/*
 * some generic framebuffer device stuff
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>
#include <signal.h>
#include <errno.h>
#include <setjmp.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <sys/stat.h>

#include <linux/kd.h>
#include <linux/vt.h>
#include <linux/fb.h>

#include "fbtools.h"

/* -------------------------------------------------------------------- */
/* exported stuff                                                       */

struct fb_fix_screeninfo   fb_fix;
struct fb_var_screeninfo   fb_var;
unsigned char             *fb_mem;
int			   fb_mem_offset = 0;
int                        fb_switch_state = FB_ACTIVE;

/* -------------------------------------------------------------------- */
/* internal variables                                                   */

static int                       fb,tty;
#if 0
static int                       bpp,black,white;
#endif

static int                       orig_vt_no = 0;
static struct vt_mode            vt_mode;

static int                       kd_mode;
static struct vt_mode            vt_omode;
static struct termios            term;
static struct fb_var_screeninfo  fb_ovar;
static unsigned short            ored[256], ogreen[256], oblue[256];
static struct fb_cmap            ocmap = { 0, 256, ored, ogreen, oblue };

/* -------------------------------------------------------------------- */
/* devices                                                              */

struct DEVS {
    char *fb0;
    char *fbnr;
    char *ttynr;
};

struct DEVS devs_default = {
    fb0:   "/dev/fb0",
    fbnr:  "/dev/fb%d",
    ttynr: "/dev/tty%d",
};
struct DEVS devs_devfs = {
    fb0:   "/dev/fb/0",
    fbnr:  "/dev/fb/%d",
    ttynr: "/dev/vc/%d",
};
struct DEVS *devices;

static void dev_init(void)
{
    struct stat dummy;

    if (NULL != devices)
	return;
    if (0 == stat("/dev/.devfsd",&dummy))
	devices = &devs_devfs;
    else
	devices = &devs_default;
}

/* -------------------------------------------------------------------- */
/* console switching                                                    */

extern int debug;

static void
fb_switch_signal(int signal)
{
    if (signal == SIGUSR1) {
	/* release */
	fb_switch_state = FB_REL_REQ;
	if (debug)
	    write(2,"vt: SIGUSR1\n",12);
    }
    if (signal == SIGUSR2) {
	/* acquisition */
	fb_switch_state = FB_ACQ_REQ;
	if (debug)
	    write(2,"vt: SIGUSR2\n",12);
    }
}

void
fb_switch_release()
{
    ioctl(tty, VT_RELDISP, 1);
    fb_switch_state = FB_INACTIVE;
    if (debug)
	write(2,"vt: release\n",12);
}

void
fb_switch_acquire()
{
    ioctl(tty, VT_RELDISP, VT_ACKACQ);
    fb_switch_state = FB_ACTIVE;
    if (debug)
	write(2,"vt: acquire\n",12);
}

int
fb_switch_init()
{
    struct sigaction act,old;

    memset(&act,0,sizeof(act));
    act.sa_handler  = fb_switch_signal;
    sigemptyset(&act.sa_mask);
    sigaction(SIGUSR1,&act,&old);
    sigaction(SIGUSR2,&act,&old);
    
    if (-1 == ioctl(tty,VT_GETMODE, &vt_mode)) {
	perror("ioctl VT_GETMODE");
	exit(1);
    }
    vt_mode.mode   = VT_PROCESS;
    vt_mode.waitv  = 0;
    vt_mode.relsig = SIGUSR1;
    vt_mode.acqsig = SIGUSR2;
    
    if (-1 == ioctl(tty,VT_SETMODE, &vt_mode)) {
	perror("ioctl VT_SETMODE");
	exit(1);
    }
    return 0;
}

/* -------------------------------------------------------------------- */
/* initialisation & cleanup                                             */

void
fb_memset (void *addr, int c, size_t len)
{
#if 1 /* defined(__powerpc__) */
    unsigned int i, *p;
    
    i = (c & 0xff) << 8;
    i |= i << 16;
    len >>= 2;
    for (p = addr; len--; p++)
	*p = i;
#else
    memset(addr, c, len);
#endif
}

static int
fb_setmode(char *name)
{
    FILE *fp;
    char line[80],label[32],value[16];
    int  geometry=0, timings=0;
    
    /* load current values */
    if (-1 == ioctl(fb,FBIOGET_VSCREENINFO,&fb_var)) {
	perror("ioctl FBIOGET_VSCREENINFO");
	exit(1);
    }
    
    if (NULL == name)
	return -1;
    if (NULL == (fp = fopen("/etc/fb.modes","r")))
	return -1;
    while (NULL != fgets(line,79,fp)) {
	if (1 == sscanf(line, "mode \"%31[^\"]\"",label) &&
	    0 == strcmp(label,name)) {
	    /* fill in new values */
	    fb_var.sync  = 0;
	    fb_var.vmode = 0;
	    while (NULL != fgets(line,79,fp) &&
		   NULL == strstr(line,"endmode")) {
		if (5 == sscanf(line," geometry %d %d %d %d %d",
				&fb_var.xres,&fb_var.yres,
				&fb_var.xres_virtual,&fb_var.yres_virtual,
				&fb_var.bits_per_pixel))
		    geometry = 1;
		if (7 == sscanf(line," timings %d %d %d %d %d %d %d",
				&fb_var.pixclock,
				&fb_var.left_margin,  &fb_var.right_margin,
				&fb_var.upper_margin, &fb_var.lower_margin,
				&fb_var.hsync_len,    &fb_var.vsync_len))
		    timings = 1;
		if (1 == sscanf(line, " hsync %15s",value) &&
		    0 == strcasecmp(value,"high"))
		    fb_var.sync |= FB_SYNC_HOR_HIGH_ACT;
		if (1 == sscanf(line, " vsync %15s",value) &&
		    0 == strcasecmp(value,"high"))
		    fb_var.sync |= FB_SYNC_VERT_HIGH_ACT;
		if (1 == sscanf(line, " csync %15s",value) &&
		    0 == strcasecmp(value,"high"))
		    fb_var.sync |= FB_SYNC_COMP_HIGH_ACT;
		if (1 == sscanf(line, " extsync %15s",value) &&
		    0 == strcasecmp(value,"true"))
		    fb_var.sync |= FB_SYNC_EXT;
		if (1 == sscanf(line, " laced %15s",value) &&
		    0 == strcasecmp(value,"true"))
		    fb_var.vmode |= FB_VMODE_INTERLACED;
		if (1 == sscanf(line, " double %15s",value) &&
		    0 == strcasecmp(value,"true"))
		    fb_var.vmode |= FB_VMODE_DOUBLE;
	    }
	    /* ok ? */
	    if (!geometry || !timings)
		return -1;
	    /* set */
	    fb_var.xoffset = 0;
	    fb_var.yoffset = 0;
	    if (-1 == ioctl(fb,FBIOPUT_VSCREENINFO,&fb_var))
		perror("ioctl FBIOPUT_VSCREENINFO");
	    /* look what we have now ... */
	    if (-1 == ioctl(fb,FBIOGET_VSCREENINFO,&fb_var)) {
		perror("ioctl FBIOGET_VSCREENINFO");
		exit(1);
	    }
	    return 0;
	}
    }
    return -1;
}

static void
fb_setvt(int vtno)
{
    struct vt_stat vts;
    char vtname[12];
    
    if (vtno < 0) {
	if (-1 == ioctl(tty,VT_OPENQRY, &vtno) || vtno == -1) {
	    perror("ioctl VT_OPENQRY");
	    exit(1);
	}
    }

    vtno &= 0xff;
    sprintf(vtname, devices->ttynr, vtno);
    chown(vtname, getuid(), getgid());
    if (-1 == access(vtname, R_OK | W_OK)) {
	fprintf(stderr,"access %s: %s\n",vtname,strerror(errno));
	exit(1);
    }
    switch (fork()) {
    case 0:
	break;
    case -1:
	perror("fork");
	exit(1);
    default:
	exit(0);
    }
    close(tty);
    close(0);
    close(1);
    close(2);
    setsid();
    open(vtname,O_RDWR);
    dup(0);
    dup(0);

    if (-1 == ioctl(tty,VT_GETSTATE, &vts)) {
	perror("ioctl VT_GETSTATE");
	exit(1);
    }
    orig_vt_no = vts.v_active;
    if (-1 == ioctl(tty,VT_ACTIVATE, vtno)) {
	perror("ioctl VT_ACTIVATE");
	exit(1);
    }
    if (-1 == ioctl(tty,VT_WAITACTIVE, vtno)) {
	perror("ioctl VT_WAITACTIVE");
	exit(1);
    }
}

/* Hmm. radeonfb needs this. matroxfb doesn't. */
static int fb_activate_current(int tty)
{
    struct vt_stat vts;
    
    if (-1 == ioctl(tty,VT_GETSTATE, &vts)) {
	perror("ioctl VT_GETSTATE");
	return -1;
    }
    if (-1 == ioctl(tty,VT_ACTIVATE, vts.v_active)) {
	perror("ioctl VT_ACTIVATE");
	return -1;
    }
    if (-1 == ioctl(tty,VT_WAITACTIVE, vts.v_active)) {
	perror("ioctl VT_WAITACTIVE");
	return -1;
    }
    return 0;
}

int
fb_init(char *device, char *mode, int vt)
{
    char   fbdev[16];
    struct vt_stat vts;
    unsigned long page_mask;

    dev_init();
    tty = 0;
    if (vt != 0)
	fb_setvt(vt);

    if (-1 == ioctl(tty,VT_GETSTATE, &vts)) {
	fprintf(stderr,"ioctl VT_GETSTATE: %s (not a linux console?)\n",
		strerror(errno));
	exit(1);
    }
    
    if (NULL == device) {
	device = getenv("FRAMEBUFFER");
	if (NULL == device) {
	    struct fb_con2fbmap c2m;
	    memset(&c2m, 0, sizeof(c2m));
	    if (-1 == (fb = open(devices->fb0,O_RDWR /* O_WRONLY */,0))) {
		fprintf(stderr,"open %s: %s\n",devices->fb0,strerror(errno));
		exit(1);
	    }
	    c2m.console = vts.v_active;
	    if (-1 == ioctl(fb, FBIOGET_CON2FBMAP, &c2m)) {
		perror("ioctl FBIOGET_CON2FBMAP");
		exit(1);
	    }
	    close(fb);
	    fprintf(stderr,"map: vt%02d => fb%d\n",
		    c2m.console, c2m.framebuffer);
	    sprintf(fbdev,devices->fbnr,c2m.framebuffer);
	    device = fbdev;
	}
    }

    /* get current settings (which we have to restore) */
    if (-1 == (fb = open(device,O_RDWR /* O_WRONLY */))) {
	fprintf(stderr,"open %s: %s\n",device,strerror(errno));
	exit(1);
    }
    if (-1 == ioctl(fb,FBIOGET_VSCREENINFO,&fb_ovar)) {
	perror("ioctl FBIOGET_VSCREENINFO");
	exit(1);
    }
    if (-1 == ioctl(fb,FBIOGET_FSCREENINFO,&fb_fix)) {
	perror("ioctl FBIOGET_FSCREENINFO");
	exit(1);
    }
    if (fb_ovar.bits_per_pixel == 8 ||
	fb_fix.visual == FB_VISUAL_DIRECTCOLOR) {
	if (-1 == ioctl(fb,FBIOGETCMAP,&ocmap)) {
	    perror("ioctl FBIOGETCMAP");
	    exit(1);
	}
    }
    if (-1 == ioctl(tty,KDGETMODE, &kd_mode)) {
	perror("ioctl KDGETMODE");
	exit(1);
    }
    if (-1 == ioctl(tty,VT_GETMODE, &vt_omode)) {
	perror("ioctl VT_GETMODE");
	exit(1);
    }
    tcgetattr(tty, &term);
    
    /* switch mode */
    fb_setmode(mode);
    
    /* checks & initialisation */
    if (-1 == ioctl(fb,FBIOGET_FSCREENINFO,&fb_fix)) {
	perror("ioctl FBIOGET_FSCREENINFO");
	exit(1);
    }
    if (fb_fix.type != FB_TYPE_PACKED_PIXELS) {
	fprintf(stderr,"can handle only packed pixel frame buffers\n");
	goto err;
    }
#if 0
    switch (fb_var.bits_per_pixel) {
    case 8:
	white = 255; black = 0; bpp = 1;
	break;
    case 15:
    case 16:
	if (fb_var.green.length == 6)
	    white = 0xffff;
	else
	    white = 0x7fff;
	black = 0; bpp = 2;
	break;
    case 24:
	white = 0xffffff; black = 0; bpp = fb_var.bits_per_pixel/8;
	break;
    case 32:
	white = 0xffffff; black = 0; bpp = fb_var.bits_per_pixel/8;
	fb_setpixels = fb_setpixels4;
	break;
    default:
	fprintf(stderr, "Oops: %i bit/pixel ???\n",
		fb_var.bits_per_pixel);
	goto err;
    }
#endif
    page_mask = getpagesize()-1;
    fb_mem_offset = (unsigned long)(fb_fix.smem_start) & page_mask;
    fb_mem = mmap(NULL,fb_fix.smem_len+fb_mem_offset,
		  PROT_READ|PROT_WRITE,MAP_SHARED,fb,0);
    if (-1L == (long)fb_mem) {
	perror("mmap");
	goto err;
    }
    /* move viewport to upper left corner */
    if (fb_var.xoffset != 0 || fb_var.yoffset != 0) {
	fb_var.xoffset = 0;
	fb_var.yoffset = 0;
	if (-1 == ioctl(fb,FBIOPAN_DISPLAY,&fb_var)) {
	    perror("ioctl FBIOPAN_DISPLAY");
	    goto err;
	}
    }
    if (-1 == ioctl(tty,KDSETMODE, KD_GRAPHICS)) {
	perror("ioctl KDSETMODE");
	goto err;
    }
    fb_activate_current(tty);

    /* cls */
    fb_memset(fb_mem+fb_mem_offset, 0, fb_fix.line_length * fb_var.yres);
    return fb;

 err:
    fb_cleanup();
    exit(1);
}

void
fb_cleanup(void)
{
    /* restore console */
    if (-1 == ioctl(tty,KDSETMODE, kd_mode))
	perror("ioctl KDSETMODE");
    if (-1 == ioctl(fb,FBIOPUT_VSCREENINFO,&fb_ovar))
	perror("ioctl FBIOPUT_VSCREENINFO");
    if (-1 == ioctl(fb,FBIOGET_FSCREENINFO,&fb_fix))
	perror("ioctl FBIOGET_FSCREENINFO");
    if (fb_ovar.bits_per_pixel == 8 ||
	fb_fix.visual == FB_VISUAL_DIRECTCOLOR) {
	if (-1 == ioctl(fb,FBIOPUTCMAP,&ocmap))
	    perror("ioctl FBIOPUTCMAP");
    }
    close(fb);

    if (-1 == ioctl(tty,VT_SETMODE, &vt_omode))
	perror("ioctl VT_SETMODE");
    if (orig_vt_no && -1 == ioctl(tty, VT_ACTIVATE, orig_vt_no))
	perror("ioctl VT_ACTIVATE");
    if (orig_vt_no && -1 == ioctl(tty, VT_WAITACTIVE, orig_vt_no))
	perror("ioctl VT_WAITACTIVE");
    tcsetattr(tty, TCSANOW, &term);
    close(tty);
}

/* -------------------------------------------------------------------- */
/* handle fatal errors                                                  */

static jmp_buf fb_fatal_cleanup;

static void
fb_catch_exit_signal(int signal)
{
    siglongjmp(fb_fatal_cleanup,signal);
}

void
fb_catch_exit_signals(void)
{
    struct sigaction act,old;
    int termsig;

    memset(&act,0,sizeof(act));
    act.sa_handler = fb_catch_exit_signal;
    sigemptyset(&act.sa_mask);
    sigaction(SIGINT, &act,&old);
    sigaction(SIGQUIT,&act,&old);
    sigaction(SIGTERM,&act,&old);

    sigaction(SIGABRT,&act,&old);
    sigaction(SIGTSTP,&act,&old);

    sigaction(SIGBUS, &act,&old);
    sigaction(SIGILL, &act,&old);
    sigaction(SIGSEGV,&act,&old);

    if (0 == (termsig = sigsetjmp(fb_fatal_cleanup,0)))
	return;

    /* cleanup */
    fb_cleanup();
    fprintf(stderr,"Oops: %s\n",sys_siglist[termsig]);
    exit(42);
}