[PATCH v2 16/16] ARM: tegra20: implement BCT patching

[Svyatoslav Ryhel]

This function allows updating bootloader from u-boot
on production devices without need in host PC.

Be aware! It works only with re-crypt BCT.

Tested-by: Robert Eckelmann <longnoserob at gmail.com> # ASUS TF101 T20
Signed-off-by: Ramin Khonsari <raminterex at yahoo.com>
Signed-off-by: Svyatoslav Ryhel <clamor95 at gmail.com>
---
 arch/arm/mach-tegra/Kconfig          |  2 +-
 arch/arm/mach-tegra/tegra20/Makefile |  5 +-
 arch/arm/mach-tegra/tegra20/bct.c    | 78 ++++++++++++++++++++++++++++
 arch/arm/mach-tegra/tegra20/bct.h    | 42 +++++++++++++++
 4 files changed, 123 insertions(+), 4 deletions(-)
 create mode 100644 arch/arm/mach-tegra/tegra20/bct.c
 create mode 100644 arch/arm/mach-tegra/tegra20/bct.h

diff --git a/arch/arm/mach-tegra/Kconfig b/arch/arm/mach-tegra/Kconfig
index 922e57726f..901235047c 100644
--- a/arch/arm/mach-tegra/Kconfig
+++ b/arch/arm/mach-tegra/Kconfig
@@ -231,7 +231,7 @@ config CMD_ENTERRCM
 
 config CMD_EBTUPDATE
 	bool "Enable 'ebtupdate' command"
-	depends on TEGRA30
+	depends on TEGRA20 || TEGRA30
 	select TEGRA_CRYPTO
 	default n
 	help
diff --git a/arch/arm/mach-tegra/tegra20/Makefile b/arch/arm/mach-tegra/tegra20/Makefile
index 67454ff5f4..991cabeec5 100644
--- a/arch/arm/mach-tegra/tegra20/Makefile
+++ b/arch/arm/mach-tegra/tegra20/Makefile
@@ -2,9 +2,8 @@
 #
 # (C) Copyright 2010,2011 Nvidia Corporation.
 
-ifdef CONFIG_SPL_BUILD
-obj-y	+= cpu.o
-endif
+obj-$(CONFIG_SPL_BUILD) += cpu.o
+obj-$(CONFIG_$(SPL_)CMD_EBTUPDATE) += bct.o
 
 # The AVP is ARMv4T architecture so we must use special compiler
 # flags for any startup files it might use.
diff --git a/arch/arm/mach-tegra/tegra20/bct.c b/arch/arm/mach-tegra/tegra20/bct.c
new file mode 100644
index 0000000000..4a7cf498dd
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra20/bct.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022, Ramin <raminterex at yahoo.com>
+ * Copyright (c) 2022, Svyatoslav Ryhel <clamor95 at gmail.com>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <log.h>
+#include <asm/arch-tegra/crypto.h>
+#include "bct.h"
+#include "uboot_aes.h"
+
+/*
+ * \param bct		boot config table start in RAM
+ * \param ect		bootloader start in RAM
+ * \param ebt_size	bootloader file size in bytes
+ */
+static int bct_patch(u8 *bct, u8 *ebt, u32 ebt_size)
+{
+	struct nvboot_config_table *bct_tbl = NULL;
+	u8 ebt_hash[AES128_KEY_LENGTH] = { 0 };
+	u8 sbk[AES128_KEY_LENGTH] = { 0 };
+	u8 *bct_hash = bct;
+	int ret;
+
+	bct += BCT_HASH;
+
+	memcpy(sbk, (u8 *)(bct + BCT_LENGTH),
+	       NVBOOT_CMAC_AES_HASH_LENGTH * 4);
+
+	ret = decrypt_data_block(bct, BCT_LENGTH, sbk);
+	if (ret)
+		return 1;
+
+	ebt_size = roundup(ebt_size, EBT_ALIGNMENT);
+
+	ret = encrypt_data_block(ebt, ebt_size, sbk);
+	if (ret)
+		return 1;
+
+	ret = sign_enc_data_block(ebt, ebt_size, ebt_hash, sbk);
+	if (ret)
+		return 1;
+
+	bct_tbl = (struct nvboot_config_table *)bct;
+
+	memcpy((u8 *)&bct_tbl->bootloader[0].crypto_hash,
+	       ebt_hash, NVBOOT_CMAC_AES_HASH_LENGTH * 4);
+	bct_tbl->bootloader[0].entry_point = CONFIG_SPL_TEXT_BASE;
+	bct_tbl->bootloader[0].load_addr = CONFIG_SPL_TEXT_BASE;
+	bct_tbl->bootloader[0].length = ebt_size;
+
+	ret = encrypt_data_block(bct, BCT_LENGTH, sbk);
+	if (ret)
+		return 1;
+
+	ret = sign_enc_data_block(bct, BCT_LENGTH, bct_hash, sbk);
+	if (ret)
+		return 1;
+
+	return 0;
+}
+
+static int do_ebtupdate(struct cmd_tbl *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	u32 bct_addr = hextoul(argv[1], NULL);
+	u32 ebt_addr = hextoul(argv[2], NULL);
+	u32 ebt_size = hextoul(argv[3], NULL);
+
+	return bct_patch((u8 *)bct_addr, (u8 *)ebt_addr, ebt_size);
+}
+
+U_BOOT_CMD(ebtupdate,	4,	0,	do_ebtupdate,
+	   "update bootloader on re-crypted Tegra20 devices",
+	   ""
+);
diff --git a/arch/arm/mach-tegra/tegra20/bct.h b/arch/arm/mach-tegra/tegra20/bct.h
new file mode 100644
index 0000000000..4b78aef7cf
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra20/bct.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef _BCT_H_
+#define _BCT_H_
+
+/*
+ * Defines the BCT parametres for T20
+ */
+#define BCT_LENGTH		0xFE0
+#define BCT_HASH		0x10
+#define EBT_ALIGNMENT		0x10
+
+/*
+ * Defines the CMAC-AES-128 hash length in 32 bit words. (128 bits = 4 words)
+ */
+#define NVBOOT_CMAC_AES_HASH_LENGTH		4
+
+/*
+ * Defines the maximum number of bootloader descriptions in the BCT.
+ */
+#define NVBOOT_MAX_BOOTLOADERS			4
+
+struct nv_bootloader_info {
+	u32 version;
+	u32 start_blk;
+	u32 start_page;
+	u32 length;
+	u32 load_addr;
+	u32 entry_point;
+	u32 attribute;
+	u32 crypto_hash[NVBOOT_CMAC_AES_HASH_LENGTH];
+};
+
+struct nvboot_config_table {
+	u32 unused0[4];
+	u32 boot_data_version;
+	u32 unused1[668];
+	struct nv_bootloader_info bootloader[NVBOOT_MAX_BOOTLOADERS];
+	u32 unused2[508];
+};
+
+#endif /* _BCT_H_ */
-- 
2.37.2