platform/x86/intel/sdsi: Add in-band BIOS lock support

As per SDSi in-band interface specification, sec titled "BIOS lock for
in-band provisioning", when IB_LOCK bit is set in control qword, the
SDSI agent is only allowed to perform the read flow, but not allowed to
provision license blob or license key. So add check for it in
sdsi_provision().

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240411025856.2782476-4-david.e.box@linux.intel.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/platform/x86/intel/sdsi.c b/drivers/platform/x86/intel/sdsi.c
index d80c2dc0ce712f20e139b3a4582397d38855e988..bb3eaf5eb382c2bba4a5e246c11da99aa9dc0a7d 100644 (file)
--- a/drivers/platform/x86/intel/sdsi.c
+++ b/drivers/platform/x86/intel/sdsi.c
@@ -67,6 +67,7 @@
 #define CTRL_OWNER                     GENMASK(5, 4)
 #define CTRL_COMPLETE                  BIT(6)
 #define CTRL_READY                     BIT(7)
+#define CTRL_INBAND_LOCK               BIT(32)
 #define CTRL_STATUS                    GENMASK(15, 8)
 #define CTRL_PACKET_SIZE               GENMASK(31, 16)
 #define CTRL_MSG_SIZE                  GENMASK(63, 48)
@@ -346,6 +347,11 @@ static int sdsi_mbox_read(struct sdsi_priv *priv, struct sdsi_mbox_info *info, s
        return sdsi_mbox_cmd_read(priv, info, data_size);
 }
 
+static bool sdsi_ib_locked(struct sdsi_priv *priv)
+{
+       return !!FIELD_GET(CTRL_INBAND_LOCK, readq(priv->control_addr));
+}
+
 static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
                              enum sdsi_command command)
 {
@@ -355,6 +361,10 @@ static ssize_t sdsi_provision(struct sdsi_priv *priv, char *buf, size_t count,
        if (count > (SDSI_SIZE_WRITE_MSG - SDSI_SIZE_CMD))
                return -EOVERFLOW;
 
+       /* Make sure In-band lock is not set */
+       if (sdsi_ib_locked(priv))
+               return -EPERM;
+
        /* Qword aligned message + command qword */
        info.size = round_up(count, SDSI_SIZE_CMD) + SDSI_SIZE_CMD;