path: root/common/usb_pd_policy.c

/* Copyright 2014 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.
 */

#include "atomic.h"
#include "charge_manager.h"
#include "common.h"
#include "console.h"
#include "ec_commands.h"
#include "flash.h"
#include "gpio.h"
#include "hooks.h"
#include "host_command.h"
#include "mkbp_event.h"
#include "registers.h"
#include "rsa.h"
#include "sha256.h"
#include "system.h"
#include "task.h"
#include "tcpm.h"
#include "timer.h"
#include "util.h"
#include "usb_api.h"
#include "usb_common.h"
#include "usb_mux.h"
#include "usb_pd.h"
#include "usbc_ppc.h"
#include "version.h"

#ifdef CONFIG_COMMON_RUNTIME
#define CPRINTS(format, args...) cprints(CC_USBPD, format, ## args)
#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
#else
#define CPRINTS(format, args...)
#define CPRINTF(format, args...)
#endif

static int rw_flash_changed = 1;

#ifdef CONFIG_MKBP_EVENT
static int dp_alt_mode_entry_get_next_event(uint8_t *data)
{
	return EC_SUCCESS;
}
DECLARE_EVENT_SOURCE(EC_MKBP_EVENT_DP_ALT_MODE_ENTERED,
		     dp_alt_mode_entry_get_next_event);

void pd_notify_dp_alt_mode_entry(void)
{
	CPRINTS("Notifying AP of DP Alt Mode Entry...");
	mkbp_send_event(EC_MKBP_EVENT_DP_ALT_MODE_ENTERED);
}
#endif /* CONFIG_MKBP_EVENT */

int pd_check_requested_voltage(uint32_t rdo, const int port)
{
	int max_ma = rdo & 0x3FF;
	int op_ma = (rdo >> 10) & 0x3FF;
	int idx = RDO_POS(rdo);
	uint32_t pdo;
	uint32_t pdo_ma;
#if defined(CONFIG_USB_PD_DYNAMIC_SRC_CAP) || \
		defined(CONFIG_USB_PD_MAX_SINGLE_SOURCE_CURRENT)
	const uint32_t *src_pdo;
	const int pdo_cnt = charge_manager_get_source_pdo(&src_pdo, port);
#else
	const uint32_t *src_pdo = pd_src_pdo;
	const int pdo_cnt = pd_src_pdo_cnt;
#endif

	/* Board specific check for this request */
	if (pd_board_check_request(rdo, pdo_cnt))
		return EC_ERROR_INVAL;

	/* check current ... */
	pdo = src_pdo[idx - 1];
	pdo_ma = (pdo & 0x3ff);
	if (op_ma > pdo_ma)
		return EC_ERROR_INVAL; /* too much op current */
	if (max_ma > pdo_ma && !(rdo & RDO_CAP_MISMATCH))
		return EC_ERROR_INVAL; /* too much max current */

	CPRINTF("Requested %d mV %d mA (for %d/%d mA)\n",
		 ((pdo >> 10) & 0x3ff) * 50, (pdo & 0x3ff) * 10,
		 op_ma * 10, max_ma * 10);

	/* Accept the requested voltage */
	return EC_SUCCESS;
}

__attribute__((weak)) int pd_board_check_request(uint32_t rdo, int pdo_cnt)
{
	int idx = RDO_POS(rdo);

	/* Check for invalid index */
	return (!idx || idx > pdo_cnt) ?
		EC_ERROR_INVAL : EC_SUCCESS;
}

#ifdef CONFIG_USB_PD_DUAL_ROLE
/* Last received source cap */
static uint32_t pd_src_caps[CONFIG_USB_PD_PORT_MAX_COUNT][PDO_MAX_OBJECTS];
static uint8_t pd_src_cap_cnt[CONFIG_USB_PD_PORT_MAX_COUNT];

/* Cap on the max voltage requested as a sink (in millivolts) */
static unsigned max_request_mv = PD_MAX_VOLTAGE_MV; /* no cap */

const uint32_t * const pd_get_src_caps(int port)
{
	ASSERT(port < CONFIG_USB_PD_PORT_MAX_COUNT);

	return pd_src_caps[port];
}

uint8_t pd_get_src_cap_cnt(int port)
{
	ASSERT(port < CONFIG_USB_PD_PORT_MAX_COUNT);

	return pd_src_cap_cnt[port];
}

void pd_process_source_cap(int port, int cnt, uint32_t *src_caps)
{
#ifdef CONFIG_CHARGE_MANAGER
	uint32_t ma, mv, pdo;
#endif
	int i;

	pd_src_cap_cnt[port] = cnt;
	for (i = 0; i < cnt; i++)
		pd_src_caps[port][i] = *src_caps++;

#ifdef CONFIG_CHARGE_MANAGER
	/* Get max power info that we could request */
	pd_find_pdo_index(pd_get_src_cap_cnt(port), pd_get_src_caps(port),
						PD_MAX_VOLTAGE_MV, &pdo);
	pd_extract_pdo_power(pdo, &ma, &mv);

	/* Set max. limit, but apply 500mA ceiling */
	charge_manager_set_ceil(port, CEIL_REQUESTOR_PD, PD_MIN_MA);
	pd_set_input_current_limit(port, ma, mv);
#endif
}

void pd_set_max_voltage(unsigned mv)
{
	max_request_mv = mv;
}

unsigned pd_get_max_voltage(void)
{
	return max_request_mv;
}

int pd_charge_from_device(uint16_t vid, uint16_t pid)
{
	/* TODO: rewrite into table if we get more of these */
	/*
	 * White-list Apple charge-through accessory since it doesn't set
	 * unconstrained bit, but we still need to charge from it when
	 * we are a sink.
	 */
	return (vid == USB_VID_APPLE && (pid == 0x1012 || pid == 0x1013));
}
#endif /* CONFIG_USB_PD_DUAL_ROLE */

static struct pd_cable cable[CONFIG_USB_PD_PORT_MAX_COUNT];

static bool is_transmit_msg_sop_prime(int port)
{
	return (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP) &&
		(cable[port].flags & CABLE_FLAGS_SOP_PRIME_ENABLE));
}

uint8_t is_sop_prime_ready(int port,
			   enum pd_data_role data_role,
			   uint32_t pd_flags)
{
	/*
	 * Ref: USB PD 3.0 sec 2.5.4: When an Explicit Contract is in place the
	 * VCONN Source (either the DFP or the UFP) can communicate with the
	 * Cable Plug(s) using SOP’/SOP’’ Packets
	 *
	 * Ref: USB PD 2.0 sec 2.4.4: When an Explicit Contract is in place the
	 * DFP (either the Source or the Sink) can communicate with the
	 * Cable Plug(s) using SOP’/SOP” Packets.
	 * Sec 3.6.11 : Before communicating with a Cable Plug a Port Should
	 * ensure that it is the Vconn Source
	 */
	if (pd_flags & PD_FLAGS_VCONN_ON && (IS_ENABLED(CONFIG_USB_PD_REV30) ||
		data_role == PD_ROLE_DFP))
		return is_transmit_msg_sop_prime(port);

	return 0;
}

void reset_pd_cable(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP))
		memset(&cable[port], 0, sizeof(cable[port]));
}

enum idh_ptype get_usb_pd_cable_type(int port)
{
	return cable[port].type;
}

union tbt_mode_resp_cable get_cable_tbt_vdo(int port)
{
	/*
	 * Return Discover mode SOP prime response for Thunderbolt-compatible
	 * mode SVDO.
	 */
	return cable[port].cable_mode_resp;
}

union tbt_mode_resp_device get_dev_tbt_vdo(int port)
{
	/*
	 * Return Discover mode SOP response for Thunderbolt-compatible
	 * mode SVDO.
	 */
	return cable[port].dev_mode_resp;
}

enum tbt_compat_cable_speed get_tbt_cable_speed(int port)
{
	/* tbt_cable_speed is zero when uninitialized */
	return cable[port].cable_mode_resp.tbt_cable_speed;
}

enum tbt_compat_rounded_support get_tbt_rounded_support(int port)
{
	/* tbt_rounded_support is zero when uninitialized */
	return cable[port].cable_mode_resp.tbt_rounded;
}

#ifdef CONFIG_USB_PD_ALT_MODE

#ifdef CONFIG_USB_PD_ALT_MODE_DFP

static struct pd_policy pe[CONFIG_USB_PD_PORT_MAX_COUNT];

static int is_vdo_present(int cnt, int index)
{
	return cnt > index;
}

static void enable_transmit_sop_prime(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP))
		cable[port].flags |= CABLE_FLAGS_SOP_PRIME_ENABLE;
}

static void disable_transmit_sop_prime(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP))
		cable[port].flags &= ~CABLE_FLAGS_SOP_PRIME_ENABLE;
}

static bool is_tbt_compat_enabled(int port)
{
	return (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE) &&
	       (cable[port].flags & CABLE_FLAGS_TBT_COMPAT_ENABLE));
}

static void enable_tbt_compat_mode(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE))
		cable[port].flags |= CABLE_FLAGS_TBT_COMPAT_ENABLE;
}

static inline void disable_tbt_compat_mode(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE))
		cable[port].flags &= ~CABLE_FLAGS_TBT_COMPAT_ENABLE;
}

static void set_tbt_compat_mode_ready(int port)
{
	if (IS_ENABLED(CONFIG_USBC_SS_MUX) &&
	    IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE)) {
		/* Connect the SBU and USB lines to the connector. */
		if (IS_ENABLED(CONFIG_USBC_PPC_SBU))
			ppc_set_sbu(port, 1);

		/* Set usb mux to Thunderbolt-compatible mode */
		usb_mux_set(port, USB_PD_MUX_TBT_COMPAT_ENABLED,
			USB_SWITCH_CONNECT, pd_get_polarity(port));
	}
}

/*
 * Ref: USB Type-C Cable and Connector Specification
 * Figure F-1 TBT3 Discovery Flow
 */
static bool is_tbt_cable_superspeed(int port)
{
	if (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE) &&
	    IS_ENABLED(CONFIG_USB_PD_DECODE_SOP)) {
		/* Product type is Active cable, hence don't check for speed */
		if (cable[port].type == IDH_PTYPE_ACABLE)
			return true;

		if (cable[port].type != IDH_PTYPE_PCABLE)
			return false;

		if (IS_ENABLED(CONFIG_USB_PD_REV30) &&
			cable[port].rev == PD_REV30)
			return cable[port].attr.p_rev30.ss ==
				USB_R30_SS_U32_U40_GEN1 ||
				cable[port].attr.p_rev30.ss ==
				USB_R30_SS_U32_U40_GEN2 ||
				cable[port].attr.p_rev30.ss ==
				USB_R30_SS_U40_GEN3;

		return cable[port].attr.p_rev20.ss ==
			USB_R20_SS_U31_GEN1 ||
			cable[port].attr.p_rev20.ss ==
			USB_R20_SS_U31_GEN1_GEN2;
	}
	return false;
}

/* Check if product supports any Modal Operation (Alternate Modes) */
static bool is_modal(int port, int cnt, uint32_t *payload)
{
	return IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE) &&
		is_vdo_present(cnt, VDO_INDEX_IDH) &&
		PD_IDH_IS_MODAL(payload[VDO_INDEX_IDH]);
}

static bool is_intel_svid(int port, int prev_svid_cnt)
{
	int i;

	/*
	 * Check if SVID0 = USB_VID_INTEL
	 * (Ref: USB Type-C cable and connector specification, Table F-9)
	 */
	if (IS_ENABLED(CONFIG_USB_PD_TBT_COMPAT_MODE)) {
		/*
		 * errata: All the Thunderbolt certified cables and docks
		 * tested have SVID1 = 0x8087
		 *
		 * For the Discover SVIDs, responder may present the SVIDs
		 * in any order hence check all SVIDs if Intel SVID present.
		 */
		for (i = prev_svid_cnt; i < pe[port].svid_cnt; i++) {
			if (pe[port].svids[i].svid == USB_VID_INTEL)
				return true;
		}
	}
	return false;
}

static inline bool is_tbt_compat_mode(int port, int cnt, uint32_t *payload)
{
	/*
	 * Ref: USB Type-C cable and connector specification
	 * F.2.5 TBT3 Device Discover Mode Responses
	 */
	return is_vdo_present(cnt, VDO_INDEX_IDH) &&
		PD_VDO_RESP_MODE_INTEL_TBT(payload[VDO_INDEX_IDH]);
}

static inline void limit_tbt_cable_speed(int port)
{
	/* Cable flags are cleared when cable reset is called */
	cable[port].flags |= CABLE_FLAGS_TBT_COMPAT_LIMIT_SPEED;
}

static inline bool is_limit_tbt_cable_speed(int port)
{
	return !!(cable[port].flags & CABLE_FLAGS_TBT_COMPAT_LIMIT_SPEED);
}

void pd_dfp_pe_init(int port)
{
	memset(&pe[port], 0, sizeof(struct pd_policy));
}

static void dfp_consume_identity(int port, int cnt, uint32_t *payload)
{
	int ptype = PD_IDH_PTYPE(payload[VDO_I(IDH)]);
	size_t identity_size = MIN(sizeof(pe[port].identity),
				   (cnt - 1) * sizeof(uint32_t));
	pd_dfp_pe_init(port);
	memcpy(&pe[port].identity, payload + 1, identity_size);

	switch (ptype) {
	case IDH_PTYPE_AMA:
/* Leave vbus ON if the following macro is false */
#if defined(CONFIG_USB_PD_DUAL_ROLE) && defined(CONFIG_USBC_VCONN_SWAP)
		/* Adapter is requesting vconn, try to supply it */
		if (PD_VDO_AMA_VCONN_REQ(payload[VDO_I(AMA)]))
			pd_try_vconn_src(port);

		/* Only disable vbus if vconn was requested */
		if (PD_VDO_AMA_VCONN_REQ(payload[VDO_I(AMA)]) &&
				!PD_VDO_AMA_VBUS_REQ(payload[VDO_I(AMA)]))
			pd_power_supply_reset(port);
#endif
		break;
	default:
		break;
	}
}

static void dfp_consume_cable_response(int port, int cnt, uint32_t *payload,
					uint16_t head)
{
	if (cable[port].is_identified)
		return;

	/* Get cable rev */
	cable[port].rev = PD_HEADER_REV(head);

	if (is_vdo_present(cnt, VDO_INDEX_IDH)) {
		cable[port].type = PD_IDH_PTYPE(payload[VDO_INDEX_IDH]);
		if (is_vdo_present(cnt, VDO_INDEX_PTYPE_CABLE1))
			cable[port].attr.raw_value =
					payload[VDO_INDEX_PTYPE_CABLE1];
	}
	/*
	 * Ref USB PD Spec 3.0  Pg 145. For active cable there are two VDOs.
	 * Hence storing the second VDO.
	 */
	if (IS_ENABLED(CONFIG_USB_PD_REV30) &&
	    is_vdo_present(cnt, VDO_INDEX_PTYPE_CABLE2) &&
	    cable[port].type == IDH_PTYPE_ACABLE)
		cable[port].attr2.raw_value = payload[VDO_INDEX_PTYPE_CABLE2];

	cable[port].is_identified = 1;
}

static int dfp_discover_ident(uint32_t *payload)
{
	payload[0] = VDO(USB_SID_PD, 1, CMD_DISCOVER_IDENT);
	return 1;
}

static int dfp_discover_svids(uint32_t *payload)
{
	payload[0] = VDO(USB_SID_PD, 1, CMD_DISCOVER_SVID);
	return 1;
}

static void dfp_consume_svids(int port, int cnt, uint32_t *payload)
{
	int i;
	uint32_t *ptr = payload + 1;
	int vdo = 1;
	uint16_t svid0, svid1;

	for (i = pe[port].svid_cnt; i < pe[port].svid_cnt + 12; i += 2) {
		if (i == SVID_DISCOVERY_MAX) {
			CPRINTF("ERR:SVIDCNT\n");
			break;
		}
		/*
		 * Verify we're still within the valid packet (count will be one
		 * for the VDM header + xVDOs)
		 */
		if (vdo >= cnt)
			break;

		svid0 = PD_VDO_SVID_SVID0(*ptr);
		if (!svid0)
			break;
		pe[port].svids[i].svid = svid0;
		pe[port].svid_cnt++;

		svid1 = PD_VDO_SVID_SVID1(*ptr);
		if (!svid1)
			break;
		pe[port].svids[i + 1].svid = svid1;
		pe[port].svid_cnt++;
		ptr++;
		vdo++;
	}
	/* TODO(tbroch) need to re-issue discover svids if > 12 */
	if (i && ((i % 12) == 0))
		CPRINTF("ERR:SVID+12\n");
}

static int dfp_discover_modes(int port, uint32_t *payload)
{
	uint16_t svid = pe[port].svids[pe[port].svid_idx].svid;
	if (pe[port].svid_idx >= pe[port].svid_cnt)
		return 0;
	payload[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
	return 1;
}

static void dfp_consume_modes(int port, int cnt, uint32_t *payload)
{
	int idx = pe[port].svid_idx;
	pe[port].svids[idx].mode_cnt = cnt - 1;
	if (pe[port].svids[idx].mode_cnt < 0) {
		CPRINTF("ERR:NOMODE\n");
	} else {
		memcpy(pe[port].svids[pe[port].svid_idx].mode_vdo, &payload[1],
		       sizeof(uint32_t) * pe[port].svids[idx].mode_cnt);
	}

	pe[port].svid_idx++;
}

static int get_mode_idx(int port, uint16_t svid)
{
	int i;

	for (i = 0; i < PD_AMODE_COUNT; i++) {
		if (pe[port].amodes[i].fx &&
		    (pe[port].amodes[i].fx->svid == svid))
			return i;
	}
	return -1;
}

struct svdm_amode_data *pd_get_amode_data(int port, uint16_t svid)
{
	int idx = get_mode_idx(port, svid);

	return (idx == -1) ? NULL : &pe[port].amodes[idx];
}

int pd_alt_mode(int port, uint16_t svid)
{
	struct svdm_amode_data *modep = pd_get_amode_data(port, svid);

	return (modep) ? modep->opos : -1;
}

int allocate_mode(int port, uint16_t svid)
{
	int i, j;
	struct svdm_amode_data *modep;
	int mode_idx = get_mode_idx(port, svid);

	if (mode_idx != -1)
		return mode_idx;

	/* There's no space to enter another mode */
	if (pe[port].amode_idx == PD_AMODE_COUNT) {
		CPRINTF("ERR:NO AMODE SPACE\n");
		return -1;
	}

	/* Allocate ...  if SVID == 0 enter default supported policy */
	for (i = 0; i < supported_modes_cnt; i++) {
		for (j = 0; j < pe[port].svid_cnt; j++) {
			struct svdm_svid_data *svidp = &pe[port].svids[j];
			if ((svidp->svid != supported_modes[i].svid) ||
			    (svid && (svidp->svid != svid)))
				continue;

			modep = &pe[port].amodes[pe[port].amode_idx];
			modep->fx = &supported_modes[i];
			modep->data = &pe[port].svids[j];
			pe[port].amode_idx++;
			return pe[port].amode_idx - 1;
		}
	}
	return -1;
}

/*
 * Enter default mode ( payload[0] == 0 ) or attempt to enter mode via svid &
 * opos
*/
uint32_t pd_dfp_enter_mode(int port, uint16_t svid, int opos)
{
	int mode_idx = allocate_mode(port, svid);
	struct svdm_amode_data *modep;
	uint32_t mode_caps;

	if (mode_idx == -1)
		return 0;
	modep = &pe[port].amodes[mode_idx];

	if (!opos) {
		/* choose the lowest as default */
		modep->opos = 1;
	} else if (opos <= modep->data->mode_cnt) {
		modep->opos = opos;
	} else {
		CPRINTF("opos error\n");
		return 0;
	}

	mode_caps = modep->data->mode_vdo[modep->opos - 1];
	if (modep->fx->enter(port, mode_caps) == -1)
		return 0;

	/* SVDM to send to UFP for mode entry */
	return VDO(modep->fx->svid, 1, CMD_ENTER_MODE | VDO_OPOS(modep->opos));
}

/*
 * Enter Thunderbolt-compatible mode
 * Reference: USB Type-C cable and connector specification, Release 2.0
 *
 * This function fills the TBT3 objects in the payload and
 * returns the number of objects it has filled.
 */
static int enter_tbt_compat_mode(int port, uint32_t *payload)
{
	union tbt_dev_mode_enter_cmd enter_dev_mode = {0};

	/* Table F-12 TBT3 Cable Enter Mode Command */
	payload[0] = pd_dfp_enter_mode(port, USB_VID_INTEL, 0) |
					VDO_SVDM_VERS(VDM_VER20);

	/* For TBT3 Cable Enter Mode Command, number of Objects is 1 */
	if (is_transmit_msg_sop_prime(port))
		return 1;

	usb_mux_set_safe_mode(port);

	/* Table F-13 TBT3 Device Enter Mode Command */
	enter_dev_mode.vendor_spec_b1 =
				cable[port].dev_mode_resp.vendor_spec_b1;
	enter_dev_mode.vendor_spec_b0 =
				cable[port].dev_mode_resp.vendor_spec_b0;
	enter_dev_mode.intel_spec_b0 = cable[port].dev_mode_resp.intel_spec_b0;
	enter_dev_mode.cable =
		get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE ?
			TBT_ENTER_PASSIVE_CABLE : TBT_ENTER_ACTIVE_CABLE;

	if (cable[port].cable_mode_resp.tbt_cable_speed == TBT_SS_TBT_GEN3) {
		enter_dev_mode.lsrx_comm =
			cable[port].cable_mode_resp.lsrx_comm;
		enter_dev_mode.retimer_type =
			cable[port].cable_mode_resp.retimer_type;
		enter_dev_mode.tbt_cable =
			cable[port].cable_mode_resp.tbt_cable;
		enter_dev_mode.tbt_rounded =
			cable[port].cable_mode_resp.tbt_rounded;
		enter_dev_mode.tbt_cable_speed =
			cable[port].cable_mode_resp.tbt_cable_speed;
	} else {
		enter_dev_mode.tbt_cable_speed = TBT_SS_U32_GEN1_GEN2;
	}
	enter_dev_mode.tbt_alt_mode = TBT_ALTERNATE_MODE;

	payload[1] = enter_dev_mode.raw_value;

	/* For TBT3 Device Enter Mode Command, number of Objects are 2 */
	return 2;
}

static int validate_mode_request(struct svdm_amode_data *modep,
				 uint16_t svid, int opos)
{
	if (!modep->fx)
		return 0;

	if (svid != modep->fx->svid) {
		CPRINTF("ERR:svid r:0x%04x != c:0x%04x\n",
			svid, modep->fx->svid);
		return 0;
	}

	if (opos != modep->opos) {
		CPRINTF("ERR:opos r:%d != c:%d\n",
			opos, modep->opos);
		return 0;
	}

	return 1;
}

static void dfp_consume_attention(int port, uint32_t *payload)
{
	uint16_t svid = PD_VDO_VID(payload[0]);
	int opos = PD_VDO_OPOS(payload[0]);
	struct svdm_amode_data *modep = pd_get_amode_data(port, svid);

	if (!modep || !validate_mode_request(modep, svid, opos))
		return;

	if (modep->fx->attention)
		modep->fx->attention(port, payload);
}

/*
 * This algorithm defaults to choosing higher pin config over lower ones in
 * order to prefer multi-function if desired.
 *
 *  NAME | SIGNALING | OUTPUT TYPE | MULTI-FUNCTION | PIN CONFIG
 * -------------------------------------------------------------
 *  A    |  USB G2   |  ?          | no             | 00_0001
 *  B    |  USB G2   |  ?          | yes            | 00_0010
 *  C    |  DP       |  CONVERTED  | no             | 00_0100
 *  D    |  PD       |  CONVERTED  | yes            | 00_1000
 *  E    |  DP       |  DP         | no             | 01_0000
 *  F    |  PD       |  DP         | yes            | 10_0000
 *
 * if UFP has NOT asserted multi-function preferred code masks away B/D/F
 * leaving only A/C/E.  For single-output dongles that should leave only one
 * possible pin config depending on whether its a converter DP->(VGA|HDMI) or DP
 * output.  If UFP is a USB-C receptacle it may assert C/D/E/F.  The DFP USB-C
 * receptacle must always choose C/D in those cases.
 */
int pd_dfp_dp_get_pin_mode(int port, uint32_t status)
{
	struct svdm_amode_data *modep =
				pd_get_amode_data(port, USB_SID_DISPLAYPORT);
	uint32_t mode_caps;
	uint32_t pin_caps;
	if (!modep)
		return 0;

	mode_caps = modep->data->mode_vdo[modep->opos - 1];

	/* TODO(crosbug.com/p/39656) revisit with DFP that can be a sink */
	pin_caps = PD_DP_PIN_CAPS(mode_caps);

	/* if don't want multi-function then ignore those pin configs */
	if (!PD_VDO_DPSTS_MF_PREF(status))
		pin_caps &= ~MODE_DP_PIN_MF_MASK;

	/* TODO(crosbug.com/p/39656) revisit if DFP drives USB Gen 2 signals */
	pin_caps &= ~MODE_DP_PIN_BR2_MASK;

	/* if C/D present they have precedence over E/F for USB-C->USB-C */
	if (pin_caps & (MODE_DP_PIN_C | MODE_DP_PIN_D))
		pin_caps &= ~(MODE_DP_PIN_E | MODE_DP_PIN_F);

	/* get_next_bit returns undefined for zero */
	if (!pin_caps)
		return 0;

	return 1 << get_next_bit(&pin_caps);
}

int pd_dfp_exit_mode(int port, uint16_t svid, int opos)
{
	struct svdm_amode_data *modep;
	int idx;

	/*
	 * Empty svid signals we should reset DFP VDM state by exiting all
	 * entered modes then clearing state.  This occurs when we've
	 * disconnected or for hard reset.
	 */
	if (!svid) {
		for (idx = 0; idx < PD_AMODE_COUNT; idx++)
			if (pe[port].amodes[idx].fx)
				pe[port].amodes[idx].fx->exit(port);

		pd_dfp_pe_init(port);
		return 0;
	}

	/*
	 * TODO(crosbug.com/p/33946) : below needs revisited to allow multiple
	 * mode exit.  Additionally it should honor OPOS == 7 as DFP's request
	 * to exit all modes.  We currently don't have any UFPs that support
	 * multiple modes on one SVID.
	 */
	modep = pd_get_amode_data(port, svid);
	if (!modep || !validate_mode_request(modep, svid, opos))
		return 0;

	/* call DFPs exit function */
	modep->fx->exit(port);
	/* exit the mode */
	modep->opos = 0;
	return 1;
}

uint16_t pd_get_identity_vid(int port)
{
	return PD_IDH_VID(pe[port].identity[0]);
}

uint16_t pd_get_identity_pid(int port)
{
	return PD_PRODUCT_PID(pe[port].identity[2]);
}

uint8_t pd_get_product_type(int port)
{
	return PD_IDH_PTYPE(pe[port].identity[0]);
}

int pd_get_svid_count(int port)
{
	return pe[port].svid_cnt;
}

uint16_t pd_get_svid(int port, uint16_t svid_idx)
{
	return pe[port].svids[svid_idx].svid;
}

uint32_t *pd_get_mode_vdo(int port, uint16_t svid_idx)
{
	return pe[port].svids[svid_idx].mode_vdo;
}

#ifdef CONFIG_CMD_USB_PD_PE
static void dump_pe(int port)
{
	const char * const idh_ptype_names[]  = {
		"UNDEF", "Hub", "Periph", "PCable", "ACable", "AMA",
		"RSV6", "RSV7"};

	int i, j, idh_ptype;
	struct svdm_amode_data *modep;
	uint32_t mode_caps;

	if (pe[port].identity[0] == 0) {
		ccprintf("No identity discovered yet.\n");
		return;
	}
	idh_ptype = PD_IDH_PTYPE(pe[port].identity[0]);
	ccprintf("IDENT:\n");
	ccprintf("\t[ID Header] %08x :: %s, VID:%04x\n", pe[port].identity[0],
		 idh_ptype_names[idh_ptype], pd_get_identity_vid(port));
	ccprintf("\t[Cert Stat] %08x\n", pe[port].identity[1]);
	for (i = 2; i < ARRAY_SIZE(pe[port].identity); i++) {
		ccprintf("\t");
		if (pe[port].identity[i])
			ccprintf("[%d] %08x ", i, pe[port].identity[i]);
	}
	ccprintf("\n");

	if (pe[port].svid_cnt < 1) {
		ccprintf("No SVIDS discovered yet.\n");
		return;
	}

	for (i = 0; i < pe[port].svid_cnt; i++) {
		ccprintf("SVID[%d]: %04x MODES:", i, pe[port].svids[i].svid);
		for (j = 0; j < pe[port].svids[j].mode_cnt; j++)
			ccprintf(" [%d] %08x", j + 1,
				 pe[port].svids[i].mode_vdo[j]);
		ccprintf("\n");
		modep = pd_get_amode_data(port, pe[port].svids[i].svid);
		if (modep) {
			mode_caps = modep->data->mode_vdo[modep->opos - 1];
			ccprintf("MODE[%d]: svid:%04x caps:%08x\n", modep->opos,
				 modep->fx->svid, mode_caps);
		}
	}
}

static int command_pe(int argc, char **argv)
{
	int port;
	char *e;
	if (argc < 3)
		return EC_ERROR_PARAM_COUNT;
	/* command: pe <port> <subcmd> <args> */
	port = strtoi(argv[1], &e, 10);
	if (*e || port >= board_get_usb_pd_port_count())
		return EC_ERROR_PARAM2;
	if (!strncasecmp(argv[2], "dump", 4))
		dump_pe(port);

	return EC_SUCCESS;
}

DECLARE_CONSOLE_COMMAND(pe, command_pe,
			"<port> dump",
			"USB PE");
#endif /* CONFIG_CMD_USB_PD_PE */

/* Return the current cable speed received from Cable Discover Mode command */
__overridable enum tbt_compat_cable_speed board_get_max_tbt_speed(int port)
{
	return cable[port].cable_mode_resp.tbt_cable_speed;
}

__overridable bool board_is_tbt_usb4_port(int port)
{
	return true;
}

static int process_tbt_compat_discover_modes(int port, uint32_t *payload)
{
	int rsize;
	enum tbt_compat_cable_speed max_tbt_speed;

	/*
	 * For active cables, Enter mode: SOP', SOP'', SOP
	 * Ref: USB Type-C Cable and Connector Specification, figure F-1: TBT3
	 * Discovery Flow and Section F.2.7 TBT3 Cable Enter Mode Command.
	 */
	if (is_transmit_msg_sop_prime(port)) {
		/* Store Discover Mode SOP' response */
		cable[port].cable_mode_resp.raw_value = payload[1];

		/* Cable does not have Intel SVID for Discover SVID */
		if (is_limit_tbt_cable_speed(port))
			cable[port].cable_mode_resp.tbt_cable_speed =
						TBT_SS_U32_GEN1_GEN2;

		max_tbt_speed = board_get_max_tbt_speed(port);
		if (cable[port].cable_mode_resp.tbt_cable_speed >
			max_tbt_speed) {
			cable[port].cable_mode_resp.tbt_cable_speed =
				max_tbt_speed;
		}

		/*
		 * Enter Mode SOP' (Cable Enter Mode) is skipped for
		 * passive cables.
		 */
		if (get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE)
			disable_transmit_sop_prime(port);

		rsize = enter_tbt_compat_mode(port, payload);
	} else {
		/* Store Discover Mode SOP response */
		cable[port].dev_mode_resp.raw_value = payload[1];

		if (is_limit_tbt_cable_speed(port)) {
			/*
			 * Passive cable has Nacked for Discover SVID.
			 * No need to do Discover modes of cable. Assign the
			 * cable discovery attributes and enter into device
			 * Thunderbolt-compatible mode.
			 */
			cable[port].cable_mode_resp.tbt_cable_speed =
				(cable[port].rev == PD_REV30 &&
				cable[port].attr.p_rev30.ss >
					USB_R30_SS_U32_U40_GEN2) ?
				TBT_SS_U32_GEN1_GEN2 :
				cable[port].attr.p_rev30.ss;

			rsize = enter_tbt_compat_mode(port, payload);
		} else {
			/* Discover modes for SOP' */
			pe[port].svid_idx--;
			rsize = dfp_discover_modes(port, payload);
			enable_transmit_sop_prime(port);
		}
	}

	return rsize;
}
#endif /* CONFIG_USB_PD_ALT_MODE_DFP */

int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload,
		uint16_t head)
{
	int cmd = PD_VDO_CMD(payload[0]);
	int cmd_type = PD_VDO_CMDT(payload[0]);
	int (*func)(int port, uint32_t *payload) = NULL;

	int rsize = 1; /* VDM header at a minimum */

	payload[0] &= ~VDO_CMDT_MASK;
	*rpayload = payload;

	if (cmd_type == CMDT_INIT) {
		switch (cmd) {
		case CMD_DISCOVER_IDENT:
			func = svdm_rsp.identity;
			break;
		case CMD_DISCOVER_SVID:
			func = svdm_rsp.svids;
			break;
		case CMD_DISCOVER_MODES:
			func = svdm_rsp.modes;
			break;
		case CMD_ENTER_MODE:
			func = svdm_rsp.enter_mode;
			break;
		case CMD_DP_STATUS:
			if (svdm_rsp.amode)
				func = svdm_rsp.amode->status;
			break;
		case CMD_DP_CONFIG:
			if (svdm_rsp.amode)
				func = svdm_rsp.amode->config;
			break;
		case CMD_EXIT_MODE:
			func = svdm_rsp.exit_mode;
			break;
#ifdef CONFIG_USB_PD_ALT_MODE_DFP
		case CMD_ATTENTION:
			/*
			 * attention is only SVDM with no response
			 * (just goodCRC) return zero here.
			 */
			dfp_consume_attention(port, payload);
			return 0;
#endif
		default:
			CPRINTF("ERR:CMD:%d\n", cmd);
			rsize = 0;
		}
		if (func)
			rsize = func(port, payload);
		else /* not supported : NACK it */
			rsize = 0;
		if (rsize >= 1)
			payload[0] |= VDO_CMDT(CMDT_RSP_ACK);
		else if (!rsize) {
			payload[0] |= VDO_CMDT(CMDT_RSP_NAK);
			rsize = 1;
		} else {
			payload[0] |= VDO_CMDT(CMDT_RSP_BUSY);
			rsize = 1;
		}
		payload[0] |= VDO_SVDM_VERS(pd_get_vdo_ver(port));
	} else if (cmd_type == CMDT_RSP_ACK) {
#ifdef CONFIG_USB_PD_ALT_MODE_DFP
		struct svdm_amode_data *modep;

		modep = pd_get_amode_data(port, PD_VDO_VID(payload[0]));
#endif
		switch (cmd) {
#ifdef CONFIG_USB_PD_ALT_MODE_DFP
		case CMD_DISCOVER_IDENT:
			/* Received a SOP Prime Discover Ident msg */
			if (is_transmit_msg_sop_prime(port)) {
				/* Store cable type */
				dfp_consume_cable_response(port, cnt, payload,
							head);
				/*
				 * Disable Thunderbolt-compatible mode if the
				 * cable does not support superspeed
				 */
				if (is_tbt_compat_enabled(port) &&
					!is_tbt_cable_superspeed(port))
					disable_tbt_compat_mode(port);

				rsize = dfp_discover_svids(payload);
				disable_transmit_sop_prime(port);
			/* Received a SOP Discover Ident Message */
			} else if (IS_ENABLED(CONFIG_USB_PD_DECODE_SOP) &&
				board_is_tbt_usb4_port(port)) {
				dfp_consume_identity(port, cnt, payload);

				/*
				 * Enable Thunderbolt-compatible mode
				 * if the modal operation is supported
				 */
				if (is_modal(port, cnt, payload)) {
					enable_tbt_compat_mode(port);
					rsize = dfp_discover_ident(payload);
					enable_transmit_sop_prime(port);
				} else {
					rsize = dfp_discover_svids(payload);
				}
			} else {
				dfp_consume_identity(port, cnt, payload);
				rsize = dfp_discover_svids(payload);
			}
#ifdef CONFIG_CHARGE_MANAGER
			if (pd_charge_from_device(pd_get_identity_vid(port),
						  pd_get_identity_pid(port)))
				charge_manager_update_dualrole(port,
							       CAP_DEDICATED);
#endif
			break;
		case CMD_DISCOVER_SVID:
			{
			int prev_svid_cnt = pe[port].svid_cnt;
			dfp_consume_svids(port, cnt, payload);
			/*
			 * Ref: USB Type-C Cable and Connector Specification,
			 * figure F-1: TBT3 Discovery Flow
			 *
			 * Check if 0x8087 is received for Discover SVID SOP.
			 * If not, disable Thunderbolt-compatible mode
			 *
			 * If 0x8087 is not received for Discover SVID SOP'
			 * limit to TBT passive Gen 2 cable
			 */
			if (is_tbt_compat_enabled(port)) {
				bool intel_svid =
					is_intel_svid(port, prev_svid_cnt);
				if (is_transmit_msg_sop_prime(port)) {
					if (!intel_svid)
						limit_tbt_cable_speed(port);
				} else if (intel_svid) {
					rsize = dfp_discover_svids(payload);
					enable_transmit_sop_prime(port);
					break;
				} else {
					disable_tbt_compat_mode(port);
				}
			}

			rsize = dfp_discover_modes(port, payload);
			disable_transmit_sop_prime(port);
			}
			break;
		case CMD_DISCOVER_MODES:
			dfp_consume_modes(port, cnt, payload);
			if (is_tbt_compat_enabled(port) &&
				is_tbt_compat_mode(port, cnt, payload)) {
				rsize = process_tbt_compat_discover_modes(
						port, payload);
				break;
			}

			disable_tbt_compat_mode(port);
			rsize = dfp_discover_modes(port, payload);
			/* enter the default mode for DFP */
			if (!rsize) {
				payload[0] = pd_dfp_enter_mode(port, 0, 0);
				if (payload[0])
					rsize = 1;
			}
			break;
		case CMD_ENTER_MODE:
			/* No response once device (and cable) acks */
			if (is_tbt_compat_enabled(port)) {
				if (is_transmit_msg_sop_prime(port)) {
					disable_transmit_sop_prime(port);
					rsize = enter_tbt_compat_mode(port,
								payload);
				} else {
					/*
					 * Update Mux state to
					 * Thunderbolt-compatible mode.
					 */
					set_tbt_compat_mode_ready(port);
					rsize = 0;
				}
			/*
			 * Continue with PD flow if Thunderbolt-compatible mode
			 * is disabled.
			 */
			} else if (!modep) {
				rsize = 0;
			} else {
				if (!modep->opos)
					pd_dfp_enter_mode(port, 0, 0);

				if (modep->opos) {
					rsize = modep->fx->status(port,
								  payload);
					payload[0] |= PD_VDO_OPOS(modep->opos);
				}
			}
			break;
		case CMD_DP_STATUS:
			/* DP status response & UFP's DP attention have same
			   payload */
			dfp_consume_attention(port, payload);
			if (modep && modep->opos)
				rsize = modep->fx->config(port, payload);
			else
				rsize = 0;
			break;
		case CMD_DP_CONFIG:
			if (modep && modep->opos && modep->fx->post_config)
				modep->fx->post_config(port);
			/* no response after DFPs ack */
			rsize = 0;
			break;
		case CMD_EXIT_MODE:
			/* no response after DFPs ack */
			rsize = 0;
			break;
#endif
		case CMD_ATTENTION:
			/* no response after DFPs ack */
			rsize = 0;
			break;
		default:
			CPRINTF("ERR:CMD:%d\n", cmd);
			rsize = 0;
		}

		payload[0] |= VDO_CMDT(CMDT_INIT);
		payload[0] |= VDO_SVDM_VERS(pd_get_vdo_ver(port));
#ifdef CONFIG_USB_PD_ALT_MODE_DFP
	} else if (cmd_type == CMDT_RSP_BUSY) {
		switch (cmd) {
		case CMD_DISCOVER_IDENT:
		case CMD_DISCOVER_SVID:
		case CMD_DISCOVER_MODES:
			/* resend if its discovery */
			rsize = 1;
			break;
		case CMD_ENTER_MODE:
			/* Error */
			CPRINTF("ERR:ENTBUSY\n");
			rsize = 0;
			break;
		case CMD_EXIT_MODE:
			rsize = 0;
			break;
		default:
			rsize = 0;
		}
	} else if (cmd_type == CMDT_RSP_NAK) {
		/* Passive cable Nacked for Discover SVID */
		if (cmd == CMD_DISCOVER_SVID && is_tbt_compat_enabled(port) &&
		    is_transmit_msg_sop_prime(port) &&
		    get_usb_pd_cable_type(port) == IDH_PTYPE_PCABLE) {
			limit_tbt_cable_speed(port);
			rsize = dfp_discover_modes(port, payload);
			disable_transmit_sop_prime(port);
		} else {
			rsize = 0;
		}
#endif /* CONFIG_USB_PD_ALT_MODE_DFP */
	} else {
		CPRINTF("ERR:CMDT:%d\n", cmd);
		/* do not answer */
		rsize = 0;
	}
	return rsize;
}

#else

int pd_svdm(int port, int cnt, uint32_t *payload, uint32_t **rpayload,
		uint16_t head)
{
	return 0;
}

#endif /* CONFIG_USB_PD_ALT_MODE */

#ifdef CONFIG_CMD_USB_PD_CABLE
static const char * const cable_type[] = {
	[IDH_PTYPE_PCABLE] = "Passive",
	[IDH_PTYPE_ACABLE] = "Active",
};

static const char * const cable_curr[] = {
	[USB_VBUS_CUR_3A] = "3A",
	[USB_VBUS_CUR_5A] = "5A",
};

static int command_cable(int argc, char **argv)
{
	int port;
	char *e;

	if (argc < 2)
		return EC_ERROR_PARAM_COUNT;
	port = strtoi(argv[1], &e, 0);
	if (*e || port >= board_get_usb_pd_port_count())
		return EC_ERROR_PARAM2;

	if (!cable[port].is_identified) {
		ccprintf("Cable not identified.\n");
		return EC_SUCCESS;
	}

	ccprintf("Cable Type: ");
	if (cable[port].type != IDH_PTYPE_PCABLE &&
		cable[port].type != IDH_PTYPE_ACABLE) {
		ccprintf("Not Emark Cable\n");
		return EC_SUCCESS;
	}
	ccprintf("%s\n", cable_type[cable[port].type]);

	/* Cable revision */
	ccprintf("Cable Rev: %d.0\n", cable[port].rev + 1);

	/*
	 * For rev 2.0, rev 3.0 active and passive cables have same bits for
	 * connector type (Bit 19:18) and current handling capability bit 6:5
	 */
	ccprintf("Connector Type: %d\n", cable[port].attr.p_rev20.connector);

	if (cable[port].attr.p_rev20.vbus_cur) {
		ccprintf("Cable Current: %s\n",
		   cable[port].attr.p_rev20.vbus_cur > ARRAY_SIZE(cable_curr) ?
		   "Invalid" : cable_curr[cable[port].attr.p_rev20.vbus_cur]);
	} else
		ccprintf("Cable Current: Invalid\n");

	/*
	 * For Rev 3.0 passive cables and Rev 2.0 active and passive cables,
	 * USB Superspeed Signaling support have same bits 2:0
	 */
	if (cable[port].type == IDH_PTYPE_PCABLE)
		ccprintf("USB Superspeed Signaling support: %d\n",
			cable[port].attr.p_rev20.ss);

	/*
	 * For Rev 3.0 active cables and Rev 2.0 active and passive cables,
	 * SOP" controller preset have same bit 3
	 */
	if (cable[port].type == IDH_PTYPE_ACABLE)
		ccprintf("SOP'' Controller: %s present\n",
			cable[port].attr.a_rev20.sop_p_p ? "" : "Not");

	if (cable[port].rev == PD_REV30) {
		/*
		 * For Rev 3.0 active and passive cables, Max Vbus vtg have
		 * same bits 10:9.
		 */
		ccprintf("Max vbus voltage: %d\n",
			20 + 10 * cable[port].attr.p_rev30.vbus_max);

		/* For Rev 3.0 Active cables */
		if (cable[port].type == IDH_PTYPE_ACABLE) {
			ccprintf("SS signaling: USB_SS_GEN%u\n",
				cable[port].attr2.a2_rev30.usb_gen ? 2 : 1);
			ccprintf("Number of SS lanes supported: %u\n",
				cable[port].attr2.a2_rev30.usb_lanes);
		}
	}
	return EC_SUCCESS;
}

DECLARE_CONSOLE_COMMAND(pdcable, command_cable,
			"<port>",
			"Cable Characteristics");
#endif /* CONFIG_CMD_USB_PD_CABLE */

static void pd_usb_billboard_deferred(void)
{
#if defined(CONFIG_USB_PD_ALT_MODE) && !defined(CONFIG_USB_PD_ALT_MODE_DFP) \
	&& !defined(CONFIG_USB_PD_SIMPLE_DFP) && defined(CONFIG_USB_BOS)

	/*
	 * TODO(tbroch)
	 * 1. Will we have multiple type-C port UFPs
	 * 2. Will there be other modes applicable to DFPs besides DP
	 */
	if (!pd_alt_mode(0, USB_SID_DISPLAYPORT))
		usb_connect();

#endif
}
DECLARE_DEFERRED(pd_usb_billboard_deferred);

#define FW_RW_END (CONFIG_EC_WRITABLE_STORAGE_OFF + \
		   CONFIG_RW_STORAGE_OFF + CONFIG_RW_SIZE)

uint8_t *flash_hash_rw(void)
{
	static struct sha256_ctx ctx;

	/* re-calculate RW hash when changed as its time consuming */
	if (rw_flash_changed) {
		rw_flash_changed = 0;
		SHA256_init(&ctx);
		SHA256_update(&ctx, (void *)CONFIG_PROGRAM_MEMORY_BASE +
			      CONFIG_RW_MEM_OFF,
			      CONFIG_RW_SIZE - RSANUMBYTES);
		return SHA256_final(&ctx);
	} else {
		return ctx.buf;
	}
}

void pd_get_info(uint32_t *info_data)
{
	void *rw_hash = flash_hash_rw();

	/* copy first 20 bytes of RW hash */
	memcpy(info_data, rw_hash, 5 * sizeof(uint32_t));
	/* copy other info into data msg */
#if defined(CONFIG_USB_PD_HW_DEV_ID_BOARD_MAJOR) && \
	defined(CONFIG_USB_PD_HW_DEV_ID_BOARD_MINOR)
	info_data[5] = VDO_INFO(CONFIG_USB_PD_HW_DEV_ID_BOARD_MAJOR,
				CONFIG_USB_PD_HW_DEV_ID_BOARD_MINOR,
				ver_get_num_commits(system_get_image_copy()),
				(system_get_image_copy() != SYSTEM_IMAGE_RO));
#else
	info_data[5] = 0;
#endif
}

int pd_custom_flash_vdm(int port, int cnt, uint32_t *payload)
{
	static int flash_offset;
	int rsize = 1; /* default is just VDM header returned */

	switch (PD_VDO_CMD(payload[0])) {
	case VDO_CMD_VERSION:
		memcpy(payload + 1, &current_image_data.version, 24);
		rsize = 7;
		break;
	case VDO_CMD_REBOOT:
		/* ensure the power supply is in a safe state */
		pd_power_supply_reset(0);
		system_reset(0);
		break;
	case VDO_CMD_READ_INFO:
		/* copy info into response */
		pd_get_info(payload + 1);
		rsize = 7;
		break;
	case VDO_CMD_FLASH_ERASE:
		/* do not kill the code under our feet */
		if (system_get_image_copy() != SYSTEM_IMAGE_RO)
			break;
		pd_log_event(PD_EVENT_ACC_RW_ERASE, 0, 0, NULL);
		flash_offset = CONFIG_EC_WRITABLE_STORAGE_OFF +
			       CONFIG_RW_STORAGE_OFF;
		flash_physical_erase(CONFIG_EC_WRITABLE_STORAGE_OFF +
				     CONFIG_RW_STORAGE_OFF, CONFIG_RW_SIZE);
		rw_flash_changed = 1;
		break;
	case VDO_CMD_FLASH_WRITE:
		/* do not kill the code under our feet */
		if ((system_get_image_copy() != SYSTEM_IMAGE_RO) ||
		    (flash_offset < CONFIG_EC_WRITABLE_STORAGE_OFF +
				    CONFIG_RW_STORAGE_OFF))
			break;
		flash_physical_write(flash_offset, 4*(cnt - 1),
				     (const char *)(payload+1));
		flash_offset += 4*(cnt - 1);
		rw_flash_changed = 1;
		break;
	case VDO_CMD_ERASE_SIG:
		/* this is not touching the code area */
		{
			uint32_t zero = 0;
			int offset;
			/* zeroes the area containing the RSA signature */
			for (offset = FW_RW_END - RSANUMBYTES;
			     offset < FW_RW_END; offset += 4)
				flash_physical_write(offset, 4,
						     (const char *)&zero);
		}
		break;
	default:
		/* Unknown : do not answer */
		return 0;
	}
	return rsize;
}

#ifdef CONFIG_USB_PD_DISCHARGE
void pd_set_vbus_discharge(int port, int enable)
{
	static struct mutex discharge_lock[CONFIG_USB_PD_PORT_MAX_COUNT];

	mutex_lock(&discharge_lock[port]);
	enable &= !board_vbus_source_enabled(port);
#ifdef CONFIG_USB_PD_DISCHARGE_GPIO
	if (!port)
		gpio_set_level(GPIO_USB_C0_DISCHARGE, enable);
#if CONFIG_USB_PD_PORT_MAX_COUNT > 1
	else
		gpio_set_level(GPIO_USB_C1_DISCHARGE, enable);
#endif /* CONFIG_USB_PD_PORT_MAX_COUNT */
#elif defined(CONFIG_USB_PD_DISCHARGE_TCPC)
	tcpc_discharge_vbus(port, enable);
#elif defined(CONFIG_USB_PD_DISCHARGE_PPC)
	ppc_discharge_vbus(port, enable);
#else
#error "PD discharge implementation not defined"
#endif
	mutex_unlock(&discharge_lock[port]);
}
#endif /* CONFIG_USB_PD_DISCHARGE */