charge: respect PDO current maximum limit

The current input limit setting doesn't respect the PDO's
current limit (e.g. when the current limit is less than
CONFIG_INPUT_CURRENT_LIMIT) and this might cause the over-draining
the charger.

BUG=b:172878439
TEST=1) make buildall
     2) modified servo-v4 which only broadcast PDOs with 250mA current
        limit and ensure the goroh won't sink more than 250mA.
        (while the CONFIG_INPUT_CURRENT_LIMIT is 512mA)
BRANCH=main

Change-Id: I09f8e6fb39a072ee38ea09a5c9898984f4122513
Signed-off-by: Eric Yilun Lin <yllin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3220037
Commit-Queue: Eric Yilun Lin <yllin@google.com>
Tested-by: Eric Yilun Lin <yllin@google.com>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
Reviewed-by: Diana Z <dzigterman@chromium.org>

3 files changed, 37 insertions, 0 deletions

diff --git a/common/charge_manager.c b/common/charge_manager.c
index 862bb28725..14c869c3b2 100644
--- a/common/charge_manager.c
+++ b/common/charge_manager.c
@@ -107,6 +107,7 @@ static int charge_current = CHARGE_CURRENT_UNINITIALIZED;
 static int charge_current_uncapped = CHARGE_CURRENT_UNINITIALIZED;
 static int charge_voltage;
 static int charge_supplier = CHARGE_SUPPLIER_NONE;
+static int charge_pd_current_uncapped = CHARGE_CURRENT_UNINITIALIZED;
 static int override_port = OVERRIDE_OFF;
 
 static int delayed_override_port = OVERRIDE_OFF;
@@ -267,6 +268,11 @@ static int charge_manager_is_seeded(void)
 	return 1;
 }
 
+int charge_manager_get_pd_current_uncapped(void)
+{
+	return charge_pd_current_uncapped;
+}
+
 #ifndef TEST_BUILD
 /**
  * Get the maximum charge current for a port.
@@ -828,6 +834,15 @@ static void charge_manager_refresh(void)
 			available_charge[new_supplier][new_port].voltage;
 	}
 
+	/*
+	 * Record the PD current limit to prevent from over-sinking
+	 * the charger.
+	 */
+	if (new_supplier == CHARGE_SUPPLIER_PD)
+		charge_pd_current_uncapped = new_charge_current_uncapped;
+	else
+		charge_pd_current_uncapped = CHARGE_CURRENT_UNINITIALIZED;
+
 	/* Change the charge limit + charge port/supplier if modified. */
 	if (new_port != charge_port || new_charge_current != charge_current ||
 	    new_supplier != charge_supplier) {
diff --git a/common/charge_state_v2.c b/common/charge_state_v2.c
index 59f38edee8..abfabda7a3 100644
--- a/common/charge_state_v2.c
+++ b/common/charge_state_v2.c
@@ -2694,6 +2694,19 @@ int charge_set_input_current_limit(int ma, int mv)
 	/* Limit input current limit to max limit for this board */
 	ma = MIN(ma, CONFIG_CHARGER_MAX_INPUT_CURRENT);
 #endif
+
+	if (IS_ENABLED(CONFIG_CHARGE_MANAGER)) {
+		int pd_current_uncapped =
+			charge_manager_get_pd_current_uncapped();
+
+		/*
+		 * clamp the input current to not exceeded the PD's limitation.
+		 */
+		if (pd_current_uncapped != CHARGE_CURRENT_UNINITIALIZED &&
+		    ma > pd_current_uncapped)
+			ma = pd_current_uncapped;
+	}
+
 	curr.desired_input_current = ma;
 #ifdef CONFIG_EC_EC_COMM_BATTERY_CLIENT
 	/* Wake up charger task to allocate current between lid and base. */
diff --git a/include/charge_manager.h b/include/charge_manager.h
index cb6591df3b..2cded28295 100644
--- a/include/charge_manager.h
+++ b/include/charge_manager.h
@@ -231,6 +231,15 @@ enum charge_supplier charge_manager_get_supplier(void);
  */
 int charge_manager_get_vbus_voltage(int port);
 
+/**
+ * Get the current limit of CHARGE_PD_SUPPLIER.
+ *
+ * @return	The CHARGE_SUPPLIER_PD current limit in mA or
+ *		CHARGE_CURRENT_UNINITIALIZED if the supplier is not
+ *		CHARGE_SUPPLIER_PD.
+ */
+int charge_manager_get_pd_current_uncapped(void);
+
 #ifdef CONFIG_USB_PD_LOGGING
 /* Save power state log entry for the given port */
 void charge_manager_save_log(int port);