generator/sections/gen-section-cxl-protocol.c

/**
 * Functions for generating pseudo-random CXL protocol error sections.
 * 
 * Author: Lawrence.Tang@arm.com
 **/

#include <stdlib.h>
#include "../../edk/BaseTypes.h"
#include "../gen-utils.h"
#include "gen-section.h"

//Generates a single pseudo-random CXL protocol error section, saving the resulting address to the given
//location. Returns the size of the newly created section.
size_t generate_section_cxl_protocol(void** location)
{
    //Create a random length for the CXL DVSEC and CXL error log.
    //The logs attached here do not necessarily conform to the specification, and are simply random.
    int dvsec_len = rand() % 64;
    int error_log_len = rand() % 64;

    //Create random bytes.
    int size = 116 + dvsec_len + error_log_len;
    UINT8* bytes = generate_random_bytes(size);

    //Set CXL agent type.
    int cxl_agent_type = rand() % 2;
    *(bytes + 8) = cxl_agent_type;
    
    //Set reserved areas to zero.
    UINT64* validation = (UINT64*)bytes;
    *validation &= 0b111111; //Validation bits 6-63.
    for (int i=0; i<7; i++)
        *(bytes + 9 + i) = 0; //Reserved bytes 9-15.

    //We only reserve bytes if it's a CXL 1.1 device, and not a host downstream port.
    if (cxl_agent_type == 0)
    {
        for (int i=0; i<3; i++)
            *(bytes + 21 + i) = 0; //CXL agent address bytes 5-7.
    }
    
    *(bytes + 34) &= ~0b111; //Device ID byte 10 bits 0-2.
    UINT32* reserved = (UINT32*)(bytes + 36);
    *reserved = 0; //Device ID bytes 12-15.
    reserved = (UINT32*)(bytes + 112);
    *reserved = 0; //Reserved bytes 112-115.

    //If the device is a host downstream port, serial/capability structure is invalid.
    if (cxl_agent_type != 0)
    {
        for (int i=0; i<68; i++)
            *(bytes + 40 + i) = 0; //Device serial & capability structure.
    }

    //Set expected values.
    UINT16* dvsec_length_field = (UINT16*)(bytes + 108);
    UINT16* error_log_len_field = (UINT16*)(bytes + 110);
    *dvsec_length_field = dvsec_len;
    *error_log_len_field = error_log_len;

    //Set return values, exit.
    *location = bytes;
    return size;
}