/* mga.c - see mga.h. Claude Opus 5.5, 2026-10-13. */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/rcm_win.h>
#include <sys/aixgsc.h>
#include <sys/rcmioctl.h>
#include "mga.h"

/* eieio: keep MMIO loads and stores in program order */
void eieio(void);
#pragma mc_func eieio { "7c0006ac" }
#pragma reg_killed_by eieio

volatile unsigned char *mga_base, *mga_fb;
unsigned int mga_pdata[8];
static gsc_handle h;
static int rcmfd = -1, made = 0;

int mga_open(void)
{
    make_gp mg;
    static gAddrRanges ar;

    rcmfd = open("/dev/rcm0", O_RDWR);
    if (rcmfd < 0) { perror("open /dev/rcm0"); return -1; }
    memset(&h, 0, sizeof h);
    strcpy(h.devname, "mga0");
    if (ioctl(rcmfd, GSC_HANDLE, &h)) { perror("GSC_HANDLE (is X running?)"); return -1; }
    memset(&mg, 0, sizeof mg);
    mg.pData = (genericPtr) mga_pdata;
    mg.length = sizeof mga_pdata;
    mg.access = EXCLUSIVE_ACCESS | ADDR_ARRAY_VERSION | ALL_ADDR_RANGES;
    mg.NumAddrRanges = 1;
    mg.AddrRanges = &ar;
    if (aixgsc(h.handle, MAKE_GP, &mg)) {
        fprintf(stderr, "MAKE_GP failed: errno %d error %d\n", errno, mg.error);
        return -1;
    }
    made = 1;
    if (mga_pdata[5] != 0x2b101a05) {
        fprintf(stderr, "unexpected device id 0x%08x\n", mga_pdata[5]);
        mga_close();
        return -1;
    }
    mga_base = (volatile unsigned char *) ar.BaseAddr;
    mga_fb = mga_base + FB_OFFSET;
    return 0;
}

void mga_close(void)
{
    unmake_gp ug;
    if (made) {
        memset(&ug, 0, sizeof ug);
        aixgsc(h.handle, UNMAKE_GP, &ug);
        made = 0;
    }
    if (rcmfd >= 0) { close(rcmfd); rcmfd = -1; }
}

void mga_out(int reg, unsigned int v)
{
    *(volatile unsigned int *)(mga_base + reg) = v;
    eieio();
}

unsigned int mga_in(int reg)
{
    unsigned int v = *(volatile unsigned int *)(mga_base + reg);
    eieio();
    return v;
}

void mga_outb(int reg, unsigned char v) { mga_base[reg] = v; eieio(); }
unsigned char mga_inb(int reg) { unsigned char v = mga_base[reg]; eieio(); return v; }

int mga_fifo(int n)
{
    long i;
    for (i = 0; i < 10000000L; i++)
        if ((int)(mga_in(FIFOSTATUS) & 0x7f) >= n) return 0;
    fprintf(stderr, "mga_fifo: timeout, FIFOSTATUS 0x%08x\n", mga_in(FIFOSTATUS));
    return -1;
}

int mga_idle(void)
{
    long i;
    for (i = 0; i < 20000000L; i++)
        if (!(mga_in(STATUS) & 0x10000)) return 0;
    fprintf(stderr, "mga_idle: timeout, STATUS 0x%08x\n", mga_in(STATUS));
    return -1;
}

void mga_getpal(unsigned char *pal)
{
    int i;
    mga_outb(PALRDADD, 0);
    for (i = 0; i < 768; i++) pal[i] = mga_inb(PALDATA);
}

void mga_setpal(const unsigned char *pal)
{
    int i;
    mga_outb(PALWTADD, 0);
    for (i = 0; i < 768; i++) mga_outb(PALDATA, pal[i]);
}

double mga_now(void)
{
    struct timeval tv;
    gettimeofday(&tv, 0);
    return tv.tv_sec + tv.tv_usec / 1e6;
}