/*
 * Copyright 1998 by Alan Hourihane, Wigan, England.
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of Alan Hourihane not be used in
 * advertising or publicity pertaining to distribution of the software without
 * specific, written prior permission.  Alan Hourihane makes no representations
 * about the suitability of this software for any purpose.  It is provided
 * "as is" without express or implied warranty.
 *
 * ALAN HOURIHANE DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL ALAN HOURIHANE BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 *
 * Authors:  Alan Hourihane, <alanh@fairlite.demon.co.uk>
 *
 * BT RAMDAC routines.
 */

#ifdef HAVE_XORG_CONFIG_H
#include <xorg-config.h>
#endif

#include "xf86.h"
#include "xf86_OSproc.h"

#define INIT_BT_RAMDAC_INFO
#include "BTPriv.h"
#include "xf86RamDacPriv.h"

void
BTramdacRestore(ScrnInfoPtr pScrn, RamDacRecPtr ramdacPtr,
				    RamDacRegRecPtr ramdacReg)
{
	int i;

	/* Here we pass a short, so that we can evaluate a mask too */
	/* So that the mask is the high byte and the data the low byte */
	/* Just the command/status registers */
	for (i=0x06;i<0x0A;i++) 
	    (*ramdacPtr->WriteDAC)
	        (pScrn, i, (ramdacReg->DacRegs[i] & 0xFF00) >> 8, 
						ramdacReg->DacRegs[i]);
}

void
BTramdacSave(ScrnInfoPtr pScrn, RamDacRecPtr ramdacPtr, 
				 RamDacRegRecPtr ramdacReg)
{
	int i;
	
	(*ramdacPtr->ReadAddress)(pScrn, 0); /* Start at index 0 */
	for (i=0;i<768;i++)
	    ramdacReg->DAC[i] = (*ramdacPtr->ReadData)(pScrn);

	/* Just the command/status registers */
	for (i=0x06;i<0x0A;i++)
	    ramdacReg->DacRegs[i] = (*ramdacPtr->ReadDAC)(pScrn, i);
}

RamDacHelperRecPtr
BTramdacProbe(ScrnInfoPtr pScrn, RamDacSupportedInfoRecPtr ramdacs/*, RamDacRecPtr ramdacPtr*/)
{
    RamDacRecPtr ramdacPtr = RAMDACSCRPTR(pScrn);
    Bool RamDacIsSupported = FALSE;
    RamDacHelperRecPtr ramdacHelperPtr = NULL;
    int BTramdac_ID = -1;
    int i, status, cmd0;

    /* Save COMMAND Register 0 */
    cmd0 = (*ramdacPtr->ReadDAC)(pScrn, BT_COMMAND_REG_0);
    /* Ensure were going to access the STATUS Register on next read */
    (*ramdacPtr->WriteDAC)(pScrn, BT_COMMAND_REG_0, 0x7F, 0x00);

    status = (*ramdacPtr->ReadDAC)(pScrn, BT_STATUS_REG);
    switch (status) {
	case 0x40:
		BTramdac_ID = ATT20C504_RAMDAC;
		break;
	case 0xD0:
		BTramdac_ID = ATT20C505_RAMDAC;
		break;
	default:
		xf86DrvMsg(pScrn->scrnIndex, X_PROBED, 
			   "Unknown BT RAMDAC type (0x%x), assuming BT485\n",
			   status);
	case 0x80:
	case 0x90:
	case 0xA0:
	case 0xB0:
	case 0x28: 	/* This is for the DEC TGA - Questionable ? */
		BTramdac_ID = BT485_RAMDAC;
		break;
    }

    /* Restore COMMAND Register 0 */
    (*ramdacPtr->WriteDAC)(pScrn, BT_COMMAND_REG_0, 0x00, cmd0);

    if (BTramdac_ID == -1) {
        xf86DrvMsg(pScrn->scrnIndex, X_PROBED, 
		"Cannot determine BT RAMDAC type, aborting\n");
	return NULL;
    } else {
        xf86DrvMsg(pScrn->scrnIndex, X_PROBED, 
		"Attached RAMDAC is %s\n", BTramdacDeviceInfo[BTramdac_ID&0xFFFF].DeviceName);
    }

    for (i=0;ramdacs[i].token != -1;i++) {
	if (ramdacs[i].token == BTramdac_ID)
	    RamDacIsSupported = TRUE;
    }

    if (!RamDacIsSupported) {
        xf86DrvMsg(pScrn->scrnIndex, X_PROBED, 
		"This BT RAMDAC is NOT supported by this driver, aborting\n");
	return NULL;
    }

    ramdacHelperPtr = RamDacHelperCreateInfoRec();
    switch(BTramdac_ID) {
	case BT485_RAMDAC:
	    ramdacHelperPtr->SetBpp = BTramdacSetBpp;
	    break;
    }
    ramdacPtr->RamDacType = BTramdac_ID;
    ramdacHelperPtr->RamDacType = BTramdac_ID;
    ramdacHelperPtr->Save = BTramdacSave;
    ramdacHelperPtr->Restore = BTramdacRestore;
	
    return ramdacHelperPtr;
}

void
BTramdacSetBpp(ScrnInfoPtr pScrn, RamDacRegRecPtr ramdacReg)
{
    /* We need to deal with Direct Colour visuals for 8bpp and other
     * good stuff for colours */
    switch (pScrn->bitsPerPixel) {
	case 32:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x10;
	    break;
	case 24:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x10;
	    break;
	case 16:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x38;
	    break;
	case 15:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x30;
	    break;
	case 8:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x40;
	    break;
	case 4:
	    ramdacReg->DacRegs[BT_COMMAND_REG_1] = 0x60;
	    break;
    }
}