hacked up smurw.c tested on an rx580 (should work on most?) invocation is like ./smurw [path to resource5 BAR] [addr] (dword to write)

smurw-gpu.c

/* smutool  Tool for SMU
 * Copyright (C) 2015  Damien Zammit <damien@zamaudio.com>
 * Copyright (C) 2023  Sheep Sun <sunxiaoyang2003@gmail.com>
 *
 * 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 3 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.
 * See <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <inttypes.h>
#include <pci/pci.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/io.h>
#include <stdlib.h>
#include <unistd.h>


#define SMU_DATA 0x204
#define SMU_ADDR 0x200


int main(int argc, char* argv[])
{

        int fd = -1;
        char *filename = argv[1];
        uint32_t target = strtoul(argv[2], 0, 0);
        uint32_t writeval = 0;
        int do_write = 0;


        if(argc > 3) {
                writeval = strtoul(argv[3], 0, 0);
                do_write = 1;
        }

        if((fd = open(filename, O_RDWR | O_SYNC)) == -1) exit(-1);
        //fprintf(stderr, "%s opened.\n", filename);


        void *map_base =
                mmap(0, 0x1000, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

        //fprintf(stderr, "%p\n", map_base);

        volatile uint32_t *smu_data_m = map_base + SMU_DATA;
        volatile uint32_t *smu_addr_m = map_base + SMU_ADDR;
        if (do_write == 0) {
                *smu_addr_m = target;
                uint32_t res = *smu_data_m;
                //fprintf(stderr, "[%p] -> 0x%08x\n",target, res) ;
                printf("0x%08x\n",res);
        } else {
                *smu_addr_m = target;
                *smu_data_m = writeval;
                //fprintf(stderr, "0x%08x -> [%p] (-> 0x%08x)\n", writeval, target, *smu_data_m);
        }

        //fprintf(stderr, "exiting\n");
        return 0;
}