USB Power Delivery core code

The protocol layer implementation for USB Power Delivery messaging.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=none
TEST=none

Change-Id: I7db75b004cf9dbf13fa1df95336f206e93236fc9
Reviewed-on: https://chromium-review.googlesource.com/189866
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>

3 files changed, 820 insertions, 0 deletions

diff --git a/common/build.mk b/common/build.mk
index 93950f9495..7189a07432 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -63,6 +63,7 @@ common-$(CONFIG_SWITCH)+=switch.o
 common-$(CONFIG_TEMP_SENSOR)+=temp_sensor.o thermal.o
 common-$(CONFIG_USB_PORT_POWER_DUMB)+=usb_port_power_dumb.o
 common-$(CONFIG_USB_PORT_POWER_SMART)+=usb_port_power_smart.o
+common-$(CONFIG_USB_POWER_DELIVERY)+=usb_pd_protocol.o
 common-$(CONFIG_VBOOT_HASH)+=sha256.o vboot_hash.o
 common-$(CONFIG_WIRELESS)+=wireless.o
 common-$(HAS_TASK_CHIPSET)+=chipset.o throttle_ap.o
diff --git a/common/console_output.c b/common/console_output.c
index 2b52da66cf..4ff5a9c478 100644
--- a/common/console_output.c
+++ b/common/console_output.c
@@ -55,6 +55,7 @@ static const char * const channel_names[] = {
 	"task",
 	"thermal",
 	"usbcharge",
+	"usbpd",
 	"vboot",
 	"hook",
 };
diff --git a/common/usb_pd_protocol.c b/common/usb_pd_protocol.c
new file mode 100644
index 0000000000..4d0ef0f90b
--- /dev/null
+++ b/common/usb_pd_protocol.c
@@ -0,0 +1,818 @@
+/* Copyright (c) 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 "adc.h"
+#include "board.h"
+#include "common.h"
+#include "console.h"
+#include "crc.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "registers.h"
+#include "task.h"
+#include "timer.h"
+#include "util.h"
+#include "usb_pd.h"
+#include "usb_pd_config.h"
+
+#ifdef CONFIG_COMMON_RUNTIME
+#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
+
+/* dump full packet on RX error */
+static int debug_dump;
+#else
+#define CPRINTF(format, args...)
+const int debug_dump;
+#endif
+
+/* Control Message type */
+enum {
+	/* 0 Reserved */
+	PD_CTRL_GOOD_CRC = 1,
+	PD_CTRL_GOTO_MIN = 2,
+	PD_CTRL_ACCEPT = 3,
+	PD_CTRL_REJECT = 4,
+	PD_CTRL_PING = 5,
+	PD_CTRL_PS_RDY = 6,
+	PD_CTRL_GET_SOURCE_CAP = 7,
+	PD_CTRL_GET_SINK_CAP = 8,
+	PD_CTRL_PROTOCOL_ERR = 9,
+	PD_CTRL_SWAP = 10,
+	/* 11 Reserved */
+	PD_CTRL_WAIT = 12,
+	PD_CTRL_SOFT_RESET = 13,
+	/* 14-15 Reserved */
+};
+
+/* Data message type */
+enum {
+	/* 0 Reserved */
+	PD_DATA_SOURCE_CAP = 1,
+	PD_DATA_REQUEST = 2,
+	PD_DATA_BIST = 3,
+	PD_DATA_SINK_CAP = 4,
+	/* 5-14 Reserved */
+	PD_DATA_VENDOR_DEF = 15,
+};
+
+/* Protocol revision */
+#define PD_REV10 0
+
+/* Port role */
+#define PD_ROLE_SINK   0
+#define PD_ROLE_SOURCE 1
+
+/* build message header */
+#define PD_HEADER(type, role, id, cnt) \
+	((type) | (PD_REV10 << 6) | \
+	 ((role) << 8) | ((id) << 9) | ((cnt) << 12))
+
+#define PD_HEADER_CNT(header)  (((header) >> 12) & 7)
+#define PD_HEADER_TYPE(header) ((header) & 0xF)
+#define PD_HEADER_ID(header)   (((header) >> 9) & 7)
+
+/* Encode 5 bits using Biphase Mark Coding */
+#define BMC(x)   ((x &  1 ? 0x001 : 0x3FF) \
+		^ (x &  2 ? 0x004 : 0x3FC) \
+		^ (x &  4 ? 0x010 : 0x3F0) \
+		^ (x &  8 ? 0x040 : 0x3C0) \
+		^ (x & 16 ? 0x100 : 0x300))
+
+/* 4b/5b + Bimark Phase encoding */
+static const uint16_t bmc4b5b[] = {
+/* 0 = 0000 */ BMC(0x1E) /* 11110 */,
+/* 1 = 0001 */ BMC(0x09) /* 01001 */,
+/* 2 = 0010 */ BMC(0x14) /* 10100 */,
+/* 3 = 0011 */ BMC(0x15) /* 10101 */,
+/* 4 = 0100 */ BMC(0x0A) /* 01010 */,
+/* 5 = 0101 */ BMC(0x0B) /* 01011 */,
+/* 6 = 0110 */ BMC(0x0E) /* 01110 */,
+/* 7 = 0111 */ BMC(0x0F) /* 01111 */,
+/* 8 = 1000 */ BMC(0x12) /* 10010 */,
+/* 9 = 1001 */ BMC(0x13) /* 10011 */,
+/* A = 1010 */ BMC(0x16) /* 10110 */,
+/* B = 1011 */ BMC(0x17) /* 10111 */,
+/* C = 1100 */ BMC(0x1A) /* 11010 */,
+/* D = 1101 */ BMC(0x1B) /* 11011 */,
+/* E = 1110 */ BMC(0x1C) /* 11100 */,
+/* F = 1111 */ BMC(0x1D) /* 11101 */,
+/* Sync-1      K-code       11000 Startsynch #1 */
+/* Sync-2      K-code       10001 Startsynch #2 */
+/* RST-1       K-code       00111 Hard Reset #1 */
+/* RST-2       K-code       11001 Hard Reset #2 */
+/* EOP         K-code       01101 EOP End Of Packet */
+/* Reserved    Error        00000 */
+/* Reserved    Error        00001 */
+/* Reserved    Error        00010 */
+/* Reserved    Error        00011 */
+/* Reserved    Error        00100 */
+/* Reserved    Error        00101 */
+/* Reserved    Error        00110 */
+/* Reserved    Error        01000 */
+/* Reserved    Error        01100 */
+/* Reserved    Error        10000 */
+/* Reserved    Error        11111 */
+};
+#define PD_SYNC1 0x18
+#define PD_SYNC2 0x11
+#define PD_RST1  0x07
+#define PD_RST2  0x19
+#define PD_EOP   0x0D
+
+static const uint8_t dec4b5b[] = {
+/* Error    */ 0x10 /* 00000 */,
+/* Error    */ 0x10 /* 00001 */,
+/* Error    */ 0x10 /* 00010 */,
+/* Error    */ 0x10 /* 00011 */,
+/* Error    */ 0x10 /* 00100 */,
+/* Error    */ 0x10 /* 00101 */,
+/* Error    */ 0x10 /* 00110 */,
+/* RST-1    */ 0x13 /* 00111 K-code: Hard Reset #1 */,
+/* Error    */ 0x10 /* 01000 */,
+/* 1 = 0001 */ 0x01 /* 01001 */,
+/* 4 = 0100 */ 0x04 /* 01010 */,
+/* 5 = 0101 */ 0x05 /* 01011 */,
+/* Error    */ 0x10 /* 01100 */,
+/* EOP      */ 0x15 /* 01101 K-code: EOP End Of Packet */,
+/* 6 = 0110 */ 0x06 /* 01110 */,
+/* 7 = 0111 */ 0x07 /* 01111 */,
+/* Error    */ 0x10 /* 10000 */,
+/* Sync-2   */ 0x12 /* 10001 K-code: Startsynch #2 */,
+/* 8 = 1000 */ 0x08 /* 10010 */,
+/* 9 = 1001 */ 0x09 /* 10011 */,
+/* 2 = 0010 */ 0x02 /* 10100 */,
+/* 3 = 0011 */ 0x03 /* 10101 */,
+/* A = 1010 */ 0x0A /* 10110 */,
+/* B = 1011 */ 0x0B /* 10111 */,
+/* Sync-1   */ 0x11 /* 11000 K-code: Startsynch #1 */,
+/* RST-2    */ 0x14 /* 11001 K-code: Hard Reset #2 */,
+/* C = 1100 */ 0x0C /* 11010 */,
+/* D = 1101 */ 0x0D /* 11011 */,
+/* E = 1110 */ 0x0E /* 11100 */,
+/* F = 1111 */ 0x0F /* 11101 */,
+/* 0 = 0000 */ 0x00 /* 11110 */,
+/* Error    */ 0x10 /* 11111 */,
+};
+
+/* Start of Packet sequence : three Sync-1 K-codes, then one Sync-2 K-code */
+#define PD_SOP (PD_SYNC1 | (PD_SYNC1<<5) | (PD_SYNC1<<10) | (PD_SYNC2<<15))
+
+/* Hard Reset sequence : three RST-1 K-codes, then one RST-2 K-code */
+#define PD_HARD_RESET (PD_RST1 | (PD_RST1 << 5) |\
+		      (PD_RST1 << 10) | (PD_RST2 << 15))
+
+/* PD counter definitions */
+#define PD_MESSAGE_ID_COUNT 7
+#define PD_RETRY_COUNT 2
+#define PD_HARD_RESET_COUNT 2
+#define PD_CAPS_COUNT 50
+
+/* Timers */
+#define PD_T_SEND_SOURCE_CAP 1500000 /* us (between 1s and 2s) */
+#define PD_T_GET_SOURCE_CAP  1500000 /* us (between 1s and 2s) */
+#define PD_T_SOURCE_ACTIVITY   45000 /* us (between 40ms and 50ms) */
+
+/* Port role at startup */
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+#define PD_ROLE_DEFAULT PD_ROLE_SINK
+#else
+#define PD_ROLE_DEFAULT PD_ROLE_SOURCE
+#endif
+
+/* current port role */
+static uint8_t pd_role = PD_ROLE_DEFAULT;
+/* 3-bit rolling message ID counter */
+static uint8_t pd_message_id;
+/* Port polarity : 0 => CC1 is CC line, 1 => CC2 is CC line */
+static uint8_t pd_polarity;
+
+static enum {
+	PD_STATE_DISABLED,
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+	PD_STATE_SNK_DISCONNECTED,
+	PD_STATE_SNK_DISCOVERY,
+	PD_STATE_SNK_TRANSITION,
+	PD_STATE_SNK_READY,
+#endif /* CONFIG_USB_PD_DUAL_ROLE */
+
+	PD_STATE_SRC_DISCONNECTED,
+	PD_STATE_SRC_DISCOVERY,
+	PD_STATE_SRC_NEGOCIATE,
+	PD_STATE_SRC_ACCEPTED,
+	PD_STATE_SRC_TRANSITION,
+	PD_STATE_SRC_READY,
+
+	PD_STATE_HARD_RESET,
+	PD_STATE_BIST,
+} pd_task_state = PD_DEFAULT_STATE;
+
+/* increment message ID counter */
+static void inc_id(void)
+{
+	pd_message_id = (pd_message_id + 1) & PD_MESSAGE_ID_COUNT;
+}
+
+static inline int encode_short(void *ctxt, int off, uint16_t val16)
+{
+	off = pd_write_sym(ctxt, off, bmc4b5b[(val16 >> 0) & 0xF]);
+	off = pd_write_sym(ctxt, off, bmc4b5b[(val16 >> 4) & 0xF]);
+	off = pd_write_sym(ctxt, off, bmc4b5b[(val16 >> 8) & 0xF]);
+	return pd_write_sym(ctxt, off, bmc4b5b[(val16 >> 12) & 0xF]);
+}
+
+static inline int encode_word(void *ctxt, int off, uint32_t val32)
+{
+	off = encode_short(ctxt, off, (val32 >> 0) & 0xFFFF);
+	return encode_short(ctxt, off, (val32 >> 16) & 0xFFFF);
+}
+
+/* prepare a 4b/5b-encoded PD message to send */
+static int prepare_message(void *ctxt, uint16_t header, uint8_t cnt,
+			   const uint32_t *data)
+{
+	int off, i;
+	crc32_init();
+	/* 64-bit preamble */
+	off = pd_write_preamble(ctxt);
+	/* Start Of Packet: 3x Sync-1 + 1x Sync-2 */
+	off = pd_write_sym(ctxt, off, BMC(PD_SYNC1));
+	off = pd_write_sym(ctxt, off, BMC(PD_SYNC1));
+	off = pd_write_sym(ctxt, off, BMC(PD_SYNC1));
+	off = pd_write_sym(ctxt, off, BMC(PD_SYNC2));
+	/* header */
+	off = encode_short(ctxt, off, header);
+	crc32_hash16(header);
+	/* data payload */
+	for (i = 0; i < cnt; i++) {
+		off = encode_word(ctxt, off, data[i]);
+		crc32_hash32(data[i]);
+	}
+	/* CRC */
+	off = encode_word(ctxt, off, crc32_result());
+	/* End Of Packet */
+	off = pd_write_sym(ctxt, off, BMC(PD_EOP));
+	/* Ensure that we have a final edge */
+	return pd_write_last_edge(ctxt, off);
+}
+
+static int analyze_rx(uint32_t *payload);
+
+static void send_hard_reset(void *ctxt)
+{
+	int off;
+
+	/* 64-bit preamble */
+	off = pd_write_preamble(ctxt);
+	/* Hard-Reset: 3x RST-1 + 1x RST-2 */
+	off = pd_write_sym(ctxt, off, BMC(PD_RST1));
+	off = pd_write_sym(ctxt, off, BMC(PD_RST1));
+	off = pd_write_sym(ctxt, off, BMC(PD_RST1));
+	off = pd_write_sym(ctxt, off, BMC(PD_RST2));
+	/* Ensure that we have a final edge */
+	off = pd_write_last_edge(ctxt, off);
+	/* Transmit the packet */
+	pd_start_tx(ctxt, off);
+	pd_tx_done();
+}
+
+static int send_validate_message(void *ctxt, uint16_t header, uint8_t cnt,
+				 const uint32_t *data)
+{
+	int r;
+	static uint32_t payload[7];
+
+	/* retry 3 times if we are not getting a valid answer */
+	for (r = 0; r <= PD_RETRY_COUNT; r++) {
+		int bit_len;
+		uint16_t head;
+		/* write the encoded packet in the transmission buffer */
+		bit_len = prepare_message(ctxt, header, cnt, data);
+		/* Transmit the packet */
+		pd_start_tx(ctxt, bit_len);
+		pd_tx_done();
+		/* starting waiting for GoodCrc */
+		pd_rx_start();
+		/* read the incoming packet if any */
+		head = analyze_rx(payload);
+		pd_rx_complete();
+		if (head > 0) { /* we got a good packet, analyze it */
+			int type = PD_HEADER_TYPE(head);
+			int nb = PD_HEADER_CNT(head);
+			uint8_t id = PD_HEADER_ID(head);
+			if (type == PD_CTRL_GOOD_CRC && nb == 0 &&
+			   id == pd_message_id) {
+				/* got the GoodCRC we were expecting */
+				inc_id();
+				return bit_len;
+			} else {
+				CPRINTF("ERR ACK/%d %04x\n", id, head);
+			}
+		}
+	}
+	/* we failed all the re-transmissions */
+	/* TODO: try HardReset */
+	CPRINTF("TX NO ACK %04x/%d\n", header, cnt);
+	return -1;
+}
+
+static int send_control(void *ctxt, int type)
+{
+	int bit_len;
+	uint16_t header = PD_HEADER(type, pd_role, pd_message_id, 0);
+
+	bit_len = send_validate_message(ctxt, header, 0, NULL);
+
+	CPRINTF("CTRL[%d]>%d\n", type, bit_len);
+
+	return bit_len;
+}
+
+static void send_goodcrc(void *ctxt, int id)
+{
+	uint16_t header = PD_HEADER(PD_CTRL_GOOD_CRC, pd_role, id, 0);
+	int bit_len = prepare_message(ctxt, header, 0, NULL);
+
+	pd_start_tx(ctxt, bit_len);
+	pd_tx_done();
+}
+
+static int send_source_cap(void *ctxt)
+{
+	int bit_len;
+	uint16_t header = PD_HEADER(PD_DATA_SOURCE_CAP, pd_role, pd_message_id,
+				    pd_src_pdo_cnt);
+
+	bit_len = send_validate_message(ctxt, header, pd_src_pdo_cnt,
+					pd_src_pdo);
+	CPRINTF("srcCAP>%d\n", bit_len);
+
+	return bit_len;
+}
+
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+static void send_sink_cap(void *ctxt)
+{
+	int bit_len;
+	uint16_t header = PD_HEADER(PD_DATA_SINK_CAP, pd_role, pd_message_id,
+				    pd_snk_pdo_cnt);
+
+	bit_len = send_validate_message(ctxt, header, pd_snk_pdo_cnt,
+					pd_snk_pdo);
+	CPRINTF("snkCAP>%d\n", bit_len);
+}
+
+static void send_request(void *ctxt, uint32_t rdo)
+{
+	int bit_len;
+	uint16_t header = PD_HEADER(PD_DATA_REQUEST, pd_role, pd_message_id, 1);
+
+	bit_len = send_validate_message(ctxt, header, 1, &rdo);
+	CPRINTF("REQ%d>\n", bit_len);
+}
+#endif /* CONFIG_USB_PD_DUAL_ROLE */
+
+static int send_bist(void *ctxt)
+{
+	uint32_t bdo = BDO(BDO_MODE_TRANSMIT, 0);
+	int bit_len;
+	uint16_t header = PD_HEADER(PD_DATA_BIST, pd_role, pd_message_id, 1);
+
+	bit_len = send_validate_message(ctxt, header, 1, &bdo);
+	CPRINTF("BIST>%d\n", bit_len);
+
+	return bit_len;
+}
+
+static void handle_vdm_request(void *ctxt, int cnt, uint32_t *payload)
+{
+	CPRINTF("Unhandled VDM VID %04x CMD %04x\n", payload[0] >> 16,
+		payload[0] & 0xFFFF);
+}
+
+static void handle_data_request(void *ctxt, uint16_t head, uint32_t *payload)
+{
+	int type = PD_HEADER_TYPE(head);
+	int cnt = PD_HEADER_CNT(head);
+
+	switch (type) {
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+	case PD_DATA_SOURCE_CAP:
+		if ((pd_task_state == PD_STATE_SNK_DISCOVERY)
+			|| (pd_task_state == PD_STATE_SNK_TRANSITION)) {
+			uint32_t rdo;
+			int res;
+			/* we were waiting for them, let's process them */
+			res = pd_choose_voltage(cnt, payload, &rdo);
+			if (res >= 0) {
+				send_request(ctxt, rdo);
+				pd_task_state = PD_STATE_SNK_TRANSITION;
+			}
+		}
+		break;
+#endif /* CONFIG_USB_PD_DUAL_ROLE */
+	case PD_DATA_REQUEST:
+		if ((pd_role == PD_ROLE_SOURCE) && (cnt == 1))
+			if (!pd_request_voltage(payload[0])) {
+				send_control(ctxt, PD_CTRL_ACCEPT);
+				pd_task_state = PD_STATE_SRC_ACCEPTED;
+				return;
+			}
+		/* the message was incorrect or cannot be satisfied */
+		send_control(ctxt, PD_CTRL_REJECT);
+		break;
+	case PD_DATA_BIST:
+		CPRINTF("BIST not supported\n");
+		break;
+	case PD_DATA_SINK_CAP:
+		break;
+	case PD_DATA_VENDOR_DEF:
+		handle_vdm_request(ctxt, cnt, payload);
+		break;
+	default:
+		CPRINTF("Unhandled data message type %d\n", type);
+	}
+}
+
+static void handle_ctrl_request(void *ctxt, uint16_t head, uint32_t *payload)
+{
+	int type = PD_HEADER_TYPE(head);
+
+	switch (type) {
+	case PD_CTRL_GOOD_CRC:
+		/* should not get it */
+		break;
+	case PD_CTRL_PING:
+		/* Nothing else to do */
+		break;
+	case PD_CTRL_GET_SOURCE_CAP:
+		send_source_cap(ctxt);
+		break;
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+	case PD_CTRL_GET_SINK_CAP:
+		send_sink_cap(ctxt);
+		break;
+	case PD_CTRL_GOTO_MIN:
+		break;
+	case PD_CTRL_PS_RDY:
+		if (pd_role == PD_ROLE_SINK)
+			pd_task_state = PD_STATE_SNK_READY;
+		break;
+#endif /* CONFIG_USB_PD_DUAL_ROLE */
+	case PD_CTRL_ACCEPT:
+		break;
+	case PD_CTRL_REJECT:
+		break;
+	case PD_CTRL_PROTOCOL_ERR:
+	case PD_CTRL_SWAP:
+	case PD_CTRL_WAIT:
+	case PD_CTRL_SOFT_RESET:
+	default:
+		CPRINTF("Unhandled ctrl message type %d\n", type);
+	}
+}
+
+static void handle_request(void *ctxt, uint16_t head, uint32_t *payload)
+{
+	int cnt = PD_HEADER_CNT(head);
+	int p;
+
+	if (PD_HEADER_TYPE(head) != 1 || cnt)
+		send_goodcrc(ctxt, PD_HEADER_ID(head));
+
+	/* dump received packet content */
+	CPRINTF("RECV %04x/%d ", head, cnt);
+	for (p = 0; p < cnt; p++)
+		CPRINTF("[%d]%08x ", p, payload[p]);
+	CPRINTF("\n");
+
+	if (cnt)
+		handle_data_request(ctxt, head, payload);
+	else
+		handle_ctrl_request(ctxt, head, payload);
+}
+
+static inline int decode_short(void *ctxt, int off, uint16_t *val16)
+{
+	uint32_t w;
+	int end;
+
+	end = pd_dequeue_bits(ctxt, off, 20, &w);
+
+#if 0 /* DEBUG */
+	CPRINTF("%d-%d: %05x %x:%x:%x:%x\n",
+		off, end, w,
+		dec4b5b[(w >> 15) & 0x1f], dec4b5b[(w >> 10) & 0x1f],
+		dec4b5b[(w >>  5) & 0x1f], dec4b5b[(w >>  0) & 0x1f]);
+#endif
+	*val16 = dec4b5b[w & 0x1f] |
+		(dec4b5b[(w >>  5) & 0x1f] << 4) |
+		(dec4b5b[(w >> 10) & 0x1f] << 8) |
+		(dec4b5b[(w >> 15) & 0x1f] << 12);
+	return end;
+}
+
+static inline int decode_word(void *ctxt, int off, uint32_t *val32)
+{
+	off = decode_short(ctxt, off, (uint16_t *)val32);
+	return decode_short(ctxt, off, ((uint16_t *)val32 + 1));
+}
+
+static int analyze_rx(uint32_t *payload)
+{
+	int bit;
+	char *msg = "---";
+	uint32_t val = 0;
+	uint16_t header;
+	uint32_t pcrc, ccrc;
+	int p, cnt;
+	/* uint32_t eop; */
+	void *ctxt;
+
+	crc32_init();
+	ctxt = pd_init_dequeue();
+
+	/* Detect preamble */
+	bit = pd_find_preamble(ctxt);
+	if (bit < 0) {
+		msg = "Preamble";
+		goto packet_err;
+	}
+
+	/* Find the Start Of Packet sequence */
+	while (bit > 0) {
+		bit = pd_dequeue_bits(ctxt, bit, 20, &val);
+		if (val == PD_SOP)
+			break;
+		/* TODO: detect SOP with 1 error code */
+		/* TODO: detect Hard reset */
+	}
+	if (bit < 0) {
+		msg = "SOP";
+		goto packet_err;
+	}
+
+	/* read header */
+	bit = decode_short(ctxt, bit, &header);
+	crc32_hash16(header);
+	cnt = PD_HEADER_CNT(header);
+
+	/* read payload data */
+	for (p = 0; p < cnt && bit > 0; p++) {
+		bit = decode_word(ctxt, bit, payload+p);
+		crc32_hash32(payload[p]);
+	}
+	if (bit < 0) {
+		msg = "len";
+		goto packet_err;
+	}
+
+	/* check transmitted CRC */
+	bit = decode_word(ctxt, bit, &pcrc);
+	ccrc = crc32_result();
+	if (bit < 0 || pcrc != ccrc) {
+		msg = "CRC";
+		if (pcrc != ccrc)
+			bit = PD_ERR_CRC;
+		/* DEBUG */CPRINTF("CRC %08x <> %08x\n", pcrc, crc32_result());
+		goto packet_err;
+	}
+
+	/* check End Of Packet */
+	/* SKIP EOP for now
+	bit = pd_dequeue_bits(ctxt, bit, 5, &eop);
+	if (bit < 0 || eop != PD_EOP) {
+		msg = "EOP";
+		goto packet_err;
+	}
+	*/
+
+	return header;
+packet_err:
+	if (debug_dump)
+		pd_dump_packet(ctxt, msg);
+	else
+		CPRINTF("RX ERR (%d)\n", bit);
+	return bit;
+}
+
+static void execute_hard_reset(void)
+{
+	pd_message_id = 0;
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+	pd_task_state = pd_role == PD_ROLE_SINK ? PD_STATE_SNK_DISCONNECTED
+						: PD_STATE_SRC_DISCONNECTED;
+#else
+	pd_task_state = PD_STATE_SRC_DISCONNECTED;
+#endif
+	pd_power_supply_reset();
+	CPRINTF("HARD RESET!\n");
+}
+
+void pd_task(void)
+{
+	int head;
+	void *ctxt = pd_hw_init();
+	uint32_t payload[7];
+	int timeout = 10000;
+	uint32_t evt;
+	int cc1_volt, cc2_volt;
+	int res;
+
+	/* Ensure the power supply is in the default state */
+	pd_power_supply_reset();
+
+	while (1) {
+		/* monitor for incoming packet */
+		pd_rx_enable_monitoring();
+		/* wait for next event/packet or timeout expiration */
+		evt = task_wait_event(timeout);
+		/* incoming packet ? */
+		if (evt & PD_EVENT_RX) {
+			head = analyze_rx(payload);
+			pd_rx_complete();
+			if (head > 0)
+				handle_request(ctxt, head, payload);
+			else if (head == PD_ERR_HARD_RESET)
+				execute_hard_reset();
+		}
+		timeout = -1;
+		switch (pd_task_state) {
+		case PD_STATE_DISABLED:
+			/* Nothing to do */
+			break;
+		case PD_STATE_SRC_DISCONNECTED:
+			/* Vnc monitoring */
+			cc1_volt = adc_read_channel(ADC_CH_CC1_PD);
+			cc2_volt = adc_read_channel(ADC_CH_CC2_PD);
+			if ((cc1_volt < PD_SRC_VNC) ||
+			    (cc2_volt < PD_SRC_VNC)) {
+				pd_polarity = !(cc1_volt < PD_SRC_VNC);
+				pd_task_state = PD_STATE_SRC_DISCOVERY;
+			}
+			timeout = 10000;
+			break;
+		case PD_STATE_SRC_DISCOVERY:
+			/* Query capabilites of the other side */
+			res = send_source_cap(ctxt);
+			/* packet was acked => PD capable device) */
+			if (res >= 0) {
+				pd_task_state = PD_STATE_SRC_NEGOCIATE;
+			} else { /* failed, retry later */
+				timeout = PD_T_SEND_SOURCE_CAP;
+			}
+			break;
+		case PD_STATE_SRC_NEGOCIATE:
+			/* wait for a "Request" message */
+			break;
+		case PD_STATE_SRC_ACCEPTED:
+			/* Accept sent, wait for the end of transition */
+			timeout = PD_POWER_SUPPLY_TRANSITION_DELAY;
+			pd_task_state = PD_STATE_SRC_TRANSITION;
+			break;
+		case PD_STATE_SRC_TRANSITION:
+			res = pd_set_power_supply_ready();
+			/* TODO error fallback */
+			/* the voltage output is good, notify the source */
+			res = send_control(ctxt, PD_CTRL_PS_RDY);
+			if (res >= 0) {
+				timeout =  PD_T_SEND_SOURCE_CAP;
+				/* it'a time to ping regularly the sink */
+				pd_task_state = PD_STATE_SRC_READY;
+			}
+			/* TODO error fallback */
+			break;
+		case PD_STATE_SRC_READY:
+			/* Verify that the sink is alive */
+			res = send_control(ctxt, PD_CTRL_PING);
+			if (res < 0) {
+				/* The sink died ... TODO */
+				pd_task_state = PD_STATE_SRC_DISCOVERY;
+				timeout = PD_T_SEND_SOURCE_CAP;
+			} else { /* schedule next keep-alive */
+				timeout = PD_T_SOURCE_ACTIVITY;
+			}
+			break;
+#ifdef CONFIG_USB_PD_DUAL_ROLE
+		case PD_STATE_SNK_DISCONNECTED:
+			/* Source connection monitoring */
+			cc1_volt = adc_read_channel(ADC_CH_CC1_PD);
+			cc2_volt = adc_read_channel(ADC_CH_CC2_PD);
+			if ((cc1_volt > PD_SNK_VA) ||
+			    (cc2_volt > PD_SNK_VA)) {
+				pd_polarity = !(cc1_volt > PD_SNK_VA);
+				pd_task_state = PD_STATE_SNK_DISCOVERY;
+			}
+			timeout = 10000;
+			break;
+		case PD_STATE_SNK_DISCOVERY:
+			res = send_control(ctxt, PD_CTRL_GET_SOURCE_CAP);
+			/* packet was acked => PD capable device) */
+			if (res >= 0) {
+				pd_task_state = PD_STATE_SNK_TRANSITION;
+			} else { /* failed, retry later */
+				timeout = PD_T_GET_SOURCE_CAP;
+			}
+			break;
+		case PD_STATE_SNK_TRANSITION:
+			break;
+		case PD_STATE_SNK_READY:
+			/* we have power and we are happy */
+			break;
+#endif /* CONFIG_USB_PD_DUAL_ROLE */
+		case PD_STATE_HARD_RESET:
+			send_hard_reset(ctxt);
+			/* reset our own state machine */
+			execute_hard_reset();
+			break;
+		case PD_STATE_BIST:
+			send_bist(ctxt);
+			pd_task_state = PD_STATE_DISABLED;
+			break;
+		}
+	}
+}
+
+void pd_rx_event(void)
+{
+	task_set_event(TASK_ID_PD, PD_EVENT_RX, 0);
+}
+
+#ifdef CONFIG_COMMON_RUNTIME
+static int command_pd(int argc, char **argv)
+{
+	if (argc < 2)
+		return EC_ERROR_PARAM1;
+
+	if (!strcasecmp(argv[1], "tx")) {
+		pd_task_state = PD_STATE_SNK_DISCOVERY;
+		task_wake(TASK_ID_PD);
+	} else if (!strcasecmp(argv[1], "rx")) {
+		pd_rx_event();
+	} else if (!strcasecmp(argv[1], "bist")) {
+		pd_task_state = PD_STATE_BIST;
+		task_wake(TASK_ID_PD);
+	} else if (!strcasecmp(argv[1], "charger")) {
+		pd_role = PD_ROLE_SOURCE;
+		pd_set_host_mode(1);
+		pd_task_state = PD_STATE_SRC_DISCONNECTED;
+		task_wake(TASK_ID_PD);
+	} else if (!strncasecmp(argv[1], "dev", 3)) {
+		if (argc >= 3) {
+			unsigned max_volt;
+			char *e;
+
+			max_volt = strtoi(argv[2], &e, 10);
+			pd_set_max_voltage(max_volt * 1000);
+		}
+
+		pd_role = PD_ROLE_SINK;
+		pd_set_host_mode(0);
+		pd_task_state = PD_STATE_SNK_DISCONNECTED;
+		task_wake(TASK_ID_PD);
+	} else if (!strcasecmp(argv[1], "clock")) {
+		int freq;
+		char *e;
+
+		if (argc < 3)
+			return EC_ERROR_PARAM2;
+
+		freq = strtoi(argv[2], &e, 10);
+		if (*e)
+			return EC_ERROR_PARAM2;
+		pd_set_clock(freq);
+		ccprintf("set TX frequency to %d Hz\n", freq);
+	} else if (!strcasecmp(argv[1], "dump")) {
+		debug_dump = !debug_dump;
+	} else if (!strncasecmp(argv[1], "hard", 4)) {
+		pd_task_state = PD_STATE_HARD_RESET;
+		task_wake(TASK_ID_PD);
+	} else if (!strncasecmp(argv[1], "ping", 4)) {
+		pd_role = PD_ROLE_SOURCE;
+		pd_set_host_mode(1);
+		pd_task_state = PD_STATE_SRC_READY;
+		task_wake(TASK_ID_PD);
+	} else if (!strncasecmp(argv[1], "state", 5)) {
+		const char * const state_names[] = {
+			"DISABLED",
+			"SNK_DISCONNECTED", "SNK_DISCOVERY", "SNK_TRANSITION",
+			"SNK_READY",
+			"SRC_DISCONNECTED", "SRC_DISCOVERY", "SRC_NEGOCIATE",
+			"SRC_READY",
+			"HARD_RESET", "BIST",
+		};
+		ccprintf("Role: %s Polarity: CC%d State: %s\n",
+			pd_role == PD_ROLE_SOURCE ? "SRC" : "SNK",
+			pd_polarity + 1, state_names[pd_task_state]);
+	} else {
+		return EC_ERROR_PARAM1;
+	}
+
+	return EC_SUCCESS;
+}
+DECLARE_CONSOLE_COMMAND(pd, command_pd,
+			"[rx|tx|hardreset|clock|connect]",
+			"USB PD",
+			NULL);
+#endif /* CONFIG_COMMON_RUNTIME */