chronovu-la8.c

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/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2011-2012 Uwe Hermann <uwe@hermann-uwe.de>
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <ftdi.h>
#include <glib.h>
#include <string.h>
#include <stdlib.h>
#include "sigrok.h"
#include "sigrok-internal.h"

#define USB_VENDOR_ID                   0x0403
#define USB_PRODUCT_ID                  0x6001
#define USB_DESCRIPTION                 "ChronoVu LA8"
#define USB_VENDOR_NAME                 "ChronoVu"
#define USB_MODEL_NAME                  "LA8"
#define USB_MODEL_VERSION               ""

#define NUM_PROBES                      8
#define TRIGGER_TYPES                   "01"
#define SDRAM_SIZE                      (8 * 1024 * 1024)
#define MIN_NUM_SAMPLES                 1

#define BS                              4096 /* Block size */
#define NUM_BLOCKS                      2048 /* Number of blocks */

static GSList *dev_insts = NULL;

/* Probes are numbered 0-7. */
static const char *probe_names[NUM_PROBES + 1] = {
        "0",
        "1",
        "2",
        "3",
        "4",
        "5",
        "6",
        "7",
        NULL,
};

/* Private, per-device-instance driver context. */
struct context {
        /** FTDI device context (used by libftdi). */
        struct ftdi_context *ftdic;

        /** The currently configured samplerate of the device. */
        uint64_t cur_samplerate;

        /** The current sampling limit (in ms). */
        uint64_t limit_msec;

        /** The current sampling limit (in number of samples). */
        uint64_t limit_samples;

        /** TODO */
        void *session_dev_id;

        /**
         * A buffer containing some (mangled) samples from the device.
         * Format: Pretty mangled-up (due to hardware reasons), see code.
         */
        uint8_t mangled_buf[BS];

        /**
         * An 8MB buffer where we'll store the de-mangled samples.
         * Format: Each sample is 1 byte, MSB is channel 7, LSB is channel 0.
         */
        uint8_t *final_buf;

        /**
         * Trigger pattern (MSB = channel 7, LSB = channel 0).
         * A 1 bit matches a high signal, 0 matches a low signal on a probe.
         * Only low/high triggers (but not e.g. rising/falling) are supported.
         */
        uint8_t trigger_pattern;

        /**
         * Trigger mask (MSB = channel 7, LSB = channel 0).
         * A 1 bit means "must match trigger_pattern", 0 means "don't care".
         */
        uint8_t trigger_mask;

        /** Time (in seconds) before the trigger times out. */
        uint64_t trigger_timeout;

        /** Tells us whether an SR_DF_TRIGGER packet was already sent. */
        int trigger_found;

        /** TODO */
        time_t done;

        /** Counter/index for the data block to be read. */
        int block_counter;

        /** The divcount value (determines the sample period) for the LA8. */
        uint8_t divcount;
};

/* This will be initialized via hw_dev_info_get()/SR_DI_SAMPLERATES. */
static uint64_t supported_samplerates[255 + 1] = { 0 };

/*
 * Min: 1 sample per 0.01us -> sample time is 0.084s, samplerate 100MHz
 * Max: 1 sample per 2.55us -> sample time is 21.391s, samplerate 392.15kHz
 */
static struct sr_samplerates samplerates = {
        .low  = 0,
        .high = 0,
        .step = 0,
        .list = supported_samplerates,
};

/* Note: Continuous sampling is not supported by the hardware. */
static int hwcaps[] = {
        SR_HWCAP_LOGIC_ANALYZER,
        SR_HWCAP_SAMPLERATE,
        SR_HWCAP_LIMIT_MSEC, /* TODO: Not yet implemented. */
        SR_HWCAP_LIMIT_SAMPLES, /* TODO: Not yet implemented. */
        0,
};

/* Function prototypes. */
static int la8_close_usb_reset_sequencer(struct context *ctx);
static int hw_dev_acquisition_stop(int dev_index, void *cb_data);
static int la8_reset(struct context *ctx);

static void fill_supported_samplerates_if_needed(void)
{
        int i;

        /* Do nothing if supported_samplerates[] is already filled. */
        if (supported_samplerates[0] != 0)
                return;

        /* Fill supported_samplerates[] with the proper values. */
        for (i = 0; i < 255; i++)
                supported_samplerates[254 - i] = SR_MHZ(100) / (i + 1);
        supported_samplerates[255] = 0;
}

/**
 * Check if the given samplerate is supported by the LA8 hardware.
 *
 * @param samplerate The samplerate (in Hz) to check.
 * @return 1 if the samplerate is supported/valid, 0 otherwise.
 */
static int is_valid_samplerate(uint64_t samplerate)
{
        int i;

        fill_supported_samplerates_if_needed();

        for (i = 0; i < 255; i++) {
                if (supported_samplerates[i] == samplerate)
                        return 1;
        }

        sr_err("la8: %s: invalid samplerate (%" PRIu64 "Hz)",
               __func__, samplerate);

        return 0;
}

/**
 * Convert a samplerate (in Hz) to the 'divcount' value the LA8 wants.
 *
 * LA8 hardware: sample period = (divcount + 1) * 10ns.
 * Min. value for divcount: 0x00 (10ns sample period, 100MHz samplerate).
 * Max. value for divcount: 0xfe (2550ns sample period, 392.15kHz samplerate).
 *
 * @param samplerate The samplerate in Hz.
 * @return The divcount value as needed by the hardware, or 0xff upon errors.
 */
static uint8_t samplerate_to_divcount(uint64_t samplerate)
{
        if (samplerate == 0) {
                sr_err("la8: %s: samplerate was 0", __func__);
                return 0xff;
        }

        if (!is_valid_samplerate(samplerate)) {
                sr_err("la8: %s: can't get divcount, samplerate invalid",
                       __func__);
                return 0xff;
        }

        return (SR_MHZ(100) / samplerate) - 1;
}

/**
 * Write data of a certain length to the LA8's FTDI device.
 *
 * @param ctx The struct containing private per-device-instance data. Must not
 *            be NULL. ctx->ftdic must not be NULL either.
 * @param buf The buffer containing the data to write. Must not be NULL.
 * @param size The number of bytes to write. Must be >= 0.
 * @return The number of bytes written, or a negative value upon errors.
 */
static int la8_write(struct context *ctx, uint8_t *buf, int size)
{
        int bytes_written;

        /* Note: Caller checked that ctx and ctx->ftdic != NULL. */

        if (!buf) {
                sr_err("la8: %s: buf was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (size < 0) {
                sr_err("la8: %s: size was < 0", __func__);
                return SR_ERR_ARG;
        }

        bytes_written = ftdi_write_data(ctx->ftdic, buf, size);

        if (bytes_written < 0) {
                sr_err("la8: %s: ftdi_write_data: (%d) %s", __func__,
                       bytes_written, ftdi_get_error_string(ctx->ftdic));
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
        } else if (bytes_written != size) {
                sr_err("la8: %s: bytes to write: %d, bytes written: %d",
                       __func__, size, bytes_written);
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
        }

        return bytes_written;
}

/**
 * Read a certain amount of bytes from the LA8's FTDI device.
 *
 * @param ctx The struct containing private per-device-instance data. Must not
 *            be NULL. ctx->ftdic must not be NULL either.
 * @param buf The buffer where the received data will be stored. Must not
 *            be NULL.
 * @param size The number of bytes to read. Must be >= 1.
 * @return The number of bytes read, or a negative value upon errors.
 */
static int la8_read(struct context *ctx, uint8_t *buf, int size)
{
        int bytes_read;

        /* Note: Caller checked that ctx and ctx->ftdic != NULL. */

        if (!buf) {
                sr_err("la8: %s: buf was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (size <= 0) {
                sr_err("la8: %s: size was <= 0", __func__);
                return SR_ERR_ARG;
        }

        bytes_read = ftdi_read_data(ctx->ftdic, buf, size);

        if (bytes_read < 0) {
                sr_err("la8: %s: ftdi_read_data: (%d) %s", __func__,
                       bytes_read, ftdi_get_error_string(ctx->ftdic));
        } else if (bytes_read != size) {
                // sr_err("la8: %s: bytes to read: %d, bytes read: %d",
                //        __func__, size, bytes_read);
        }

        return bytes_read;
}

static int la8_close(struct context *ctx)
{
        int ret;

        if (!ctx) {
                sr_err("la8: %s: ctx was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (!ctx->ftdic) {
                sr_err("la8: %s: ctx->ftdic was NULL", __func__);
                return SR_ERR_ARG;
        }

        if ((ret = ftdi_usb_close(ctx->ftdic)) < 0) {
                sr_err("la8: %s: ftdi_usb_close: (%d) %s",
                       __func__, ret, ftdi_get_error_string(ctx->ftdic));
        }

        return ret;
}

/**
 * Close the ChronoVu LA8 USB port and reset the LA8 sequencer logic.
 *
 * @param ctx The struct containing private per-device-instance data.
 * @return SR_OK upon success, SR_ERR_ARG upon invalid arguments.
 */
static int la8_close_usb_reset_sequencer(struct context *ctx)
{
        /* Magic sequence of bytes for resetting the LA8 sequencer logic. */
        uint8_t buf[8] = {0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01};
        int ret;

        if (!ctx) {
                sr_err("la8: %s: ctx was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (!ctx->ftdic) {
                sr_err("la8: %s: ctx->ftdic was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (ctx->ftdic->usb_dev) {
                /* Reset the LA8 sequencer logic, then wait 100ms. */
                sr_dbg("la8: Resetting sequencer logic.");
                (void) la8_write(ctx, buf, 8); /* Ignore errors. */
                g_usleep(100 * 1000);

                /* Purge FTDI buffers, then reset and close the FTDI device. */
                sr_dbg("la8: Purging buffers, resetting+closing FTDI device.");

                /* Log errors, but ignore them (i.e., don't abort). */
                if ((ret = ftdi_usb_purge_buffers(ctx->ftdic)) < 0)
                        sr_err("la8: %s: ftdi_usb_purge_buffers: (%d) %s",
                            __func__, ret, ftdi_get_error_string(ctx->ftdic));
                if ((ret = ftdi_usb_reset(ctx->ftdic)) < 0)
                        sr_err("la8: %s: ftdi_usb_reset: (%d) %s", __func__,
                               ret, ftdi_get_error_string(ctx->ftdic));
                if ((ret = ftdi_usb_close(ctx->ftdic)) < 0)
                        sr_err("la8: %s: ftdi_usb_close: (%d) %s", __func__,
                               ret, ftdi_get_error_string(ctx->ftdic));
        }

        /* Close USB device, deinitialize and free the FTDI context. */
        ftdi_free(ctx->ftdic); /* Returns void. */
        ctx->ftdic = NULL;

        return SR_OK;
}

/**
 * Reset the ChronoVu LA8.
 *
 * The LA8 must be reset after a failed read/write operation or upon timeouts.
 *
 * @param ctx The struct containing private per-device-instance data.
 * @return SR_OK upon success, SR_ERR upon failure.
 */
static int la8_reset(struct context *ctx)
{
        uint8_t buf[BS];
        time_t done, now;
        int bytes_read;

        if (!ctx) {
                sr_err("la8: %s: ctx was NULL", __func__);
                return SR_ERR_ARG;
        }

        if (!ctx->ftdic) {
                sr_err("la8: %s: ctx->ftdic was NULL", __func__);
                return SR_ERR_ARG;
        }

        sr_dbg("la8: Resetting the device.");

        /*
         * Purge pending read data from the FTDI hardware FIFO until
         * no more data is left, or a timeout occurs (after 20s).
         */
        done = 20 + time(NULL);
        do {
                /* TODO: Ignore errors? Check for < 0 at least! */
                bytes_read = la8_read(ctx, (uint8_t *)&buf, BS);
                now = time(NULL);
        } while ((done > now) && (bytes_read > 0));

        /* Reset the LA8 sequencer logic and close the USB port. */
        (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */

        sr_dbg("la8: Device reset finished.");

        return SR_OK;
}

static int configure_probes(struct context *ctx, GSList *probes)
{
        struct sr_probe *probe;
        GSList *l;
        uint8_t probe_bit;
        char *tc;

        /* Note: Caller checked that ctx != NULL. */

        ctx->trigger_pattern = 0;
        ctx->trigger_mask = 0; /* Default to "don't care" for all probes. */

        for (l = probes; l; l = l->next) {
                probe = (struct sr_probe *)l->data;

                if (!probe) {
                        sr_err("la8: %s: probe was NULL", __func__);
                        return SR_ERR;
                }

                /* Skip disabled probes. */
                if (!probe->enabled)
                        continue;

                /* Skip (enabled) probes with no configured trigger. */
                if (!probe->trigger)
                        continue;

                /* Note: Must only be run if probe->trigger != NULL. */
                if (probe->index < 0 || probe->index > 7) {
                        sr_err("la8: %s: invalid probe index %d, must be "
                               "between 0 and 7", __func__, probe->index);
                        return SR_ERR;
                }

                probe_bit = (1 << (probe->index - 1));

                /* Configure the probe's trigger mask and trigger pattern. */
                for (tc = probe->trigger; tc && *tc; tc++) {
                        ctx->trigger_mask |= probe_bit;

                        /* Sanity check, LA8 only supports low/high trigger. */
                        if (*tc != '0' && *tc != '1') {
                                sr_err("la8: %s: invalid trigger '%c', only "
                                       "'0'/'1' supported", __func__, *tc);
                                return SR_ERR;
                        }

                        if (*tc == '1')
                                ctx->trigger_pattern |= probe_bit;
                }
        }

        sr_dbg("la8: trigger_mask = 0x%x, trigger_pattern = 0x%x",
               ctx->trigger_mask, ctx->trigger_pattern);

        return SR_OK;
}

static int hw_init(const char *devinfo)
{
        int ret;
        struct sr_dev_inst *sdi;
        struct context *ctx;

        /* Avoid compiler errors. */
        (void)devinfo;

        /* Allocate memory for our private driver context. */
        if (!(ctx = g_try_malloc(sizeof(struct context)))) {
                sr_err("la8: %s: struct context malloc failed", __func__);
                goto err_free_nothing;
        }

        /* Set some sane defaults. */
        ctx->ftdic = NULL;
        ctx->cur_samplerate = SR_MHZ(100); /* 100MHz == max. samplerate */
        ctx->limit_msec = 0;
        ctx->limit_samples = 0;
        ctx->session_dev_id = NULL;
        memset(ctx->mangled_buf, 0, BS);
        ctx->final_buf = NULL;
        ctx->trigger_pattern = 0x00; /* Value irrelevant, see trigger_mask. */
        ctx->trigger_mask = 0x00; /* All probes are "don't care". */
        ctx->trigger_timeout = 10; /* Default to 10s trigger timeout. */
        ctx->trigger_found = 0;
        ctx->done = 0;
        ctx->block_counter = 0;
        ctx->divcount = 0; /* 10ns sample period == 100MHz samplerate */

        /* Allocate memory where we'll store the de-mangled data. */
        if (!(ctx->final_buf = g_try_malloc(SDRAM_SIZE))) {
                sr_err("la8: %s: final_buf malloc failed", __func__);
                goto err_free_ctx;
        }

        /* Allocate memory for the FTDI context (ftdic) and initialize it. */
        if (!(ctx->ftdic = ftdi_new())) {
                sr_err("la8: %s: ftdi_new failed", __func__);
                goto err_free_final_buf;
        }

        /* Check for the device and temporarily open it. */
        if ((ret = ftdi_usb_open_desc(ctx->ftdic, USB_VENDOR_ID,
                        USB_PRODUCT_ID, USB_DESCRIPTION, NULL)) < 0) {
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
                goto err_free_ftdic;
        }
        sr_dbg("la8: Found LA8 device (%04x:%04x).", USB_VENDOR_ID,
               USB_PRODUCT_ID);

        /* Register the device with libsigrok. */
        sdi = sr_dev_inst_new(0, SR_ST_INITIALIZING,
                        USB_VENDOR_NAME, USB_MODEL_NAME, USB_MODEL_VERSION);
        if (!sdi) {
                sr_err("la8: %s: sr_dev_inst_new failed", __func__);
                goto err_close_ftdic;
        }

        sdi->priv = ctx;

        dev_insts = g_slist_append(dev_insts, sdi);

        sr_spew("la8: Device init successful.");

        /* Close device. We'll reopen it again when we need it. */
        (void) la8_close(ctx); /* Log, but ignore errors. */

        return 1;

err_close_ftdic:
        (void) la8_close(ctx); /* Log, but ignore errors. */
err_free_ftdic:
        free(ctx->ftdic); /* NOT g_free()! */
err_free_final_buf:
        g_free(ctx->final_buf);
err_free_ctx:
        g_free(ctx);
err_free_nothing:

        return 0;
}

static int hw_dev_open(int dev_index)
{
        int ret;
        struct sr_dev_inst *sdi;
        struct context *ctx;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        sr_dbg("la8: Opening LA8 device (%04x:%04x).", USB_VENDOR_ID,
               USB_PRODUCT_ID);

        /* Open the device. */
        if ((ret = ftdi_usb_open_desc(ctx->ftdic, USB_VENDOR_ID,
                        USB_PRODUCT_ID, USB_DESCRIPTION, NULL)) < 0) {
                sr_err("la8: %s: ftdi_usb_open_desc: (%d) %s",
                       __func__, ret, ftdi_get_error_string(ctx->ftdic));
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
                return SR_ERR;
        }
        sr_dbg("la8: Device opened successfully.");

        /* Purge RX/TX buffers in the FTDI chip. */
        if ((ret = ftdi_usb_purge_buffers(ctx->ftdic)) < 0) {
                sr_err("la8: %s: ftdi_usb_purge_buffers: (%d) %s",
                       __func__, ret, ftdi_get_error_string(ctx->ftdic));
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
                goto err_dev_open_close_ftdic;
        }
        sr_dbg("la8: FTDI buffers purged successfully.");

        /* Enable flow control in the FTDI chip. */
        if ((ret = ftdi_setflowctrl(ctx->ftdic, SIO_RTS_CTS_HS)) < 0) {
                sr_err("la8: %s: ftdi_setflowcontrol: (%d) %s",
                       __func__, ret, ftdi_get_error_string(ctx->ftdic));
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
                goto err_dev_open_close_ftdic;
        }
        sr_dbg("la8: FTDI flow control enabled successfully.");

        /* Wait 100ms. */
        g_usleep(100 * 1000);

        sdi->status = SR_ST_ACTIVE;

        return SR_OK;

err_dev_open_close_ftdic:
        (void) la8_close(ctx); /* Log, but ignore errors. */
        return SR_ERR;
}

static int set_samplerate(struct sr_dev_inst *sdi, uint64_t samplerate)
{
        struct context *ctx;

        /* Note: Caller checked that sdi and sdi->priv != NULL. */

        ctx = sdi->priv;

        sr_spew("la8: Trying to set samplerate to %" PRIu64 "Hz.", samplerate);

        fill_supported_samplerates_if_needed();

        /* Check if this is a samplerate supported by the hardware. */
        if (!is_valid_samplerate(samplerate))
                return SR_ERR;

        /* Set the new samplerate. */
        ctx->cur_samplerate = samplerate;

        sr_dbg("la8: Samplerate set to %" PRIu64 "Hz.", ctx->cur_samplerate);

        return SR_OK;
}

static int hw_dev_close(int dev_index)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        sr_dbg("la8: Closing device.");

        if (sdi->status == SR_ST_ACTIVE) {
                sr_dbg("la8: Status ACTIVE, closing device.");
                /* TODO: Really ignore errors here, or return SR_ERR? */
                (void) la8_close_usb_reset_sequencer(ctx); /* Ignore errors. */
        } else {
                sr_spew("la8: Status not ACTIVE, nothing to do.");
        }

        sdi->status = SR_ST_INACTIVE;

        sr_dbg("la8: Freeing sample buffer.");
        g_free(ctx->final_buf);

        return SR_OK;
}

static int hw_cleanup(void)
{
        GSList *l;
        struct sr_dev_inst *sdi;
        int ret = SR_OK;

        /* Properly close all devices. */
        for (l = dev_insts; l; l = l->next) {
                if (!(sdi = l->data)) {
                        /* Log error, but continue cleaning up the rest. */
                        sr_err("la8: %s: sdi was NULL, continuing", __func__);
                        ret = SR_ERR_BUG;
                        continue;
                }
                sr_dev_inst_free(sdi); /* Returns void. */
        }
        g_slist_free(dev_insts); /* Returns void. */
        dev_insts = NULL;

        return ret;
}

static void *hw_dev_info_get(int dev_index, int dev_info_id)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        void *info;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return NULL;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return NULL;
        }

        sr_spew("la8: %s: dev_index %d, dev_info_id %d.", __func__,
                dev_index, dev_info_id);

        switch (dev_info_id) {
        case SR_DI_INST:
                info = sdi;
                sr_spew("la8: %s: Returning sdi.", __func__);
                break;
        case SR_DI_NUM_PROBES:
                info = GINT_TO_POINTER(NUM_PROBES);
                sr_spew("la8: %s: Returning number of probes: %d.", __func__,
                        NUM_PROBES);
                break;
        case SR_DI_PROBE_NAMES:
                info = probe_names;
                sr_spew("la8: %s: Returning probenames.", __func__);
                break;
        case SR_DI_SAMPLERATES:
                fill_supported_samplerates_if_needed();
                info = &samplerates;
                sr_spew("la8: %s: Returning samplerates.", __func__);
                break;
        case SR_DI_TRIGGER_TYPES:
                info = (char *)TRIGGER_TYPES;
                sr_spew("la8: %s: Returning trigger types: %s.", __func__,
                        TRIGGER_TYPES);
                break;
        case SR_DI_CUR_SAMPLERATE:
                info = &ctx->cur_samplerate;
                sr_spew("la8: %s: Returning samplerate: %" PRIu64 "Hz.",
                        __func__, ctx->cur_samplerate);
                break;
        default:
                /* Unknown device info ID, return NULL. */
                sr_err("la8: %s: Unknown device info ID", __func__);
                info = NULL;
                break;
        }

        return info;
}

static int hw_dev_status_get(int dev_index)
{
        struct sr_dev_inst *sdi;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL, device not found", __func__);
                return SR_ST_NOT_FOUND;
        }

        sr_dbg("la8: Returning status: %d.", sdi->status);

        return sdi->status;
}

static int *hw_hwcap_get_all(void)
{
        sr_spew("la8: Returning list of device capabilities.");

        return hwcaps;
}

static int hw_dev_config_set(int dev_index, int hwcap, void *value)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        sr_spew("la8: %s: dev_index %d, hwcap %d", __func__, dev_index, hwcap);

        switch (hwcap) {
        case SR_HWCAP_SAMPLERATE:
                if (set_samplerate(sdi, *(uint64_t *)value) == SR_ERR) {
                        sr_err("la8: %s: setting samplerate failed.", __func__);
                        return SR_ERR;
                }
                sr_dbg("la8: SAMPLERATE = %" PRIu64, ctx->cur_samplerate);
                break;
        case SR_HWCAP_PROBECONFIG:
                if (configure_probes(ctx, (GSList *)value) != SR_OK) {
                        sr_err("la8: %s: probe config failed.", __func__);
                        return SR_ERR;
                }
                break;
        case SR_HWCAP_LIMIT_MSEC:
                if (*(uint64_t *)value == 0) {
                        sr_err("la8: %s: LIMIT_MSEC can't be 0.", __func__);
                        return SR_ERR;
                }
                ctx->limit_msec = *(uint64_t *)value;
                sr_dbg("la8: LIMIT_MSEC = %" PRIu64, ctx->limit_msec);
                break;
        case SR_HWCAP_LIMIT_SAMPLES:
                if (*(uint64_t *)value < MIN_NUM_SAMPLES) {
                        sr_err("la8: %s: LIMIT_SAMPLES too small.", __func__);
                        return SR_ERR;
                }
                ctx->limit_samples = *(uint64_t *)value;
                sr_dbg("la8: LIMIT_SAMPLES = %" PRIu64, ctx->limit_samples);
                break;
        default:
                /* Unknown capability, return SR_ERR. */
                sr_err("la8: %s: Unknown capability.", __func__);
                return SR_ERR;
                break;
        }

        return SR_OK;
}

/**
 * Get a block of data from the LA8.
 *
 * @param ctx The struct containing private per-device-instance data. Must not
 *            be NULL. ctx->ftdic must not be NULL either.
 * @return SR_OK upon success, or SR_ERR upon errors.
 */
static int la8_read_block(struct context *ctx)
{
        int i, byte_offset, m, mi, p, index, bytes_read;
        time_t now;

        /* Note: Caller checked that ctx and ctx->ftdic != NULL. */

        sr_spew("la8: Reading block %d.", ctx->block_counter);

        bytes_read = la8_read(ctx, ctx->mangled_buf, BS);

        /* If first block read got 0 bytes, retry until success or timeout. */
        if ((bytes_read == 0) && (ctx->block_counter == 0)) {
                do {
                        sr_spew("la8: Reading block 0 (again).");
                        bytes_read = la8_read(ctx, ctx->mangled_buf, BS);
                        /* TODO: How to handle read errors here? */
                        now = time(NULL);
                } while ((ctx->done > now) && (bytes_read == 0));
        }

        /* Check if block read was successful or a timeout occured. */
        if (bytes_read != BS) {
                sr_err("la8: Trigger timed out. Bytes read: %d.", bytes_read);
                (void) la8_reset(ctx); /* Ignore errors. */
                return SR_ERR;
        }

        /* De-mangle the data. */
        sr_spew("la8: Demangling block %d.", ctx->block_counter);
        byte_offset = ctx->block_counter * BS;
        m = byte_offset / (1024 * 1024);
        mi = m * (1024 * 1024);
        for (i = 0; i < BS; i++) {
                p = i & (1 << 0);
                index = m * 2 + (((byte_offset + i) - mi) / 2) * 16;
                index += (ctx->divcount == 0) ? p : (1 - p);
                ctx->final_buf[index] = ctx->mangled_buf[i];
        }

        return SR_OK;
}

static void send_block_to_session_bus(struct context *ctx, int block)
{
        int i;
        uint8_t sample, expected_sample;
        struct sr_datafeed_packet packet;
        struct sr_datafeed_logic logic;
        int trigger_point; /* Relative trigger point (in this block). */

        /* Note: No sanity checks on ctx/block, caller is responsible. */

        /* Check if we can find the trigger condition in this block. */
        trigger_point = -1;
        expected_sample = ctx->trigger_pattern & ctx->trigger_mask;
        for (i = 0; i < BS; i++) {
                /* Don't continue if the trigger was found previously. */
                if (ctx->trigger_found)
                        break;

                /*
                 * Also, don't continue if triggers are "don't care", i.e. if
                 * no trigger conditions were specified by the user. In that
                 * case we don't want to send an SR_DF_TRIGGER packet at all.
                 */
                if (ctx->trigger_mask == 0x00)
                        break;

                sample = *(ctx->final_buf + (block * BS) + i);

                if ((sample & ctx->trigger_mask) == expected_sample) {
                        trigger_point = i;
                        ctx->trigger_found = 1;
                        break;
                }
        }

        /* If no trigger was found, send one SR_DF_LOGIC packet. */
        if (trigger_point == -1) {
                /* Send an SR_DF_LOGIC packet to the session bus. */
                sr_spew("la8: sending SR_DF_LOGIC packet (%d bytes) for "
                        "block %d", BS, block);
                packet.type = SR_DF_LOGIC;
                packet.payload = &logic;
                logic.length = BS;
                logic.unitsize = 1;
                logic.data = ctx->final_buf + (block * BS);
                sr_session_send(ctx->session_dev_id, &packet);
                return;
        }

        /*
         * We found the trigger, so some special handling is needed. We have
         * to send an SR_DF_LOGIC packet with the samples before the trigger
         * (if any), then the SD_DF_TRIGGER packet itself, then another
         * SR_DF_LOGIC packet with the samples after the trigger (if any).
         */

        /* TODO: Send SR_DF_TRIGGER packet before or after the actual sample? */

        /* If at least one sample is located before the trigger... */
        if (trigger_point > 0) {
                /* Send pre-trigger SR_DF_LOGIC packet to the session bus. */
                sr_spew("la8: sending pre-trigger SR_DF_LOGIC packet, "
                        "start = %d, length = %d", block * BS, trigger_point);
                packet.type = SR_DF_LOGIC;
                packet.payload = &logic;
                logic.length = trigger_point;
                logic.unitsize = 1;
                logic.data = ctx->final_buf + (block * BS);
                sr_session_send(ctx->session_dev_id, &packet);
        }

        /* Send the SR_DF_TRIGGER packet to the session bus. */
        sr_spew("la8: sending SR_DF_TRIGGER packet, sample = %d",
                (block * BS) + trigger_point);
        packet.type = SR_DF_TRIGGER;
        packet.payload = NULL;
        sr_session_send(ctx->session_dev_id, &packet);

        /* If at least one sample is located after the trigger... */
        if (trigger_point < (BS - 1)) {
                /* Send post-trigger SR_DF_LOGIC packet to the session bus. */
                sr_spew("la8: sending post-trigger SR_DF_LOGIC packet, "
                        "start = %d, length = %d",
                        (block * BS) + trigger_point, BS - trigger_point);
                packet.type = SR_DF_LOGIC;
                packet.payload = &logic;
                logic.length = BS - trigger_point;
                logic.unitsize = 1;
                logic.data = ctx->final_buf + (block * BS) + trigger_point;
                sr_session_send(ctx->session_dev_id, &packet);
        }
}

static int receive_data(int fd, int revents, void *cb_data)
{
        int i, ret;
        struct sr_dev_inst *sdi;
        struct context *ctx;

        /* Avoid compiler errors. */
        (void)fd;
        (void)revents;

        if (!(sdi = cb_data)) {
                sr_err("la8: %s: cb_data was NULL", __func__);
                return FALSE;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return FALSE;
        }

        if (!ctx->ftdic) {
                sr_err("la8: %s: ctx->ftdic was NULL", __func__);
                return FALSE;
        }

        /* Get one block of data. */
        if ((ret = la8_read_block(ctx)) < 0) {
                sr_err("la8: %s: la8_read_block error: %d", __func__, ret);
                hw_dev_acquisition_stop(sdi->index, sdi);
                return FALSE;
        }

        /* We need to get exactly NUM_BLOCKS blocks (i.e. 8MB) of data. */
        if (ctx->block_counter != (NUM_BLOCKS - 1)) {
                ctx->block_counter++;
                return TRUE;
        }

        sr_dbg("la8: Sampling finished, sending data to session bus now.");

        /* All data was received and demangled, send it to the session bus. */
        for (i = 0; i < NUM_BLOCKS; i++)
                send_block_to_session_bus(ctx, i);

        hw_dev_acquisition_stop(sdi->index, sdi);

        // return FALSE; /* FIXME? */
        return TRUE;
}

static int hw_dev_acquisition_start(int dev_index, void *cb_data)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        struct sr_datafeed_packet packet;
        struct sr_datafeed_header header;
        uint8_t buf[4];
        int bytes_written;

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!ctx->ftdic) {
                sr_err("la8: %s: ctx->ftdic was NULL", __func__);
                return SR_ERR_BUG;
        }

        ctx->divcount = samplerate_to_divcount(ctx->cur_samplerate);
        if (ctx->divcount == 0xff) {
                sr_err("la8: %s: invalid divcount/samplerate", __func__);
                return SR_ERR;
        }

        sr_dbg("la8: Starting acquisition.");

        /* Fill acquisition parameters into buf[]. */
        buf[0] = ctx->divcount;
        buf[1] = 0xff; /* This byte must always be 0xff. */
        buf[2] = ctx->trigger_pattern;
        buf[3] = ctx->trigger_mask;

        /* Start acquisition. */
        bytes_written = la8_write(ctx, buf, 4);

        if (bytes_written < 0) {
                sr_err("la8: Acquisition failed to start.");
                return SR_ERR;
        } else if (bytes_written != 4) {
                sr_err("la8: Acquisition failed to start.");
                return SR_ERR; /* TODO: Other error and return code? */
        }

        sr_dbg("la8: Acquisition started successfully.");

        ctx->session_dev_id = cb_data;

        /* Send header packet to the session bus. */
        sr_dbg("la8: Sending SR_DF_HEADER.");
        packet.type = SR_DF_HEADER;
        packet.payload = &header;
        header.feed_version = 1;
        gettimeofday(&header.starttime, NULL);
        header.samplerate = ctx->cur_samplerate;
        header.num_logic_probes = NUM_PROBES;
        sr_session_send(ctx->session_dev_id, &packet);

        /* Time when we should be done (for detecting trigger timeouts). */
        ctx->done = (ctx->divcount + 1) * 0.08388608 + time(NULL)
                        + ctx->trigger_timeout;
        ctx->block_counter = 0;
        ctx->trigger_found = 0;

        /* Hook up a dummy handler to receive data from the LA8. */
        sr_source_add(-1, G_IO_IN, 0, receive_data, sdi);

        return SR_OK;
}

static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
{
        struct sr_dev_inst *sdi;
        struct context *ctx;
        struct sr_datafeed_packet packet;

        sr_dbg("la8: Stopping acquisition.");

        if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
                sr_err("la8: %s: sdi was NULL", __func__);
                return SR_ERR_BUG;
        }

        if (!(ctx = sdi->priv)) {
                sr_err("la8: %s: sdi->priv was NULL", __func__);
                return SR_ERR_BUG;
        }

        /* Send end packet to the session bus. */
        sr_dbg("la8: Sending SR_DF_END.");
        packet.type = SR_DF_END;
        sr_session_send(cb_data, &packet);

        return SR_OK;
}

SR_PRIV struct sr_dev_driver chronovu_la8_driver_info = {
        .name = "chronovu-la8",
        .longname = "ChronoVu LA8",
        .api_version = 1,
        .init = hw_init,
        .cleanup = hw_cleanup,
        .dev_open = hw_dev_open,
        .dev_close = hw_dev_close,
        .dev_info_get = hw_dev_info_get,
        .dev_status_get = hw_dev_status_get,
        .hwcap_get_all = hw_hwcap_get_all,
        .dev_config_set = hw_dev_config_set,
        .dev_acquisition_start = hw_dev_acquisition_start,
        .dev_acquisition_stop = hw_dev_acquisition_stop,
};