chromeos: On ARM platforms VBNV lives in the EC

This patch renames the x86 way of doing things to
explicitly mention CMOS (which is not available on
our ARM platforms) and adds an implementation to
get VBNV through the Chrome EC. We might want to
refine this further in the future to allow VBNV
in the EC even on x86 platforms. Will be fixed when
that appears. Also, not all ARM platforms running
ChromeOS might use the Google EC in the future, in
which case this code will need additional work.

Signed-off-by: Stefan Reinauer <reinauer@google.com>

Change-Id: Ice09d0e277dbb131f9ad763e762e8877007db901
Reviewed-on: https://chromium-review.googlesource.com/167540
Reviewed-by: David Hendrix <dhendrix@chromium.org>
Tested-by: Stefan Reinauer <reinauer@google.com>
Commit-Queue: Stefan Reinauer <reinauer@google.com>
(cherry picked from commit 8df6cdbcacb082af88c069ef8b542b44ff21d97a)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6616
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <dhendrix@chromium.org>

3 files changed, 145 insertions, 2 deletions

diff --git a/src/vendorcode/google/chromeos/Makefile.inc b/src/vendorcode/google/chromeos/Makefile.inc
index ccde71a102..b9e42da92c 100644
--- a/src/vendorcode/google/chromeos/Makefile.inc
+++ b/src/vendorcode/google/chromeos/Makefile.inc
@@ -17,9 +17,12 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 ##
 
-romstage-$(CONFIG_ARCH_ROMSTAGE_X86_32) += vbnv.c
-ramstage-$(CONFIG_ARCH_RAMSTAGE_X86_32) += vbnv.c
+romstage-$(CONFIG_ARCH_ROMSTAGE_X86_32) += vbnv_cmos.c
+ramstage-$(CONFIG_ARCH_RAMSTAGE_X86_32) += vbnv_cmos.c
+romstage-$(CONFIG_ARCH_ROMSTAGE_ARMV7) += vbnv_ec.c
+ramstage-$(CONFIG_ARCH_RAMSTAGE_ARMV7) += vbnv_ec.c
 romstage-$(CONFIG_ARCH_ROMSTAGE_X86_32) += vboot.c
+
 ramstage-y += gnvs.c
 romstage-y += fmap.c
 ramstage-y += fmap.c
diff --git a/src/vendorcode/google/chromeos/vbnv.c b/src/vendorcode/google/chromeos/vbnv_cmos.c
index a13726d04b..a13726d04b 100644
--- a/src/vendorcode/google/chromeos/vbnv.c
+++ b/src/vendorcode/google/chromeos/vbnv_cmos.c
diff --git a/src/vendorcode/google/chromeos/vbnv_ec.c b/src/vendorcode/google/chromeos/vbnv_ec.c
new file mode 100644
index 0000000000..78da5414d4
--- /dev/null
+++ b/src/vendorcode/google/chromeos/vbnv_ec.c
@@ -0,0 +1,140 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2011 The ChromiumOS Authors.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <types.h>
+#include <string.h>
+#include <console/console.h>
+#include <arch/early_variables.h>
+#include <ec/google/chromeec/ec.h>
+#include "chromeos.h"
+
+#define VBNV_BLOCK_SIZE 16	/* Size of NV storage block in bytes */
+
+/* Constants for NV storage.  We use this rather than structs and
+ * bitfields so the data format is consistent across platforms and
+ * compilers.
+ */
+#define HEADER_OFFSET                0
+#define HEADER_MASK                     0xC0
+#define HEADER_SIGNATURE                0x40
+#define HEADER_FIRMWARE_SETTINGS_RESET  0x20
+#define HEADER_KERNEL_SETTINGS_RESET    0x10
+
+#define BOOT_OFFSET                  1
+#define BOOT_DEBUG_RESET_MODE           0x80
+#define BOOT_DISABLE_DEV_REQUEST        0x40
+#define BOOT_OPROM_NEEDED               0x20
+#define BOOT_TRY_B_COUNT_MASK           0x0F
+
+#define RECOVERY_OFFSET              2
+#define LOCALIZATION_OFFSET          3
+
+#define DEV_FLAGS_OFFSET             4
+#define DEV_BOOT_USB_MASK               0x01
+#define DEV_BOOT_SIGNED_ONLY_MASK       0x02
+
+#define KERNEL_FIELD_OFFSET         11
+#define CRC_OFFSET                  15
+
+static int vbnv_initialized CAR_GLOBAL;
+static uint8_t vbnv[VBNV_BLOCK_SIZE] CAR_GLOBAL;
+
+/* Wrappers for accessing the variables marked as CAR_GLOBAL. */
+static inline int is_vbnv_initialized(void)
+{
+	return car_get_var(vbnv_initialized);
+}
+
+static inline uint8_t *vbnv_data_addr(int index)
+{
+	uint8_t *vbnv_arr = car_get_var_ptr(vbnv);
+
+	return &vbnv_arr[index];
+}
+
+static inline uint8_t vbnv_data(int index)
+{
+	return *vbnv_data_addr(index);
+}
+
+/* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial.  A
+ * table-based algorithm would be faster, but for only 15 bytes isn't
+ * worth the code size.
+ */
+
+static uint8_t crc8(const uint8_t * data, int len)
+{
+	unsigned crc = 0;
+	int i, j;
+
+	for (j = len; j; j--, data++) {
+		crc ^= (*data << 8);
+		for (i = 8; i; i--) {
+			if (crc & 0x8000)
+				crc ^= (0x1070 << 3);
+			crc <<= 1;
+		}
+	}
+
+	return (uint8_t) (crc >> 8);
+}
+
+void read_vbnv(uint8_t *vbnv_copy)
+{
+	google_chromeec_vbnv_context(1, vbnv_copy, VBNV_BLOCK_SIZE);
+
+	/* Check data for consistency */
+	if ((HEADER_SIGNATURE != (vbnv_copy[HEADER_OFFSET] & HEADER_MASK))
+	    || (crc8(vbnv_copy, CRC_OFFSET) != vbnv_copy[CRC_OFFSET])) {
+
+		/* Data is inconsistent (bad CRC or header),
+		 * so reset to defaults
+		 */
+		memset(vbnv_copy, 0, VBNV_BLOCK_SIZE);
+		vbnv_copy[HEADER_OFFSET] =
+		    (HEADER_SIGNATURE | HEADER_FIRMWARE_SETTINGS_RESET |
+		     HEADER_KERNEL_SETTINGS_RESET);
+	}
+}
+
+void save_vbnv(const uint8_t *vbnv_copy)
+{
+	google_chromeec_vbnv_context(0, (uint8_t *)vbnv_copy, VBNV_BLOCK_SIZE);
+}
+
+static void vbnv_setup(void)
+{
+	read_vbnv(vbnv_data_addr(0));
+	car_set_var(vbnv_initialized, 1);
+}
+
+int get_recovery_mode_from_vbnv(void)
+{
+	if (!is_vbnv_initialized())
+		vbnv_setup();
+	return vbnv_data(RECOVERY_OFFSET);
+}
+
+int vboot_wants_oprom(void)
+{
+	if (!is_vbnv_initialized())
+		vbnv_setup();
+
+	return (vbnv_data(BOOT_OFFSET) & BOOT_OPROM_NEEDED) ? 1 : 0;
+}