libsigrok/src/hardware/dslogic/protocol.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2013 Bert Vermeulen <bert@biot.com>
 * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
 *
 * 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 <math.h>
#include <glib.h>
#include <glib/gstdio.h>
#include "protocol.h"

#define DS_CMD_GET_FW_VERSION		0xb0
#define DS_CMD_GET_REVID_VERSION	0xb1
#define DS_CMD_START			0xb2
#define DS_CMD_CONFIG			0xb3
#define DS_CMD_SETTING			0xb4
#define DS_CMD_CONTROL			0xb5
#define DS_CMD_STATUS			0xb6
#define DS_CMD_STATUS_INFO		0xb7
#define DS_CMD_WR_REG			0xb8
#define DS_CMD_WR_NVM			0xb9
#define DS_CMD_RD_NVM			0xba
#define DS_CMD_RD_NVM_PRE		0xbb
#define DS_CMD_GET_HW_INFO		0xbc

#define DS_START_FLAGS_STOP		(1 << 7)
#define DS_START_FLAGS_CLK_48MHZ	(1 << 6)
#define DS_START_FLAGS_SAMPLE_WIDE	(1 << 5)
#define DS_START_FLAGS_MODE_LA		(1 << 4)

#define DS_ADDR_COMB			0x68
#define DS_ADDR_EEWP			0x70
#define DS_ADDR_VTH			0x78

#define DS_MAX_LOGIC_DEPTH		SR_MHZ(16)
#define DS_MAX_LOGIC_SAMPLERATE		SR_MHZ(100)
#define DS_MAX_TRIG_PERCENT		90

#define DS_MODE_TRIG_EN			(1 << 0)
#define DS_MODE_CLK_TYPE		(1 << 1)
#define DS_MODE_CLK_EDGE		(1 << 2)
#define DS_MODE_RLE_MODE		(1 << 3)
#define DS_MODE_DSO_MODE		(1 << 4)
#define DS_MODE_HALF_MODE		(1 << 5)
#define DS_MODE_QUAR_MODE		(1 << 6)
#define DS_MODE_ANALOG_MODE		(1 << 7)
#define DS_MODE_FILTER			(1 << 8)
#define DS_MODE_INSTANT			(1 << 9)
#define DS_MODE_STRIG_MODE		(1 << 11)
#define DS_MODE_STREAM_MODE		(1 << 12)
#define DS_MODE_LPB_TEST		(1 << 13)
#define DS_MODE_EXT_TEST		(1 << 14)
#define DS_MODE_INT_TEST		(1 << 15)

#define DSLOGIC_ATOMIC_SAMPLES		(sizeof(uint64_t) * 8)
#define DSLOGIC_ATOMIC_BYTES		sizeof(uint64_t)

/*
 * The FPGA is configured with TLV tuples. Length is specified as the
 * number of 16-bit words.
 */
#define _DS_CFG(variable, wordcnt) ((variable << 8) | wordcnt)
#define DS_CFG_START		0xf5a5f5a5
#define DS_CFG_MODE		_DS_CFG(0, 1)
#define DS_CFG_DIVIDER		_DS_CFG(1, 2)
#define DS_CFG_COUNT		_DS_CFG(3, 2)
#define DS_CFG_TRIG_POS		_DS_CFG(5, 2)
#define DS_CFG_TRIG_GLB		_DS_CFG(7, 1)
#define DS_CFG_CH_EN		_DS_CFG(8, 1)
#define DS_CFG_TRIG		_DS_CFG(64, 160)
#define DS_CFG_END		0xfa5afa5a

#pragma pack(push, 1)

struct version_info {
	uint8_t major;
	uint8_t minor;
};

struct cmd_start_acquisition {
	uint8_t flags;
	uint8_t sample_delay_h;
	uint8_t sample_delay_l;
};

struct dslogic_fpga_config {
	uint32_t sync;

	uint16_t mode_header;
	uint16_t mode;
	uint16_t divider_header;
	uint32_t divider;
	uint16_t count_header;
	uint32_t count;
	uint16_t trig_pos_header;
	uint32_t trig_pos;
	uint16_t trig_glb_header;
	uint16_t trig_glb;
	uint16_t ch_en_header;
	uint16_t ch_en;

	uint16_t trig_header;
	uint16_t trig_mask0[NUM_TRIGGER_STAGES];
	uint16_t trig_mask1[NUM_TRIGGER_STAGES];
	uint16_t trig_value0[NUM_TRIGGER_STAGES];
	uint16_t trig_value1[NUM_TRIGGER_STAGES];
	uint16_t trig_edge0[NUM_TRIGGER_STAGES];
	uint16_t trig_edge1[NUM_TRIGGER_STAGES];
	uint16_t trig_logic0[NUM_TRIGGER_STAGES];
	uint16_t trig_logic1[NUM_TRIGGER_STAGES];
	uint32_t trig_count[NUM_TRIGGER_STAGES];

	uint32_t end_sync;
};

#pragma pack(pop)

/*
 * This should be larger than the FPGA bitstream image so that it'll get
 * uploaded in one big operation. There seem to be issues when uploading
 * it in chunks.
 */
#define FW_BUFSIZE (1024 * 1024)

#define FPGA_UPLOAD_DELAY (10 * 1000)

#define USB_TIMEOUT (3 * 1000)

static int command_get_fw_version(libusb_device_handle *devhdl,
				  struct version_info *vi)
{
	int ret;

	ret = libusb_control_transfer(devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
		LIBUSB_ENDPOINT_IN, DS_CMD_GET_FW_VERSION, 0x0000, 0x0000,
		(unsigned char *)vi, sizeof(struct version_info), USB_TIMEOUT);

	if (ret < 0) {
		sr_err("Unable to get version info: %s.",
		       libusb_error_name(ret));
		return SR_ERR;
	}

	return SR_OK;
}

static int command_get_revid_version(struct sr_dev_inst *sdi, uint8_t *revid)
{
	struct sr_usb_dev_inst *usb = sdi->conn;
	libusb_device_handle *devhdl = usb->devhdl;
	int ret;

	ret = libusb_control_transfer(devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
		LIBUSB_ENDPOINT_IN, DS_CMD_GET_REVID_VERSION, 0x0000, 0x0000,
		revid, 1, USB_TIMEOUT);

	if (ret < 0) {
		sr_err("Unable to get REVID: %s.", libusb_error_name(ret));
		return SR_ERR;
	}

	return SR_OK;
}

static int command_start_acquisition(const struct sr_dev_inst *sdi)
{
	struct sr_usb_dev_inst *usb;
	struct dslogic_mode mode;
	int ret;

	mode.flags = DS_START_FLAGS_MODE_LA | DS_START_FLAGS_SAMPLE_WIDE;
	mode.sample_delay_h = mode.sample_delay_l = 0;

	usb = sdi->conn;
	ret = libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
			LIBUSB_ENDPOINT_OUT, DS_CMD_START, 0x0000, 0x0000,
			(unsigned char *)&mode, sizeof(mode), USB_TIMEOUT);
	if (ret < 0) {
		sr_err("Failed to send start command: %s.", libusb_error_name(ret));
		return SR_ERR;
	}

	return SR_OK;
}

static int command_stop_acquisition(const struct sr_dev_inst *sdi)
{
	struct sr_usb_dev_inst *usb;
	struct dslogic_mode mode;
	int ret;

	mode.flags = DS_START_FLAGS_STOP;
	mode.sample_delay_h = mode.sample_delay_l = 0;

	usb = sdi->conn;
	ret = libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
			LIBUSB_ENDPOINT_OUT, DS_CMD_START, 0x0000, 0x0000,
			(unsigned char *)&mode, sizeof(struct dslogic_mode), USB_TIMEOUT);
	if (ret < 0) {
		sr_err("Failed to send stop command: %s.", libusb_error_name(ret));
		return SR_ERR;
	}

	return SR_OK;
}

SR_PRIV int dslogic_fpga_firmware_upload(const struct sr_dev_inst *sdi)
{
	const char *name = NULL;
	uint64_t sum;
	struct sr_resource bitstream;
	struct drv_context *drvc;
	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	unsigned char *buf;
	ssize_t chunksize;
	int transferred;
	int result, ret;
	const uint8_t cmd[3] = {0, 0, 0};

	drvc = sdi->driver->context;
	devc = sdi->priv;
	usb = sdi->conn;

	if (!strcmp(devc->profile->model, "DSLogic")) {
		if (devc->cur_threshold < 1.40)
			name = DSLOGIC_FPGA_FIRMWARE_3V3;
		else
			name = DSLOGIC_FPGA_FIRMWARE_5V;
	} else if (!strcmp(devc->profile->model, "DSLogic Pro")){
		name = DSLOGIC_PRO_FPGA_FIRMWARE;
	} else if (!strcmp(devc->profile->model, "DSLogic Plus")){
		name = DSLOGIC_PLUS_FPGA_FIRMWARE;
	} else if (!strcmp(devc->profile->model, "DSLogic Basic")){
		name = DSLOGIC_BASIC_FPGA_FIRMWARE;
	} else if (!strcmp(devc->profile->model, "DSCope")) {
		name = DSCOPE_FPGA_FIRMWARE;
	} else {
		sr_err("Failed to select FPGA firmware.");
		return SR_ERR;
	}

	sr_dbg("Uploading FPGA firmware '%s'.", name);

	result = sr_resource_open(drvc->sr_ctx, &bitstream,
			SR_RESOURCE_FIRMWARE, name);
	if (result != SR_OK)
		return result;

	/* Tell the device firmware is coming. */
	if ((ret = libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
			LIBUSB_ENDPOINT_OUT, DS_CMD_CONFIG, 0x0000, 0x0000,
			(unsigned char *)&cmd, sizeof(cmd), USB_TIMEOUT)) < 0) {
		sr_err("Failed to upload FPGA firmware: %s.", libusb_error_name(ret));
		sr_resource_close(drvc->sr_ctx, &bitstream);
		return SR_ERR;
	}

	/* Give the FX2 time to get ready for FPGA firmware upload. */
	g_usleep(FPGA_UPLOAD_DELAY);

	buf = g_malloc(FW_BUFSIZE);
	sum = 0;
	result = SR_OK;
	while (1) {
		chunksize = sr_resource_read(drvc->sr_ctx, &bitstream,
				buf, FW_BUFSIZE);
		if (chunksize < 0)
			result = SR_ERR;
		if (chunksize <= 0)
			break;

		if ((ret = libusb_bulk_transfer(usb->devhdl, 2 | LIBUSB_ENDPOINT_OUT,
				buf, chunksize, &transferred, USB_TIMEOUT)) < 0) {
			sr_err("Unable to configure FPGA firmware: %s.",
					libusb_error_name(ret));
			result = SR_ERR;
			break;
		}
		sum += transferred;
		sr_spew("Uploaded %" PRIu64 "/%" PRIu64 " bytes.",
			sum, bitstream.size);

		if (transferred != chunksize) {
			sr_err("Short transfer while uploading FPGA firmware.");
			result = SR_ERR;
			break;
		}
	}
	g_free(buf);
	sr_resource_close(drvc->sr_ctx, &bitstream);

	if (result == SR_OK)
		sr_dbg("FPGA firmware upload done.");

	return result;
}

static unsigned int enabled_channel_count(const struct sr_dev_inst *sdi)
{
	unsigned int count = 0;
	for (const GSList *l = sdi->channels; l; l = l->next) {
		const struct sr_channel *const probe = (struct sr_channel *)l->data;
		if (probe->enabled)
			count++;
	}
	return count;
}

static uint16_t enabled_channel_mask(const struct sr_dev_inst *sdi)
{
	unsigned int mask = 0;
	for (const GSList *l = sdi->channels; l; l = l->next) {
		const struct sr_channel *const probe = (struct sr_channel *)l->data;
		if (probe->enabled)
			mask |= 1 << probe->index;
	}
	return mask;
}

/*
 * Get the session trigger and configure the FPGA structure
 * accordingly.
 */
static void set_trigger(const struct sr_dev_inst *sdi,
	struct dslogic_fpga_config *cfg)
{
	struct sr_trigger *trigger;
	struct sr_trigger_stage *stage;
	struct sr_trigger_match *match;
	struct dev_context *devc;
	const GSList *l, *m;
	const unsigned int num_enabled_channels = enabled_channel_count(sdi);
	int num_trigger_stages = 0;

	int channelbit, i = 0;
	uint32_t trigger_point;

	devc = sdi->priv;

	cfg->ch_en = enabled_channel_mask(sdi);

	cfg->trig_mask0[0] = 0xffff;
	cfg->trig_mask1[0] = 0xffff;

	cfg->trig_value0[0] = 0;
	cfg->trig_value1[0] = 0;

	cfg->trig_edge0[0] = 0;
	cfg->trig_edge1[0] = 0;

	cfg->trig_logic0[0] = 2;
	cfg->trig_logic1[0] = 2;

	cfg->trig_count[0] = 0;

	cfg->trig_glb = num_enabled_channels << 4;

	for (i = 1; i < NUM_TRIGGER_STAGES; i++) {
		cfg->trig_mask0[i] = 0xffff;
		cfg->trig_mask1[i] = 0xffff;
		cfg->trig_value0[i] = 0;
		cfg->trig_value1[i] = 0;
		cfg->trig_edge0[i] = 0;
		cfg->trig_edge1[i] = 0;
		cfg->trig_logic0[i] = 2;
		cfg->trig_logic1[i] = 2;
		cfg->trig_count[i] = 0;
	}

	trigger_point = (devc->capture_ratio * devc->limit_samples) / 100;
	if (trigger_point < DSLOGIC_ATOMIC_SAMPLES)
		trigger_point = DSLOGIC_ATOMIC_SAMPLES;
	const uint32_t mem_depth = devc->profile->mem_depth;
	const uint32_t max_trigger_point = devc->continuous_mode ? ((mem_depth * 10) / 100) :
		((mem_depth * DS_MAX_TRIG_PERCENT) / 100);
	if (trigger_point > max_trigger_point)
		trigger_point = max_trigger_point;
	cfg->trig_pos = trigger_point & ~(DSLOGIC_ATOMIC_SAMPLES - 1);

	if (!(trigger = sr_session_trigger_get(sdi->session))) {
		sr_dbg("No session trigger found");
		return;
	}

	for (l = trigger->stages; l; l = l->next) {
		stage = l->data;
		num_trigger_stages++;
		for (m = stage->matches; m; m = m->next) {
			match = m->data;
			if (!match->channel->enabled)
				/* Ignore disabled channels with a trigger. */
				continue;
			channelbit = 1 << (match->channel->index);
			/* Simple trigger support (event). */
			if (match->match == SR_TRIGGER_ONE) {
				cfg->trig_mask0[0] &= ~channelbit;
				cfg->trig_mask1[0] &= ~channelbit;
				cfg->trig_value0[0] |= channelbit;
				cfg->trig_value1[0] |= channelbit;
			} else if (match->match == SR_TRIGGER_ZERO) {
				cfg->trig_mask0[0] &= ~channelbit;
				cfg->trig_mask1[0] &= ~channelbit;
			} else if (match->match == SR_TRIGGER_FALLING) {
				cfg->trig_mask0[0] &= ~channelbit;
				cfg->trig_mask1[0] &= ~channelbit;
				cfg->trig_edge0[0] |= channelbit;
				cfg->trig_edge1[0] |= channelbit;
			} else if (match->match == SR_TRIGGER_RISING) {
				cfg->trig_mask0[0] &= ~channelbit;
				cfg->trig_mask1[0] &= ~channelbit;
				cfg->trig_value0[0] |= channelbit;
				cfg->trig_value1[0] |= channelbit;
				cfg->trig_edge0[0] |= channelbit;
				cfg->trig_edge1[0] |= channelbit;
			} else if (match->match == SR_TRIGGER_EDGE) {
				cfg->trig_edge0[0] |= channelbit;
				cfg->trig_edge1[0] |= channelbit;
			}
		}
	}

	cfg->trig_glb |= num_trigger_stages;

	return;
}

static int fpga_configure(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	uint8_t c[3];
	struct dslogic_fpga_config cfg;
	uint16_t v16;
	uint32_t v32;
	int transferred, len, ret;

	sr_dbg("Configuring FPGA.");

	usb = sdi->conn;
	devc = sdi->priv;

	WL32(&cfg.sync, DS_CFG_START);
	WL16(&cfg.mode_header, DS_CFG_MODE);
	WL16(&cfg.divider_header, DS_CFG_DIVIDER);
	WL16(&cfg.count_header, DS_CFG_COUNT);
	WL16(&cfg.trig_pos_header, DS_CFG_TRIG_POS);
	WL16(&cfg.trig_glb_header, DS_CFG_TRIG_GLB);
	WL16(&cfg.ch_en_header, DS_CFG_CH_EN);
	WL16(&cfg.trig_header, DS_CFG_TRIG);
	WL32(&cfg.end_sync, DS_CFG_END);

	/* Pass in the length of a fixed-size struct. Really. */
	len = sizeof(struct dslogic_fpga_config) / 2;
	c[0] = len & 0xff;
	c[1] = (len >> 8) & 0xff;
	c[2] = (len >> 16) & 0xff;

	ret = libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR |
			LIBUSB_ENDPOINT_OUT, DS_CMD_SETTING, 0x0000, 0x0000,
			c, sizeof(c), USB_TIMEOUT);
	if (ret < 0) {
		sr_err("Failed to send FPGA configure command: %s.",
			libusb_error_name(ret));
		return SR_ERR;
	}

	v16 = 0x0000;

	if (devc->mode == DS_OP_INTERNAL_TEST)
		v16 = DS_MODE_INT_TEST;
	else if (devc->mode == DS_OP_EXTERNAL_TEST)
		v16 = DS_MODE_EXT_TEST;
	else if (devc->mode == DS_OP_LOOPBACK_TEST)
		v16 = DS_MODE_LPB_TEST;

	if (devc->cur_samplerate == DS_MAX_LOGIC_SAMPLERATE * 2)
		v16 |= DS_MODE_HALF_MODE;
	else if (devc->cur_samplerate == DS_MAX_LOGIC_SAMPLERATE * 4)
		v16 |= DS_MODE_QUAR_MODE;

	if (devc->continuous_mode)
		v16 |= DS_MODE_STREAM_MODE;
	if (devc->external_clock) {
		v16 |= DS_MODE_CLK_TYPE;
		if (devc->clock_edge == DS_EDGE_FALLING)
			v16 |= DS_MODE_CLK_EDGE;
	}
	if (devc->limit_samples > DS_MAX_LOGIC_DEPTH *
		ceil(devc->cur_samplerate * 1.0 / DS_MAX_LOGIC_SAMPLERATE)
		&& !devc->continuous_mode) {
		/* Enable RLE for long captures.
		 * Without this, captured data present errors.
		 */
		v16 |= DS_MODE_RLE_MODE;
	}

	WL16(&cfg.mode, v16);
	v32 = ceil(DS_MAX_LOGIC_SAMPLERATE * 1.0 / devc->cur_samplerate);
	WL32(&cfg.divider, v32);

	/* Number of 16-sample units. */
	WL32(&cfg.count, devc->limit_samples / 16);

	set_trigger(sdi, &cfg);

	len = sizeof(struct dslogic_fpga_config);
	ret = libusb_bulk_transfer(usb->devhdl, 2 | LIBUSB_ENDPOINT_OUT,
			(unsigned char *)&cfg, len, &transferred, USB_TIMEOUT);
	if (ret < 0 || transferred != len) {
		sr_err("Failed to send FPGA configuration: %s.", libusb_error_name(ret));
		return SR_ERR;
	}

	return SR_OK;
}

SR_PRIV int dslogic_set_voltage_threshold(const struct sr_dev_inst *sdi, double threshold)
{
	int ret;
	struct dev_context *const devc = sdi->priv;
	const struct sr_usb_dev_inst *const usb = sdi->conn;
	const uint8_t value = (threshold / 5.0) * 255;
	const uint16_t cmd = value | (DS_ADDR_VTH << 8);

	/* Send the control command. */
	ret = libusb_control_transfer(usb->devhdl,
			LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_OUT,
			DS_CMD_WR_REG, 0x0000, 0x0000,
			(unsigned char *)&cmd, sizeof(cmd), 3000);
	if (ret < 0) {
		sr_err("Unable to set voltage-threshold register: %s.",
		libusb_error_name(ret));
		return SR_ERR;
	}

	devc->cur_threshold = threshold;

	return SR_OK;
}

SR_PRIV int dslogic_dev_open(struct sr_dev_inst *sdi, struct sr_dev_driver *di)
{
	libusb_device **devlist;
	struct sr_usb_dev_inst *usb;
	struct libusb_device_descriptor des;
	struct dev_context *devc;
	struct drv_context *drvc;
	struct version_info vi;
	int ret, i, device_count;
	uint8_t revid;
	char connection_id[64];

	drvc = di->context;
	devc = sdi->priv;
	usb = sdi->conn;

	if (sdi->status == SR_ST_ACTIVE)
		/* Device is already in use. */
		return SR_ERR;

	device_count = libusb_get_device_list(drvc->sr_ctx->libusb_ctx, &devlist);
	if (device_count < 0) {
		sr_err("Failed to get device list: %s.",
		       libusb_error_name(device_count));
		return SR_ERR;
	}

	for (i = 0; i < device_count; i++) {
		libusb_get_device_descriptor(devlist[i], &des);

		if (des.idVendor != devc->profile->vid
		    || des.idProduct != devc->profile->pid)
			continue;

		if ((sdi->status == SR_ST_INITIALIZING) ||
				(sdi->status == SR_ST_INACTIVE)) {
			/*
			 * Check device by its physical USB bus/port address.
			 */
			usb_get_port_path(devlist[i], connection_id, sizeof(connection_id));
			if (strcmp(sdi->connection_id, connection_id))
				/* This is not the one. */
				continue;
		}

		if (!(ret = libusb_open(devlist[i], &usb->devhdl))) {
			if (usb->address == 0xff)
				/*
				 * First time we touch this device after FW
				 * upload, so we don't know the address yet.
				 */
				usb->address = libusb_get_device_address(devlist[i]);
		} else {
			sr_err("Failed to open device: %s.",
			       libusb_error_name(ret));
			break;
		}

		if (libusb_has_capability(LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER)) {
			if (libusb_kernel_driver_active(usb->devhdl, USB_INTERFACE) == 1) {
				if ((ret = libusb_detach_kernel_driver(usb->devhdl, USB_INTERFACE)) < 0) {
					sr_err("Failed to detach kernel driver: %s.",
						libusb_error_name(ret));
					return SR_ERR;
				}
			}
		}

		ret = command_get_fw_version(usb->devhdl, &vi);
		if (ret != SR_OK) {
			sr_err("Failed to get firmware version.");
			break;
		}

		ret = command_get_revid_version(sdi, &revid);
		if (ret != SR_OK) {
			sr_err("Failed to get REVID.");
			break;
		}

		/*
		 * Changes in major version mean incompatible/API changes, so
		 * bail out if we encounter an incompatible version.
		 * Different minor versions are OK, they should be compatible.
		 */
		if (vi.major != DSLOGIC_REQUIRED_VERSION_MAJOR) {
			sr_err("Expected firmware version %d.x, "
			       "got %d.%d.", DSLOGIC_REQUIRED_VERSION_MAJOR,
			       vi.major, vi.minor);
			break;
		}

		sdi->status = SR_ST_ACTIVE;
		sr_info("Opened device on %d.%d (logical) / %s (physical), "
			"interface %d, firmware %d.%d.",
			usb->bus, usb->address, connection_id,
			USB_INTERFACE, vi.major, vi.minor);

		sr_info("Detected REVID=%d, it's a Cypress CY7C68013%s.",
			revid, (revid != 1) ? " (FX2)" : "A (FX2LP)");

		break;
	}
	libusb_free_device_list(devlist, 1);

	if (sdi->status != SR_ST_ACTIVE)
		return SR_ERR;

	return SR_OK;
}

SR_PRIV struct dev_context *dslogic_dev_new(void)
{
	struct dev_context *devc;

	devc = g_malloc0(sizeof(struct dev_context));
	devc->profile = NULL;
	devc->fw_updated = 0;
	devc->cur_samplerate = 0;
	devc->limit_samples = 0;
	devc->capture_ratio = 0;
	devc->continuous_mode = FALSE;
	devc->clock_edge = DS_EDGE_RISING;

	return devc;
}

static void abort_acquisition(struct dev_context *devc)
{
	int i;

	devc->acq_aborted = TRUE;

	for (i = devc->num_transfers - 1; i >= 0; i--) {
		if (devc->transfers[i])
			libusb_cancel_transfer(devc->transfers[i]);
	}
}

static void finish_acquisition(struct sr_dev_inst *sdi)
{
	struct dev_context *devc;

	devc = sdi->priv;

	std_session_send_df_end(sdi);

	usb_source_remove(sdi->session, devc->ctx);

	devc->num_transfers = 0;
	g_free(devc->transfers);
}

static void free_transfer(struct libusb_transfer *transfer)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	unsigned int i;

	sdi = transfer->user_data;
	devc = sdi->priv;

	g_free(transfer->buffer);
	transfer->buffer = NULL;
	libusb_free_transfer(transfer);

	for (i = 0; i < devc->num_transfers; i++) {
		if (devc->transfers[i] == transfer) {
			devc->transfers[i] = NULL;
			break;
		}
	}

	devc->submitted_transfers--;
	if (devc->submitted_transfers == 0)
		finish_acquisition(sdi);
}

static void resubmit_transfer(struct libusb_transfer *transfer)
{
	int ret;

	if ((ret = libusb_submit_transfer(transfer)) == LIBUSB_SUCCESS)
		return;

	sr_err("%s: %s", __func__, libusb_error_name(ret));
	free_transfer(transfer);

}

static void send_data(struct sr_dev_inst *sdi,
	uint8_t *data, size_t length, size_t sample_width)
{
	const struct sr_datafeed_logic logic = {
		.length = length,
		.unitsize = sample_width,
		.data = data
	};

	const struct sr_datafeed_packet packet = {
		.type = SR_DF_LOGIC,
		.payload = &logic
	};

	sr_session_send(sdi, &packet);
}

static void LIBUSB_CALL receive_transfer(struct libusb_transfer *transfer)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	gboolean packet_has_error = FALSE;
	struct sr_datafeed_packet packet;
	unsigned int num_samples;
	int trigger_offset, cur_sample_count;
	const int unitsize = 2;

	sdi = transfer->user_data;
	devc = sdi->priv;

	/*
	 * If acquisition has already ended, just free any queued up
	 * transfer that come in.
	 */
	if (devc->acq_aborted) {
		free_transfer(transfer);
		return;
	}

	sr_dbg("receive_transfer(): status %s received %d bytes.",
		libusb_error_name(transfer->status), transfer->actual_length);

	/* Save incoming transfer before reusing the transfer struct. */
	cur_sample_count = transfer->actual_length / unitsize;

	switch (transfer->status) {
	case LIBUSB_TRANSFER_NO_DEVICE:
		abort_acquisition(devc);
		free_transfer(transfer);
		return;
	case LIBUSB_TRANSFER_COMPLETED:
	case LIBUSB_TRANSFER_TIMED_OUT: /* We may have received some data though. */
		break;
	default:
		packet_has_error = TRUE;
		break;
	}

	if (transfer->actual_length == 0 || packet_has_error) {
		devc->empty_transfer_count++;
		if (devc->empty_transfer_count > MAX_EMPTY_TRANSFERS) {
			/*
			 * The FX2 gave up. End the acquisition, the frontend
			 * will work out that the samplecount is short.
			 */
			abort_acquisition(devc);
			free_transfer(transfer);
		} else {
			resubmit_transfer(transfer);
		}
		return;
	} else {
		devc->empty_transfer_count = 0;
	}

	if (!devc->limit_samples || devc->sent_samples < devc->limit_samples) {
		/* Send the incoming transfer to the session bus. */
		if (devc->limit_samples && devc->sent_samples + cur_sample_count > devc->limit_samples)
			num_samples = devc->limit_samples - devc->sent_samples;
		else
			num_samples = cur_sample_count;

		if (devc->trigger_pos > devc->sent_samples
			&& devc->trigger_pos <= devc->sent_samples + num_samples) {
			/* DSLogic trigger in this block. Send trigger position. */
			trigger_offset = devc->trigger_pos - devc->sent_samples;
			/* Pre-trigger samples. */
			send_data(sdi, (uint8_t *)transfer->buffer,
				trigger_offset * unitsize, unitsize);
			devc->sent_samples += trigger_offset;
			/* Trigger position. */
			devc->trigger_pos = 0;
			packet.type = SR_DF_TRIGGER;
			packet.payload = NULL;
			sr_session_send(sdi, &packet);
			/* Post trigger samples. */
			num_samples -= trigger_offset;
			send_data(sdi, (uint8_t *)transfer->buffer
					+ trigger_offset * unitsize, num_samples * unitsize, unitsize);
			devc->sent_samples += num_samples;
		} else {
			send_data(sdi, (uint8_t *)transfer->buffer,
				num_samples * unitsize, unitsize);
			devc->sent_samples += num_samples;
		}
	}

	if (devc->limit_samples && devc->sent_samples >= devc->limit_samples) {
		abort_acquisition(devc);
		free_transfer(transfer);
	} else
		resubmit_transfer(transfer);
}

static int receive_data(int fd, int revents, void *cb_data)
{
	struct timeval tv;
	struct drv_context *drvc;

	(void)fd;
	(void)revents;

	drvc = (struct drv_context *)cb_data;

	tv.tv_sec = tv.tv_usec = 0;
	libusb_handle_events_timeout(drvc->sr_ctx->libusb_ctx, &tv);

	return TRUE;
}

static size_t to_bytes_per_ms(const struct sr_dev_inst *sdi)
{
	const struct dev_context *const devc = sdi->priv;
	const size_t ch_count = enabled_channel_count(sdi);

	if (devc->continuous_mode)
		return (devc->cur_samplerate * ch_count) / (1000 * 8);


	/* If we're in buffered mode, the transfer rate is not so important,
	 * but we expect to get at least 10% of the high-speed USB bandwidth.
	 */
	return 35000000 / (1000 * 10);
}

static size_t get_buffer_size(const struct sr_dev_inst *sdi)
{
	/*
	 * The buffer should be large enough to hold 10ms of data and
	 * a multiple of the size of a data atom.
	 */
	const size_t block_size = enabled_channel_count(sdi) * 512;
	const size_t s = 10 * to_bytes_per_ms(sdi);
	return ((s + block_size - 1) / block_size) * block_size;
}

static unsigned int get_number_of_transfers(const struct sr_dev_inst *sdi)
{
	/* Total buffer size should be able to hold about 100ms of data. */
	const unsigned int s = get_buffer_size(sdi);
	const unsigned int n = (100 * to_bytes_per_ms(sdi) + s - 1) / s;
	return (n > NUM_SIMUL_TRANSFERS) ? NUM_SIMUL_TRANSFERS : n;
}

static unsigned int get_timeout(const struct sr_dev_inst *sdi)
{
	const size_t total_size = get_buffer_size(sdi) *
		get_number_of_transfers(sdi);
	const unsigned int timeout = total_size / to_bytes_per_ms(sdi);
	return timeout + timeout / 4; /* Leave a headroom of 25% percent. */
}

static int start_transfers(const struct sr_dev_inst *sdi)
{
	const size_t size = get_buffer_size(sdi);
	const unsigned int num_transfers = get_number_of_transfers(sdi);
	const unsigned int timeout = get_timeout(sdi);

	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	struct libusb_transfer *transfer;
	unsigned int i;
	int ret;
	unsigned char *buf;

	devc = sdi->priv;
	usb = sdi->conn;

	devc->sent_samples = 0;
	devc->acq_aborted = FALSE;
	devc->empty_transfer_count = 0;
	devc->submitted_transfers = 0;

	g_free(devc->transfers);
	devc->transfers = g_try_malloc0(sizeof(*devc->transfers) * num_transfers);
	if (!devc->transfers) {
		sr_err("USB transfers malloc failed.");
		return SR_ERR_MALLOC;
	}

	devc->num_transfers = num_transfers;
	for (i = 0; i < num_transfers; i++) {
		if (!(buf = g_try_malloc(size))) {
			sr_err("USB transfer buffer malloc failed.");
			return SR_ERR_MALLOC;
		}
		transfer = libusb_alloc_transfer(0);
		libusb_fill_bulk_transfer(transfer, usb->devhdl,
				6 | LIBUSB_ENDPOINT_IN, buf, size,
				receive_transfer, (void *)sdi, timeout);
		sr_info("submitting transfer: %d", i);
		if ((ret = libusb_submit_transfer(transfer)) != 0) {
			sr_err("Failed to submit transfer: %s.",
			       libusb_error_name(ret));
			libusb_free_transfer(transfer);
			g_free(buf);
			abort_acquisition(devc);
			return SR_ERR;
		}
		devc->transfers[i] = transfer;
		devc->submitted_transfers++;
	}

	std_session_send_df_header(sdi);

	return SR_OK;
}

static void LIBUSB_CALL trigger_receive(struct libusb_transfer *transfer)
{
	const struct sr_dev_inst *sdi;
	struct dslogic_trigger_pos *tpos;
	struct dev_context *devc;

	sdi = transfer->user_data;
	devc = sdi->priv;
	if (transfer->status == LIBUSB_TRANSFER_CANCELLED) {
		sr_dbg("Trigger transfer canceled.");
		/* Terminate session. */
		std_session_send_df_end(sdi);
		usb_source_remove(sdi->session, devc->ctx);
		devc->num_transfers = 0;
		g_free(devc->transfers);
	} else if (transfer->status == LIBUSB_TRANSFER_COMPLETED
			&& transfer->actual_length == sizeof(struct dslogic_trigger_pos)) {
		tpos = (struct dslogic_trigger_pos *)transfer->buffer;
		sr_info("tpos real_pos %d ram_saddr %d cnt %d", tpos->real_pos,
			tpos->ram_saddr, tpos->remain_cnt);
		devc->trigger_pos = tpos->real_pos;
		g_free(tpos);
		start_transfers(sdi);
	}
	libusb_free_transfer(transfer);
}

SR_PRIV int dslogic_acquisition_start(const struct sr_dev_inst *sdi)
{
	const unsigned int timeout = get_timeout(sdi);

	struct sr_dev_driver *di;
	struct drv_context *drvc;
	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	struct dslogic_trigger_pos *tpos;
	struct libusb_transfer *transfer;
	int ret;

	if (sdi->status != SR_ST_ACTIVE)
		return SR_ERR_DEV_CLOSED;

	di = sdi->driver;
	drvc = di->context;
	devc = sdi->priv;
	usb = sdi->conn;

	devc->ctx = drvc->sr_ctx;
	devc->sent_samples = 0;
	devc->empty_transfer_count = 0;
	devc->acq_aborted = FALSE;

	usb_source_add(sdi->session, devc->ctx, timeout, receive_data, drvc);

	if ((ret = command_stop_acquisition(sdi)) != SR_OK)
		return ret;

	if ((ret = fpga_configure(sdi)) != SR_OK)
		return ret;

	if ((ret = command_start_acquisition(sdi)) != SR_OK)
		return ret;

	sr_dbg("Getting trigger.");
	tpos = g_malloc(sizeof(struct dslogic_trigger_pos));
	transfer = libusb_alloc_transfer(0);
	libusb_fill_bulk_transfer(transfer, usb->devhdl, 6 | LIBUSB_ENDPOINT_IN,
			(unsigned char *)tpos, sizeof(struct dslogic_trigger_pos),
			trigger_receive, (void *)sdi, 0);
	if ((ret = libusb_submit_transfer(transfer)) < 0) {
		sr_err("Failed to request trigger: %s.", libusb_error_name(ret));
		libusb_free_transfer(transfer);
		g_free(tpos);
		return SR_ERR;
	}

	devc->transfers = g_try_malloc0(sizeof(*devc->transfers));
	if (!devc->transfers) {
		sr_err("USB trigger_pos transfer malloc failed.");
		return SR_ERR_MALLOC;
	}
	devc->num_transfers = 1;
	devc->submitted_transfers++;
	devc->transfers[0] = transfer;

	return ret;
}

SR_PRIV int dslogic_acquisition_stop(struct sr_dev_inst *sdi)
{
	command_stop_acquisition(sdi);
	abort_acquisition(sdi->priv);
	return SR_OK;
}