data_specification.c

Go to the documentation of this file.

/*
 * Copyright (c) 2014 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 "data_specification.h"
 
#include <sark.h>
#include <debug.h>
 
enum {
    DATA_SPECIFICATION_MAGIC_NUMBER = 0xAD130AD6,
    DATA_SPECIFICATION_VERSION = 0x00010000,
    VERSION_MASK = 0xFFFF,
    VERSION_SHIFT = 16
};
 
#define N_REGIONS 32
 
 
static inline void verify_checksum(data_specification_metadata_t *ds_regions,
        uint32_t region) {
    uint32_t *data = ds_regions->regions[region].pointer;
    uint32_t checksum = ds_regions->regions[region].checksum;
    uint32_t n_words = ds_regions->regions[region].n_words;
 
    // If the region is not in use or marked as having no size, skip
    if (data == NULL || n_words == 0) {
        return;
    }
 
    // Do simple unsigned 32-bit checksum
    uint32_t sum = 0;
    for (uint32_t i = 0; i < n_words; i++) {
        sum += data[i];
    }
    if (sum != checksum) {
        log_error("[ERROR] Region %u with %u words starting at 0x%08x: "
                "checksum %u does not match computed sum %u",
                region, n_words, data, checksum, sum);
        rt_error(RTE_SWERR);
    }
 
    // Avoid checking this again (unless it is changed)
    ds_regions->regions[region].checksum = 0;
    ds_regions->regions[region].n_words = 0;
}
 
data_specification_metadata_t *data_specification_get_data_address(void) {
    // Get pointer to 1st virtual processor info struct in SRAM
    vcpu_t *virtual_processor_table = (vcpu_t*) SV_VCPU;
 
    // Get the address this core's DTCM data starts at from the user data
    // member of the structure associated with this virtual processor
    uint user0 = virtual_processor_table[spin1_get_core_id()].user0;
 
    log_debug("SDRAM data begins at address: %08x", user0);
 
    // Cast to the correct type
    data_specification_metadata_t *ds_regions = (data_specification_metadata_t *) user0;
    for (uint32_t region = 0; region < N_REGIONS; region++) {
        verify_checksum(ds_regions, region);
    }
 
    return ds_regions;
}
 
bool data_specification_read_header(
        data_specification_metadata_t *ds_regions) {
    // Check for the magic number
    if (ds_regions->magic_number != DATA_SPECIFICATION_MAGIC_NUMBER) {
        log_error("[ERROR] Magic number is incorrect: %08x", ds_regions->magic_number);
        return false;
    }
 
    if (ds_regions->version != DATA_SPECIFICATION_VERSION) {
        log_error("[ERROR] Version number is incorrect: %08x", ds_regions->version);
        return false;
    }
 
    // Log what we have found
    log_info("magic = %08x, version = %d.%d", ds_regions->magic_number,
            ds_regions->version >> VERSION_SHIFT,
            ds_regions->version & VERSION_MASK);
 
    return true;
}