mb/google/bluey: Rename LB_BOOT_MODE_LOW_BATTERY for clarity

The current LB_BOOT_MODE_LOW_BATTERY actually implies a state where the
battery is below the critical threshold but a charger is attached,
allowing the system to boot into a charging-only or limited state.

Update the enum name to LB_BOOT_MODE_LOW_BATTERY_CHARGING across
coreboot tables and libpayload to better reflect this hardware state.

Changes:
- Rename boot mode enums in commonlib and libpayload.
- Update bluey mainboard logic to use the more descriptive name.
- Refactor is_low_power_boot() to is_low_power_boot_with_charger()
  to improve code readability.
- Ensure the charger-present condition is explicitly checked in
  romstage when setting the boot mode.

TEST=Verify bluey boots into off-mode charging and low-battery
charging modes correctly.

Change-Id: I2478c7519c781a8b5af78445899b7f9bf412cf42
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/90845
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Jayvik Desai <jayvik@google.com>

payloads/libpayload/include/coreboot_tables.h

@@ -456,8 +456,11 @@ struct cb_panel_poweroff {
 };
 
 enum boot_mode_t {
+	/* Regular boot scenarios */
 	CB_BOOT_MODE_NORMAL,
-	CB_BOOT_MODE_LOW_BATTERY,
+	/* Device is booting in low-batter w/ charger attached */
+	CB_BOOT_MODE_LOW_BATTERY_CHARGING,
+	/* Device is booting in due to charger insertion */
 	CB_BOOT_MODE_OFFMODE_CHARGING,
 };
 

src/commonlib/include/commonlib/coreboot_tables.h

@@ -639,8 +639,11 @@ struct lb_panel_poweroff {
 };
 
 enum boot_mode_t {
+	/* Regular boot scenarios */
 	LB_BOOT_MODE_NORMAL,
-	LB_BOOT_MODE_LOW_BATTERY,
+	/* Device is booting in low-batter w/ charger attached */
+	LB_BOOT_MODE_LOW_BATTERY_CHARGING,
+	/* Device is booting in due to charger insertion */
 	LB_BOOT_MODE_OFFMODE_CHARGING,
 };
 

src/mainboard/google/bluey/mainboard.c

@@ -63,13 +63,15 @@ static enum boot_mode_t get_boot_mode(void)
 	return boot_mode;
 }
 
-static bool is_low_power_boot(void)
+static bool is_low_power_boot_with_charger(void)
 {
+	bool ret = false;
 	enum boot_mode_t boot_mode = get_boot_mode();
-	if ((boot_mode == LB_BOOT_MODE_LOW_BATTERY) ||
+	if ((boot_mode == LB_BOOT_MODE_LOW_BATTERY_CHARGING) ||
 	    (boot_mode == LB_BOOT_MODE_OFFMODE_CHARGING))
-		return true;
-	return false;
+		ret = true;
+
+	return ret;
 }
 
 static void enable_usb_camera(void)
@@ -99,7 +101,7 @@ static void setup_usb(void)
 static void setup_usb_late(void *unused)
 {
 	/* Skip USB initialization if boot mode is "low-battery" or "off-mode charging"*/
-	if (is_low_power_boot())
+	if (is_low_power_boot_with_charger())
 		return;
 
 	setup_usb_host0();
@@ -119,15 +121,15 @@ void lb_add_boot_mode(struct lb_header *header)
 	mode->size = sizeof(*mode);
 	mode->boot_mode = get_boot_mode();
 
-	/* Enable charging only during off-mode or low-battery mode and charger present */
-	if (is_low_power_boot() && google_chromeec_is_charger_present())
+	/* Enable charging only during off-mode or low-battery mode with charger present */
+	if (is_low_power_boot_with_charger())
 		enable_slow_battery_charging();
 }
 
 bool mainboard_needs_pcie_init(void)
 {
 	/* Skip PCIe initialization if boot mode is "low-battery" or "off-mode charging"*/
-	if (is_low_power_boot())
+	if (is_low_power_boot_with_charger())
 		return false;
 
 	return true;
@@ -152,7 +154,7 @@ static void mainboard_init(struct device *dev)
 	configure_parallel_charging();
 
 	/* Skip mainboard initialization if boot mode is "low-battery" or "off-mode charging"*/
-	if (is_low_power_boot())
+	if (is_low_power_boot_with_charger())
 		return;
 
 	gpi_firmware_load(QUP_0_GSI_BASE);

src/mainboard/google/bluey/romstage.c

@@ -39,8 +39,9 @@ static enum boot_mode_t set_boot_mode(void)
 	enum boot_mode_t boot_mode_new = LB_BOOT_MODE_NORMAL;
 	if (is_off_mode())
 		boot_mode_new = LB_BOOT_MODE_OFFMODE_CHARGING;
-	else if (google_chromeec_is_below_critical_threshold())
-		boot_mode_new = LB_BOOT_MODE_LOW_BATTERY;
+	else if (google_chromeec_is_below_critical_threshold() &&
+			 google_chromeec_is_charger_present())
+		boot_mode_new = LB_BOOT_MODE_LOW_BATTERY_CHARGING;
 	boot_mode = boot_mode_new;
 	return boot_mode_new;
 }