[PATCH v7 7/7] fpga: zynqmp: support loading encrypted bitfiles

[Adrian Fiergolski]

Add supporting new compatible string "u-boot,zynqmp-fpga-enc" to handle
loading encrypted bitfiles.

This feature requires encrypted FSBL,as according to UG1085:
"The CSU automatically locks out the AES key, stored in either BBRAM or eFUSEs,
 as a key source to the AES engine if the FSBL is not encrypted. This prevents
 using the BBRAM or eFUSE as the key source to the AES engine during run-time
 applications."

Signed-off-and-tested-by: Adrian Fiergolski <adrian.fiergolski at fastree3d.com>
---
 doc/uImage.FIT/source_file_format.txt |  2 ++
 drivers/fpga/zynqmppl.c               | 14 ++++++++++----
 include/fpga.h                        |  1 +
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/doc/uImage.FIT/source_file_format.txt b/doc/uImage.FIT/source_file_format.txt
index 461e2af2a8..6870111840 100644
--- a/doc/uImage.FIT/source_file_format.txt
+++ b/doc/uImage.FIT/source_file_format.txt
@@ -188,6 +188,8 @@ the '/images' node should have the following layout:
     "u-boot,fpga-legacy" - the generic fpga loading routine.
     "u-boot,zynqmp-fpga-ddrauth" - signed non-encrypted FPGA bitstream for
     Xilinx Zynq UltraScale+ (ZymqMP) device.
+    "u-boot,zynqmp-fpga-enc" - encrypted FPGA bitstream for Xilinx Zynq
+    UltraScale+ (ZynqMP) device.
 
   Optional nodes:
   - hash-1 : Each hash sub-node represents separate hash or checksum
diff --git a/drivers/fpga/zynqmppl.c b/drivers/fpga/zynqmppl.c
index 0ce641e495..1090734936 100644
--- a/drivers/fpga/zynqmppl.c
+++ b/drivers/fpga/zynqmppl.c
@@ -214,7 +214,7 @@ static int zynqmp_load(xilinx_desc **desc_ptr, const void *buf, size_t bsize,
 	fpga_desc *fdesc = container_of((void *)desc_ptr, fpga_desc, devdesc);
 
 	if (fdesc && fdesc->compatible &&
-	    !strcmp(fdesc->compatible, "u-boot,zynqmp-fpga-ddrauth")) {
+	    strncmp(fdesc->compatible, "u-boot,fpga-legacy", 18)) {
 		struct fpga_secure_info info = { 0 };
 
 		if (!CONFIG_IS_ENABLED(FPGA_LOAD_SECURE)) {
@@ -226,9 +226,15 @@ static int zynqmp_load(xilinx_desc **desc_ptr, const void *buf, size_t bsize,
 			printf("%s: Missing load operation\n", __func__);
 			return FPGA_FAIL;
 		}
-		/* DDR authentication */
-		info.authflag = 1;
-		info.encflag = 2;
+		if (!strncmp(fdesc->compatible+19, "enc", 3)) {
+		  /* Encryption using device key */
+		  info.authflag = FPGA_NO_ENC_OR_NO_AUTH;
+		  info.encflag = FPGA_ENC_DEV_KEY;
+		} else {
+		  /* DDR authentication */
+		  info.authflag = ZYNQMP_FPGA_AUTH_DDR;
+		  info.encflag = FPGA_NO_ENC_OR_NO_AUTH;
+		}
 		return desc->operations->loads(desc, buf, bsize, &info);
 	}
 
diff --git a/include/fpga.h b/include/fpga.h
index 2891f32106..cdf80fedf6 100644
--- a/include/fpga.h
+++ b/include/fpga.h
@@ -20,6 +20,7 @@
 /* device numbers must be non-negative */
 #define FPGA_INVALID_DEVICE	-1
 
+#define FPGA_ENC_DEV_KEY	0
 #define FPGA_ENC_USR_KEY	1
 #define FPGA_NO_ENC_OR_NO_AUTH	2
 
-- 
2.35.1