Hello.
Elias Oltmanns wrote:
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>
[...]
diff --git a/include/linux/ata.h b/include/linux/ata.h
index 80364b6..d9a94bd 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -707,6 +707,23 @@ static inline int ata_id_has_dword_io(const u16 *id)
return 0;
}
+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 you read the comments to the words 82:84 and 85:87, they say that
the former indicate the supported features, and the latter indicate the
enabed features AND in case a feature can't be disabled, the latter
words will have the corresponding bit set. So it should be sufficient to
check only one word.
+ */
+ if (ata_id_major_version(id) >= 7
+ && (((id[ATA_ID_CFSSE] & 0xC000) == 0x4000
+ && id[ATA_ID_CFSSE] & (1 << 13))
+ || ((id[ATA_ID_CSF_DEFAULT] & 0xC000) == 0x4000
+ && (id[ATA_ID_CSF_DEFAULT] & (1 << 13)))))
I think that it's preferrable to leave the operator on the same line
with the first operand...
WBR, Sergei
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