+ * both and only return zero if none of them indicates otherwise.
+ */
+ if ((id[ATA_ID_CFSSE] & 0xC000) == 0x4000
+ && id[ATA_ID_CFSSE] & (1 << 13))
+ return id[ATA_ID_CFSSE] & (1 << 13);
+ if ((id[ATA_ID_CSF_DEFAULT] & 0xC000) == 0x4000)
+ return id[ATA_ID_CSF_DEFAULT] & (1 << 13);
+ return 0;
+}
+
static inline int ata_id_has_fua(const u16 *id)
{
if ((id[ATA_ID_CFSSE] & 0xC000) != 0x4000)
--
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