tpm: lookup the the TPM interface instead of TIS device

This will allow to introduce new devices implementing TPM.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>

hw/i386/acpi-build.c

@@ -208,7 +208,7 @@ static void acpi_get_misc_info(AcpiMiscInfo *info)
     }
 
     info->has_hpet = hpet_find();
-    info->tpm_version = tpm_get_version();
+    info->tpm_version = tpm_get_version(tpm_find());
     info->pvpanic_port = pvpanic_port();
     info->applesmc_io_base = applesmc_port();
 }

include/sysemu/tpm.h

@@ -19,7 +19,7 @@ int tpm_config_parse(QemuOptsList *opts_list, const char *optarg);
 int tpm_init(void);
 void tpm_cleanup(void);
 
-typedef enum  TPMVersion {
+typedef enum TPMVersion {
     TPM_VERSION_UNSPEC = 0,
     TPM_VERSION_1_2 = 1,
     TPM_VERSION_2_0 = 2,
@@ -44,20 +44,25 @@ typedef struct TPMIfClass {
     void (*request_completed)(TPMIf *obj);
 } TPMIfClass;
 
-TPMVersion tpm_tis_get_tpm_version(Object *obj);
-
 #define TYPE_TPM_TIS                "tpm-tis"
 
-static inline TPMVersion tpm_get_version(void)
+/* returns NULL unless there is exactly one TPM device */
+static inline TPMIf *tpm_find(void)
 {
-#ifdef CONFIG_TPM
-    Object *obj = object_resolve_path_type("", TYPE_TPM_TIS, NULL);
+    Object *obj = object_resolve_path_type("", TYPE_TPM_IF, NULL);
+
+    return TPM_IF(obj);
+}
 
-    if (obj) {
-        return tpm_tis_get_tpm_version(obj);
+TPMVersion tpm_tis_get_tpm_version(Object *obj);
+
+static inline TPMVersion tpm_get_version(TPMIf *ti)
+{
+    if (!ti) {
+        return TPM_VERSION_UNSPEC;
     }
-#endif
-    return TPM_VERSION_UNSPEC;
+
+    return tpm_tis_get_tpm_version(OBJECT(ti));
 }
 
 #endif /* QEMU_TPM_H */