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/* Copyright 2020 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.
*/
/* USB-C Overcurrent Protection Common Code */
#include "atomic.h"
#include "common.h"
#include "console.h"
#include "hooks.h"
#include "timer.h"
#include "usb_common.h"
#include "usb_pd.h"
#include "usbc_ocp.h"
#include "util.h"
#ifndef TEST_BUILD
#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
#define CPRINTS(format, args...) cprints(CC_USBPD, format, ## args)
#else
#define CPRINTF(args...)
#define CPRINTS(args...)
#endif
/*
* PD 3.1 Ver 1.3 7.1.7.1 Output Over Current Protection
*
* "After three consecutive over current events Source Shall go to
* ErrorRecovery.
*
* Sources Should attempt to send a Hard Reset message when over
* current protection engages followed by an Alert Message indicating
* an OCP event once an Explicit Contract has been established.
*
* The Source Shall prevent continual system or port cycling if over
* current protection continues to engage after initially resuming
* either default operation or renegotiation. Latching off the port or
* system is an acceptable response to recurring over current."
*
* Our policy will be first two OCPs -> hard reset
* 3rd -> ErrorRecovery
* 4th -> port latched off
*/
#define OCP_HR_CNT 2
#define OCP_MAX_CNT 4
/*
* Number of seconds until a latched-off port is re-enabled for sourcing after
* detecting a physical disconnect.
*/
#define OCP_COOLDOWN_DELAY_US (2 * SECOND)
/*
* A per-port table that indicates how many VBUS overcurrent events have
* occurred. This table is cleared after detecting a physical disconnect of the
* sink.
*/
static uint8_t oc_event_cnt_tbl[CONFIG_USB_PD_PORT_MAX_COUNT];
/* A flag for ports with sink device connected. */
static atomic_t snk_connected_ports;
static void clear_oc_tbl(void)
{
int port;
for (port = 0; port < board_get_usb_pd_port_count(); port++)
/*
* Only clear the table if the port partner is no longer
* attached after debouncing.
*/
if ((!(BIT(port) & (uint32_t)snk_connected_ports)) &&
oc_event_cnt_tbl[port]) {
oc_event_cnt_tbl[port] = 0;
CPRINTS("C%d: OC events cleared", port);
}
}
DECLARE_DEFERRED(clear_oc_tbl);
static atomic_t port_oc_reset_req;
static void re_enable_ports(void)
{
uint32_t ports = atomic_clear(&port_oc_reset_req);
while (ports) {
int port = __fls(ports);
ports &= ~BIT(port);
/*
* Let the board know that the overcurrent is
* over since we've completed our recovery actions by now.
*/
board_overcurrent_event(port, 0);
/* Queue up an Alert message for the partner */
pd_send_alert_msg(port, ADO_OCP_EVENT);
}
}
DECLARE_DEFERRED(re_enable_ports);
int usbc_ocp_add_event(int port)
{
int delay = 0;
if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
CPRINTS("%s(%d) Invalid port!", __func__, port);
return EC_ERROR_INVAL;
}
/* Let the board specific code know about the OC event. */
board_overcurrent_event(port, 1);
oc_event_cnt_tbl[port]++;
/* The port overcurrented, so don't clear it's OC events. */
atomic_clear_bits(&snk_connected_ports, 1 << port);
if (oc_event_cnt_tbl[port] >= OCP_MAX_CNT) {
CPRINTS("C%d: OC event limit reached! "
"Source path disabled until physical disconnect.",
port);
pd_power_supply_reset(port);
} else if (oc_event_cnt_tbl[port] <= OCP_HR_CNT) {
/*
* Hard reset for the first few offenses, sending an alert after
* at least the time we need to hard reset and make a new
* contract.
*/
pd_send_hard_reset(port);
delay = PD_T_SRC_RECOVER + 100*MSEC;
} else {
/*
* ErrorRecovery must be performed past the third OCP event,
* queueing up the alert for after it completes and a new
* contract is in place
*/
pd_set_error_recovery(port);
delay = PD_T_ERROR_RECOVERY + 100*MSEC;
}
if (delay) {
atomic_or(&port_oc_reset_req, BIT(port));
hook_call_deferred(&re_enable_ports_data, delay);
}
return EC_SUCCESS;
}
int usbc_ocp_clear_event_counter(int port)
{
if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
CPRINTS("%s(%d) Invalid port!", __func__, port);
return EC_ERROR_INVAL;
}
/*
* If we are clearing our event table in quick succession, we may be in
* an overcurrent loop where we are also detecting a disconnect on the
* CC pins. Therefore, let's not clear it just yet and the let the
* limit be reached. This way, we won't send the hard reset and
* actually detect the physical disconnect.
*/
if (oc_event_cnt_tbl[port]) {
hook_call_deferred(&clear_oc_tbl_data,
OCP_COOLDOWN_DELAY_US);
}
return EC_SUCCESS;
}
int usbc_ocp_is_port_latched_off(int port)
{
if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
CPRINTS("%s(%d) Invalid port!", __func__, port);
return 0;
}
return oc_event_cnt_tbl[port] >= OCP_MAX_CNT;
}
void usbc_ocp_snk_is_connected(int port, bool connected)
{
if ((port < 0) || (port >= board_get_usb_pd_port_count())) {
CPRINTS("%s(%d) Invalid port!", __func__, port);
return;
}
if (connected)
atomic_or(&snk_connected_ports, 1 << port);
else
atomic_clear_bits(&snk_connected_ports, 1 << port);
}
__overridable void board_overcurrent_event(int port, int is_overcurrented)
{
/* Do nothing by default. Boards with overcurrent GPIOs may override */
}
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