usb_pd: Add host command to limit external charger voltage / current

PD charger voltage + current can now be limited with
EC_CMD_EXTERNAL_POWER_LIMIT. The limit is automatically cleared when the
AP transitions out of S0 into S3 / suspend.

BUG=chrome-os-partner:43285
TEST=Manual on Samus w/ zinger.
- Plug zinger, verify charging at 20V/3A.
- `ectool extpwrlimit 3000 12000 --dev=1`, verify charging at 12V/3A
- `ectool extpwrlimit 1000 5000 --dev=1`, verify charging at 5V/1A
- Plug zinger into other port, verify still charging at 5V/1A
- `powerd_dbus_suspend`, verify charging at 20V/3A
- `chglim 2000 12000`, verify charging at 12V/2A
- `ectool extpwrlimit 0xffff 0xffff --dev=1`, verify charging at 20V/3A
- `chglim 1000 20000`, verify charging at 20V/1A
- `chglim`, verify charging at 20V/3A
BRANCH=ryu

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I6cd5377be91b3df75f99cb414fd3fa5a463b56cb
Reviewed-on: https://chromium-review.googlesource.com/293954
Reviewed-by: Todd Broch <tbroch@chromium.org>
Reviewed-by: Alec Berg <alecaberg@chromium.org>

8 files changed, 130 insertions, 23 deletions

diff --git a/board/ryu/board.h b/board/ryu/board.h
index 4d8111b79c..3a22f811c9 100644
--- a/board/ryu/board.h
+++ b/board/ryu/board.h
@@ -22,6 +22,7 @@
 /* Optional features */
 #undef CONFIG_CMD_HASH
 #define CONFIG_CHARGE_MANAGER
+#define CONFIG_CHARGE_MANAGER_EXTERNAL_POWER_LIMIT
 #define CONFIG_CHARGE_RAMP_HW
 #define CONFIG_FORCE_CONSOLE_RESUME
 #define CONFIG_STM_HWTIMER32
diff --git a/common/charge_manager.c b/common/charge_manager.c
index 4e21bdf2bd..ef74438368 100644
--- a/common/charge_manager.c
+++ b/common/charge_manager.c
@@ -855,3 +855,76 @@ DECLARE_CONSOLE_COMMAND(chgoverride, command_charge_port_override,
 	"[port | -1 | -2]",
 	"Force charging from a given port (-1 = off, -2 = disable charging)",
 	NULL);
+
+#ifdef CONFIG_CHARGE_MANAGER_EXTERNAL_POWER_LIMIT
+static void charge_manager_set_external_power_limit(int current_lim,
+						    int voltage_lim)
+{
+	int port;
+
+	if (current_lim == EC_POWER_LIMIT_NONE)
+		current_lim = CHARGE_CEIL_NONE;
+	if (voltage_lim == EC_POWER_LIMIT_NONE)
+		voltage_lim = PD_MAX_VOLTAGE_MV;
+
+	for (port = 0; port < CONFIG_USB_PD_PORT_COUNT; ++port) {
+		charge_manager_set_ceil(port, CEIL_REQUESTOR_HOST, current_lim);
+		pd_set_external_voltage_limit(port, voltage_lim);
+	}
+}
+
+/*
+ * On transition out of S0, disable all external power limits, in case AP
+ * failed to clear them.
+ */
+static void charge_manager_external_power_limit_off(void)
+{
+	charge_manager_set_external_power_limit(EC_POWER_LIMIT_NONE,
+						EC_POWER_LIMIT_NONE);
+}
+DECLARE_HOOK(HOOK_CHIPSET_SUSPEND, charge_manager_external_power_limit_off,
+	     HOOK_PRIO_DEFAULT);
+
+static int hc_external_power_limit(struct host_cmd_handler_args *args)
+{
+	const struct ec_params_external_power_limit_v1 *p = args->params;
+
+	charge_manager_set_external_power_limit(p->current_lim,
+						p->voltage_lim);
+
+	return EC_SUCCESS;
+}
+DECLARE_HOST_COMMAND(EC_CMD_EXTERNAL_POWER_LIMIT,
+		     hc_external_power_limit,
+		     EC_VER_MASK(1));
+
+static int command_external_power_limit(int argc, char **argv)
+{
+	int max_current;
+	int max_voltage;
+	char *e;
+
+	if (argc >= 2) {
+		max_current = strtoi(argv[1], &e, 10);
+		if (*e)
+			return EC_ERROR_PARAM1;
+	} else
+		max_current = EC_POWER_LIMIT_NONE;
+
+	if (argc >= 3) {
+		max_voltage = strtoi(argv[2], &e, 10);
+		if (*e)
+			return EC_ERROR_PARAM1;
+	} else
+		max_voltage = EC_POWER_LIMIT_NONE;
+
+	charge_manager_set_external_power_limit(max_current, max_voltage);
+	ccprintf("max req: %dmA %dmV\n", max_current, max_voltage);
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(chglim, command_external_power_limit,
+	"[max_current (mA)] [max_voltage (mV)]",
+	"Set max charger current / voltage",
+	NULL);
+#endif /* CONFIG_CHARGE_MANAGER_EXTERNAL_POWER_LIMIT */
diff --git a/common/usb_pd_policy.c b/common/usb_pd_policy.c
index 16a9fefa7a..91bbdb15e4 100644
--- a/common/usb_pd_policy.c
+++ b/common/usb_pd_policy.c
@@ -34,7 +34,7 @@ static int rw_flash_changed = 1;
 
 #ifdef CONFIG_USB_PD_DUAL_ROLE
 /* Cap on the max voltage requested as a sink (in millivolts) */
-static unsigned max_request_mv = -1; /* no cap */
+static unsigned max_request_mv = PD_MAX_VOLTAGE_MV; /* no cap */
 
 /**
  * Find PDO index that offers the most amount of power and stays within
@@ -53,10 +53,6 @@ static int pd_find_pdo_index(int cnt, uint32_t *src_caps, int max_mv)
 	int cur_mv;
 #endif
 
-	/* max_mv of -1 represents max limit */
-	if (max_mv == -1)
-		max_mv = PD_MAX_VOLTAGE_MV;
-
 	/* max voltage is always limited by this boards max request */
 	max_mv = MIN(max_mv, PD_MAX_VOLTAGE_MV);
 
@@ -155,7 +151,7 @@ void pd_process_source_cap(int port, int cnt, uint32_t *src_caps)
 	int pdo_index;
 
 	/* Get max power info that we could request */
-	pdo_index = pd_find_pdo_index(cnt, src_caps, -1);
+	pdo_index = pd_find_pdo_index(cnt, src_caps, PD_MAX_VOLTAGE_MV);
 	if (pdo_index < 0)
 		pdo_index = 0;
 	pd_extract_pdo_power(src_caps[pdo_index], &ma, &mv);
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
index b124ad0245..b6507baa5c 100644
--- a/common/usb_pd_protocol.c
+++ b/common/usb_pd_protocol.c
@@ -2725,6 +2725,19 @@ void pd_request_source_voltage(int port, int mv)
 
 	task_wake(PD_PORT_TO_TASK_ID(port));
 }
+
+void pd_set_external_voltage_limit(int port, int mv)
+{
+	pd_set_max_voltage(mv);
+
+	if (pd[port].task_state == PD_STATE_SNK_READY ||
+	    pd[port].task_state == PD_STATE_SNK_TRANSITION) {
+		/* Set flag to send new power request in pd_task */
+		pd[port].new_power_request = 1;
+		task_wake(PD_PORT_TO_TASK_ID(port));
+	}
+}
+
 #endif /* CONFIG_USB_PD_DUAL_ROLE */
 
 static int command_pd(int argc, char **argv)
diff --git a/include/config.h b/include/config.h
index b718941a12..4685c89f59 100644
--- a/include/config.h
+++ b/include/config.h
@@ -247,6 +247,9 @@
 /* Compile charge manager */
 #undef CONFIG_CHARGE_MANAGER
 
+/* Handle the external power limit host command in charge manager */
+#undef CONFIG_CHARGE_MANAGER_EXTERNAL_POWER_LIMIT
+
 /* Compile input current ramping support */
 #undef CONFIG_CHARGE_RAMP
 
diff --git a/include/ec_commands.h b/include/ec_commands.h
index f64ffd6eac..fa820b7ebb 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -2842,14 +2842,18 @@ struct ec_params_current_limit {
 } __packed;
 
 /*
- * Set maximum external power current.
+ * Set maximum external voltage / current.
  */
-#define EC_CMD_EXT_POWER_CURRENT_LIMIT 0xa2
+#define EC_CMD_EXTERNAL_POWER_LIMIT 0xa2
 
-struct ec_params_ext_power_current_limit {
-	uint32_t limit; /* in mA */
+/* Command v0 is used only on Spring and is obsolete + unsupported */
+struct ec_params_external_power_limit_v1 {
+	uint16_t current_lim; /* in mA, or EC_POWER_LIMIT_NONE to clear limit */
+	uint16_t voltage_lim; /* in mV, or EC_POWER_LIMIT_NONE to clear limit */
 } __packed;
 
+#define EC_POWER_LIMIT_NONE 0xffff
+
 /*****************************************************************************/
 /* Smart battery pass-through */
 
diff --git a/include/usb_pd.h b/include/usb_pd.h
index 5b42b687e0..6ca88bb55a 100644
--- a/include/usb_pd.h
+++ b/include/usb_pd.h
@@ -947,6 +947,15 @@ int pd_set_power_supply_ready(int port);
 void pd_request_source_voltage(int port, int mv);
 
 /**
+ * Set a voltage limit from the PD source.
+ *
+ * If the source is currently active, it triggers a new negotiation.
+ * @param port USB-C port number
+ * @param mv limit voltage in millivolts.
+ */
+void pd_set_external_voltage_limit(int port, int mv);
+
+/**
  * Set the PD input current limit.
  *
  * @param port USB-C port number
diff --git a/util/ectool.c b/util/ectool.c
index 8fa08b4b10..c6a40f4b34 100644
--- a/util/ectool.c
+++ b/util/ectool.c
@@ -43,8 +43,6 @@ static struct option long_opts[] = {
 
 const char help_str[] =
 	"Commands:\n"
-	"  extpwrcurrentlimit\n"
-	"      Set the maximum external power current\n"
 	"  autofanctrl <on>\n"
 	"      Turn on automatic fan speed control.\n"
 	"  backlight <enabled>\n"
@@ -93,6 +91,8 @@ const char help_str[] =
 	"      Sets the SMI mask for EC host events\n"
 	"  eventsetwakemask <mask>\n"
 	"      Sets the wake mask for EC host events\n"
+	"  extpwrlimit\n"
+	"      Set the maximum external power limit\n"
 	"  fanduty <percent>\n"
 	"      Forces the fan PWM to a constant duty cycle\n"
 	"  flasherase <offset> <size>\n"
@@ -4829,26 +4829,34 @@ int cmd_lcd_backlight(int argc, char *argv[])
 }
 
 
-int cmd_ext_power_current_limit(int argc, char *argv[])
+int cmd_ext_power_limit(int argc, char *argv[])
 {
-	struct ec_params_ext_power_current_limit p;
-	int rv;
+	/* Version 1 is used, no support for obsolete version 0 */
+	struct ec_params_external_power_limit_v1 p;
 	char *e;
 
-	if (argc != 2) {
-		fprintf(stderr, "Usage: %s <max_current_mA>\n", argv[0]);
+	if (argc != 3) {
+		fprintf(stderr,
+			"Usage: %s <max_current_mA> <max_voltage_mV>\n",
+			argv[0]);
 		return -1;
 	}
 
-	p.limit = strtol(argv[1], &e, 0);
+	p.current_lim = strtol(argv[1], &e, 0);
 	if (e && *e) {
-		fprintf(stderr, "Bad value.\n");
+		fprintf(stderr, "Bad param1.\n");
 		return -1;
 	}
 
-	rv = ec_command(EC_CMD_EXT_POWER_CURRENT_LIMIT, 0, &p, sizeof(p),
-			NULL, 0);
-	return rv;
+	p.voltage_lim = strtol(argv[2], &e, 0);
+	if (e && *e) {
+		fprintf(stderr, "Bad param2.\n");
+		return -1;
+	}
+
+	/* Send version 1 of command */
+	return ec_command(EC_CMD_EXTERNAL_POWER_LIMIT, 1, &p, sizeof(p),
+			  NULL, 0);
 }
 
 
@@ -6315,7 +6323,6 @@ int cmd_pd_write_log(int argc, char *argv[])
 
 /* NULL-terminated list of commands */
 const struct command commands[] = {
-	{"extpwrcurrentlimit", cmd_ext_power_current_limit},
 	{"autofanctrl", cmd_thermal_auto_fan_ctrl},
 	{"backlight", cmd_lcd_backlight},
 	{"battery", cmd_battery},
@@ -6340,6 +6347,7 @@ const struct command commands[] = {
 	{"eventsetscimask", cmd_host_event_set_sci_mask},
 	{"eventsetsmimask", cmd_host_event_set_smi_mask},
 	{"eventsetwakemask", cmd_host_event_set_wake_mask},
+	{"extpwrlimit", cmd_ext_power_limit},
 	{"fanduty", cmd_fanduty},
 	{"flasherase", cmd_flash_erase},
 	{"flashprotect", cmd_flash_protect},