Change in coreboot[master]: [wip]vboot_logic: Set VB2_CONTEXT_EC_TRUSTED in verstage_main

[Hsuan-ting Chen (Code Review)]

Attention is currently required from: Hsuan Ting Chen.
Hello Hsuan Ting Chen,

I'd like you to do a code review. Please visit

https://review.coreboot.org/c/coreboot/+/57048

to review the following change.

Change subject: [wip]vboot_logic: Set VB2_CONTEXT_EC_TRUSTED in verstage_main
......................................................................

[wip]vboot_logic: Set VB2_CONTEXT_EC_TRUSTED in verstage_main

We will introduce a new ctx field stores the current bootmode in
crrev/c/2944250 (ctx->bootmode), which will be leveraged in both
vboot flow and elog_add_boot_reason in coreboot.

In current steps of deciding bootmode, a function vb2ex_ec_trusted
is required. This function checks gpio EC_IN_RW pin and will return
'trusted' only if EC is not in RW. Therefore, we need to implement
similar utilities in coreboot.

We will deprecate vb2ex_ec_trusted and use the flag,
VB2_CONTEXT_EC_TRUSTED, in vboot, vb2api_fw_phase1 and set that flag
in coreboot, verstage_main.

Also add a help function get_ec_in_rw which needed to be implemented
per mainboard.

WIP:
Only support volteer, trogdor now.

BUG=b:177196147, b:181931817
BRANCH=none
TEST=TBD

Signed-off-by: Hsuan Ting Chen 
Change-Id: I479c8f80e45cc524ba87db4293d19b29bdfa2192
---
M src/include/bootmode.h
M src/mainboard/google/trogdor/chromeos.c
M src/mainboard/google/volteer/chromeos.c
M src/security/vboot/bootmode.c
M src/security/vboot/vboot_logic.c
5 files changed, 22 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/48/57048/1

diff --git a/src/include/bootmode.h b/src/include/bootmode.h
index aadecba..6cfd751 100644
--- a/src/include/bootmode.h
+++ b/src/include/bootmode.h
@@ -11,6 +11,7 @@
 int clear_recovery_mode_switch(void);
 int get_wipeout_mode_switch(void);
 int get_lid_switch(void);
+int get_ec_in_rw(void);

/* Return 1 if display initialization is required. 0 if not. */
 int display_init_required(void);
diff --git a/src/mainboard/google/trogdor/chromeos.c b/src/mainboard/google/trogdor/chromeos.c
index c218388..8f86073 100644
--- a/src/mainboard/google/trogdor/chromeos.c
+++ b/src/mainboard/google/trogdor/chromeos.c
@@ -48,3 +48,9 @@
 {
    return gpio_irq_status(GPIO_H1_AP_INT);
 }
+
+int get_ec_in_rw(void)
+{
+	/* Read GPIO_EC_IN_RW. */
+	return gpio_get(GPIO_EC_IN_RW);
+}
diff --git a/src/mainboard/google/volteer/chromeos.c b/src/mainboard/google/volteer/chromeos.c
index abd50c5..baa5913 100644
--- a/src/mainboard/google/volteer/chromeos.c
+++ b/src/mainboard/google/volteer/chromeos.c
@@ -32,3 +32,9 @@
    gpios = variant_cros_gpios(&num);
    chromeos_acpi_gpio_generate(gpios, num);
 }
+
+int get_ec_in_rw(void)
+{
+	/* Read GPIO_EC_IN_RW. */
+	return gpio_get(GPIO_EC_IN_RW);
+}
diff --git a/src/security/vboot/bootmode.c b/src/security/vboot/bootmode.c
index 6c05109..0c18674 100644
--- a/src/security/vboot/bootmode.c
+++ b/src/security/vboot/bootmode.c
@@ -57,6 +57,11 @@
    return 0;
 }

+int __weak get_ec_in_rw(void)
+{
+	return 1;
+}
+
 #if CONFIG(VBOOT_NO_BOARD_SUPPORT)
 /**
  * TODO: Create flash protection interface which implements get_write_protect_state.
diff --git a/src/security/vboot/vboot_logic.c b/src/security/vboot/vboot_logic.c
index 5ea4916..03701fc 100644
--- a/src/security/vboot/vboot_logic.c
+++ b/src/security/vboot/vboot_logic.c
@@ -321,6 +321,10 @@
    if (!CONFIG(VBOOT_MUST_REQUEST_DISPLAY) || CONFIG(VBOOT_ALWAYS_ENABLE_DISPLAY))
    	ctx->flags |= VB2_CONTEXT_DISPLAY_INIT;

+	/* EC is trusted if EC is not in RW */
+	if (!get_ec_in_rw())
+		ctx->flags |= VB2_CONTEXT_EC_TRUSTED;
+
    /* Do early init (set up secdata and NVRAM, load GBB) */
    printk(BIOS_INFO, "Phase 1\n");
    rv = vb2api_fw_phase1(ctx);