/*
 * Copyright 2024, Haiku Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *              Jérôme Duval <jerome.duval@gmail.com>
 */


#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <OS.h>


extern const char *__progname;
static const char *kCommandName = __progname;


// usage
static const char *kUsage =
"Usage: %s [ <options> ] [ command ] [ args ]\n"
"\n"
"Options:\n"
"  --count <n>      - Read n registers.\n"
;


static void
print_usage(bool error)
{
        // print usage
        fprintf((error ? stderr : stdout), kUsage, kCommandName);
}


static void
print_usage_and_exit(bool error)
{
        print_usage(error);
        exit(error ? 1 : 0);
}


int
main(int argc, const char *const *argv)
{
        const char *const *programArgs = NULL;
        int32_t programArgCount = 0;
        uint32_t count = 1;

        // parse arguments
        for (int argi = 1; argi < argc; argi++) {
                const char *arg = argv[argi];
                if (arg[0] == '-') {
                        if (strcmp(arg, "-h") == 0 || strcmp(arg, "--help") == 0) {
                                print_usage_and_exit(false);
                        } else if (strcmp(arg, "--count") == 0) {
                                count = strtol(argv[++argi], (char **)NULL, 10);
                                if (count == 0 && errno != 0)
                                        print_usage_and_exit(true);
                        } else {
                                print_usage_and_exit(true);
                        }
                } else {
                        programArgs = argv + argi;
                        programArgCount = argc - argi;
                        break;
                }
        }
        
        bool write = false;
        uint32 value = 0;
        if (programArgCount < 2) {
                print_usage_and_exit(true);
        }
        if (strcmp(programArgs[0], "read") == 0) {
                if (programArgCount >= 4) {
                        const char *arg = programArgs[1];
                        if (arg[0] == '-') {
                                if (strcmp(arg, "--count") == 0) {
                                        count = strtol(programArgs[2], (char **)NULL, 10);
                                        if (count == 0 && errno != 0)
                                                print_usage_and_exit(true);
                                        programArgCount -= 2;
                                        programArgs += 2;
                                } else {
                                        print_usage_and_exit(true);
                                }
                        }
                }
        } else if (strcmp(programArgs[0], "write") == 0) {
                write = true;
        } else
                print_usage_and_exit(true);
        programArgCount--;
        programArgs++;

        area_id area = find_area("intel extreme mmio");
        if (area < 0) {
                fprintf(stderr, "couldn't find intel extreme mmio area\n");
                exit(1);
        }

        void* regs;
        uint32 protection = B_READ_AREA | (write ? B_WRITE_AREA : 0);
        area_id clone = clone_area("clone regs", &regs, B_ANY_ADDRESS, protection, area);
        if (clone < B_OK) {
                fprintf(stderr, "couldn't clone intel extreme mmio area\n");
                exit(1);
        }

        while (programArgCount > 0) {
                const char* arg = programArgs[0];
                programArgCount--;
                programArgs++;
                if (write) {
                        if (programArgCount < 1)
                                print_usage_and_exit(true);
                        const char* val = programArgs[0];
                        if (val[0] == '0' && (val[1] == 'x' || val[1] == 'X'))
                                value = strtol(val + 2, (char **)NULL, 16);
                        else
                                value = strtol(val, (char **)NULL, 10);
                        if (value == 0 && errno != 0)
                                print_usage_and_exit(true);
                        programArgCount--;
                        programArgs++;
                }
                uint64_t address;
                if (arg[0] == '0' && (arg[1] == 'x' || arg[1] == 'X')) {
                        address = strtol(arg + 2, (char **)NULL, 16);
                } else
                        address = strtol(arg, (char **)NULL, 10);
                if (address == 0 && errno != 0)
                        print_usage_and_exit(true);

                for (uint32_t i = 0; i < count; i++) {
                        addr_t addr = (addr_t)regs + address + i * sizeof(uint32);
                        if (write) {
                                *(uint32*)addr = value;
                        } else {
                                printf("(0x%08" B_PRIxADDR "): 0x%08" B_PRIx32 "\n", address + i * sizeof(uint32), *(uint32*)addr);
                        }
                }
        }

        delete_area(clone);
        exit(0);
}