hdata/tpmrel: detect tpm not present by looking up the stinfo->status

Skiboot detects if tpm is present by checking if a secureboot_tpm_info
entry exists. However, if a tpm is not present, hostboot also creates a
secureboot_tpm_info entry. In this case, hostboot creates an empty
entry, but setting the field tpm_status to TPM_NOT_PRESENT.

This detects if tpm is not present by looking up the stinfo->status.

This fixes the "TPMREL: TPM node not found for chip_id=0 (HB bug)"
issue, reproduced when skiboot is running on a system that has no tpm.

Signed-off-by: Claudio Carvalho <cclaudio@linux.vnet.ibm.com>
Tested-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

hdata/tpmrel.c

@@ -59,6 +59,14 @@ static void tpmrel_add_firmware_event_log(const struct HDIF_common_hdr *hdif_hdr
 					      TPMREL_IDATA_SECUREBOOT_TPM_INFO,
 					      i, NULL);
 
+		/*
+		 * If tpm is not present, hostboot creates an empty
+		 * secureboot_tpm_info entry, but setting
+		 * tpm_status=TPM_NOT_PRESENT
+		 */
+		if (stinfo->tpm_status == TPM_NOT_PRESENT)
+			continue;
+
 		xscom = find_xscom_for_chip(be32_to_cpu(stinfo->chip_id));
 		if (xscom) {
 			dt_for_each_node(xscom, node) {