[libsigrok.git] / src / hardware / rdtech-tc / protocol.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2020 Andreas Sandberg <andreas@sandberg.pp.se>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#include <glib.h>
#include <libsigrok/libsigrok.h>
#include <math.h>
#include <nettle/aes.h>
#include <stdlib.h>
#include <string.h>

#include "libsigrok-internal.h"
#include "protocol.h"

#define PROBE_TO_MS	1000
#define WRITE_TO_MS	1
#define POLL_PERIOD_MS	100

static const char *poll_cmd = "getva";

/*
 * Response data (raw sample data) consists of three adjacent chunks
 * of 64 bytes each. These chunks start with their magic string, and
 * end in a 32bit checksum field. Measurement values are scattered
 * across these 192 bytes total size. All multi-byte integer values
 * are represented in little endian format. Typical size is 32 bits.
 */

#define MAGIC_PAC1	0x70616331	/* 'pac1' */
#define MAGIC_PAC2	0x70616332	/* 'pac2' */
#define MAGIC_PAC3	0x70616333	/* 'pac3' */

#define PAC_LEN 64
#define PAC_CRC_POS (PAC_LEN - sizeof(uint32_t))

/* Offset to PAC block from start of poll data */
#define OFF_PAC1 (0 * PAC_LEN)
#define OFF_PAC2 (1 * PAC_LEN)
#define OFF_PAC3 (2 * PAC_LEN)
#define TC_POLL_LEN (3 * PAC_LEN)

#define OFF_MODEL 4
#define LEN_MODEL 4

#define OFF_FW_VER 8
#define LEN_FW_VER 4

#define OFF_SERIAL 12

static const uint8_t AES_KEY[] = {
	0x58, 0x21, 0xfa, 0x56, 0x01, 0xb2, 0xf0, 0x26,
	0x87, 0xff, 0x12, 0x04, 0x62, 0x2a, 0x4f, 0xb0,
	0x86, 0xf4, 0x02, 0x60, 0x81, 0x6f, 0x9a, 0x0b,
	0xa7, 0xf1, 0x06, 0x61, 0x9a, 0xb8, 0x72, 0x88,
};

static const struct binary_analog_channel rdtech_tc_channels[] = {
	{ "V",  {   0 + 48, BVT_LE_UINT32, 1e-4, }, 4, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "I",  {   0 + 52, BVT_LE_UINT32, 1e-5, }, 5, SR_MQ_CURRENT, SR_UNIT_AMPERE },
	{ "D+", {  64 + 32, BVT_LE_UINT32, 1e-2, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "D-", {  64 + 36, BVT_LE_UINT32, 1e-2, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "E0", {  64 + 12, BVT_LE_UINT32, 1e-3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	{ "E1", {  64 + 20, BVT_LE_UINT32, 1e-3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	ALL_ZERO,
};

static gboolean check_pac_crc(uint8_t *data)
{
	uint16_t crc;
	uint32_t crc_field;

	crc = sr_crc16(SR_CRC16_DEFAULT_INIT, data, PAC_CRC_POS);
	crc_field = read_u32le(&data[PAC_CRC_POS]);
	if (crc != crc_field) {
		sr_spew("CRC error. Calculated: %0x" PRIx16 ", expected: %0x" PRIx32,
			crc, crc_field);
		return FALSE;
	}

	return TRUE;
}

static int process_poll_pkt(struct dev_context *devc, uint8_t *dst)
{
	struct aes256_ctx ctx;
	gboolean ok;

	aes256_set_decrypt_key(&ctx, AES_KEY);
	aes256_decrypt(&ctx, TC_POLL_LEN, dst, devc->buf);

	ok = TRUE;
	ok &= read_u32be(&dst[OFF_PAC1]) == MAGIC_PAC1;
	ok &= read_u32be(&dst[OFF_PAC2]) == MAGIC_PAC2;
	ok &= read_u32be(&dst[OFF_PAC3]) == MAGIC_PAC3;
	if (!ok) {
		sr_err("Invalid poll response packet (magic values).");
		return SR_ERR_DATA;
	}

	ok &= check_pac_crc(&dst[OFF_PAC1]);
	ok &= check_pac_crc(&dst[OFF_PAC2]);
	ok &= check_pac_crc(&dst[OFF_PAC3]);
	if (!ok) {
		sr_err("Invalid poll response packet (checksum).");
		return SR_ERR_DATA;
	}

	return SR_OK;
}

SR_PRIV int rdtech_tc_probe(struct sr_serial_dev_inst *serial, struct dev_context *devc)
{
	int len;
	uint8_t poll_pkt[TC_POLL_LEN];

	len = serial_write_blocking(serial,
		poll_cmd, strlen(poll_cmd), WRITE_TO_MS);
	if (len < 0) {
		sr_err("Failed to send probe request.");
		return SR_ERR;
	}

	len = serial_read_blocking(serial, devc->buf, TC_POLL_LEN, PROBE_TO_MS);
	if (len != TC_POLL_LEN) {
		sr_err("Failed to read probe response.");
		return SR_ERR;
	}

	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
		sr_err("Unrecognized TC device!");
		return SR_ERR;
	}

	devc->channels = rdtech_tc_channels;
	devc->dev_info.model_name = g_strndup((const char *)&poll_pkt[OFF_MODEL], LEN_MODEL);
	devc->dev_info.fw_ver = g_strndup((const char *)&poll_pkt[OFF_FW_VER], LEN_FW_VER);
	devc->dev_info.serial_num = read_u32le(&poll_pkt[OFF_SERIAL]);

	return SR_OK;
}

SR_PRIV int rdtech_tc_poll(const struct sr_dev_inst *sdi, gboolean force)
{
	struct dev_context *devc;
	int64_t now, elapsed;
	struct sr_serial_dev_inst *serial;
	int len;

	/*
	 * Don't send the request while receive data is being accumulated.
	 */
	devc = sdi->priv;
	if (!force && devc->buflen)
		return SR_OK;

	/*
	 * Send the request when the transmit interval was reached. Or
	 * when the caller forced the transmission.
	 */
	now = g_get_monotonic_time() / 1000;
	elapsed = now - devc->cmd_sent_at;
	if (!force && elapsed < POLL_PERIOD_MS)
		return SR_OK;

	/*
	 * Transmit another measurement request. Only advance the
	 * interval after successful transmission.
	 */
	serial = sdi->conn;
	len = serial_write_blocking(serial,
		poll_cmd, strlen(poll_cmd), WRITE_TO_MS);
	if (len < 0) {
		sr_err("Unable to send poll request.");
		return SR_ERR;
	}
	devc->cmd_sent_at = now;

	return SR_OK;
}

static int handle_poll_data(struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	uint8_t poll_pkt[TC_POLL_LEN];
	size_t i;
	GSList *ch;
	int ret;

	devc = sdi->priv;
	sr_spew("Received poll packet (len: %zu).", devc->buflen);
	if (devc->buflen < TC_POLL_LEN) {
		sr_err("Insufficient poll packet length: %zu", devc->buflen);
		return SR_ERR_DATA;
	}

	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
		sr_err("Failed to process poll packet.");
		return SR_ERR_DATA;
	}

	i = 0;
	for (ch = sdi->channels; ch; ch = g_slist_next(ch)) {
		ret = bv_send_analog_channel(sdi, ch->data,
			&devc->channels[i], poll_pkt, TC_POLL_LEN);
		i++;
		if (ret != SR_OK)
			return ret;
	}

	sr_sw_limits_update_samples_read(&devc->limits, 1);
	if (sr_sw_limits_check(&devc->limits))
		sr_dev_acquisition_stop(sdi);

	return SR_OK;
}

static int recv_poll_data(struct sr_dev_inst *sdi, struct sr_serial_dev_inst *serial)
{
	struct dev_context *devc;
	size_t space;
	int len;
	int ret;

	/* Receive data became available. Drain the transport layer. */
	devc = sdi->priv;
	while (devc->buflen < TC_POLL_LEN) {
		space = sizeof(devc->buf) - devc->buflen;
		len = serial_read_nonblocking(serial,
			&devc->buf[devc->buflen], space);
		if (len < 0)
			return SR_ERR_IO;
		if (len == 0)
			return SR_OK;
		devc->buflen += len;
	}

	/*
	 * TODO Want to (re-)synchronize to the packet stream? The
	 * 'pac1' string literal would be a perfect match for that.
	 */

	/* Process packets when their reception has completed. */
	while (devc->buflen >= TC_POLL_LEN) {
		ret = handle_poll_data(sdi);
		if (ret != SR_OK)
			return ret;
		devc->buflen -= TC_POLL_LEN;
		if (devc->buflen)
			memmove(&devc->buf[0], &devc->buf[TC_POLL_LEN], devc->buflen);
	}

	return SR_OK;
}

SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	struct sr_serial_dev_inst *serial;
	int ret;

	(void)fd;

	if (!(sdi = cb_data))
		return TRUE;
	if (!(devc = sdi->priv))
		return TRUE;

	/* Handle availability of receive data. */
	serial = sdi->conn;
	if (revents == G_IO_IN) {
		ret = recv_poll_data(sdi, serial);
		if (ret != SR_OK)
			sr_dev_acquisition_stop(sdi);
	}

	/* Check configured acquisition limits. */
	if (sr_sw_limits_check(&devc->limits)) {
		sr_dev_acquisition_stop(sdi);
		return TRUE;
	}

	/* Periodically retransmit measurement requests. */
	(void)rdtech_tc_poll(sdi, FALSE);

	return TRUE;
}
Commit	Line	Data
	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2020 Andreas Sandberg <andreas@sandberg.pp.se>
	5	*
	6	* This program is free software: you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation, either version 3 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <config.h>
	21
	22	#include <glib.h>
	23	#include <libsigrok/libsigrok.h>
	24	#include <math.h>
	25	#include <nettle/aes.h>
	26	#include <stdlib.h>
	27	#include <string.h>
	28
	29	#include "libsigrok-internal.h"
	30	#include "protocol.h"
	31
	32	#define PROBE_TO_MS 1000
	33	#define WRITE_TO_MS 1
	34	#define POLL_PERIOD_MS 100
	35
	36	static const char *poll_cmd = "getva";
	37
	38	/*
	39	* Response data (raw sample data) consists of three adjacent chunks
	40	* of 64 bytes each. These chunks start with their magic string, and
	41	* end in a 32bit checksum field. Measurement values are scattered
	42	* across these 192 bytes total size. All multi-byte integer values
	43	* are represented in little endian format. Typical size is 32 bits.
	44	*/
	45
	46	#define MAGIC_PAC1 0x70616331 /* 'pac1' */
	47	#define MAGIC_PAC2 0x70616332 /* 'pac2' */
	48	#define MAGIC_PAC3 0x70616333 /* 'pac3' */
	49
	50	#define PAC_LEN 64
	51	#define PAC_CRC_POS (PAC_LEN - sizeof(uint32_t))
	52
	53	/* Offset to PAC block from start of poll data */
	54	#define OFF_PAC1 (0 * PAC_LEN)
	55	#define OFF_PAC2 (1 * PAC_LEN)
	56	#define OFF_PAC3 (2 * PAC_LEN)
	57	#define TC_POLL_LEN (3 * PAC_LEN)
	58
	59	#define OFF_MODEL 4
	60	#define LEN_MODEL 4
	61
	62	#define OFF_FW_VER 8
	63	#define LEN_FW_VER 4
	64
	65	#define OFF_SERIAL 12
	66
	67	static const uint8_t AES_KEY[] = {
	68	0x58, 0x21, 0xfa, 0x56, 0x01, 0xb2, 0xf0, 0x26,
	69	0x87, 0xff, 0x12, 0x04, 0x62, 0x2a, 0x4f, 0xb0,
	70	0x86, 0xf4, 0x02, 0x60, 0x81, 0x6f, 0x9a, 0x0b,
	71	0xa7, 0xf1, 0x06, 0x61, 0x9a, 0xb8, 0x72, 0x88,
	72	};
	73
	74	static const struct binary_analog_channel rdtech_tc_channels[] = {
	75	{ "V", { 0 + 48, BVT_LE_UINT32, 1e-4, }, 4, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	76	{ "I", { 0 + 52, BVT_LE_UINT32, 1e-5, }, 5, SR_MQ_CURRENT, SR_UNIT_AMPERE },
	77	{ "D+", { 64 + 32, BVT_LE_UINT32, 1e-2, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	78	{ "D-", { 64 + 36, BVT_LE_UINT32, 1e-2, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	79	{ "E0", { 64 + 12, BVT_LE_UINT32, 1e-3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	80	{ "E1", { 64 + 20, BVT_LE_UINT32, 1e-3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	81	ALL_ZERO,
	82	};
	83
	84	static gboolean check_pac_crc(uint8_t *data)
	85	{
	86	uint16_t crc;
	87	uint32_t crc_field;
	88
	89	crc = sr_crc16(SR_CRC16_DEFAULT_INIT, data, PAC_CRC_POS);
	90	crc_field = read_u32le(&data[PAC_CRC_POS]);
	91	if (crc != crc_field) {
	92	sr_spew("CRC error. Calculated: %0x" PRIx16 ", expected: %0x" PRIx32,
	93	crc, crc_field);
	94	return FALSE;
	95	}
	96
	97	return TRUE;
	98	}
	99
	100	static int process_poll_pkt(struct dev_context devc, uint8_t dst)
	101	{
	102	struct aes256_ctx ctx;
	103	gboolean ok;
	104
	105	aes256_set_decrypt_key(&ctx, AES_KEY);
	106	aes256_decrypt(&ctx, TC_POLL_LEN, dst, devc->buf);
	107
	108	ok = TRUE;
	109	ok &= read_u32be(&dst[OFF_PAC1]) == MAGIC_PAC1;
	110	ok &= read_u32be(&dst[OFF_PAC2]) == MAGIC_PAC2;
	111	ok &= read_u32be(&dst[OFF_PAC3]) == MAGIC_PAC3;
	112	if (!ok) {
	113	sr_err("Invalid poll response packet (magic values).");
	114	return SR_ERR_DATA;
	115	}
	116
	117	ok &= check_pac_crc(&dst[OFF_PAC1]);
	118	ok &= check_pac_crc(&dst[OFF_PAC2]);
	119	ok &= check_pac_crc(&dst[OFF_PAC3]);
	120	if (!ok) {
	121	sr_err("Invalid poll response packet (checksum).");
	122	return SR_ERR_DATA;
	123	}
	124
	125	return SR_OK;
	126	}
	127
	128	SR_PRIV int rdtech_tc_probe(struct sr_serial_dev_inst serial, struct dev_context devc)
	129	{
	130	int len;
	131	uint8_t poll_pkt[TC_POLL_LEN];
	132
	133	len = serial_write_blocking(serial,
	134	poll_cmd, strlen(poll_cmd), WRITE_TO_MS);
	135	if (len < 0) {
	136	sr_err("Failed to send probe request.");
	137	return SR_ERR;
	138	}
	139
	140	len = serial_read_blocking(serial, devc->buf, TC_POLL_LEN, PROBE_TO_MS);
	141	if (len != TC_POLL_LEN) {
	142	sr_err("Failed to read probe response.");
	143	return SR_ERR;
	144	}
	145
	146	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
	147	sr_err("Unrecognized TC device!");
	148	return SR_ERR;
	149	}
	150
	151	devc->channels = rdtech_tc_channels;
	152	devc->dev_info.model_name = g_strndup((const char *)&poll_pkt[OFF_MODEL], LEN_MODEL);
	153	devc->dev_info.fw_ver = g_strndup((const char *)&poll_pkt[OFF_FW_VER], LEN_FW_VER);
	154	devc->dev_info.serial_num = read_u32le(&poll_pkt[OFF_SERIAL]);
	155
	156	return SR_OK;
	157	}
	158
	159	SR_PRIV int rdtech_tc_poll(const struct sr_dev_inst *sdi, gboolean force)
	160	{
	161	struct dev_context *devc;
	162	int64_t now, elapsed;
	163	struct sr_serial_dev_inst *serial;
	164	int len;
	165
	166	/*
	167	* Don't send the request while receive data is being accumulated.
	168	*/
	169	devc = sdi->priv;
	170	if (!force && devc->buflen)
	171	return SR_OK;
	172
	173	/*
	174	* Send the request when the transmit interval was reached. Or
	175	* when the caller forced the transmission.
	176	*/
	177	now = g_get_monotonic_time() / 1000;
	178	elapsed = now - devc->cmd_sent_at;
	179	if (!force && elapsed < POLL_PERIOD_MS)
	180	return SR_OK;
	181
	182	/*
	183	* Transmit another measurement request. Only advance the
	184	* interval after successful transmission.
	185	*/
	186	serial = sdi->conn;
	187	len = serial_write_blocking(serial,
	188	poll_cmd, strlen(poll_cmd), WRITE_TO_MS);
	189	if (len < 0) {
	190	sr_err("Unable to send poll request.");
	191	return SR_ERR;
	192	}
	193	devc->cmd_sent_at = now;
	194
	195	return SR_OK;
	196	}
	197
	198	static int handle_poll_data(struct sr_dev_inst *sdi)
	199	{
	200	struct dev_context *devc;
	201	uint8_t poll_pkt[TC_POLL_LEN];
	202	size_t i;
	203	GSList *ch;
	204	int ret;
	205
	206	devc = sdi->priv;
	207	sr_spew("Received poll packet (len: %zu).", devc->buflen);
	208	if (devc->buflen < TC_POLL_LEN) {
	209	sr_err("Insufficient poll packet length: %zu", devc->buflen);
	210	return SR_ERR_DATA;
	211	}
	212
	213	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
	214	sr_err("Failed to process poll packet.");
	215	return SR_ERR_DATA;
	216	}
	217
	218	i = 0;
	219	for (ch = sdi->channels; ch; ch = g_slist_next(ch)) {
	220	ret = bv_send_analog_channel(sdi, ch->data,
	221	&devc->channels[i], poll_pkt, TC_POLL_LEN);
	222	i++;
	223	if (ret != SR_OK)
	224	return ret;
	225	}
	226
	227	sr_sw_limits_update_samples_read(&devc->limits, 1);
	228	if (sr_sw_limits_check(&devc->limits))
	229	sr_dev_acquisition_stop(sdi);
	230
	231	return SR_OK;
	232	}
	233
	234	static int recv_poll_data(struct sr_dev_inst sdi, struct sr_serial_dev_inst serial)
	235	{
	236	struct dev_context *devc;
	237	size_t space;
	238	int len;
	239	int ret;
	240
	241	/* Receive data became available. Drain the transport layer. */
	242	devc = sdi->priv;
	243	while (devc->buflen < TC_POLL_LEN) {
	244	space = sizeof(devc->buf) - devc->buflen;
	245	len = serial_read_nonblocking(serial,
	246	&devc->buf[devc->buflen], space);
	247	if (len < 0)
	248	return SR_ERR_IO;
	249	if (len == 0)
	250	return SR_OK;
	251	devc->buflen += len;
	252	}
	253
	254	/*
	255	* TODO Want to (re-)synchronize to the packet stream? The
	256	* 'pac1' string literal would be a perfect match for that.
	257	*/
	258
	259	/* Process packets when their reception has completed. */
	260	while (devc->buflen >= TC_POLL_LEN) {
	261	ret = handle_poll_data(sdi);
	262	if (ret != SR_OK)
	263	return ret;
	264	devc->buflen -= TC_POLL_LEN;
	265	if (devc->buflen)
	266	memmove(&devc->buf[0], &devc->buf[TC_POLL_LEN], devc->buflen);
	267	}
	268
	269	return SR_OK;
	270	}
	271
	272	SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
	273	{
	274	struct sr_dev_inst *sdi;
	275	struct dev_context *devc;
	276	struct sr_serial_dev_inst *serial;
	277	int ret;
	278
	279	(void)fd;
	280
	281	if (!(sdi = cb_data))
	282	return TRUE;
	283	if (!(devc = sdi->priv))
	284	return TRUE;
	285
	286	/* Handle availability of receive data. */
	287	serial = sdi->conn;
	288	if (revents == G_IO_IN) {
	289	ret = recv_poll_data(sdi, serial);
	290	if (ret != SR_OK)
	291	sr_dev_acquisition_stop(sdi);
	292	}
	293
	294	/* Check configured acquisition limits. */
	295	if (sr_sw_limits_check(&devc->limits)) {
	296	sr_dev_acquisition_stop(sdi);
	297	return TRUE;
	298	}
	299
	300	/* Periodically retransmit measurement requests. */
	301	(void)rdtech_tc_poll(sdi, FALSE);
	302
	303	return TRUE;
	304	}