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/* Copyright 2015 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Charge input current limit ramp module for Chrome EC */
#include "charge_manager.h"
#include "charge_ramp.h"
#include "common.h"
#include "console.h"
#include "ec_commands.h"
#include "task.h"
#include "timer.h"
#include "usb_pd.h"
#include "util.h"
#define CPRINTS(format, args...) cprints(CC_USBCHARGE, format, ## args)
/* Number of times to ramp current searching for limit before stable charging */
#define RAMP_COUNT 3
/* Maximum allowable time charger can be unplugged to be considered an OCP */
#define OC_RECOVER_MAX_TIME (SECOND)
/* Delay for running state machine when board is not consuming full current */
#define CURRENT_DRAW_DELAY (5*SECOND)
/* Current ramp increment */
#define RAMP_CURR_INCR_MA 64
#define RAMP_CURR_DELAY (500*MSEC)
#define RAMP_CURR_START_MA 500
/* How much to backoff the input current limit when limit has been found */
#define RAMP_ICL_BACKOFF (2*RAMP_CURR_INCR_MA)
/* Interval at which VBUS voltage is monitored in stable state */
#define STABLE_VBUS_MONITOR_INTERVAL (SECOND)
/* Time to delay for stablizing the charging current */
#define STABLIZE_DELAY (5*SECOND)
enum chg_ramp_state {
CHG_RAMP_DISCONNECTED,
CHG_RAMP_CHARGE_DETECT_DELAY,
CHG_RAMP_OVERCURRENT_DETECT,
CHG_RAMP_RAMP,
CHG_RAMP_STABILIZE,
CHG_RAMP_STABLE,
};
static enum chg_ramp_state ramp_st;
struct oc_info {
timestamp_t ts;
uint64_t recover;
int sup;
int icl;
};
/* OCP info for each over-current */
static struct oc_info oc_info[CONFIG_USB_PD_PORT_COUNT][RAMP_COUNT];
static int oc_info_idx[CONFIG_USB_PD_PORT_COUNT];
#define ACTIVE_OC_INFO (oc_info[active_port][oc_info_idx[active_port]])
/* Active charging information */
static int active_port = CHARGE_PORT_NONE;
static int active_sup;
static int active_icl;
static int active_vtg;
static timestamp_t reg_time;
static int stablize_port;
static int stablize_sup;
/* Maximum/minimum input current limit for active charger */
static int max_icl;
static int min_icl;
void chg_ramp_charge_supplier_change(int port, int supplier, int current,
timestamp_t registration_time, int voltage)
{
/*
* If the last active port was a valid port and the port
* has changed, then this may have been an over-current.
*/
if (active_port != CHARGE_PORT_NONE &&
port != active_port) {
if (oc_info_idx[active_port] == RAMP_COUNT - 1)
oc_info_idx[active_port] = 0;
else
oc_info_idx[active_port]++;
ACTIVE_OC_INFO.ts = get_time();
ACTIVE_OC_INFO.sup = active_sup;
ACTIVE_OC_INFO.icl = active_icl;
}
/* Set new active port, set ramp state, and wake ramp task */
active_port = port;
active_sup = supplier;
active_vtg = voltage;
/* Set min and max input current limit based on if ramp is allowed */
if (board_is_ramp_allowed(active_sup)) {
min_icl = RAMP_CURR_START_MA;
max_icl = board_get_ramp_current_limit(active_sup, current);
} else {
min_icl = max_icl = current;
}
reg_time = registration_time;
if (ramp_st != CHG_RAMP_STABILIZE) {
ramp_st = (active_port == CHARGE_PORT_NONE) ?
CHG_RAMP_DISCONNECTED : CHG_RAMP_CHARGE_DETECT_DELAY;
CPRINTS("Ramp reset: st%d", ramp_st);
task_wake(TASK_ID_CHG_RAMP);
}
}
int chg_ramp_get_current_limit(void)
{
/*
* If we are ramping or stable, then use the active input
* current limit. Otherwise, use the minimum input current
* limit.
*/
switch (ramp_st) {
case CHG_RAMP_RAMP:
case CHG_RAMP_STABILIZE:
case CHG_RAMP_STABLE:
return active_icl;
default:
return min_icl;
}
}
int chg_ramp_is_detected(void)
{
/* Charger detected (charge detect delay has passed) */
return ramp_st > CHG_RAMP_CHARGE_DETECT_DELAY;
}
int chg_ramp_is_stable(void)
{
return ramp_st == CHG_RAMP_STABLE;
}
void chg_ramp_task(void)
{
int task_wait_time = -1;
int i, lim;
uint64_t detect_end_time_us = 0, time_us;
int last_active_port = CHARGE_PORT_NONE;
/*
* Static initializer so that we don't clobber early calls to this
* module.
*/
static enum chg_ramp_state ramp_st_prev = CHG_RAMP_DISCONNECTED,
ramp_st_new = CHG_RAMP_DISCONNECTED;
int active_icl_new;
/* Clear last OCP supplier to guarantee we ramp on first connect */
for (i = 0; i < CONFIG_USB_PD_PORT_COUNT; i++)
oc_info[i][0].sup = CHARGE_SUPPLIER_NONE;
while (1) {
ramp_st_new = ramp_st;
active_icl_new = active_icl;
switch (ramp_st) {
case CHG_RAMP_DISCONNECTED:
/* Do nothing */
task_wait_time = -1;
break;
case CHG_RAMP_CHARGE_DETECT_DELAY:
/* Delay for charge_manager to determine supplier */
/*
* On entry to state, or if port changes, store the
* OC recovery time, and calculate the detect end
* time to exit this state.
*/
if (ramp_st_prev != ramp_st ||
active_port != last_active_port) {
last_active_port = active_port;
ACTIVE_OC_INFO.recover =
reg_time.val - ACTIVE_OC_INFO.ts.val;
detect_end_time_us = get_time().val +
CHARGE_DETECT_DELAY;
task_wait_time = CHARGE_DETECT_DELAY;
break;
}
/* If detect delay has not passed, set wait time */
time_us = get_time().val;
if (time_us < detect_end_time_us) {
task_wait_time = detect_end_time_us - time_us;
break;
}
/* Detect delay is over, fall through to next state */
ramp_st_new = CHG_RAMP_OVERCURRENT_DETECT;
/* notify host of power info change */
pd_send_host_event(PD_EVENT_POWER_CHANGE);
case CHG_RAMP_OVERCURRENT_DETECT:
/* Check if we should ramp or go straight to stable */
task_wait_time = SECOND;
/* Skip ramp for specific suppliers */
if (!board_is_ramp_allowed(active_sup)) {
active_icl_new = min_icl;
ramp_st_new = CHG_RAMP_STABLE;
break;
}
/*
* If we are not drawing full charge, then don't ramp,
* just wait in this state, until we are.
*/
if (!board_is_consuming_full_charge()) {
task_wait_time = CURRENT_DRAW_DELAY;
break;
}
/*
* Compare recent OCP events, if all info matches,
* then we don't need to ramp anymore.
*/
for (i = 0; i < RAMP_COUNT; i++) {
if (oc_info[active_port][i].sup != active_sup ||
oc_info[active_port][i].recover >
OC_RECOVER_MAX_TIME)
break;
}
if (i == RAMP_COUNT) {
/* Found OC threshold! */
active_icl_new = ACTIVE_OC_INFO.icl -
RAMP_ICL_BACKOFF;
ramp_st_new = CHG_RAMP_STABLE;
} else {
/*
* Need to ramp to find OC threshold, start
* at the minimum input current limit.
*/
active_icl_new = min_icl;
ramp_st_new = CHG_RAMP_RAMP;
}
break;
case CHG_RAMP_RAMP:
/* Keep ramping until we find the limit */
task_wait_time = RAMP_CURR_DELAY;
/* Pause ramping if we are not drawing full current */
if (!board_is_consuming_full_charge()) {
task_wait_time = CURRENT_DRAW_DELAY;
break;
}
/* If VBUS is sagging a lot, then stop ramping */
if (board_is_vbus_too_low(CHG_RAMP_VBUS_RAMPING)) {
CPRINTS("VBUS low");
active_icl_new = MAX(min_icl, active_icl -
RAMP_ICL_BACKOFF);
ramp_st_new = CHG_RAMP_STABILIZE;
task_wait_time = STABLIZE_DELAY;
stablize_port = active_port;
stablize_sup = active_sup;
break;
}
/* Ramp the current limit if we haven't reached max */
if (active_icl == max_icl)
ramp_st_new = CHG_RAMP_STABLE;
else if (active_icl + RAMP_CURR_INCR_MA > max_icl)
active_icl_new = max_icl;
else
active_icl_new = active_icl + RAMP_CURR_INCR_MA;
break;
case CHG_RAMP_STABILIZE:
/* Wait for current to stabilize after ramp is done */
/* Use default delay for exiting this state */
task_wait_time = SECOND;
if (active_port == stablize_port &&
active_sup == stablize_sup) {
ramp_st_new = CHG_RAMP_STABLE;
break;
}
ramp_st_new = active_port == CHARGE_PORT_NONE ?
CHG_RAMP_DISCONNECTED :
CHG_RAMP_CHARGE_DETECT_DELAY;
break;
case CHG_RAMP_STABLE:
/* Maintain input current limit */
/* On entry log charging stats */
if (ramp_st_prev != ramp_st) {
#ifdef CONFIG_USB_PD_LOGGING
charge_manager_save_log(active_port);
#endif
/* notify host of power info change */
pd_send_host_event(PD_EVENT_POWER_CHANGE);
}
/* Keep an eye on VBUS and restart ramping if it dips */
if (board_is_ramp_allowed(active_sup) &&
board_is_vbus_too_low(CHG_RAMP_VBUS_STABLE)) {
CPRINTS("VBUS low; Re-ramp");
max_icl = MAX(min_icl,
max_icl - RAMP_ICL_BACKOFF);
active_icl_new = min_icl;
ramp_st_new = CHG_RAMP_RAMP;
}
task_wait_time = STABLE_VBUS_MONITOR_INTERVAL;
break;
}
if (ramp_st != ramp_st_new || active_icl != active_icl_new)
CPRINTS("Ramp p%d st%d %dmA %dmA",
active_port, ramp_st_new, min_icl,
active_icl_new);
ramp_st_prev = ramp_st;
ramp_st = ramp_st_new;
active_icl = active_icl_new;
/* Set the input current limit */
lim = chg_ramp_get_current_limit();
board_set_charge_limit(active_port, active_sup, lim,
lim, active_vtg);
if (ramp_st == CHG_RAMP_STABILIZE)
/*
* When in stabilize state, supplier/port may change
* and we don't want to wake up task until we have
* slept this amount of time.
*/
usleep(task_wait_time);
else
task_wait_event(task_wait_time);
}
}
#ifdef CONFIG_CMD_CHGRAMP
static int command_chgramp(int argc, char **argv)
{
int i;
int port;
ccprintf("Chg Ramp:\nState: %d\nMin ICL: %d\nActive ICL: %d\n",
ramp_st, min_icl, active_icl);
for (port = 0; port < CONFIG_USB_PD_PORT_COUNT; port++) {
ccprintf("Port %d:\n", port);
ccprintf(" OC idx:%d\n", oc_info_idx[port]);
for (i = 0; i < RAMP_COUNT; i++) {
ccprintf(" OC %d: s%d recover%lu icl%d\n", i,
oc_info[port][i].sup,
oc_info[port][i].recover,
oc_info[port][i].icl);
}
}
return EC_SUCCESS;
}
DECLARE_CONSOLE_COMMAND(chgramp, command_chgramp,
"",
"Dump charge ramp state info");
#endif
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