[PATCH v5 1/8] 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.mao at 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.
Changes in V5
- Drop the dependence on OF_BOARD.

 common/bloblist.c  | 11 +++++++++++
 include/bloblist.h | 20 ++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/common/bloblist.c b/common/bloblist.c
index 2d373910b6..980b1ddbcb 100644
--- a/common/bloblist.c
+++ b/common/bloblist.c
@@ -542,3 +542,14 @@ int bloblist_maybe_init(void)
 
 	return 0;
 }
+
+int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig)
+{
+	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..f7e800f681 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.
+ */
+int bloblist_check_reg_conv(ulong rfdt, ulong rzero, ulong rsig);
+
 #endif /* __BLOBLIST_H */
-- 
2.25.1