[U-Boot] [RFC 5/9] arm: omap5: add secure ROM signature verify API

[Andreas Dannenberg]

From: Daniel Allred <d-allred at ti.com>

Adds an API that verifies a signature attached to an image (binary
blob). This API is basically a entry to a secure ROM service provided by
the device and accessed via an SMC call, using a particular calling
convention.

Signed-off-by: Daniel Allred <d-allred at ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg at ti.com>
---
 arch/arm/cpu/armv7/omap5/Makefile           |  1 +
 arch/arm/cpu/armv7/omap5/sec_fxns.c         | 70 +++++++++++++++++++++++++++++
 arch/arm/include/asm/arch-omap5/sys_proto.h |  4 ++
 3 files changed, 75 insertions(+)
 create mode 100644 arch/arm/cpu/armv7/omap5/sec_fxns.c

diff --git a/arch/arm/cpu/armv7/omap5/Makefile b/arch/arm/cpu/armv7/omap5/Makefile
index 3caba86..d373bf4 100644
--- a/arch/arm/cpu/armv7/omap5/Makefile
+++ b/arch/arm/cpu/armv7/omap5/Makefile
@@ -14,3 +14,4 @@ obj-y	+= hw_data.o
 obj-y	+= abb.o
 obj-y	+= fdt.o
 obj-$(CONFIG_IODELAY_RECALIBRATION) += dra7xx_iodelay.o
+obj-$(CONFIG_TI_SECURE_DEVICE) += sec_fxns.o
diff --git a/arch/arm/cpu/armv7/omap5/sec_fxns.c b/arch/arm/cpu/armv7/omap5/sec_fxns.c
new file mode 100644
index 0000000..766333a
--- /dev/null
+++ b/arch/arm/cpu/armv7/omap5/sec_fxns.c
@@ -0,0 +1,70 @@
+/*
+ *
+ * Common security functions that rely on secure ROM services
+ *
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Daniel Allred    <d-allred at ti.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/arch/sys_proto.h>
+#include <asm/omap_common.h>
+
+#define SIGNATURE_LENGTH				(0x118)
+
+/* API Index for OMAP5, DRA7xx */
+#define API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX	(0x0000000E)
+
+int secure_boot_verify_image(void **image, size_t *size)
+{
+	int result = 1;
+	u32 cert_addr, sig_addr;
+	size_t cert_size;
+
+#ifndef CONFIG_SYS_DCACHE_OFF
+	/* Perform cache writeback on input buffer */
+	flush_dcache_range(
+		(u32)*image,
+		(u32)*image + roundup(*size, ARCH_DMA_MINALIGN));
+#endif
+	cert_addr = (uint32_t)*image;
+	*size -= SIGNATURE_LENGTH;   /* Subtract out the signature size */
+	cert_size = *size;
+	sig_addr = cert_addr + cert_size;
+
+	/* Check if image load address is 32-bit aligned */
+	if (0 != (0x3 & cert_addr)) {
+		puts("Image is not 4-byte aligned.\n");
+		result = 1;
+		goto auth_exit;
+	}
+
+	/* Image size also should be multiple of 4 */
+	if (0 != (0x3 & cert_size)) {
+		puts("Image size is not 4-byte aligned.\n");
+		result = 1;
+		goto auth_exit;
+	}
+
+	/* Call ROM HAL API to verify certificate signature */
+	debug("%s: load_addr = %x, size = %x, sig_addr = %x\n", __func__,
+	      cert_addr, cert_size, sig_addr);
+
+	result = secure_rom_call(
+		API_HAL_KM_VERIFYCERTIFICATESIGNATURE_INDEX, 0, 0,
+		4, cert_addr, cert_size, sig_addr, 0xFFFFFFFF);
+auth_exit:
+	if (result != 0) {
+		puts("Authentication failed!\n");
+		printf("Return Value = %08X\n", result);
+		hang();
+	}
+
+	printf("Authentication passed: %s\n", (char *)sig_addr);
+
+	return result;
+}
diff --git a/arch/arm/include/asm/arch-omap5/sys_proto.h b/arch/arm/include/asm/arch-omap5/sys_proto.h
index ab0e7fa..b175124 100644
--- a/arch/arm/include/asm/arch-omap5/sys_proto.h
+++ b/arch/arm/include/asm/arch-omap5/sys_proto.h
@@ -84,4 +84,8 @@ static inline u32 usec_to_32k(u32 usec)
 #define OMAP5_SERVICE_L2ACTLR_SET    0x104
 #define OMAP5_SERVICE_ACR_SET        0x107
 
+#ifdef CONFIG_TI_SECURE_DEVICE
+int secure_boot_verify_image(void **p_image, size_t *p_size);
+#endif
+
 #endif
-- 
2.6.4