libata: check for trusted computing in IDENTIFY DEVICE data

ATA-8 and later mirrors the TRUSTED COMPUTING SUPPORTED bit in word 48 of
the IDENTIFY DEVICE data.  Check this before issuing a READ LOG PAGE
command to avoid issues with buggy devices.  The only downside is that
we can't support Security Send / Receive for a device with an older
revision due to the conflicting use of this field in earlier
specifications.

tj: The reason we need this is because some devices which don't
    support READ LOG PAGE lock up after getting issued that command.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

2 files changed, 12 insertions, 1 deletions

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 697f5f896b19..ca57b03ab950 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2413,6 +2413,9 @@ static void ata_dev_config_trusted(struct ata_device *dev)
         u64 trusted_cap;
         unsigned int err;
 
+        if (!ata_id_has_trusted(dev->id))
+                return;
+
         if (!ata_identify_page_supported(dev, ATA_LOG_SECURITY)) {
                 ata_dev_warn(dev,
                              "Security Log not supported\n");
diff --git a/include/linux/ata.h b/include/linux/ata.h
index e65ae4b2ed48..c7a353825450 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -60,7 +60,8 @@ enum {
         ATA_ID_FW_REV           = 23,
         ATA_ID_PROD             = 27,
         ATA_ID_MAX_MULTSECT     = 47,
-        ATA_ID_DWORD_IO         = 48,
+        ATA_ID_DWORD_IO         = 48,   /* before ATA-8 */
+        ATA_ID_TRUSTED          = 48,   /* ATA-8 and later */
         ATA_ID_CAPABILITY       = 49,
         ATA_ID_OLD_PIO_MODES    = 51,
         ATA_ID_OLD_DMA_MODES    = 52,
@@ -889,6 +890,13 @@ static inline bool ata_id_has_dword_io(const u16 *id)
         return id[ATA_ID_DWORD_IO] & (1 << 0);
 }
 
+static inline bool ata_id_has_trusted(const u16 *id)
+{
+        if (ata_id_major_version(id) <= 7)
+                return false;
+        return id[ATA_ID_TRUSTED] & (1 << 0);
+}
+
 static inline bool ata_id_has_unload(const u16 *id)
 {
         if (ata_id_major_version(id) >= 7 &&