live_packet_gather.c

Go to the documentation of this file.

/*
 * Copyright (c) 2015 The University of Manchester
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
 
#include <common-typedefs.h>
#include <circular_buffer.h>
#include <data_specification.h>
#include <debug.h>
#include <simulation.h>
#include <spin1_api.h>
#include <eieio.h>
 
typedef struct lpg_provenance_data_t {
    uint32_t number_of_overflows_no_payload;
    uint32_t number_of_overflows_with_payload;
    uint32_t number_of_gathered_events;
    uint32_t number_of_sent_messages;
} lpg_provenance_data_t;
 
typedef struct key_translation_entry {
    // The key to check against after masking
    uint32_t key;
    // The mask to apply to the key
    uint32_t mask;
    // The atom identifier to add to the computed index
    uint32_t lo_atom;
} key_translation_entry;
 
struct lpg_config {
    uint32_t apply_prefix;
    uint32_t prefix;
    uint32_t prefix_type;
    uint32_t packet_type;
    uint32_t key_right_shift;
    uint32_t payload_timestamp;
    uint32_t payload_apply_prefix;
    uint32_t payload_prefix;
    uint32_t payload_right_shift;
    uint32_t sdp_tag;
    uint32_t sdp_dest;
    uint32_t packets_per_timestamp;
    uint32_t received_key_mask;
    uint32_t translated_key_right_shift;
    uint32_t n_translation_entries;
    key_translation_entry translation_table[];
};
 
enum {
    MC_PACKET = -1, 
    SDP = 0,        
    USER = 1,       
    DMA = 2,        
    TIMER = 3       
};
 
enum {
    SYSTEM_REGION,
    CONFIGURATION_REGION,
    PROVENANCE_REGION
};
 
enum packet_types {
    NO_PAYLOAD_16,
    PAYLOAD_16,
    NO_PAYLOAD_32,
    PAYLOAD_32
};
 
// Globals
static sdp_msg_t g_event_message;
 
static uint16_t *sdp_msg_aer_header;
 
static uint16_t *sdp_msg_aer_payload_prefix = NULL;
 
static uint16_t *sdp_msg_aer_data;
 
static uint32_t time;
 
static uint32_t packets_sent;
 
static uint32_t buffer_index;
 
static uint16_t eieio_constant_header;
 
static uint8_t event_size;
 
static uint8_t sdp_msg_aer_header_len;
 
static uint32_t simulation_ticks = 0;
 
static uint32_t infinite_run = FALSE;
 
static circular_buffer without_payload_buffer;
 
static circular_buffer with_payload_buffer;
 
static bool processing_events = false;
 
static lpg_provenance_data_t provenance_data;
 
static struct lpg_config *config;
 
#define FLAG_IS_SET(flags, bit)     (((flags) & (bit)) != 0)
 
#define CLAMP8(value)               ((value) & 0xFF)
 
#define CLAMP16(value)              ((value) & 0xFFFF)
 
#define HAVE_PAYLOAD(pkt_type)      FLAG_IS_SET(pkt_type, 0x1)
 
#define HAVE_WIDE_LOAD(pkt_type)    FLAG_IS_SET(pkt_type, 0x2)
 
#define BUFFER_CAPACITY 256
 
static inline bool find_translation_entry(uint32_t key, uint32_t *index) {
    if (!config->n_translation_entries) {
        return false;
    }
 
    uint32_t imin = 0;
    uint32_t imax = config->n_translation_entries;
 
    while (imin < imax) {
        uint32_t imid = (imax + imin) >> 1;
        key_translation_entry entry = config->translation_table[imid];
        if ((key & entry.mask) == entry.key) {
            *index = imid;
            return true;
        } else if (entry.key < key) {
 
            // Entry must be in upper part of the table
            imin = imid + 1;
        } else {
            // Entry must be in lower part of the table
            imax = imid;
        }
    }
    return false;
}
 
static inline uint32_t translated_key(uint32_t key) {
    uint32_t index = 0;
 
    // If there isn't an entry, don't translate
    if (!find_translation_entry(key, &index)) {
        return key & config->received_key_mask;
    }
 
    key_translation_entry entry = config->translation_table[index];
 
    // Pre-shift the key as requested
    uint32_t shifted_key = key & ~entry.mask;
    if (config->translated_key_right_shift) {
        shifted_key = shifted_key >> config->translated_key_right_shift;
    }
    return shifted_key + entry.lo_atom;
}
 
static inline void write_word(void *base, uint32_t index, uint32_t value) {
    uint16_t *ary = base;
    uint32_t idx = index * 2;
    ary[idx++] = CLAMP16(value);
    ary[idx] = CLAMP16(value >> 16);
}
 
static inline void write_short(void *base, uint32_t index, uint32_t value) {
    uint16_t *ary = base;
    ary[index] = CLAMP16(value);
}
 
static inline uint8_t get_event_count(void) {
    uint8_t event_count = buffer_index;
    // If there are payloads, it takes two buffer values to encode them
    if (HAVE_PAYLOAD(config->packet_type)) {
        event_count >>= 1;
    }
    return event_count;
}
 
static void flush_events(void) {
    // Send the event message only if there is data
    if ((buffer_index > 0) && (
            (config->packets_per_timestamp == 0) ||
            (packets_sent < config->packets_per_timestamp))) {
        // Get the event count depending on if there is a payload or not
        uint8_t event_count = get_event_count();
 
        // insert appropriate header
        sdp_msg_aer_header[0] = eieio_constant_header | CLAMP8(event_count);
 
        g_event_message.length =
                sizeof(sdp_hdr_t) + sdp_msg_aer_header_len +
                event_count * event_size;
 
        // Add the timestamp if required
        if (sdp_msg_aer_payload_prefix && config->payload_timestamp) {
            if (!HAVE_WIDE_LOAD(config->packet_type)) {
                write_short(sdp_msg_aer_payload_prefix, 0, time);
            } else {
                write_word(sdp_msg_aer_payload_prefix, 0, time);
            }
        }
 
        spin1_send_sdp_msg(&g_event_message, 1);
        packets_sent++;
        provenance_data.number_of_sent_messages++;
    }
 
    // reset counter
    buffer_index = 0;
}
 
static void record_provenance_data(address_t provenance_region_address) {
    lpg_provenance_data_t *sdram = (void *) provenance_region_address;
    // Copy provenance data into SDRAM region
    *sdram = provenance_data;
}
 
// Callbacks
static void timer_callback(UNUSED uint unused0, UNUSED uint unused1) {
    // flush the spike message and sent it over the Ethernet
    flush_events();
 
    // increase time variable to keep track of current timestep
    time++;
    log_debug("Timer tick %u", time);
 
    // Reset the count of packets sent in the current timestep
    packets_sent = 0;
 
    // check if the simulation has run to completion
    if (simulation_is_finished()) {
        simulation_handle_pause_resume(NULL);
 
        // Subtract 1 from the time so this tick gets done again on the next
        // run
        time--;
 
        simulation_ready_to_read();
    }
}
 
static inline void flush_events_if_full(void) {
    if ((get_event_count() + 1) * event_size > BUFFER_CAPACITY) {
        flush_events();
    }
}
 
static void process_incoming_event(uint key) {
    log_debug("Processing key %x", key);
 
    // process the received spike
    if (!HAVE_WIDE_LOAD(config->packet_type)) {
        // 16 bit packet
        write_short(sdp_msg_aer_data, buffer_index++,
                key >> config->key_right_shift);
 
        // if there is a payload to be added
        if (HAVE_PAYLOAD(config->packet_type) && !config->payload_timestamp) {
            write_short(sdp_msg_aer_data, buffer_index++, 0);
        } else if (HAVE_PAYLOAD(config->packet_type) && config->payload_timestamp) {
            write_short(sdp_msg_aer_data, buffer_index++, time);
        }
    } else {
        // 32 bit packet
        write_word(sdp_msg_aer_data, buffer_index++, key);
 
        // if there is a payload to be added
        if (HAVE_PAYLOAD(config->packet_type) && !config->payload_timestamp) {
            write_word(sdp_msg_aer_data, buffer_index++, 0);
        } else if (HAVE_PAYLOAD(config->packet_type) && config->payload_timestamp) {
            write_word(sdp_msg_aer_data, buffer_index++, time);
        }
    }
    provenance_data.number_of_gathered_events++;
}
 
static void process_incoming_event_payload(uint key, uint payload) {
    log_debug("Processing key %x, payload %x", key, payload);
 
    // process the received spike
    if (!HAVE_WIDE_LOAD(config->packet_type)) {
        //16 bit packet
        write_short(sdp_msg_aer_data, buffer_index++,
                key >> config->key_right_shift);
 
        //if there is a payload to be added
        if (HAVE_PAYLOAD(config->packet_type) && !config->payload_timestamp) {
            write_short(sdp_msg_aer_data, buffer_index++,
                    payload >> config->payload_right_shift);
        } else if (HAVE_PAYLOAD(config->packet_type) && config->payload_timestamp) {
            write_short(sdp_msg_aer_data, buffer_index++, time);
        }
    } else {
        //32 bit packet
        write_word(sdp_msg_aer_data, buffer_index++, key);
 
        //if there is a payload to be added
        if (HAVE_PAYLOAD(config->packet_type) && !config->payload_timestamp) {
            write_word(sdp_msg_aer_data, buffer_index++, payload);
        } else if (HAVE_PAYLOAD(config->packet_type) && config->payload_timestamp) {
            write_word(sdp_msg_aer_data, buffer_index++, time);
        }
    }
    provenance_data.number_of_gathered_events++;
}
 
static void incoming_event_process_callback(
        UNUSED uint unused0, UNUSED uint unused1) {
    do {
        uint32_t key, payload;
 
        if (circular_buffer_get_next(without_payload_buffer, &key)) {
            key = translated_key(key);
            process_incoming_event(key);
        } else if (circular_buffer_get_next(with_payload_buffer, &key)
                && circular_buffer_get_next(with_payload_buffer, &payload)) {
            key = translated_key(key);
            process_incoming_event_payload(key, payload);
        } else {
            processing_events = false;
            break;
        }
 
        // send packet if enough data is stored
        flush_events_if_full();
    } while (processing_events);
}
 
static void incoming_event_callback(uint key, UNUSED uint unused) {
    log_debug("Received key %x", key);
 
    if (circular_buffer_add(without_payload_buffer, key)) {
        if (!processing_events) {
            processing_events = true;
            spin1_trigger_user_event(0, 0);
        }
    } else {
        provenance_data.number_of_overflows_no_payload++;
    }
}
 
static void incoming_event_payload_callback(uint key, uint payload) {
    log_debug("Received key %x, payload %x", key, payload);
 
    if (circular_buffer_add(with_payload_buffer, key)) {
        circular_buffer_add(with_payload_buffer, payload);
        if (!processing_events) {
            processing_events = true;
            spin1_trigger_user_event(0, 0);
        }
    } else {
        provenance_data.number_of_overflows_with_payload++;
    }
}
 
static bool read_parameters(struct lpg_config *sdram_config) {
    uint32_t n_bytes = sizeof(struct lpg_config) +
            (sdram_config->n_translation_entries * sizeof(key_translation_entry));
    config = spin1_malloc(n_bytes);
    if (config == NULL) {
        log_error("Could not allocate space for config!");
        return false;
 
    }
    spin1_memcpy(config, sdram_config, n_bytes);
 
    log_info("apply_prefix: %d", config->apply_prefix);
    log_info("prefix: %08x", config->prefix);
    log_info("prefix_type: %d", config->prefix_type);
    log_info("packet_type: %d", config->packet_type);
    log_info("key_right_shift: %d", config->key_right_shift);
    log_info("payload_timestamp: %d", config->payload_timestamp);
    log_info("payload_apply_prefix: %d", config->payload_apply_prefix);
    log_info("payload_prefix: %08x", config->payload_prefix);
    log_info("payload_right_shift: %d", config->payload_right_shift);
    log_info("sdp_tag: %d", config->sdp_tag);
    log_info("sdp_dest: 0x%04x", config->sdp_dest);
    log_info("packets_per_timestamp: %d", config->packets_per_timestamp);
    log_info("n_translation_entries: %d", config->n_translation_entries);
    for (uint32_t i = 0; i < config->n_translation_entries; i++) {
        key_translation_entry *entry = &config->translation_table[i];
        log_info("key = 0x%08x, mask = 0x%08x, lo_atom = 0x%08x",
                entry->key, entry->mask, entry->lo_atom);
    }
 
    return true;
}
 
static bool initialize(uint32_t *timer_period) {
    // Get the address this core's DTCM data starts at from SRAM
    data_specification_metadata_t *ds_regions =
            data_specification_get_data_address();
 
    // Read the header
    if (!data_specification_read_header(ds_regions)) {
        return false;
    }
 
    // Get the timing details and set up the simulation interface
    if (!simulation_initialise(
            data_specification_get_region(SYSTEM_REGION, ds_regions),
            APPLICATION_NAME_HASH, timer_period, &simulation_ticks,
            &infinite_run, &time, SDP, DMA)) {
        return false;
    }
    simulation_set_provenance_function(
            record_provenance_data,
            data_specification_get_region(PROVENANCE_REGION, ds_regions));
 
    // Fix simulation ticks to be one extra timer period to soak up last events
    if (infinite_run != TRUE) {
        simulation_ticks++;
    }
 
    // Read the parameters
    return read_parameters(
            data_specification_get_region(CONFIGURATION_REGION, ds_regions));
}
 
static bool configure_sdp_msg(void) {
    log_debug("configure_sdp_msg");
 
    switch (config->packet_type) {
    case NO_PAYLOAD_16:
        event_size = 2;
        break;
    case PAYLOAD_16:
        event_size = 4;
        break;
    case NO_PAYLOAD_32:
        event_size = 4;
        break;
    case PAYLOAD_32:
        event_size = 8;
        break;
    default:
        log_error("unknown packet type: %d", config->packet_type);
        return false;
    }
 
    // initialise SDP header
    g_event_message.tag = config->sdp_tag;
    // No reply required
    g_event_message.flags = 0x07;
    // Chip 0,0
    g_event_message.dest_addr = config->sdp_dest;
    // Dump through Ethernet
    g_event_message.dest_port = PORT_ETH;
    // Set up monitoring address and port
    g_event_message.srce_addr = spin1_get_chip_id();
    g_event_message.srce_port = (3 << PORT_SHIFT) | spin1_get_core_id();
 
    // check incompatible options
    if (config->payload_timestamp && config->payload_apply_prefix
            && HAVE_PAYLOAD(config->packet_type)) {
        log_error("Timestamp can either be included as payload prefix or as"
                "payload to each key, not both");
        return false;
    }
    if (config->payload_timestamp && !config->payload_apply_prefix
            && !HAVE_PAYLOAD(config->packet_type)) {
        log_error("Timestamp can either be included as payload prefix or as"
                "payload to each key, but current configuration does not"
                "specify either of these");
        return false;
    }
 
    // initialise AER header
    // pointer to data space
    sdp_msg_aer_header = &g_event_message.cmd_rc;
 
    eieio_constant_header = 0;
    eieio_constant_header |= config->apply_prefix << APPLY_PREFIX;
    eieio_constant_header |= config->prefix_type << PREFIX_UPPER;
    eieio_constant_header |= config->payload_apply_prefix << APPLY_PAYLOAD_PREFIX;
    eieio_constant_header |= config->payload_timestamp << PAYLOAD_IS_TIMESTAMP;
    eieio_constant_header |= config->packet_type << PACKET_TYPE;
 
    // pointers for AER packet header, prefix and data
    // Point to the half-word after main header half-word
    sdp_msg_aer_data = sdp_msg_aer_header + 1;
    if (config->apply_prefix) {
        // pointer to key prefix, so data is one half-word further ahead
        write_short(sdp_msg_aer_header, 1, config->prefix);
        sdp_msg_aer_data++;
    }
 
    if (config->payload_apply_prefix) {
        // pointer to payload prefix
        sdp_msg_aer_payload_prefix = sdp_msg_aer_data;
 
        if (!HAVE_WIDE_LOAD(config->packet_type)) {
            //16 bit payload prefix; advance data position by one half word
            sdp_msg_aer_data++;
            if (!config->payload_timestamp) {
                // add payload prefix as required - not a timestamp
                write_short(sdp_msg_aer_payload_prefix, 0, config->payload_prefix);
            }
        } else {
            //32 bit payload prefix; advance data position by two half words
            sdp_msg_aer_data += 2;
            if (!config->payload_timestamp) {
                // add payload prefix as required - not a timestamp
                write_word(sdp_msg_aer_payload_prefix, 0, config->payload_prefix);
            }
        }
    }
 
    // compute header length in bytes
    sdp_msg_aer_header_len =
            (sdp_msg_aer_data - sdp_msg_aer_header) * sizeof(uint16_t);
 
    log_debug("sdp_msg_aer_header: %08x", sdp_msg_aer_header);
    log_debug("sdp_msg_aer_payload_prefix: %08x", sdp_msg_aer_payload_prefix);
    log_debug("sdp_msg_aer_data: %08x", sdp_msg_aer_data);
    log_debug("sdp_msg_aer_header_len: %d", sdp_msg_aer_header_len);
 
    packets_sent = 0;
    buffer_index = 0;
 
    return true;
}
 
void c_main(void) {
    // Configure system
    uint32_t timer_period = 0;
    if (!initialize(&timer_period)) {
        log_error("Error in initialisation - exiting!");
        rt_error(RTE_SWERR);
    }
 
    // Configure SDP message
    if (!configure_sdp_msg()) {
        rt_error(RTE_SWERR);
    }
 
    // Set up circular buffers for multicast message reception
    without_payload_buffer = circular_buffer_initialize(BUFFER_CAPACITY);
    with_payload_buffer = circular_buffer_initialize(BUFFER_CAPACITY * 2);
 
    // Set timer_callback
    spin1_set_timer_tick(timer_period);
 
    // Register callbacks
    spin1_callback_on(MC_PACKET_RECEIVED, incoming_event_callback, MC_PACKET);
    spin1_callback_on(
            MCPL_PACKET_RECEIVED, incoming_event_payload_callback, MC_PACKET);
    spin1_callback_on(USER_EVENT, incoming_event_process_callback, USER);
    spin1_callback_on(TIMER_TICK, timer_callback, TIMER);
 
    // Start the time at "-1" so that the first tick will be 0
    time = UINT32_MAX;
    simulation_run();
}