ARM: tegra124: implement BCT patching

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 and AES
encrypted devices.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

arch/arm/mach-tegra/Kconfig

@@ -247,7 +247,7 @@ config CMD_ENTERRCM
 
 config CMD_EBTUPDATE
 	bool "Enable 'ebtupdate' command"
-	depends on TEGRA20 || TEGRA30
+	depends on TEGRA20 || TEGRA30 || TEGRA124
 	select TEGRA_CRYPTO
 	help
 	  Updating u-boot from within u-boot in rather complex or even

arch/arm/mach-tegra/tegra124/Makefile

@@ -6,6 +6,7 @@
 #
 
 obj-$(CONFIG_XPL_BUILD) += cpu.o
+obj-$(CONFIG_$(XPL_)CMD_EBTUPDATE) += bct.o
 
 obj-y	+= clock.o
 obj-y	+= pmc.o

arch/arm/mach-tegra/tegra124/bct.c

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022, Ramin <raminterex@yahoo.com>
+ * Copyright (c) 2022, Svyatoslav Ryhel <clamor95@gmail.com>
+ */
+
+#include <command.h>
+#include <log.h>
+#include <vsprintf.h>
+#include <asm/arch-tegra/crypto.h>
+#include "bct.h"
+#include "uboot_aes.h"
+
+/* Device with "sbk burned: false" will expose zero key */
+const u8 nosbk[AES128_KEY_LENGTH] = { 0 };
+
+/*
+ * @param  bct		boot config table start in RAM
+ * @param  ect		bootloader start in RAM
+ * @param  ebt_size	bootloader file size in bytes
+ * Return: 0, or 1 if failed
+ */
+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 bct_hash[AES128_KEY_LENGTH] = { 0 };
+	u8 sbk[AES128_KEY_LENGTH] = { 0 };
+	u8 *sbct = bct + UBCT_LENGTH;
+	bool encrypted;
+	int ret;
+
+	ebt_size = roundup(ebt_size, EBT_ALIGNMENT);
+
+	memcpy(sbk, (u8 *)(bct + UBCT_LENGTH + SBCT_LENGTH),
+	       NVBOOT_CMAC_AES_HASH_LENGTH * 4);
+
+	encrypted = memcmp(&sbk, &nosbk, AES128_KEY_LENGTH);
+
+	if (encrypted) {
+		ret = decrypt_data_block(sbct, SBCT_LENGTH, sbk);
+		if (ret)
+			return 1;
+
+		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;
+
+	if (encrypted) {
+		ret = encrypt_data_block(sbct, SBCT_LENGTH, sbk);
+		if (ret)
+			return 1;
+	}
+
+	ret = sign_enc_data_block(sbct, SBCT_LENGTH, bct_hash, sbk);
+	if (ret)
+		return 1;
+
+	memcpy((u8 *)&bct_tbl->crypto_hash, bct_hash,
+	       NVBOOT_CMAC_AES_HASH_LENGTH * 4);
+
+	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 Tegra124 devices",
+	   ""
+);

arch/arm/mach-tegra/tegra124/bct.h

@@ -0,0 +1,55 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef _BCT_H_
+#define _BCT_H_
+
+/*
+ * Defines the BCT parametres for T124
+ */
+#define UBCT_LENGTH		0x6b0  /* bytes */
+#define SBCT_LENGTH		0x1950 /* bytes */
+
+#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 RSA modulus length in 32 bit words used for PKC secure boot.
+ */
+#define NVBOOT_SE_RSA_MODULUS_LENGTH		64
+
+/*
+ * 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;
+
+	/* Specifies the AES-CMAC MAC or RSASSA-PSS signature of the BL. */
+	u32 crypto_hash[NVBOOT_CMAC_AES_HASH_LENGTH];
+	u32 bl_rsa_sig[NVBOOT_SE_RSA_MODULUS_LENGTH];
+};
+
+struct nvboot_config_table {
+	u32 ubct_unused1[196];
+	u32 crypto_hash[NVBOOT_CMAC_AES_HASH_LENGTH];
+	u32 ubct_unused2[228];
+
+	u32 sbct_unused1[1318];
+	u32 bootloader_used;
+	struct nv_bootloader_info bootloader[NVBOOT_MAX_BOOTLOADERS];
+	u32 sbct_unused2;
+};
+
+#endif /* _BCT_H_ */