[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

/*
 * 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)
#if TC_POLL_LEN > RDTECH_TC_RSPBUFSIZE
#  error "response length exceeds receive buffer space"
#endif

#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 rdtech_tc_channel_desc rdtech_tc_channels[] = {
	{ "V",  {   0 + 48, BVT_LE_UINT32, 1, }, { 100, 1e6, }, 4, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "I",  {   0 + 52, BVT_LE_UINT32, 1, }, {  10, 1e6, }, 5, SR_MQ_CURRENT, SR_UNIT_AMPERE },
	{ "D+", {  64 + 32, BVT_LE_UINT32, 1, }, {  10, 1e3, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "D-", {  64 + 36, BVT_LE_UINT32, 1, }, {  10, 1e3, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	{ "E0", {  64 + 12, BVT_LE_UINT32, 1, }, {   1, 1e3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	{ "E1", {  64 + 20, BVT_LE_UINT32, 1, }, {   1, 1e3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
};

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)
{
	static const char *poll_cmd_cdc = "getva";
	static const char *poll_cmd_ble = "bgetva\r\n";

	int len;
	uint8_t poll_pkt[TC_POLL_LEN];

	/* Construct the request text. Which differs across transports. */
	devc->is_bluetooth = ser_name_is_bt(serial);
	snprintf(devc->req_text, sizeof(devc->req_text), "%s",
		devc->is_bluetooth ? poll_cmd_ble : poll_cmd_cdc);
	sr_dbg("is bluetooth %d -> poll request '%s'.",
		devc->is_bluetooth, devc->req_text);

	/* Transmit the request. */
	len = serial_write_blocking(serial,
		devc->req_text, strlen(devc->req_text), WRITE_TO_MS);
	if (len < 0) {
		sr_err("Failed to send probe request.");
		return SR_ERR;
	}

	/* Receive a response. */
	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->channel_count = ARRAY_SIZE(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->rdlen)
		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,
		devc->req_text, strlen(devc->req_text), 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 ch_idx;
	const struct rdtech_tc_channel_desc *pch;
	int ret;
	float v;

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

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

	ret = SR_OK;
	std_session_send_df_frame_begin(sdi);
	for (ch_idx = 0; ch_idx < devc->channel_count; ch_idx++) {
		pch = &devc->channels[ch_idx];
		ret = bv_get_value(&v, &pch->spec, poll_pkt, TC_POLL_LEN);
		if (ret != SR_OK)
			break;
		ret = feed_queue_analog_submit(devc->feeds[ch_idx], v, 1);
		if (ret != SR_OK)
			break;
	}
	std_session_send_df_frame_end(sdi);

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

	return ret;
}

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->rdlen < TC_POLL_LEN) {
		space = sizeof(devc->buf) - devc->rdlen;
		len = serial_read_nonblocking(serial,
			&devc->buf[devc->rdlen], space);
		if (len < 0)
			return SR_ERR_IO;
		if (len == 0)
			return SR_OK;
		devc->rdlen += 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->rdlen >= TC_POLL_LEN) {
		ret = handle_poll_data(sdi);
		if (ret != SR_OK)
			return ret;
		devc->rdlen -= TC_POLL_LEN;
		if (devc->rdlen)
			memmove(devc->buf, &devc->buf[TC_POLL_LEN], devc->rdlen);
	}

	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
cae33a58 AS	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>
ea5fc667	21
cae33a58	22	#include <glib.h>
cae33a58	23	#include <libsigrok/libsigrok.h>
ea5fc667 GS	24	#include <math.h>
	25	#include <nettle/aes.h>
	26	#include <stdlib.h>
	27	#include <string.h>
	28
cae33a58 AS	29	#include "libsigrok-internal.h"
	30	#include "protocol.h"
	31
861fa81f GS	32	#define PROBE_TO_MS 1000
	33	#define WRITE_TO_MS 1
	34	#define POLL_PERIOD_MS 100
cae33a58	35
a780870c GS	36	/*
	37	* Response data (raw sample data) consists of three adjacent chunks
	38	* of 64 bytes each. These chunks start with their magic string, and
	39	* end in a 32bit checksum field. Measurement values are scattered
	40	* across these 192 bytes total size. All multi-byte integer values
	41	* are represented in little endian format. Typical size is 32 bits.
	42	*/
	43
	44	#define MAGIC_PAC1 0x70616331 /* 'pac1' */
	45	#define MAGIC_PAC2 0x70616332 /* 'pac2' */
	46	#define MAGIC_PAC3 0x70616333 /* 'pac3' */
cae33a58	47
cae33a58	48	#define PAC_LEN 64
a780870c	49	#define PAC_CRC_POS (PAC_LEN - sizeof(uint32_t))
cae33a58 AS	50
	51	/* Offset to PAC block from start of poll data */
	52	#define OFF_PAC1 (0 * PAC_LEN)
	53	#define OFF_PAC2 (1 * PAC_LEN)
	54	#define OFF_PAC3 (2 * PAC_LEN)
a780870c	55	#define TC_POLL_LEN (3 * PAC_LEN)
37b68953 GS	56	#if TC_POLL_LEN > RDTECH_TC_RSPBUFSIZE
	57	# error "response length exceeds receive buffer space"
	58	#endif
cae33a58 AS	59
	60	#define OFF_MODEL 4
	61	#define LEN_MODEL 4
	62
	63	#define OFF_FW_VER 8
	64	#define LEN_FW_VER 4
	65
	66	#define OFF_SERIAL 12
	67
	68	static const uint8_t AES_KEY[] = {
	69	0x58, 0x21, 0xfa, 0x56, 0x01, 0xb2, 0xf0, 0x26,
	70	0x87, 0xff, 0x12, 0x04, 0x62, 0x2a, 0x4f, 0xb0,
	71	0x86, 0xf4, 0x02, 0x60, 0x81, 0x6f, 0x9a, 0x0b,
	72	0xa7, 0xf1, 0x06, 0x61, 0x9a, 0xb8, 0x72, 0x88,
	73	};
	74
b3df7668 GS	75	static const struct rdtech_tc_channel_desc rdtech_tc_channels[] = {
	76	{ "V", { 0 + 48, BVT_LE_UINT32, 1, }, { 100, 1e6, }, 4, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	77	{ "I", { 0 + 52, BVT_LE_UINT32, 1, }, { 10, 1e6, }, 5, SR_MQ_CURRENT, SR_UNIT_AMPERE },
	78	{ "D+", { 64 + 32, BVT_LE_UINT32, 1, }, { 10, 1e3, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	79	{ "D-", { 64 + 36, BVT_LE_UINT32, 1, }, { 10, 1e3, }, 2, SR_MQ_VOLTAGE, SR_UNIT_VOLT },
	80	{ "E0", { 64 + 12, BVT_LE_UINT32, 1, }, { 1, 1e3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
	81	{ "E1", { 64 + 20, BVT_LE_UINT32, 1, }, { 1, 1e3, }, 3, SR_MQ_ENERGY, SR_UNIT_WATT_HOUR },
cae33a58 AS	82	};
cae33a58 AS	83
a780870c	84	static gboolean check_pac_crc(uint8_t *data)
cae33a58 AS	85	{
	86	uint16_t crc;
	87	uint32_t crc_field;
	88
a780870c GS	89	crc = sr_crc16(SR_CRC16_DEFAULT_INIT, data, PAC_CRC_POS);
a780870c GS	90	crc_field = read_u32le(&data[PAC_CRC_POS]);
cae33a58 AS	91	if (crc != crc_field) {
	92	sr_spew("CRC error. Calculated: %0x" PRIx16 ", expected: %0x" PRIx32,
	93	crc, crc_field);
a780870c	94	return FALSE;
cae33a58	95	}
a780870c GS	96
a780870c GS	97	return TRUE;
cae33a58 AS	98	}
cae33a58 AS	99
5955b58c	100	static int process_poll_pkt(struct dev_context devc, uint8_t dst)
cae33a58 AS	101	{
cae33a58 AS	102	struct aes256_ctx ctx;
a780870c	103	gboolean ok;
cae33a58 AS	104
	105	aes256_set_decrypt_key(&ctx, AES_KEY);
	106	aes256_decrypt(&ctx, TC_POLL_LEN, dst, devc->buf);
	107
a780870c GS	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;
cae33a58 AS	115	}
cae33a58 AS	116
a780870c GS	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;
cae33a58 AS	123	}
	124
	125	return SR_OK;
	126	}
	127
5955b58c	128	SR_PRIV int rdtech_tc_probe(struct sr_serial_dev_inst serial, struct dev_context devc)
cae33a58	129	{
37b68953 GS	130	static const char *poll_cmd_cdc = "getva";
	131	static const char *poll_cmd_ble = "bgetva\r\n";
	132
cae33a58 AS	133	int len;
	134	uint8_t poll_pkt[TC_POLL_LEN];
	135
37b68953 GS	136	/* Construct the request text. Which differs across transports. */
	137	devc->is_bluetooth = ser_name_is_bt(serial);
	138	snprintf(devc->req_text, sizeof(devc->req_text), "%s",
	139	devc->is_bluetooth ? poll_cmd_ble : poll_cmd_cdc);
	140	sr_dbg("is bluetooth %d -> poll request '%s'.",
	141	devc->is_bluetooth, devc->req_text);
	142
	143	/* Transmit the request. */
861fa81f	144	len = serial_write_blocking(serial,
37b68953	145	devc->req_text, strlen(devc->req_text), WRITE_TO_MS);
861fa81f	146	if (len < 0) {
a780870c	147	sr_err("Failed to send probe request.");
cae33a58 AS	148	return SR_ERR;
	149	}
	150
37b68953	151	/* Receive a response. */
861fa81f	152	len = serial_read_blocking(serial, devc->buf, TC_POLL_LEN, PROBE_TO_MS);
cae33a58 AS	153	if (len != TC_POLL_LEN) {
	154	sr_err("Failed to read probe response.");
	155	return SR_ERR;
	156	}
	157
	158	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
	159	sr_err("Unrecognized TC device!");
	160	return SR_ERR;
	161	}
	162
	163	devc->channels = rdtech_tc_channels;
b3df7668	164	devc->channel_count = ARRAY_SIZE(rdtech_tc_channels);
a780870c GS	165	devc->dev_info.model_name = g_strndup((const char *)&poll_pkt[OFF_MODEL], LEN_MODEL);
	166	devc->dev_info.fw_ver = g_strndup((const char *)&poll_pkt[OFF_FW_VER], LEN_FW_VER);
	167	devc->dev_info.serial_num = read_u32le(&poll_pkt[OFF_SERIAL]);
cae33a58 AS	168
	169	return SR_OK;
	170	}
	171
a82490b6	172	SR_PRIV int rdtech_tc_poll(const struct sr_dev_inst *sdi, gboolean force)
cae33a58	173	{
c1f9428a	174	struct dev_context *devc;
a82490b6	175	int64_t now, elapsed;
c1f9428a	176	struct sr_serial_dev_inst *serial;
861fa81f	177	int len;
cae33a58	178
8817bd6f GS	179	/*
	180	* Don't send the request while receive data is being accumulated.
	181	*/
a82490b6	182	devc = sdi->priv;
e2bcf2e3	183	if (!force && devc->rdlen)
8817bd6f GS	184	return SR_OK;
	185
	186	/*
	187	* Send the request when the transmit interval was reached. Or
	188	* when the caller forced the transmission.
	189	*/
a82490b6 GS	190	now = g_get_monotonic_time() / 1000;
a82490b6 GS	191	elapsed = now - devc->cmd_sent_at;
861fa81f	192	if (!force && elapsed < POLL_PERIOD_MS)
a82490b6 GS	193	return SR_OK;
a82490b6 GS	194
8817bd6f GS	195	/*
	196	* Transmit another measurement request. Only advance the
	197	* interval after successful transmission.
	198	*/
c1f9428a	199	serial = sdi->conn;
861fa81f	200	len = serial_write_blocking(serial,
37b68953	201	devc->req_text, strlen(devc->req_text), WRITE_TO_MS);
861fa81f	202	if (len < 0) {
cae33a58 AS	203	sr_err("Unable to send poll request.");
	204	return SR_ERR;
	205	}
a82490b6	206	devc->cmd_sent_at = now;
cae33a58 AS	207
	208	return SR_OK;
	209	}
	210
269f1e0e	211	static int handle_poll_data(struct sr_dev_inst *sdi)
cae33a58	212	{
c1f9428a	213	struct dev_context *devc;
cae33a58	214	uint8_t poll_pkt[TC_POLL_LEN];
b3df7668 GS	215	size_t ch_idx;
b3df7668 GS	216	const struct rdtech_tc_channel_desc *pch;
269f1e0e	217	int ret;
b3df7668	218	float v;
cae33a58	219
c1f9428a	220	devc = sdi->priv;
e2bcf2e3 GS	221	sr_spew("Received poll packet (len: %zu).", devc->rdlen);
	222	if (devc->rdlen < TC_POLL_LEN) {
	223	sr_err("Insufficient poll packet length: %zu", devc->rdlen);
269f1e0e	224	return SR_ERR_DATA;
cae33a58 AS	225	}
	226
	227	if (process_poll_pkt(devc, poll_pkt) != SR_OK) {
	228	sr_err("Failed to process poll packet.");
269f1e0e	229	return SR_ERR_DATA;
cae33a58 AS	230	}
cae33a58 AS	231
15ceaf9d GS	232	ret = SR_OK;
15ceaf9d GS	233	std_session_send_df_frame_begin(sdi);
b3df7668 GS	234	for (ch_idx = 0; ch_idx < devc->channel_count; ch_idx++) {
	235	pch = &devc->channels[ch_idx];
	236	ret = bv_get_value(&v, &pch->spec, poll_pkt, TC_POLL_LEN);
	237	if (ret != SR_OK)
15ceaf9d	238	break;
b3df7668	239	ret = feed_queue_analog_submit(devc->feeds[ch_idx], v, 1);
269f1e0e	240	if (ret != SR_OK)
15ceaf9d	241	break;
5955b58c	242	}
15ceaf9d	243	std_session_send_df_frame_end(sdi);
cae33a58	244
15ceaf9d	245	sr_sw_limits_update_frames_read(&devc->limits, 1);
269f1e0e GS	246	if (sr_sw_limits_check(&devc->limits))
	247	sr_dev_acquisition_stop(sdi);
	248
15ceaf9d	249	return ret;
cae33a58 AS	250	}
cae33a58 AS	251
269f1e0e	252	static int recv_poll_data(struct sr_dev_inst sdi, struct sr_serial_dev_inst serial)
cae33a58	253	{
c1f9428a	254	struct dev_context *devc;
8817bd6f	255	size_t space;
cae33a58	256	int len;
269f1e0e	257	int ret;
cae33a58	258
8817bd6f	259	/* Receive data became available. Drain the transport layer. */
c1f9428a	260	devc = sdi->priv;
e2bcf2e3 GS	261	while (devc->rdlen < TC_POLL_LEN) {
e2bcf2e3 GS	262	space = sizeof(devc->buf) - devc->rdlen;
8817bd6f	263	len = serial_read_nonblocking(serial,
e2bcf2e3	264	&devc->buf[devc->rdlen], space);
269f1e0e GS	265	if (len < 0)
	266	return SR_ERR_IO;
	267	if (len == 0)
	268	return SR_OK;
e2bcf2e3	269	devc->rdlen += len;
cae33a58 AS	270	}
cae33a58 AS	271
8817bd6f GS	272	/*
	273	* TODO Want to (re-)synchronize to the packet stream? The
	274	* 'pac1' string literal would be a perfect match for that.
	275	*/
	276
	277	/* Process packets when their reception has completed. */
e2bcf2e3	278	while (devc->rdlen >= TC_POLL_LEN) {
269f1e0e GS	279	ret = handle_poll_data(sdi);
	280	if (ret != SR_OK)
	281	return ret;
e2bcf2e3 GS	282	devc->rdlen -= TC_POLL_LEN;
	283	if (devc->rdlen)
	284	memmove(devc->buf, &devc->buf[TC_POLL_LEN], devc->rdlen);
269f1e0e	285	}
269f1e0e GS	286
269f1e0e GS	287	return SR_OK;
cae33a58 AS	288	}
	289
	290	SR_PRIV int rdtech_tc_receive_data(int fd, int revents, void *cb_data)
	291	{
	292	struct sr_dev_inst *sdi;
	293	struct dev_context *devc;
	294	struct sr_serial_dev_inst *serial;
269f1e0e	295	int ret;
cae33a58 AS	296
	297	(void)fd;
	298
	299	if (!(sdi = cb_data))
	300	return TRUE;
cae33a58 AS	301	if (!(devc = sdi->priv))
	302	return TRUE;
	303
269f1e0e	304	/* Handle availability of receive data. */
cae33a58	305	serial = sdi->conn;
269f1e0e GS	306	if (revents == G_IO_IN) {
	307	ret = recv_poll_data(sdi, serial);
	308	if (ret != SR_OK)
	309	sr_dev_acquisition_stop(sdi);
	310	}
cae33a58	311
269f1e0e	312	/* Check configured acquisition limits. */
cae33a58 AS	313	if (sr_sw_limits_check(&devc->limits)) {
	314	sr_dev_acquisition_stop(sdi);
	315	return TRUE;
	316	}
	317
269f1e0e GS	318	/* Periodically retransmit measurement requests. */
269f1e0e GS	319	(void)rdtech_tc_poll(sdi, FALSE);
cae33a58 AS	320
	321	return TRUE;
	322	}