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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.
*/
/*
* Thunderbolt alternate mode support
* Refer to USB Type-C Cable and Connector Specification Release 2.0 Section F
*/
#include <stdbool.h>
#include <stdint.h>
#include "compile_time_macros.h"
#include "console.h"
#include "tcpm.h"
#include "usb_mux.h"
#include "usb_pd.h"
#include "usb_pd_dpm.h"
#include "usb_pd_tbt.h"
#include "usb_pe_sm.h"
#include "usb_tbt_alt_mode.h"
#ifdef CONFIG_COMMON_RUNTIME
#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
#define CPRINTS(format, args...) cprints(CC_USBPD, format, ## args)
#else
#define CPRINTF(format, args...)
#define CPRINTS(format, args...)
#endif
static int tbt_prints(const char *string, int port)
{
return CPRINTS("C%d: TBT %s", port, string);
}
/* The states of Thunderbolt negotiation */
enum tbt_states {
TBT_START = 0,
TBT_ENTER_SOP_NACKED,
TBT_ACTIVE,
TBT_ENTER_SOP_RETRY,
TBT_INACTIVE,
TBT_STATE_COUNT,
};
static enum tbt_states tbt_state[CONFIG_USB_PD_PORT_MAX_COUNT];
static const uint8_t state_vdm_cmd[TBT_STATE_COUNT] = {
[TBT_START] = CMD_ENTER_MODE,
[TBT_ACTIVE] = CMD_EXIT_MODE,
[TBT_ENTER_SOP_NACKED] = CMD_EXIT_MODE,
[TBT_ENTER_SOP_RETRY] = CMD_ENTER_MODE,
};
void tbt_init(int port)
{
tbt_state[port] = TBT_START;
}
void tbt_teardown(int port)
{
tbt_prints("teardown", port);
tbt_state[port] = TBT_INACTIVE;
}
static void tbt_entry_failed(int port)
{
tbt_prints("alt mode protocol failed!", port);
tbt_state[port] = TBT_INACTIVE;
dpm_set_mode_entry_done(port);
}
static bool tbt_response_valid(int port, enum tcpm_transmit_type type,
char *cmdt, int vdm_cmd)
{
enum tbt_states st = tbt_state[port];
/*
* Check for an unexpected response.
* If Thunderbolt is inactive, ignore the command.
*/
if ((st != TBT_INACTIVE && state_vdm_cmd[st] != vdm_cmd) ||
(get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE &&
type != TCPC_TX_SOP)) {
tbt_entry_failed(port);
return false;
}
return true;
}
void intel_vdm_acked(int port, enum tcpm_transmit_type type, int vdo_count,
uint32_t *vdm)
{
const uint8_t vdm_cmd = PD_VDO_CMD(vdm[0]);
if (!tbt_response_valid(port, type, "ACK", vdm_cmd))
return;
switch (tbt_state[port]) {
case TBT_START:
case TBT_ENTER_SOP_RETRY:
set_tbt_compat_mode_ready(port);
dpm_set_mode_entry_done(port);
tbt_state[port] = TBT_ACTIVE;
tbt_prints("enter mode SOP", port);
break;
case TBT_ACTIVE:
/*
* Request to exit mode successful, so put it in
* inactive state.
*/
tbt_prints("exit mode SOP", port);
tbt_state[port] = TBT_INACTIVE;
break;
case TBT_ENTER_SOP_NACKED:
/*
* The request to exit the mode was successful,
* so try to enter the mode again.
*/
tbt_state[port] = TBT_ENTER_SOP_RETRY;
break;
case TBT_INACTIVE:
/*
* This can occur if the mode is shutdown because
* the CPU is being turned off, and an exit mode
* command has been sent.
*/
break;
default:
/* Invalid or unexpected negotiation state */
CPRINTF("%s called with invalid state %d\n",
__func__, tbt_state[port]);
tbt_entry_failed(port);
break;
}
}
void intel_vdm_naked(int port, enum tcpm_transmit_type type, uint8_t vdm_cmd)
{
if (!tbt_response_valid(port, type, "NACK", vdm_cmd))
return;
switch (tbt_state[port]) {
case TBT_START:
/*
* If a request to enter Thunderbolt mode is NAK'ed, this
* likely means the partner is already in Thunderbolt alt mode,
* so request to exit the mode first before retrying the enter
* command. This can happen if the EC is restarted
*/
tbt_state[port] = TBT_ENTER_SOP_NACKED;
break;
case TBT_ENTER_SOP_RETRY:
/*
* Another NAK on the second attempt to enter Thunderbolt mode.
* Give up.
*/
tbt_entry_failed(port);
break;
default:
CPRINTS("C%d: NAK for cmd %d in state %d", port,
vdm_cmd, tbt_state[port]);
tbt_entry_failed(port);
break;
}
}
int tbt_setup_next_vdm(int port, int vdo_count, uint32_t *vdm)
{
const struct pd_discovery *disc =
pd_get_am_discovery(port, TCPC_TX_SOP);
struct svdm_amode_data *modep;
int vdo_count_ret = 0;
if (vdo_count < VDO_MAX_SIZE ||
!disc->identity.idh.modal_support ||
!is_tbt_cable_superspeed(port) ||
get_tbt_cable_speed(port) < TBT_SS_U31_GEN1) {
return -1;
}
switch (tbt_state[port]) {
case TBT_START:
case TBT_ENTER_SOP_RETRY:
if (tbt_state[port] == TBT_START)
tbt_prints("attempt to enter mode", port);
/*
* Note: If it's not a Passive cable, the tbt_setup_next_vdm()
* function will return zero
*/
if (get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE) {
vdo_count_ret =
enter_tbt_compat_mode(port, TCPC_TX_SOP, vdm);
}
/*
* TODO(b/148528713): Add support for Thunderbolt active cable.
*/
break;
case TBT_ENTER_SOP_NACKED:
case TBT_ACTIVE:
/*
* Called to exit Thunderbolt alt mode, either when the mode is
* active and the system is shutting down, or when an initial
* request to enter the mode is NAK'ed. This can happen if EC
* is restarted while Thunderbolt mode is active.
*/
if (get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE) {
modep = pd_get_amode_data(port,
TCPC_TX_SOP, USB_VID_INTEL);
if (!(modep && modep->opos))
return -1;
vdm[0] = VDO(USB_VID_INTEL, 1, CMD_EXIT_MODE) |
VDO_OPOS(modep->opos) |
VDO_CMDT(CMDT_INIT) |
VDO_SVDM_VERS(
pd_get_vdo_ver(port, TCPC_TX_SOP));
vdo_count_ret = 1;
}
break;
case TBT_INACTIVE:
/* Thunderbolt mode is inactive */
return -1;
default:
CPRINTF("%s called with invalid state %d\n",
__func__, tbt_state[port]);
return -1;
}
return vdo_count_ret;
}
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