[PATCH v4 1/9] bloblist: add API to check the register conventions

[Raymond Mao]

Add bloblist_check_reg_conv() to check whether the bloblist is compliant
to the register conventions defined in Firmware Handoff specification.
This API can be used for all Arm platforms.

Signed-off-by: Raymond Mao <raymond....@linaro.org>
---
Changes in v2
- Refactor of bloblist_check_reg_conv().
Changes in v3
- bloblist_check_reg_conv() returns -ENOENT if OF_BOARD is disabled.
Changes in v4
- Add checking of signature register.

 common/bloblist.c  | 14 ++++++++++++++
 include/bloblist.h | 20 ++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/common/bloblist.c b/common/bloblist.c
index 9daf0d2b13..acf67304d0 100644
--- a/common/bloblist.c
+++ b/common/bloblist.c
@@ -542,3 +542,17 @@ int bloblist_maybe_init(void)
 
        return 0;
 }
+
+int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig)
+{
+       if (!IS_ENABLED(CONFIG_OF_BOARD))
+               return -ENOENT;
+
+       if (rzero || rsig != (BLOBLIST_MAGIC | BLOBLIST_REGCONV_VER) ||
+           rfdt != (ulong)bloblist_find(BLOBLISTT_CONTROL_FDT, 0)) {
+               gd->bloblist = NULL;  /* Reset the gd bloblist pointer */
+               return -EIO;
+       }
+
+       return 0;
+}
diff --git a/include/bloblist.h b/include/bloblist.h
index 84fc943819..bf9e12ebf8 100644
--- a/include/bloblist.h
+++ b/include/bloblist.h
@@ -78,6 +78,13 @@ enum {
        BLOBLIST_VERSION        = 1,
        BLOBLIST_MAGIC          = 0x4a0fb10b,
 
+       /*
+        * FIXME:
+        * Register convention version should be placed into a higher byte
+        * https://github.com/FirmwareHandoff/firmware_handoff/issues/32
+        */
+       BLOBLIST_REGCONV_VER    = 1 << 24,
+
        BLOBLIST_BLOB_ALIGN_LOG2 = 3,
        BLOBLIST_BLOB_ALIGN      = 1 << BLOBLIST_BLOB_ALIGN_LOG2,
 
@@ -461,4 +468,17 @@ static inline int bloblist_maybe_init(void)
 }
 #endif /* BLOBLIST */
 
+/**
+ * bloblist_check_reg_conv() - Check whether the bloblist is compliant to
+ *                            the register conventions according to the
+ *                            Firmware Handoff spec.
+ *
+ * @rfdt:  Register that holds the FDT base address.
+ * @rzero: Register that must be zero.
+ * @rsig:  Register that holds signature and register conventions version.
+ * Return: 0 if OK, -EIO if the bloblist is not compliant to the register
+ *        conventions, -ENOENT if OF_BOARD is disabled.
+ */
+int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig);
+
 #endif /* __BLOBLIST_H */
-- 
2.25.1