/* mgaprobe.c - become the RCM graphics process for mga0, report what the
 * kernel maps, read a few engine registers, let go. Reads only.
 * Claude Opus 5.5, 2026-10-13.
 * cc: xlc -o mgaprobe mgaprobe.c -bI:/usr/lib/rcm.exp
 * usage: mgaprobe [-h]   (-h: only get the gsc handle, don't MAKE_GP) */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/rcm_win.h>
#include <sys/aixgsc.h>
#include <sys/rcmioctl.h>

int main(int argc, char **argv)
{
    gsc_handle h;
    make_gp mg;
    unmake_gp ug;
    gAddrRanges ar;
    unsigned int pd[8];
    volatile unsigned char *base;
    int fd, rc, i;

    fd = open("/dev/rcm0", O_RDWR);
    if (fd < 0) { perror("open /dev/rcm0"); return 1; }
    memset(&h, 0, sizeof h);
    strcpy(h.devname, "mga0");
    rc = ioctl(fd, GSC_HANDLE, &h);
    printf("GSC_HANDLE rc=%d errno=%d handle=0x%x\n", rc, rc ? errno : 0, h.handle);
    if (rc || (argc > 1 && strcmp(argv[1], "-h") == 0)) return rc != 0;

    memset(&mg, 0, sizeof mg); memset(pd, 0, sizeof pd); memset(&ar, 0, sizeof ar);
    mg.pData = (genericPtr) pd;
    mg.length = sizeof pd;
    mg.access = EXCLUSIVE_ACCESS | ADDR_ARRAY_VERSION | ALL_ADDR_RANGES;
    mg.NumAddrRanges = 1;
    mg.AddrRanges = &ar;
    rc = aixgsc(h.handle, MAKE_GP, &mg);
    printf("MAKE_GP rc=%d errno=%d error=%d segment=%p\n", rc, rc ? errno : 0, mg.error,
           (void *) mg.segment);
    if (rc) return 1;
    for (i = 0; i < 8; i++) printf("pData[%d] = 0x%08x\n", i, pd[i]);
    printf("range: base=%p len=0x%x id=%u\n", ar.BaseAddr, ar.RangeLength, ar.AddrRangeID);

    base = (volatile unsigned char *) ar.BaseAddr;
    printf("FIFOSTATUS 0x1e10 = 0x%08x\n", *(volatile unsigned int *)(base + 0x1e10));
    printf("STATUS     0x1e14 = 0x%08x\n", *(volatile unsigned int *)(base + 0x1e14));
    printf("OPMODE     0x1e54 = 0x%08x\n", *(volatile unsigned int *)(base + 0x1e54));
    printf("MACCESS    0x1c04 = 0x%08x\n", *(volatile unsigned int *)(base + 0x1c04));
    printf("PITCH      0x1c8c = 0x%08x\n", *(volatile unsigned int *)(base + 0x1c8c));
    printf("YDSTORG    0x1c94 = 0x%08x\n", *(volatile unsigned int *)(base + 0x1c94));

    memset(&ug, 0, sizeof ug);
    rc = aixgsc(h.handle, UNMAKE_GP, &ug);
    printf("UNMAKE_GP rc=%d error=%d\n", rc, ug.error);
    return 0;
}