vboot: create NVRAM flag to pause after EC software sync

Previously, it is impossible to programmatically enable/disable
Alt OS mode in eve.  This is because only EC-RW supports the
kbatboot keyboard matrix functionality.  But, as part of the
campfire boot flow, the keyboard matrix is retrieved *immediately*
after jumping into EC-RW.  We need to insert a small pause in
order to allow for some entity (autotest/servo) to send a kbatboot
command, simulating the Alt OS keyboard press hotkey.

BUG=b:117140648
TEST=Manually use crossystem to set post_ec_sync_delay=1
     Reboot, and wait for the delay to begin
     Run `kbatboot 1 4 1` in EC console
     Check that AP console contains:
       "vb2_post_ec_sync_hooks: post_ec_sync_delay 5000 ms..."
TEST=make clean && make runtests

Change-Id: I1305357199d87b80b4edc4e311015106ab07de65
Reviewed-on: https://chromium-review.googlesource.com/c/1256644
Commit-Queue: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Trybot-Ready: Joel Kitching <kitching@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>

9 files changed, 64 insertions, 2 deletions

diff --git a/firmware/2lib/2nvstorage.c b/firmware/2lib/2nvstorage.c
index 424567a0..98ee9d06 100644
--- a/firmware/2lib/2nvstorage.c
+++ b/firmware/2lib/2nvstorage.c
@@ -181,6 +181,10 @@ uint32_t vb2_nv_get(struct vb2_context *ctx, enum vb2_nv_param param)
 
 	case VB2_NV_DISABLE_ALT_OS_REQUEST:
 		return GETBIT(VB2_NV_OFFS_MISC, VB2_NV_MISC_DISABLE_ALT_OS);
+
+	case VB2_NV_POST_EC_SYNC_DELAY:
+		return GETBIT(VB2_NV_OFFS_MISC,
+			      VB2_NV_MISC_POST_EC_SYNC_DELAY);
 	}
 
 	/*
@@ -370,6 +374,10 @@ void vb2_nv_set(struct vb2_context *ctx,
 	case VB2_NV_DISABLE_ALT_OS_REQUEST:
 		SETBIT(VB2_NV_OFFS_MISC, VB2_NV_MISC_DISABLE_ALT_OS);
 		break;
+
+	case VB2_NV_POST_EC_SYNC_DELAY:
+		SETBIT(VB2_NV_OFFS_MISC, VB2_NV_MISC_POST_EC_SYNC_DELAY);
+		break;
 	}
 
 	/*
diff --git a/firmware/2lib/include/2nvstorage.h b/firmware/2lib/include/2nvstorage.h
index 7a8f4d95..b7a28fd5 100644
--- a/firmware/2lib/include/2nvstorage.h
+++ b/firmware/2lib/include/2nvstorage.h
@@ -102,6 +102,11 @@ enum vb2_nv_param {
 	VB2_NV_ENABLE_ALT_OS_REQUEST,
 	/* Disable AltOS Mode on next boot. */
 	VB2_NV_DISABLE_ALT_OS_REQUEST,
+	/*
+	 * Add a short delay after EC software sync for any interaction
+	 * with EC-RW (persistent).
+	 */
+	VB2_NV_POST_EC_SYNC_DELAY,
 };
 
 /* Set default boot in developer mode */
diff --git a/firmware/2lib/include/2nvstorage_fields.h b/firmware/2lib/include/2nvstorage_fields.h
index 4459703d..d37f4fcb 100644
--- a/firmware/2lib/include/2nvstorage_fields.h
+++ b/firmware/2lib/include/2nvstorage_fields.h
@@ -70,12 +70,13 @@ enum vb2_nv_offset {
 #define VB2_NV_TPM_CLEAR_OWNER_DONE            0x02
 #define VB2_NV_TPM_REBOOTED                    0x04
 
-/* Fields in VB2_NV_OFFS_MISC (unused = 0xc0) */
+/* Fields in VB2_NV_OFFS_MISC (unused = 0x80) */
 #define VB2_NV_MISC_UNLOCK_FASTBOOT            0x01
 #define VB2_NV_MISC_BOOT_ON_AC_DETECT          0x02
 #define VB2_NV_MISC_TRY_RO_SYNC		       0x04
 #define VB2_NV_MISC_BATTERY_CUTOFF             0x08
 #define VB2_NV_MISC_ENABLE_ALT_OS              0x10
 #define VB2_NV_MISC_DISABLE_ALT_OS             0x20
+#define VB2_NV_MISC_POST_EC_SYNC_DELAY         0x40
 
 #endif  /* VBOOT_REFERENCE_VBOOT_2NVSTORAGE_FIELDS_H_ */
diff --git a/firmware/include/vboot_nvstorage.h b/firmware/include/vboot_nvstorage.h
index e41d92c3..0823ea37 100644
--- a/firmware/include/vboot_nvstorage.h
+++ b/firmware/include/vboot_nvstorage.h
@@ -128,6 +128,11 @@ typedef enum VbNvParam {
 	VBNV_ENABLE_ALT_OS_REQUEST,
 	/* Disable AltOS Mode on next boot. */
 	VBNV_DISABLE_ALT_OS_REQUEST,
+	/*
+	 * Add a short delay after EC software sync for any interaction
+	 * with EC-RW (persistent).
+	 */
+	VBNV_POST_EC_SYNC_DELAY,
 } VbNvParam;
 
 /* Set default boot in developer mode */
diff --git a/firmware/lib/vboot_api_kernel.c b/firmware/lib/vboot_api_kernel.c
index 08254a47..4145e3d0 100644
--- a/firmware/lib/vboot_api_kernel.c
+++ b/firmware/lib/vboot_api_kernel.c
@@ -406,6 +406,25 @@ static void vb2_kernel_cleanup(struct vb2_context *ctx, VbCommonParams *cparams)
 	shared->timer_vb_select_and_load_kernel_exit = VbExGetTimer();
 }
 
+VbError_t vb2_post_ec_sync_hooks(struct vb2_context *ctx,
+				 VbCommonParams *cparams) {
+	/*
+	 * Pause for any events to be sent to EC-RW, after it is guaranteed
+	 * to be running.  Can be used for simulating boot hotkeys.
+	 *
+	 * TODO(b/117140648): Accept keyboard input to skip/disable the delay.
+	 */
+	const int post_ec_sync_delay_msec = 5 * 1000;
+	if (vb2_nv_get(ctx, VB2_NV_POST_EC_SYNC_DELAY)) {
+		VB2_DEBUG("vb2_post_ec_sync_hooks: "
+			  "post_ec_sync_delay %d ms...\n",
+			  post_ec_sync_delay_msec);
+		VbExSleepMs(post_ec_sync_delay_msec);
+	}
+
+	return VBERROR_SUCCESS;
+}
+
 int VbAltOSForceChromeOS(void) {
 	return 0;
 }
@@ -519,11 +538,15 @@ VbError_t VbSelectAndLoadKernel(VbCommonParams *cparams,
 
 	/*
 	 * Do EC software sync if necessary.  This has UI, but it's just a
-	 * single non-interactive WAIT screen.
+	 * single non-interactive WAIT screen.  Perform any post-EC software
+	 * sync hooks, if early interaction with EC-RW is necessary.
 	 */
 	retval = ec_sync_all(&ctx, cparams);
 	if (retval)
 		goto VbSelectAndLoadKernel_exit;
+	retval = vb2_post_ec_sync_hooks(&ctx, cparams);
+	if (retval)
+		goto VbSelectAndLoadKernel_exit;
 
 	/*
 	 * Check whether confirmation screen or picker screen need to be
diff --git a/firmware/lib/vboot_nvstorage.c b/firmware/lib/vboot_nvstorage.c
index c060b27a..4e3138a4 100644
--- a/firmware/lib/vboot_nvstorage.c
+++ b/firmware/lib/vboot_nvstorage.c
@@ -67,6 +67,7 @@
 #define MISC_BATTERY_CUTOFF_REQUEST	0x08
 #define MISC_ENABLE_ALT_OS_REQUEST      0x10
 #define MISC_DISABLE_ALT_OS_REQUEST     0x20
+#define MISC_POST_EC_SYNC_DELAY         0x40
 
 #define KERNEL_FIELD_OFFSET         11
 #define CRC_OFFSET                  15
@@ -249,6 +250,11 @@ int VbNvGet(VbNvContext *context, VbNvParam param, uint32_t *dest)
 			 ?  1 : 0;
 		return 0;
 
+	case VBNV_POST_EC_SYNC_DELAY:
+		*dest = (raw[MISC_OFFSET] & MISC_POST_EC_SYNC_DELAY)
+			 ?  1 : 0;
+		return 0;
+
 	default:
 		return 1;
 	}
@@ -495,6 +501,13 @@ int VbNvSet(VbNvContext *context, VbNvParam param, uint32_t value)
 			raw[MISC_OFFSET] &= ~MISC_DISABLE_ALT_OS_REQUEST;
 		break;
 
+	case VBNV_POST_EC_SYNC_DELAY:
+		if (value)
+			raw[MISC_OFFSET] |= MISC_POST_EC_SYNC_DELAY;
+		else
+			raw[MISC_OFFSET] &= ~MISC_POST_EC_SYNC_DELAY;
+		break;
+
 	default:
 		return 1;
 	}
diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c
index 7aeb161a..51cda89f 100644
--- a/host/lib/crossystem.c
+++ b/host/lib/crossystem.c
@@ -583,6 +583,8 @@ int VbGetSystemPropertyInt(const char *name)
 		value = VbGetNvStorage(VBNV_ENABLE_ALT_OS_REQUEST);
 	} else if (!strcasecmp(name, "disable_alt_os_request")) {
 		value = VbGetNvStorage(VBNV_DISABLE_ALT_OS_REQUEST);
+	} else if (!strcasecmp(name, "post_ec_sync_delay")) {
+		value = VbGetNvStorage(VBNV_POST_EC_SYNC_DELAY);
 	}
 
 	return value;
@@ -732,6 +734,8 @@ int VbSetSystemPropertyInt(const char *name, int value)
 		return VbSetNvStorage(VBNV_ENABLE_ALT_OS_REQUEST, value);
 	} else if (!strcasecmp(name, "disable_alt_os_request")) {
 		return VbSetNvStorage(VBNV_DISABLE_ALT_OS_REQUEST, value);
+	} else if (!strcasecmp(name, "post_ec_sync_delay")) {
+		return VbSetNvStorage(VBNV_POST_EC_SYNC_DELAY, value);
 	}
 
 	return -1;
diff --git a/tests/vb2_nvstorage_tests.c b/tests/vb2_nvstorage_tests.c
index 836282f0..4a2e2794 100644
--- a/tests/vb2_nvstorage_tests.c
+++ b/tests/vb2_nvstorage_tests.c
@@ -58,6 +58,7 @@ static struct nv_field nvfields[] = {
 	{VB2_NV_TRY_RO_SYNC, 0, 1, 0, "try read only software sync"},
 	{VB2_NV_ENABLE_ALT_OS_REQUEST, 0, 1, 0, "enable alt-os request"},
 	{VB2_NV_DISABLE_ALT_OS_REQUEST, 0, 1, 0, "disable alt-os request"},
+	{VB2_NV_POST_EC_SYNC_DELAY, 0, 1, 0, "enable post-ec sync delay"},
 	{0, 0, 0, 0, NULL}
 };
 
diff --git a/utility/crossystem.c b/utility/crossystem.c
index 0e80b81a..6d293683 100644
--- a/utility/crossystem.c
+++ b/utility/crossystem.c
@@ -58,6 +58,8 @@ const Param sys_param_list[] = {
   {"ecfw_act", IS_STRING, "Active EC firmware"},
   {"enable_alt_os_request", CAN_WRITE,
    "Enable AltOS mode on next boot (writable)"},
+  {"post_ec_sync_delay", CAN_WRITE,
+   "Short delay after EC software sync (persistent, writable)"},
   {"fmap_base", 0, "Main firmware flashmap physical address", "0x%08x"},
   {"fwb_tries", CAN_WRITE, "Try firmware B count (writable)"},
   {"fw_vboot2", 0, "1 if firmware was selected by vboot2 or 0 otherwise"},