]> sigrok.org Git - libsigrok.git/blobdiff - src/hardware/sysclk-lwla/protocol.c
sysclk-lwla: Implement support for LWLA1016
[libsigrok.git] / src / hardware / sysclk-lwla / protocol.c
index ba676f69a72c7804bfc6aed3b2bdcca359ce1fa8..46a9d6c9d56a7dc37e443f1127e34d6d69b78e92 100644 (file)
 
 #include <config.h>
 #include <string.h>
+#include "lwla.h"
 #include "protocol.h"
 
-/* Bit mask for the RLE repeat-count-follows flag. */
-#define RLE_FLAG_LEN_FOLLOWS ((uint64_t)1 << 35)
-
-/* Start address of capture status memory area to read. */
-#define CAP_STAT_ADDR 5
-
-/* Number of 64-bit words read from the capture status memory. */
-#define CAP_STAT_LEN 5
-
-/* The bitstream filenames are indexed by the clock_config enumeration.
+/* Status polling interval during acquisition.
  */
-static const char bitstream_map[][32] = {
-       "sysclk-lwla1034-off.rbf",
-       "sysclk-lwla1034-int.rbf",
-       "sysclk-lwla1034-extpos.rbf",
-       "sysclk-lwla1034-extneg.rbf",
-};
+#define POLL_INTERVAL 100 /* ms */
 
 /* Submit an already filled-in USB transfer.
  */
@@ -57,237 +44,129 @@ static int submit_transfer(struct dev_context *devc,
        return SR_OK;
 }
 
-/* Set up the LWLA in preparation for an acquisition session.
+/* Set up transfer for the next register in a write sequence.
  */
-static int capture_setup(const struct sr_dev_inst *sdi)
+static void next_reg_write(struct acquisition_state *acq)
 {
-       struct dev_context *devc;
-       struct acquisition_state *acq;
-       uint64_t divider_count;
-       uint64_t trigger_mask;
-       uint64_t memory_limit;
-       uint16_t command[3 + (10 * 4)];
-
-       devc = sdi->priv;
-       acq  = devc->acquisition;
-
-       command[0] = LWLA_WORD(CMD_CAP_SETUP);
-       command[1] = LWLA_WORD(0); /* address */
-       command[2] = LWLA_WORD(10); /* length */
-
-       command[3] = LWLA_WORD_0(devc->channel_mask);
-       command[4] = LWLA_WORD_1(devc->channel_mask);
-       command[5] = LWLA_WORD_2(devc->channel_mask);
-       command[6] = LWLA_WORD_3(devc->channel_mask);
-
-       /* Set the clock divide counter maximum for samplerates of up to
-        * 100 MHz. At the highest samplerate of 125 MHz the clock divider
-        * is bypassed.
-        */
-       if (!acq->bypass_clockdiv && devc->samplerate > 0)
-               divider_count = SR_MHZ(100) / devc->samplerate - 1;
-       else
-               divider_count = 0;
-
-       command[7]  = LWLA_WORD_0(divider_count);
-       command[8]  = LWLA_WORD_1(divider_count);
-       command[9]  = LWLA_WORD_2(divider_count);
-       command[10] = LWLA_WORD_3(divider_count);
-
-       command[11] = LWLA_WORD_0(devc->trigger_values);
-       command[12] = LWLA_WORD_1(devc->trigger_values);
-       command[13] = LWLA_WORD_2(devc->trigger_values);
-       command[14] = LWLA_WORD_3(devc->trigger_values);
-
-       command[15] = LWLA_WORD_0(devc->trigger_edge_mask);
-       command[16] = LWLA_WORD_1(devc->trigger_edge_mask);
-       command[17] = LWLA_WORD_2(devc->trigger_edge_mask);
-       command[18] = LWLA_WORD_3(devc->trigger_edge_mask);
-
-       trigger_mask = devc->trigger_mask;
-       /* Set bits to select external TRG input edge. */
-       if (devc->cfg_trigger_source == TRIGGER_EXT_TRG)
-               switch (devc->cfg_trigger_slope) {
-               case EDGE_POSITIVE:
-                       trigger_mask |= (uint64_t)1 << 35;
-                       break;
-               case EDGE_NEGATIVE:
-                       trigger_mask |= (uint64_t)1 << 34;
-                       break;
-               }
-
-       command[19] = LWLA_WORD_0(trigger_mask);
-       command[20] = LWLA_WORD_1(trigger_mask);
-       command[21] = LWLA_WORD_2(trigger_mask);
-       command[22] = LWLA_WORD_3(trigger_mask);
-
-       /* Set the capture memory full threshold. This is slightly less
-        * than the actual maximum, most likely in order to compensate for
-        * pipeline latency.
-        */
-       memory_limit = MEMORY_DEPTH - 16;
+       struct regval *regval;
 
-       command[23] = LWLA_WORD_0(memory_limit);
-       command[24] = LWLA_WORD_1(memory_limit);
-       command[25] = LWLA_WORD_2(memory_limit);
-       command[26] = LWLA_WORD_3(memory_limit);
+       regval = &acq->reg_sequence[acq->reg_seq_pos];
 
-       /* Fill remaining words with zeroes. */
-       memset(&command[27], 0, sizeof(command) - 27 * sizeof(command[0]));
+       acq->xfer_buf_out[0] = LWLA_WORD(CMD_WRITE_REG);
+       acq->xfer_buf_out[1] = LWLA_WORD(regval->reg);
+       acq->xfer_buf_out[2] = LWLA_WORD_0(regval->val);
+       acq->xfer_buf_out[3] = LWLA_WORD_1(regval->val);
 
-       return lwla_send_command(sdi->conn, command, ARRAY_SIZE(command));
+       acq->xfer_out->length = 4 * sizeof(acq->xfer_buf_out[0]);
 }
 
-/* Issue a register write command as an asynchronous USB transfer.
+/* Set up transfer for the next register in a read sequence.
  */
-static int issue_write_reg(const struct sr_dev_inst *sdi,
-                          unsigned int reg, unsigned int value)
+static void next_reg_read(struct acquisition_state *acq)
 {
-       struct dev_context *devc;
-       struct acquisition_state *acq;
-
-       devc = sdi->priv;
-       acq  = devc->acquisition;
+       unsigned int addr;
 
-       acq->xfer_buf_out[0] = LWLA_WORD(CMD_WRITE_REG);
-       acq->xfer_buf_out[1] = LWLA_WORD(reg);
-       acq->xfer_buf_out[2] = LWLA_WORD_0(value);
-       acq->xfer_buf_out[3] = LWLA_WORD_1(value);
+       addr = acq->reg_sequence[acq->reg_seq_pos].reg;
 
-       acq->xfer_out->length = 4 * sizeof(uint16_t);
+       acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_REG);
+       acq->xfer_buf_out[1] = LWLA_WORD(addr);
 
-       return submit_transfer(devc, acq->xfer_out);
+       acq->xfer_out->length = 2 * sizeof(acq->xfer_buf_out[0]);
 }
 
-/* Issue a register write command as an asynchronous USB transfer for the
- * next register/value pair of the currently active register write sequence.
+/* Decode the response to a register read request.
  */
-static int issue_next_write_reg(const struct sr_dev_inst *sdi)
+static int read_reg_response(struct acquisition_state *acq)
 {
-       struct dev_context *devc;
-       struct regval_pair *regval;
-       int ret;
+       uint32_t value;
 
-       devc = sdi->priv;
-
-       if (devc->reg_write_pos >= devc->reg_write_len) {
-               sr_err("Already written all registers in sequence.");
-               return SR_ERR_BUG;
+       if (acq->xfer_in->actual_length != 4) {
+               sr_err("Received size %d doesn't match expected size 4.",
+                      acq->xfer_in->actual_length);
+               return SR_ERR;
        }
-       regval = &devc->reg_write_seq[devc->reg_write_pos];
-
-       ret = issue_write_reg(sdi, regval->reg, regval->val);
-       if (ret != SR_OK)
-               return ret;
+       value = LWLA_TO_UINT32(acq->xfer_buf_in[0]);
+       acq->reg_sequence[acq->reg_seq_pos].val = value;
 
-       ++devc->reg_write_pos;
        return SR_OK;
 }
 
-/* Issue a capture status request as an asynchronous USB transfer.
+/* Enter a new state and submit the corresponding request to the device.
  */
-static void request_capture_status(const struct sr_dev_inst *sdi)
+static int submit_request(const struct sr_dev_inst *sdi,
+                         enum protocol_state state)
 {
        struct dev_context *devc;
        struct acquisition_state *acq;
+       int ret;
 
        devc = sdi->priv;
        acq  = devc->acquisition;
 
-       acq->xfer_buf_out[0] = LWLA_WORD(CMD_CAP_STATUS);
-       acq->xfer_buf_out[1] = LWLA_WORD(CAP_STAT_ADDR);
-       acq->xfer_buf_out[2] = LWLA_WORD(CAP_STAT_LEN);
-
-       acq->xfer_out->length = 3 * sizeof(uint16_t);
-
-       if (submit_transfer(devc, acq->xfer_out) == SR_OK)
-               devc->state = STATE_STATUS_REQUEST;
-}
+       devc->state = state;
 
-/* Issue a request for the capture buffer fill level as
- * an asynchronous USB transfer.
- */
-static void request_capture_length(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-       struct acquisition_state *acq;
+       acq->xfer_out->length = 0;
+       acq->reg_seq_pos = 0;
+       acq->reg_seq_len = 0;
 
-       devc = sdi->priv;
-       acq  = devc->acquisition;
+       /* Perform the model-specific action for the new state. */
+       ret = (*devc->model->prepare_request)(sdi);
 
-       acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_REG);
-       acq->xfer_buf_out[1] = LWLA_WORD(REG_MEM_FILL);
+       if (ret != SR_OK) {
+               devc->transfer_error = TRUE;
+               return ret;
+       }
 
-       acq->xfer_out->length = 2 * sizeof(uint16_t);
+       if (acq->reg_seq_pos < acq->reg_seq_len) {
+               if ((state & STATE_EXPECT_RESPONSE) != 0)
+                       next_reg_read(acq);
+               else
+                       next_reg_write(acq);
+       }
 
-       if (submit_transfer(devc, acq->xfer_out) == SR_OK)
-               devc->state = STATE_LENGTH_REQUEST;
+       return submit_transfer(devc, acq->xfer_out);
 }
 
-/* Initiate the capture memory read operation:  Reset the acquisition state
- * and start a sequence of register writes in order to set up the device for
- * reading from the capture buffer.
+/* Evaluate and act on the response to a capture status request.
  */
-static void issue_read_start(const struct sr_dev_inst *sdi)
+static void handle_status_response(const struct sr_dev_inst *sdi)
 {
        struct dev_context *devc;
        struct acquisition_state *acq;
-       struct regval_pair *regvals;
+       unsigned int old_status;
 
        devc = sdi->priv;
        acq  = devc->acquisition;
+       old_status = acq->status;
 
-       /* Reset RLE state. */
-       acq->rle = RLE_STATE_DATA;
-       acq->sample  = 0;
-       acq->run_len = 0;
-
-       acq->samples_done = 0;
-
-       /* For some reason, the start address is 4 rather than 0. */
-       acq->mem_addr_done = 4;
-       acq->mem_addr_next = 4;
-       acq->mem_addr_stop = acq->mem_addr_fill;
-
-       /* Sample position in the packet output buffer. */
-       acq->out_index = 0;
-
-       regvals = devc->reg_write_seq;
-
-       regvals[0].reg = REG_DIV_BYPASS;
-       regvals[0].val = 1;
-
-       regvals[1].reg = REG_MEM_CTRL;
-       regvals[1].val = MEM_CTRL_CLR_IDX;
-
-       regvals[2].reg = REG_MEM_START;
-       regvals[2].val = 4;
-
-       devc->reg_write_pos = 0;
-       devc->reg_write_len = 3;
+       if ((*devc->model->handle_response)(sdi) != SR_OK) {
+               devc->transfer_error = TRUE;
+               return;
+       }
+       devc->state = STATE_STATUS_WAIT;
 
-       if (issue_next_write_reg(sdi) == SR_OK)
-               devc->state = STATE_READ_PREPARE;
-}
+       sr_spew("Captured %zu words, %" PRIu64 " ms, status 0x%02X.",
+               acq->mem_addr_fill, acq->duration_now, acq->status);
 
-/* Issue a command as an asynchronous USB transfer which returns the device
- * to normal state after a read operation.  Sets a new device context state
- * on success.
- */
-static void issue_read_end(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-
-       devc = sdi->priv;
+       if ((~old_status & acq->status & STATUS_TRIGGERED) != 0)
+               sr_info("Capture triggered.");
 
-       if (issue_write_reg(sdi, REG_DIV_BYPASS, 0) == SR_OK)
-               devc->state = STATE_READ_END;
+       if (acq->duration_now >= acq->duration_max) {
+               sr_dbg("Time limit reached, stopping capture.");
+               submit_request(sdi, STATE_STOP_CAPTURE);
+       } else if ((acq->status & STATUS_TRIGGERED) == 0) {
+               sr_spew("Waiting for trigger.");
+       } else if ((acq->status & STATUS_MEM_AVAIL) == 0) {
+               sr_dbg("Capture memory filled.");
+               submit_request(sdi, STATE_LENGTH_REQUEST);
+       } else if ((acq->status & STATUS_CAPTURING) != 0) {
+               sr_spew("Sampling in progress.");
+       }
 }
 
-/* Decode an incoming response to a buffer fill level request and act on it
- * as appropriate.  Note that this function changes the device context state.
+/* Evaluate and act on the response to a capture length request.
  */
-static void process_capture_length(const struct sr_dev_inst *sdi)
+static void handle_length_response(const struct sr_dev_inst *sdi)
 {
        struct dev_context *devc;
        struct acquisition_state *acq;
@@ -295,319 +174,171 @@ static void process_capture_length(const struct sr_dev_inst *sdi)
        devc = sdi->priv;
        acq  = devc->acquisition;
 
-       if (acq->xfer_in->actual_length != 4) {
-               sr_err("Received size %d doesn't match expected size 4.",
-                      acq->xfer_in->actual_length);
+       if ((*devc->model->handle_response)(sdi) != SR_OK) {
                devc->transfer_error = TRUE;
                return;
        }
-       acq->mem_addr_fill = LWLA_TO_UINT32(acq->xfer_buf_in[0]);
-
-       sr_dbg("%zu words in capture buffer.", acq->mem_addr_fill);
-
-       if (acq->mem_addr_fill > 0 && !devc->cancel_requested)
-               issue_read_start(sdi);
-       else
-               issue_read_end(sdi);
-}
-
-/* Initiate a sequence of register write commands with the effect of
- * cancelling a running capture operation.  This sets a new device state
- * if issuing the first command succeeds.
- */
-static void issue_stop_capture(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-       struct regval_pair *regvals;
-
-       devc = sdi->priv;
+       acq->rle = RLE_STATE_DATA;
+       acq->sample = 0;
+       acq->run_len = 0;
+       acq->samples_done = 0;
+       acq->mem_addr_done = acq->mem_addr_next;
+       acq->out_index = 0;
 
-       if (devc->stopping_in_progress)
+       if (acq->mem_addr_next >= acq->mem_addr_stop) {
+               submit_request(sdi, STATE_READ_FINISH);
                return;
-
-       regvals = devc->reg_write_seq;
-
-       regvals[0].reg = REG_LONG_ADDR;
-       regvals[0].val = LREG_CAP_CTRL;
-
-       regvals[1].reg = REG_LONG_LOW;
-       regvals[1].val = 0;
-
-       regvals[2].reg = REG_LONG_HIGH;
-       regvals[2].val = 0;
-
-       regvals[3].reg = REG_LONG_STROBE;
-       regvals[3].val = 0;
-
-       regvals[4].reg = REG_DIV_BYPASS;
-       regvals[4].val = 0;
-
-       devc->reg_write_pos = 0;
-       devc->reg_write_len = 5;
-
-       if (issue_next_write_reg(sdi) == SR_OK) {
-               devc->stopping_in_progress = TRUE;
-               devc->state = STATE_STOP_CAPTURE;
        }
+       sr_dbg("%zu words in capture buffer.",
+              acq->mem_addr_stop - acq->mem_addr_next);
+
+       submit_request(sdi, STATE_READ_PREPARE);
 }
 
-/* Decode an incoming capture status response and act on it as appropriate.
- * Note that this function changes the device state.
+/* Evaluate and act on the response to a capture length request.
  */
-static void process_capture_status(const struct sr_dev_inst *sdi)
+static void handle_read_response(const struct sr_dev_inst *sdi)
 {
-       uint64_t duration;
        struct dev_context *devc;
        struct acquisition_state *acq;
-       unsigned int mem_fill;
-       unsigned int flags;
+       struct sr_datafeed_packet packet;
+       struct sr_datafeed_logic logic;
+       size_t end_addr;
 
        devc = sdi->priv;
        acq  = devc->acquisition;
 
-       if (acq->xfer_in->actual_length != CAP_STAT_LEN * 8) {
-               sr_err("Received size %d doesn't match expected size %d.",
-                      acq->xfer_in->actual_length, CAP_STAT_LEN * 8);
-               devc->transfer_error = TRUE;
-               return;
-       }
-
-       mem_fill = LWLA_TO_UINT32(acq->xfer_buf_in[0]);
-       duration = LWLA_TO_UINT32(acq->xfer_buf_in[4])
-               | ((uint64_t)LWLA_TO_UINT32(acq->xfer_buf_in[5]) << 32);
-       flags = LWLA_TO_UINT32(acq->xfer_buf_in[8]) & STATUS_FLAG_MASK;
+       /* Prepare session packet. */
+       packet.type    = SR_DF_LOGIC;
+       packet.payload = &logic;
+       logic.unitsize = (devc->model->num_channels + 7) / 8;
+       logic.data     = acq->out_packet;
 
-       /* The LWLA1034 runs at 125 MHz if the clock divider is bypassed.
-        * However, the time base used for the duration is apparently not
-        * adjusted for this "boost" mode.  Whereas normally the duration
-        * unit is 1 ms, it is 0.8 ms when the clock divider is bypassed.
-        * As 0.8 = 100 MHz / 125 MHz, it seems that the internal cycle
-        * counter period is the same as at the 100 MHz setting.
+       end_addr = MIN(acq->mem_addr_next, acq->mem_addr_stop);
+       acq->in_index = 0;
+       /*
+        * Repeatedly call the model-specific read response handler until
+        * all data received in the transfer has been accounted for.
         */
-       if (acq->bypass_clockdiv)
-               acq->duration_now = duration * 4 / 5;
-       else
-               acq->duration_now = duration;
-
-       sr_spew("Captured %u words, %" PRIu64 " ms, flags 0x%02X.",
-               mem_fill, acq->duration_now, flags);
+       while (!devc->cancel_requested
+                       && (acq->run_len > 0 || acq->mem_addr_done < end_addr)
+                       && acq->samples_done < acq->samples_max) {
 
-       if ((flags & STATUS_TRIGGERED) > (acq->capture_flags & STATUS_TRIGGERED))
-               sr_info("Capture triggered.");
-
-       acq->capture_flags = flags;
+               if ((*devc->model->handle_response)(sdi) != SR_OK) {
+                       devc->transfer_error = TRUE;
+                       return;
+               }
+               if (acq->out_index * logic.unitsize >= PACKET_SIZE) {
+                       /* Send off full logic packet. */
+                       logic.length = acq->out_index * logic.unitsize;
+                       sr_session_send(sdi, &packet);
+                       acq->out_index = 0;
+               }
+       }
 
-       if (acq->duration_now >= acq->duration_max) {
-               sr_dbg("Time limit reached, stopping capture.");
-               issue_stop_capture(sdi);
+       if (!devc->cancel_requested
+                       && acq->samples_done < acq->samples_max
+                       && acq->mem_addr_next < acq->mem_addr_stop) {
+               /* Request the next block. */
+               submit_request(sdi, STATE_READ_REQUEST);
                return;
        }
-       devc->state = STATE_STATUS_WAIT;
 
-       if ((acq->capture_flags & STATUS_TRIGGERED) == 0) {
-               sr_spew("Waiting for trigger.");
-       } else if ((acq->capture_flags & STATUS_MEM_AVAIL) == 0) {
-               sr_dbg("Capture memory filled.");
-               request_capture_length(sdi);
-       } else if ((acq->capture_flags & STATUS_CAPTURING) != 0) {
-               sr_spew("Sampling in progress.");
+       /* Send partially filled packet as it is the last one. */
+       if (!devc->cancel_requested && acq->out_index > 0) {
+               logic.length = acq->out_index * logic.unitsize;
+               sr_session_send(sdi, &packet);
+               acq->out_index = 0;
        }
+       submit_request(sdi, STATE_READ_FINISH);
 }
 
-/* Issue a capture buffer read request as an asynchronous USB transfer.
- * The address and size of the memory area to read are derived from the
- * current acquisition state.
+/* Destroy and unset the acquisition state record.
  */
-static void request_read_mem(const struct sr_dev_inst *sdi)
+static void clear_acquisition_state(const struct sr_dev_inst *sdi)
 {
        struct dev_context *devc;
        struct acquisition_state *acq;
-       size_t count;
 
        devc = sdi->priv;
        acq  = devc->acquisition;
 
-       if (acq->mem_addr_next >= acq->mem_addr_stop)
-               return;
-
-       /* Always read a multiple of 8 device words. */
-       count = (acq->mem_addr_stop - acq->mem_addr_next + 7) / 8 * 8;
-       count = MIN(count, READ_CHUNK_LEN);
-
-       acq->xfer_buf_out[0] = LWLA_WORD(CMD_READ_MEM);
-       acq->xfer_buf_out[1] = LWLA_WORD_0(acq->mem_addr_next);
-       acq->xfer_buf_out[2] = LWLA_WORD_1(acq->mem_addr_next);
-       acq->xfer_buf_out[3] = LWLA_WORD_0(count);
-       acq->xfer_buf_out[4] = LWLA_WORD_1(count);
-
-       acq->xfer_out->length = 5 * sizeof(uint16_t);
+       devc->acquisition = NULL;
 
-       if (submit_transfer(devc, acq->xfer_out) == SR_OK) {
-               acq->mem_addr_next += count;
-               devc->state = STATE_READ_REQUEST;
+       if (acq) {
+               libusb_free_transfer(acq->xfer_out);
+               libusb_free_transfer(acq->xfer_in);
+               g_free(acq);
        }
 }
 
-/* Demangle and decompress incoming sample data from the capture buffer.
- * The data chunk is taken from the acquisition state, and is expected to
- * contain a multiple of 8 device words.
- * All data currently in the acquisition buffer will be processed.  Packets
- * of decoded samples are sent off to the session bus whenever the output
- * buffer becomes full while decoding.
+/* USB I/O source callback.
  */
-static int process_sample_data(const struct sr_dev_inst *sdi)
+static int transfer_event(int fd, int revents, void *cb_data)
 {
-       uint64_t sample;
-       uint64_t high_nibbles;
-       uint64_t word;
+       const struct sr_dev_inst *sdi;
        struct dev_context *devc;
-       struct acquisition_state *acq;
-       uint8_t *out_p;
-       uint32_t *slice;
+       struct drv_context *drvc;
+       struct timeval tv;
        struct sr_datafeed_packet packet;
-       struct sr_datafeed_logic logic;
-       size_t expect_len;
-       size_t actual_len;
-       size_t out_max_samples;
-       size_t out_run_samples;
-       size_t ri;
-       size_t in_words_left;
-       size_t si;
+       int ret;
 
-       devc = sdi->priv;
-       acq  = devc->acquisition;
+       (void)fd;
 
-       if (acq->mem_addr_done >= acq->mem_addr_stop
-                       || acq->samples_done >= acq->samples_max)
-               return SR_OK;
+       sdi  = cb_data;
+       devc = sdi->priv;
+       drvc = sdi->driver->context;
 
-       in_words_left = MIN(acq->mem_addr_stop - acq->mem_addr_done,
-                           READ_CHUNK_LEN);
-       expect_len = LWLA1034_MEMBUF_LEN(in_words_left) * sizeof(uint32_t);
-       actual_len = acq->xfer_in->actual_length;
+       if (!devc || !drvc)
+               return G_SOURCE_REMOVE;
 
-       if (actual_len != expect_len) {
-               sr_err("Received size %zu does not match expected size %zu.",
-                      actual_len, expect_len);
+       /* Handle pending USB events without blocking. */
+       tv.tv_sec  = 0;
+       tv.tv_usec = 0;
+       ret = libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx,
+                                                    &tv, NULL);
+       if (ret != 0) {
+               sr_err("Event handling failed: %s.", libusb_error_name(ret));
                devc->transfer_error = TRUE;
-               return SR_ERR;
        }
-       acq->mem_addr_done += in_words_left;
 
-       /* Prepare session packet. */
-       packet.type    = SR_DF_LOGIC;
-       packet.payload = &logic;
-       logic.unitsize = UNIT_SIZE;
-       logic.data     = acq->out_packet;
-
-       slice = acq->xfer_buf_in;
-       si = 0; /* word index within slice */
-
-       for (;;) {
-               /* Calculate number of samples to write into packet. */
-               out_max_samples = MIN(acq->samples_max - acq->samples_done,
-                                     PACKET_LENGTH - acq->out_index);
-               out_run_samples = MIN(acq->run_len, out_max_samples);
-
-               /* Expand run-length samples into session packet. */
-               sample = acq->sample;
-               out_p = &acq->out_packet[acq->out_index * UNIT_SIZE];
-
-               for (ri = 0; ri < out_run_samples; ++ri) {
-                       out_p[0] =  sample        & 0xFF;
-                       out_p[1] = (sample >>  8) & 0xFF;
-                       out_p[2] = (sample >> 16) & 0xFF;
-                       out_p[3] = (sample >> 24) & 0xFF;
-                       out_p[4] = (sample >> 32) & 0xFF;
-                       out_p += UNIT_SIZE;
-               }
-               acq->run_len -= out_run_samples;
-               acq->out_index += out_run_samples;
-               acq->samples_done += out_run_samples;
-
-               /* Packet full or sample count limit reached? */
-               if (out_run_samples == out_max_samples) {
-                       logic.length = acq->out_index * UNIT_SIZE;
-                       sr_session_send(sdi, &packet);
-                       acq->out_index = 0;
-
-                       if (acq->samples_done >= acq->samples_max)
-                               return SR_OK; /* sample limit reached */
-                       if (acq->run_len > 0)
-                               continue; /* need another packet */
-               }
-
-               if (in_words_left == 0)
-                       break; /* done with current chunk */
-
-               /* Now work on the current slice. */
-               high_nibbles = LWLA_TO_UINT32(slice[8]);
-               word = LWLA_TO_UINT32(slice[si]);
-               word |= (high_nibbles << (4 * si + 4)) & ((uint64_t)0xF << 32);
-
-               if (acq->rle == RLE_STATE_DATA) {
-                       acq->sample = word & ALL_CHANNELS_MASK;
-                       acq->run_len = ((word >> NUM_CHANNELS) & 1) + 1;
-                       if (word & RLE_FLAG_LEN_FOLLOWS)
-                               acq->rle = RLE_STATE_LEN;
-               } else {
-                       acq->run_len += word << 1;
-                       acq->rle = RLE_STATE_DATA;
-               }
-
-               /* Move to next word. */
-               si = (si + 1) % 8;
-               if (si == 0)
-                       slice += 9;
-               --in_words_left;
-       }
-
-       /* Send out partially filled packet if this was the last chunk. */
-       if (acq->mem_addr_done >= acq->mem_addr_stop && acq->out_index > 0) {
-               logic.length = acq->out_index * UNIT_SIZE;
-               sr_session_send(sdi, &packet);
-               acq->out_index = 0;
+       if (!devc->transfer_error && devc->state == STATE_STATUS_WAIT) {
+               if (devc->cancel_requested)
+                       submit_request(sdi, STATE_STOP_CAPTURE);
+               else if (revents == 0) /* status poll timeout */
+                       submit_request(sdi, STATE_STATUS_REQUEST);
        }
-       return SR_OK;
-}
-
-/* Finish an acquisition session.  This sends the end packet to the session
- * bus and removes the listener for asynchronous USB transfers.
- */
-static void end_acquisition(struct sr_dev_inst *sdi)
-{
-       struct drv_context *drvc;
-       struct dev_context *devc;
-       struct sr_datafeed_packet packet;
 
-       drvc = sdi->driver->context;
-       devc = sdi->priv;
+       /* Stop processing events if an error occurred on a transfer. */
+       if (devc->transfer_error)
+               devc->state = STATE_IDLE;
 
-       if (devc->state == STATE_IDLE)
-               return;
+       if (devc->state != STATE_IDLE)
+               return G_SOURCE_CONTINUE;
 
-       devc->state = STATE_IDLE;
+       sr_info("Acquisition stopped.");
 
-       /* Remove USB file descriptors from polling. */
-       usb_source_remove(sdi->session, drvc->sr_ctx);
+       /* We are done, clean up and send end packet to session bus. */
+       clear_acquisition_state(sdi);
 
        packet.type = SR_DF_END;
+       packet.payload = NULL;
        sr_session_send(sdi, &packet);
 
-       lwla_free_acquisition_state(devc->acquisition);
-       devc->acquisition = NULL;
-       devc->cancel_requested = FALSE;
+       return G_SOURCE_REMOVE;
 }
 
 /* USB output transfer completion callback.
  */
-static void LIBUSB_CALL receive_transfer_out(struct libusb_transfer *transfer)
+static void LIBUSB_CALL transfer_out_completed(struct libusb_transfer *transfer)
 {
-       struct sr_dev_inst *sdi;
+       const struct sr_dev_inst *sdi;
        struct dev_context *devc;
+       struct acquisition_state *acq;
 
        sdi  = transfer->user_data;
        devc = sdi->priv;
+       acq  = devc->acquisition;
 
        if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
                sr_err("Transfer to device failed: %d.", transfer->status);
@@ -615,49 +346,57 @@ static void LIBUSB_CALL receive_transfer_out(struct libusb_transfer *transfer)
                return;
        }
 
-       if (devc->reg_write_pos < devc->reg_write_len) {
-               issue_next_write_reg(sdi);
-       } else {
-               switch (devc->state) {
-               case STATE_START_CAPTURE:
+       /* If this was a read request, wait for the response. */
+       if ((devc->state & STATE_EXPECT_RESPONSE) != 0) {
+               submit_transfer(devc, acq->xfer_in);
+               return;
+       }
+       if (acq->reg_seq_pos < acq->reg_seq_len)
+               acq->reg_seq_pos++; /* register write completed */
+
+       /* Repeat until all queued registers have been written. */
+       if (acq->reg_seq_pos < acq->reg_seq_len && !devc->cancel_requested) {
+               next_reg_write(acq);
+               submit_transfer(devc, acq->xfer_out);
+               return;
+       }
+
+       switch (devc->state) {
+       case STATE_START_CAPTURE:
+               sr_info("Acquisition started.");
+
+               if (!devc->cancel_requested)
                        devc->state = STATE_STATUS_WAIT;
-                       break;
-               case STATE_STATUS_REQUEST:
-                       devc->state = STATE_STATUS_RESPONSE;
-                       submit_transfer(devc, devc->acquisition->xfer_in);
-                       break;
-               case STATE_STOP_CAPTURE:
-                       if (!devc->cancel_requested)
-                               request_capture_length(sdi);
-                       else
-                               end_acquisition(sdi);
-                       break;
-               case STATE_LENGTH_REQUEST:
-                       devc->state = STATE_LENGTH_RESPONSE;
-                       submit_transfer(devc, devc->acquisition->xfer_in);
-                       break;
-               case STATE_READ_PREPARE:
-                       request_read_mem(sdi);
-                       break;
-               case STATE_READ_REQUEST:
-                       devc->state = STATE_READ_RESPONSE;
-                       submit_transfer(devc, devc->acquisition->xfer_in);
-                       break;
-               case STATE_READ_END:
-                       end_acquisition(sdi);
-                       break;
-               default:
-                       sr_err("Unexpected device state %d.", devc->state);
-                       break;
-               }
+               else
+                       submit_request(sdi, STATE_STOP_CAPTURE);
+               break;
+       case STATE_STOP_CAPTURE:
+               if (!devc->cancel_requested)
+                       submit_request(sdi, STATE_LENGTH_REQUEST);
+               else
+                       devc->state = STATE_IDLE;
+               break;
+       case STATE_READ_PREPARE:
+               if (acq->mem_addr_next < acq->mem_addr_stop && !devc->cancel_requested)
+                       submit_request(sdi, STATE_READ_REQUEST);
+               else
+                       submit_request(sdi, STATE_READ_FINISH);
+               break;
+       case STATE_READ_FINISH:
+               devc->state = STATE_IDLE;
+               break;
+       default:
+               sr_err("Unexpected device state %d.", devc->state);
+               devc->transfer_error = TRUE;
+               break;
        }
 }
 
 /* USB input transfer completion callback.
  */
-static void LIBUSB_CALL receive_transfer_in(struct libusb_transfer *transfer)
+static void LIBUSB_CALL transfer_in_completed(struct libusb_transfer *transfer)
 {
-       struct sr_dev_inst *sdi;
+       const struct sr_dev_inst *sdi;
        struct dev_context *devc;
        struct acquisition_state *acq;
 
@@ -666,112 +405,101 @@ static void LIBUSB_CALL receive_transfer_in(struct libusb_transfer *transfer)
        acq  = devc->acquisition;
 
        if (transfer->status != LIBUSB_TRANSFER_COMPLETED) {
-               sr_err("Transfer from device failed: %d.", transfer->status);
+               sr_err("Transfer from device failed (state %d): %s.",
+                      devc->state, libusb_error_name(transfer->status));
+               devc->transfer_error = TRUE;
+               return;
+       }
+       if ((devc->state & STATE_EXPECT_RESPONSE) == 0) {
+               sr_err("Unexpected completion of input transfer (state %d).",
+                      devc->state);
                devc->transfer_error = TRUE;
                return;
        }
 
+       if (acq->reg_seq_pos < acq->reg_seq_len && !devc->cancel_requested) {
+               /* Complete register read sequence. */
+               if (read_reg_response(acq) != SR_OK) {
+                       devc->transfer_error = TRUE;
+                       return;
+               }
+               /* Repeat until all queued registers have been read. */
+               if (++acq->reg_seq_pos < acq->reg_seq_len) {
+                       next_reg_read(acq);
+                       submit_transfer(devc, acq->xfer_out);
+                       return;
+               }
+       }
+
        switch (devc->state) {
-       case STATE_STATUS_RESPONSE:
-               process_capture_status(sdi);
-               break;
-       case STATE_LENGTH_RESPONSE:
-               process_capture_length(sdi);
+       case STATE_STATUS_REQUEST:
+               if (devc->cancel_requested)
+                       submit_request(sdi, STATE_STOP_CAPTURE);
+               else
+                       handle_status_response(sdi);
                break;
-       case STATE_READ_RESPONSE:
-               if (process_sample_data(sdi) == SR_OK
-                               && acq->mem_addr_next < acq->mem_addr_stop
-                               && acq->samples_done < acq->samples_max)
-                       request_read_mem(sdi);
+       case STATE_LENGTH_REQUEST:
+               if (devc->cancel_requested)
+                       submit_request(sdi, STATE_READ_FINISH);
                else
-                       issue_read_end(sdi);
+                       handle_length_response(sdi);
+               break;
+       case STATE_READ_REQUEST:
+               handle_read_response(sdi);
                break;
        default:
                sr_err("Unexpected device state %d.", devc->state);
+               devc->transfer_error = TRUE;
                break;
        }
 }
 
-/* Initialize the LWLA.  This downloads a bitstream into the FPGA
- * and executes a simple device test sequence.
+/* Set up the acquisition state record.
  */
-SR_PRIV int lwla_init_device(const struct sr_dev_inst *sdi)
+static int init_acquisition_state(const struct sr_dev_inst *sdi)
 {
-       uint64_t value;
        struct dev_context *devc;
-       int ret;
+       struct sr_usb_dev_inst *usb;
+       struct acquisition_state *acq;
 
        devc = sdi->priv;
+       usb  = sdi->conn;
 
-       /* Force reload of bitstream */
-       devc->cur_clock_config = CONF_CLOCK_NONE;
-
-       ret = lwla_set_clock_config(sdi);
-       if (ret != SR_OK)
-               return ret;
-
-       ret = lwla_read_long_reg(sdi->conn, LREG_TEST_ID, &value);
-       if (ret != SR_OK)
-               return ret;
-
-       /* Ignore the value returned by the first read */
-       ret = lwla_read_long_reg(sdi->conn, LREG_TEST_ID, &value);
-       if (ret != SR_OK)
-               return ret;
-
-       if (value != UINT64_C(0x1234567887654321)) {
-               sr_err("Received invalid test word 0x%016" PRIX64 ".", value);
+       if (devc->acquisition) {
+               sr_err("Acquisition still in progress?");
+               return SR_ERR;
+       }
+       if (devc->cfg_clock_source == CLOCK_INTERNAL && devc->samplerate == 0) {
+               sr_err("Samplerate not set.");
                return SR_ERR;
        }
-       return SR_OK;
-}
-
-/* Select the LWLA clock configuration.  If the clock source changed from
- * the previous setting, this will download a new bitstream to the FPGA.
- */
-SR_PRIV int lwla_set_clock_config(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-       struct drv_context *drvc;
-       int ret;
-       enum clock_config choice;
 
-       devc = sdi->priv;
-       drvc = sdi->driver->context;
+       acq = g_try_malloc0(sizeof(struct acquisition_state));
+       if (!acq)
+               return SR_ERR_MALLOC;
 
-       if (sdi->status == SR_ST_INACTIVE)
-               choice = CONF_CLOCK_NONE;
-       else if (devc->cfg_clock_source == CLOCK_INTERNAL)
-               choice = CONF_CLOCK_INT;
-       else if (devc->cfg_clock_edge == EDGE_POSITIVE)
-               choice = CONF_CLOCK_EXT_RISE;
-       else
-               choice = CONF_CLOCK_EXT_FALL;
-
-       if (choice != devc->cur_clock_config) {
-               devc->cur_clock_config = CONF_CLOCK_NONE;
-               ret = lwla_send_bitstream(drvc->sr_ctx, sdi->conn,
-                                         bitstream_map[choice]);
-               if (ret == SR_OK)
-                       devc->cur_clock_config = choice;
-               return ret;
+       acq->xfer_in = libusb_alloc_transfer(0);
+       if (!acq->xfer_in) {
+               g_free(acq);
+               return SR_ERR_MALLOC;
+       }
+       acq->xfer_out = libusb_alloc_transfer(0);
+       if (!acq->xfer_out) {
+               libusb_free_transfer(acq->xfer_in);
+               g_free(acq);
+               return SR_ERR_MALLOC;
        }
-       return SR_OK;
-}
 
-/* Configure the LWLA in preparation for an acquisition session.
- */
-SR_PRIV int lwla_setup_acquisition(const struct sr_dev_inst *sdi)
-{
-       struct dev_context *devc;
-       struct sr_usb_dev_inst *usb;
-       struct acquisition_state *acq;
-       struct regval_pair regvals[7];
-       int ret;
+       libusb_fill_bulk_transfer(acq->xfer_out, usb->devhdl, EP_COMMAND,
+                                 (unsigned char *)acq->xfer_buf_out, 0,
+                                 &transfer_out_completed,
+                                 (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
 
-       devc = sdi->priv;
-       usb  = sdi->conn;
-       acq  = devc->acquisition;
+       libusb_fill_bulk_transfer(acq->xfer_in, usb->devhdl, EP_REPLY,
+                                 (unsigned char *)acq->xfer_buf_in,
+                                 sizeof(acq->xfer_buf_in),
+                                 &transfer_in_completed,
+                                 (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
 
        if (devc->limit_msec > 0) {
                acq->duration_max = devc->limit_msec;
@@ -790,10 +518,8 @@ SR_PRIV int lwla_setup_acquisition(const struct sr_dev_inst *sdi)
        if (devc->cfg_clock_source == CLOCK_INTERNAL) {
                sr_info("Internal clock, samplerate %" PRIu64 ".",
                        devc->samplerate);
-               if (devc->samplerate == 0)
-                       return SR_ERR_BUG;
-               /* At 125 MHz, the clock divider is bypassed. */
-               acq->bypass_clockdiv = (devc->samplerate > SR_MHZ(100));
+               /* Ramp up clock speed to enable samplerates above 100 MS/s. */
+               acq->clock_boost = (devc->samplerate > SR_MHZ(100));
 
                /* If only one of the limits is set, derive the other one. */
                if (devc->limit_msec == 0 && devc->limit_samples > 0)
@@ -803,170 +529,62 @@ SR_PRIV int lwla_setup_acquisition(const struct sr_dev_inst *sdi)
                        acq->samples_max = devc->limit_msec
                                        * devc->samplerate / 1000;
        } else {
-               acq->bypass_clockdiv = TRUE;
+               acq->clock_boost = TRUE;
 
-               if (devc->cfg_clock_edge == EDGE_NEGATIVE)
-                       sr_info("External clock, falling edge.");
-               else
+               if (devc->cfg_clock_edge == EDGE_POSITIVE)
                        sr_info("External clock, rising edge.");
+               else
+                       sr_info("External clock, falling edge.");
        }
 
-       regvals[0].reg = REG_MEM_CTRL;
-       regvals[0].val = MEM_CTRL_CLR_IDX;
-
-       regvals[1].reg = REG_MEM_CTRL;
-       regvals[1].val = MEM_CTRL_WRITE;
-
-       regvals[2].reg = REG_LONG_ADDR;
-       regvals[2].val = LREG_CAP_CTRL;
-
-       regvals[3].reg = REG_LONG_LOW;
-       regvals[3].val = CAP_CTRL_CLR_TIMEBASE | CAP_CTRL_FLUSH_FIFO
-                      | CAP_CTRL_CLR_FIFOFULL | CAP_CTRL_CLR_COUNTER;
-       regvals[4].reg = REG_LONG_HIGH;
-       regvals[4].val = 0;
+       acq->rle_enabled = devc->cfg_rle;
+       devc->acquisition = acq;
 
-       regvals[5].reg = REG_LONG_STROBE;
-       regvals[5].val = 0;
-
-       regvals[6].reg = REG_DIV_BYPASS;
-       regvals[6].val = acq->bypass_clockdiv;
-
-       ret = lwla_write_regs(usb, regvals, ARRAY_SIZE(regvals));
-       if (ret != SR_OK)
-               return ret;
-
-       return capture_setup(sdi);
+       return SR_OK;
 }
 
-/* Start the capture operation on the LWLA device.  Beginning with this
- * function, all USB transfers will be asynchronous until the end of the
- * acquisition session.
- */
 SR_PRIV int lwla_start_acquisition(const struct sr_dev_inst *sdi)
 {
+       struct drv_context *drvc;
        struct dev_context *devc;
-       struct sr_usb_dev_inst *usb;
-       struct acquisition_state *acq;
-       struct regval_pair *regvals;
+       int ret;
 
+       drvc = sdi->driver->context;
        devc = sdi->priv;
-       usb  = sdi->conn;
-       acq  = devc->acquisition;
-
-       acq->duration_now  = 0;
-       acq->mem_addr_fill = 0;
-       acq->capture_flags = 0;
 
-       libusb_fill_bulk_transfer(acq->xfer_out, usb->devhdl, EP_COMMAND,
-                                 (unsigned char *)acq->xfer_buf_out, 0,
-                                 &receive_transfer_out,
-                                 (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
-
-       libusb_fill_bulk_transfer(acq->xfer_in, usb->devhdl, EP_REPLY,
-                                 (unsigned char *)acq->xfer_buf_in,
-                                 sizeof acq->xfer_buf_in,
-                                 &receive_transfer_in,
-                                 (struct sr_dev_inst *)sdi, USB_TIMEOUT_MS);
-
-       regvals = devc->reg_write_seq;
-
-       regvals[0].reg = REG_LONG_ADDR;
-       regvals[0].val = LREG_CAP_CTRL;
-
-       regvals[1].reg = REG_LONG_LOW;
-       regvals[1].val = CAP_CTRL_TRG_EN;
-
-       regvals[2].reg = REG_LONG_HIGH;
-       regvals[2].val = 0;
-
-       regvals[3].reg = REG_LONG_STROBE;
-       regvals[3].val = 0;
-
-       devc->reg_write_pos = 0;
-       devc->reg_write_len = 4;
-
-       devc->state = STATE_START_CAPTURE;
-
-       return issue_next_write_reg(sdi);
-}
-
-/* Allocate an acquisition state object.
- */
-SR_PRIV struct acquisition_state *lwla_alloc_acquisition_state(void)
-{
-       struct acquisition_state *acq;
+       if (devc->state != STATE_IDLE) {
+               sr_err("Not in idle state, cannot start acquisition.");
+               return SR_ERR;
+       }
+       devc->cancel_requested = FALSE;
+       devc->transfer_error = FALSE;
 
-       acq = g_malloc0(sizeof(struct acquisition_state));
+       ret = init_acquisition_state(sdi);
+       if (ret != SR_OK)
+               return ret;
 
-       acq->xfer_in = libusb_alloc_transfer(0);
-       if (!acq->xfer_in) {
-               sr_err("Transfer malloc failed.");
-               g_free(acq);
-               return NULL;
+       ret = (*devc->model->setup_acquisition)(sdi);
+       if (ret != SR_OK) {
+               sr_err("Failed to set up device for acquisition.");
+               clear_acquisition_state(sdi);
+               return ret;
        }
-
-       acq->xfer_out = libusb_alloc_transfer(0);
-       if (!acq->xfer_out) {
-               sr_err("Transfer malloc failed.");
-               libusb_free_transfer(acq->xfer_in);
-               g_free(acq);
-               return NULL;
+       /* Register event source for asynchronous USB I/O. */
+       ret = usb_source_add(sdi->session, drvc->sr_ctx, POLL_INTERVAL,
+                            &transfer_event, (struct sr_dev_inst *)sdi);
+       if (ret != SR_OK) {
+               clear_acquisition_state(sdi);
+               return ret;
        }
+       ret = submit_request(sdi, STATE_START_CAPTURE);
 
-       return acq;
-}
-
-/* Deallocate an acquisition state object.
- */
-SR_PRIV void lwla_free_acquisition_state(struct acquisition_state *acq)
-{
-       if (acq) {
-               libusb_free_transfer(acq->xfer_out);
-               libusb_free_transfer(acq->xfer_in);
-               g_free(acq);
+       if (ret == SR_OK) {
+               /* Send header packet to the session bus. */
+               ret = std_session_send_df_header(sdi, LOG_PREFIX);
        }
-}
-
-/* USB I/O source callback.
- */
-SR_PRIV int lwla_receive_data(int fd, int revents, void *cb_data)
-{
-       struct sr_dev_inst *sdi;
-       struct dev_context *devc;
-       struct drv_context *drvc;
-       struct timeval tv;
-       int ret;
-
-       (void)fd;
-
-       sdi  = cb_data;
-       devc = sdi->priv;
-       drvc = sdi->driver->context;
-
-       if (!devc || !drvc)
-               return FALSE;
-
-       /* No timeout: return immediately. */
-       tv.tv_sec  = 0;
-       tv.tv_usec = 0;
-
-       ret = libusb_handle_events_timeout_completed(drvc->sr_ctx->libusb_ctx,
-                                                    &tv, NULL);
-       if (ret != 0)
-               sr_err("Event handling failed: %s.", libusb_error_name(ret));
-
-       /* If no event flags are set the timeout must have expired. */
-       if (revents == 0 && devc->state == STATE_STATUS_WAIT) {
-               if (devc->cancel_requested)
-                       issue_stop_capture(sdi);
-               else
-                       request_capture_status(sdi);
+       if (ret != SR_OK) {
+               usb_source_remove(sdi->session, drvc->sr_ctx);
+               clear_acquisition_state(sdi);
        }
-
-       /* Check if an error occurred on a transfer. */
-       if (devc->transfer_error)
-               end_acquisition(sdi);
-
-       return TRUE;
+       return ret;
 }