/*
        Copyright 1999, Be Incorporated.   All Rights Reserved.
        This file may be used under the terms of the Be Sample Code License.

        Other authors:
        Mark Watson;
        Rudolf Cornelissen 3/2002-1/2016.
*/

/* standard kernel driver stuff */
#include <KernelExport.h>
#include <ISA.h>
#include <PCI.h>
#include <OS.h>
#include <directories.h>
#include <driver_settings.h>
#include <malloc.h>
#include <stdlib.h> // for strtoXX
#include "AGP.h"

/* this is for the standardized portion of the driver API */
/* currently only one operation is defined: B_GET_ACCELERANT_SIGNATURE */
#include <graphic_driver.h>

/* this is for sprintf() */
#include <stdio.h>

/* this is for string compares */
#include <string.h>

/* The private interface between the accelerant and the kernel driver. */
#include "DriverInterface.h"
#include "macros.h"

#define get_pci(o, s) (*pci_bus->read_pci_config)(pcii->bus, pcii->device, pcii->function, (o), (s))
#define set_pci(o, s, v) (*pci_bus->write_pci_config)(pcii->bus, pcii->device, pcii->function, (o), (s), (v))

#define MAX_DEVICES       8

#define DEVICE_FORMAT "%04x_%04x_%02x%02x%02x" // apsed

/* Tell the kernel what revision of the driver API we support */
int32   api_version = B_CUR_DRIVER_API_VERSION; // apsed, was 2, is 2 in R5

/* these structures are private to the kernel driver */
typedef struct device_info device_info;

typedef struct {
        timer           te;                             /* timer entry for add_timer() */
        device_info     *di;                    /* pointer to the owning device */
        bigtime_t       when_target;    /* when we're supposed to wake up */
} timer_info;

struct device_info {
        uint32          is_open;                        /* a count of how many times the devices has been opened */
        area_id         shared_area;            /* the area shared between the driver and all of the accelerants */
        shared_info     *si;                            /* a pointer to the shared area, for convenience */
        vuint32         *regs;                          /* kernel's pointer to memory mapped registers */
        pci_info        pcii;                                   /* a convenience copy of the pci info for this device */
        char            name[B_OS_NAME_LENGTH]; /* where we keep the name of the device for publishing and comparing */
};

typedef struct {
        uint32          count;                          /* number of devices actually found */
        benaphore       kernel;                         /* for serializing opens/closes */
        char            *device_names[MAX_DEVICES+1];   /* device name pointer storage */
        device_info     di[MAX_DEVICES];        /* device specific stuff */
} DeviceData;

/* prototypes for our private functions */
static status_t open_hook (const char* name, uint32 flags, void** cookie);
static status_t close_hook (void* dev);
static status_t free_hook (void* dev);
static status_t read_hook (void* dev, off_t pos, void* buf, size_t* len);
static status_t write_hook (void* dev, off_t pos, const void* buf, size_t* len);
static status_t control_hook (void* dev, uint32 msg, void *buf, size_t len);
static status_t map_device(device_info *di);
static void unmap_device(device_info *di);
static void probe_devices(void);
static int32 eng_interrupt(void *data);

static DeviceData               *pd;
static isa_module_info  *isa_bus = NULL;
static pci_module_info  *pci_bus = NULL;
static agp_gart_module_info *agp_bus = NULL;
static device_hooks graphics_device_hooks = {
        open_hook,
        close_hook,
        free_hook,
        control_hook,
        read_hook,
        write_hook,
        NULL,
        NULL,
        NULL,
        NULL
};

#define VENDOR_ID_VIA   0x1106 /* Via */

static uint16 via_device_list[] = {
        0x3022, /* CLE266 Unichrome Pro (CLE3022) */
        0x3108, /* K8M800 Unichrome Pro (unknown chiptype) */
        0x3122, /* CLE266 Unichrome Pro (CLE3122) */
        0x3205, /* KM400 Unichrome (VT3205) */
//      0x3344, /* P4M800 Pro (VT3344) */
        0x7205, /* KM400 Unichrome (VT7205) */
        0
};

static struct {
        uint16  vendor;
        uint16  *devices;
} SupportedDevices[] = {
        {VENDOR_ID_VIA, via_device_list},
        {0x0000, NULL}
};

static settings current_settings = { // see comments in skel.settings
        // for driver
        DRIVER_PREFIX ".accelerant",
        false,      // dumprom
        // for accelerant
        0x00000000, // logmask
        0,          // memory
        true,       // usebios
        true,       // hardcursor
        false,          // switchhead
        false,          // force_pci
        false,          // unhide_fw
        true,           // pgm_panel
};

static void dumprom (void *rom, uint32 size)
{
        int fd;
        uint32 cnt;

        fd = open (kUserDirectory "/" DRIVER_PREFIX ".rom",
                O_WRONLY | O_CREAT, 0666);
        if (fd < 0) return;

        /* apparantly max. 32kb may be written at once;
         * the ROM size is a multiple of that anyway. */
        for (cnt = 0; (cnt < size); cnt += 32768)
                write (fd, ((void *)(((uint8 *)rom) + cnt)), 32768);
        close (fd);
}

/* return 1 if vblank interrupt has occured */
static int caused_vbi(vuint32 * regs)
{
//      return (ENG_REG32(RG32_CRTC_INTS) & 0x00000001);
return 0;
}

/* clear the vblank interrupt */
static void clear_vbi(vuint32 * regs)
{
//      ENG_REG32(RG32_CRTC_INTS) = 0x00000001;
}

static void enable_vbi(vuint32 * regs)
{
        /* clear the vblank interrupt */
//      ENG_REG32(RG32_CRTC_INTS) = 0x00000001;
        /* enable nVidia interrupt source vblank */
//      ENG_REG32(RG32_CRTC_INTE) |= 0x00000001;
        /* enable nVidia interrupt system hardware (b0-1) */
//      ENG_REG32(RG32_MAIN_INTE) = 0x00000001;
}

static void disable_vbi(vuint32 * regs)
{
        /* disable nVidia interrupt source vblank */
//      ENG_REG32(RG32_CRTC_INTE) &= 0xfffffffe;
        /* clear the vblank interrupt */
//      ENG_REG32(RG32_CRTC_INTS) = 0x00000001;
        /* disable nVidia interrupt system hardware (b0-1) */
//      ENG_REG32(RG32_MAIN_INTE) = 0x00000000;
}

/*
        init_hardware() - Returns B_OK if one is
        found, otherwise returns B_ERROR so the driver will be unloaded.
*/
status_t
init_hardware(void) {
        long            pci_index = 0;
        pci_info        pcii;
        bool            found_one = false;

        /* choke if we can't find the PCI bus */
        if (get_module(B_PCI_MODULE_NAME, (module_info **)&pci_bus) != B_OK)
                return B_ERROR;

        /* choke if we can't find the ISA bus */
        if (get_module(B_ISA_MODULE_NAME, (module_info **)&isa_bus) != B_OK)
        {
                put_module(B_PCI_MODULE_NAME);
                return B_ERROR;
        }

        /* while there are more pci devices */
        while ((*pci_bus->get_nth_pci_info)(pci_index, &pcii) == B_NO_ERROR) {
                int vendor = 0;

                /* if we match a supported vendor */
                while (SupportedDevices[vendor].vendor) {
                        if (SupportedDevices[vendor].vendor == pcii.vendor_id) {
                                uint16 *devices = SupportedDevices[vendor].devices;
                                /* while there are more supported devices */
                                while (*devices) {
                                        /* if we match a supported device */
                                        if (*devices == pcii.device_id ) {

                                                found_one = true;
                                                goto done;
                                        }
                                        /* next supported device */
                                        devices++;
                                }
                        }
                        vendor++;
                }
                /* next pci_info struct, please */
                pci_index++;
        }

done:
        /* put away the module manager */
        put_module(B_PCI_MODULE_NAME);
        return (found_one ? B_OK : B_ERROR);
}

status_t
init_driver(void) {
        void *settings_handle;

        // get driver/accelerant settings, apsed
        settings_handle  = load_driver_settings (DRIVER_PREFIX ".settings");
        if (settings_handle != NULL) {
                const char *item;
                char       *end;
                uint32      value;

                // for driver
                item = get_driver_parameter (settings_handle, "accelerant", "", "");
                if ((strlen (item) > 0) && (strlen (item) < sizeof (current_settings.accelerant) - 1)) {
                        strcpy (current_settings.accelerant, item);
                }
                current_settings.dumprom = get_driver_boolean_parameter (settings_handle, "dumprom", false, false);

                // for accelerant
                item = get_driver_parameter (settings_handle, "logmask", "0x00000000", "0x00000000");
                value = strtoul (item, &end, 0);
                if (*end == '\0') current_settings.logmask = value;

                item = get_driver_parameter (settings_handle, "memory", "0", "0");
                value = strtoul (item, &end, 0);
                if (*end == '\0') current_settings.memory = value;

                current_settings.hardcursor = get_driver_boolean_parameter (settings_handle, "hardcursor", false, false);
                current_settings.usebios = get_driver_boolean_parameter (settings_handle, "usebios", false, false);
                current_settings.switchhead = get_driver_boolean_parameter (settings_handle, "switchhead", false, false);
                current_settings.force_pci = get_driver_boolean_parameter (settings_handle, "force_pci", false, false);
                current_settings.unhide_fw = get_driver_boolean_parameter (settings_handle, "unhide_fw", false, false);
                current_settings.pgm_panel = get_driver_boolean_parameter (settings_handle, "pgm_panel", false, false);

                unload_driver_settings (settings_handle);
        }

        /* get a handle for the pci bus */
        if (get_module(B_PCI_MODULE_NAME, (module_info **)&pci_bus) != B_OK)
                return B_ERROR;

        /* get a handle for the isa bus */
        if (get_module(B_ISA_MODULE_NAME, (module_info **)&isa_bus) != B_OK)
        {
                put_module(B_PCI_MODULE_NAME);
                return B_ERROR;
        }

        /* get a handle for the agp bus if it exists */
        get_module(B_AGP_GART_MODULE_NAME, (module_info **)&agp_bus);

        /* driver private data */
        pd = (DeviceData *)calloc(1, sizeof(DeviceData));
        if (!pd) {
                if (agp_bus)
                        put_module(B_AGP_GART_MODULE_NAME);
                put_module(B_ISA_MODULE_NAME);
                put_module(B_PCI_MODULE_NAME);
                return B_ERROR;
        }
        /* initialize the benaphore */
        INIT_BEN(pd->kernel);
        /* find all of our supported devices */
        probe_devices();
        return B_OK;
}

const char **
publish_devices(void) {
        /* return the list of supported devices */
        return (const char **)pd->device_names;
}

device_hooks *
find_device(const char *name) {
        int index = 0;
        while (pd->device_names[index]) {
                if (strcmp(name, pd->device_names[index]) == 0)
                        return &graphics_device_hooks;
                index++;
        }
        return NULL;

}

void uninit_driver(void) {

        /* free the driver data */
        DELETE_BEN(pd->kernel);
        free(pd);
        pd = NULL;

        /* put the pci module away */
        put_module(B_PCI_MODULE_NAME);
        put_module(B_ISA_MODULE_NAME);

        /* put the agp module away if it's there */
        if (agp_bus)
                put_module(B_AGP_GART_MODULE_NAME);
}

static status_t map_device(device_info *di)
{
        char buffer[B_OS_NAME_LENGTH]; /*memory for device name*/
        shared_info *si = di->si;
        uint32  tmpUlong;
        pci_info *pcii = &(di->pcii);
        system_info sysinfo;

        /*storage for the physical to virtual table (used for dma buffer)*/
//      physical_entry physical_memory[2];
//      #define G400_DMA_BUFFER_SIZE 1024*1024

        /* variables for making copy of ROM */
        uint8* rom_temp;
        area_id rom_area;

        /* Nvidia cards have registers in [0] and framebuffer in [1] */
        int registers = 1;
        int frame_buffer = 0;
//      int pseudo_dma = 2;

        /* enable memory mapped IO, disable VGA I/O - this is defined in the PCI standard */
        tmpUlong = get_pci(PCI_command, 2);
        /* enable PCI access */
        tmpUlong |= PCI_command_memory;
        /* enable busmastering */
        tmpUlong |= PCI_command_master;
        /* disable ISA I/O access */
        tmpUlong &= ~PCI_command_io;
        set_pci(PCI_command, 2, tmpUlong);

        /*work out which version of BeOS is running*/
        get_system_info(&sysinfo);
        if (0)//sysinfo.kernel_build_date[0]=='J')/*FIXME - better ID version*/
        {
                si->use_clone_bugfix = 1;
        }
        else
        {
                si->use_clone_bugfix = 0;
        }

        /* work out a name for the register mapping */
        sprintf(buffer, DEVICE_FORMAT " regs",
                di->pcii.vendor_id, di->pcii.device_id,
                di->pcii.bus, di->pcii.device, di->pcii.function);

        /* get a virtual memory address for the registers*/
        si->regs_area = map_physical_memory(
                buffer,
                /* WARNING: Nvidia needs to map regs as viewed from PCI space! */
                di->pcii.u.h0.base_registers_pci[registers],
                di->pcii.u.h0.base_register_sizes[registers],
                B_ANY_KERNEL_ADDRESS,
                B_CLONEABLE_AREA | (si->use_clone_bugfix ? B_READ_AREA|B_WRITE_AREA : 0),
                (void **)&(di->regs));
        si->clone_bugfix_regs = (uint32 *) di->regs;

        /* if mapping registers to vmem failed then pass on error */
        if (si->regs_area < 0) return si->regs_area;

        /* work out a name for the ROM mapping*/
        sprintf(buffer, DEVICE_FORMAT " rom",
                di->pcii.vendor_id, di->pcii.device_id,
                di->pcii.bus, di->pcii.device, di->pcii.function);

        /* disable ROM shadowing, we want the guaranteed exact contents of the chip */
        /* warning:
         * don't touch: (confirmed) NV04, NV05, NV05-M64, NV11 all shutoff otherwise.
         * NV18, NV28 and NV34 keep working.
         * confirmed NV28 and NV34 to use upper part of shadowed ROM for scratch purposes,
         * however the actual ROM content (so the used part) is intact (confirmed). */
        //set_pci(ENCFG_ROMSHADOW, 4, 0);

        /* get ROM memory mapped base adress - this is defined in the PCI standard */
        tmpUlong = get_pci(PCI_rom_base, 4);
        if (tmpUlong)
        {
                /* ROM was assigned an adress, so enable ROM decoding - see PCI standard */
                tmpUlong |= 0x00000001;
                set_pci(PCI_rom_base, 4, tmpUlong);

                rom_area = map_physical_memory(
                        buffer,
                        di->pcii.u.h0.rom_base_pci,
                        di->pcii.u.h0.rom_size,
                        B_ANY_KERNEL_ADDRESS,
                        B_READ_AREA,
                        (void **)&(rom_temp)
                );

                /* check if we got the BIOS signature (might fail on laptops..) */
                if (rom_temp[0]!=0x55 || rom_temp[1]!=0xaa)
                {
                        /* apparantly no ROM is mapped here */
                        delete_area(rom_area);
                        rom_area = -1;
                        /* force using ISA legacy map as fall-back */
                        tmpUlong = 0x00000000;
                }
        }

        if (!tmpUlong)
        {
                /* ROM was not assigned an adress, fetch it from ISA legacy memory map! */
                rom_area = map_physical_memory(
                        buffer,
                        0x000c0000,
                        65536,
                        B_ANY_KERNEL_ADDRESS,
                        B_READ_AREA,
                        (void **)&(rom_temp)
                );
        }

        /* if mapping ROM to vmem failed then clean up and pass on error */
        if (rom_area < 0) {
                delete_area(si->regs_area);
                si->regs_area = -1;
                return rom_area;
        }

        /* dump ROM to file if selected in skel.settings
         * (ROM always fits in 64Kb: checked TNT1 - FX5950) */
        if (current_settings.dumprom) dumprom (rom_temp, 65536);
        /* make a copy of ROM for future reference */
        memcpy (si->rom_mirror, rom_temp, 65536);

        /* disable ROM decoding - this is defined in the PCI standard, and delete the area */
        tmpUlong = get_pci(PCI_rom_base, 4);
        tmpUlong &= 0xfffffffe;
        set_pci(PCI_rom_base, 4, tmpUlong);
        delete_area(rom_area);

        /* work out a name for the framebuffer mapping*/
        sprintf(buffer, DEVICE_FORMAT " framebuffer",
                di->pcii.vendor_id, di->pcii.device_id,
                di->pcii.bus, di->pcii.device, di->pcii.function);

        /* map the framebuffer into vmem, using Write Combining*/
        si->fb_area = map_physical_memory(
                buffer,
                /* WARNING: Nvidia needs to map framebuffer as viewed from PCI space! */
                di->pcii.u.h0.base_registers_pci[frame_buffer],
                di->pcii.u.h0.base_register_sizes[frame_buffer],
                B_ANY_KERNEL_BLOCK_ADDRESS | B_WRITE_COMBINING_MEMORY,
                B_READ_AREA | B_WRITE_AREA | B_CLONEABLE_AREA,
                &(si->framebuffer));

        /*if failed with write combining try again without*/
        if (si->fb_area < 0) {
                si->fb_area = map_physical_memory(
                        buffer,
                        /* WARNING: Nvidia needs to map framebuffer as viewed from PCI space! */
                        di->pcii.u.h0.base_registers_pci[frame_buffer],
                        di->pcii.u.h0.base_register_sizes[frame_buffer],
                        B_ANY_KERNEL_BLOCK_ADDRESS,
                        B_READ_AREA | B_WRITE_AREA | B_CLONEABLE_AREA,
                        &(si->framebuffer));
        }

        /* if there was an error, delete our other areas and pass on error*/
        if (si->fb_area < 0)
        {
                delete_area(si->regs_area);
                si->regs_area = -1;
                return si->fb_area;
        }
//fixme: retest for card coldstart and PCI/virt_mem mapping!!
        /* remember the DMA address of the frame buffer for BDirectWindow?? purposes */
        si->framebuffer_pci = (void *)(addr_t) di->pcii.u.h0.base_registers_pci[frame_buffer];

        // remember settings for use here and in accelerant
        si->settings = current_settings;

        /* in any case, return the result */
        return si->fb_area;
}

static void unmap_device(device_info *di) {
        shared_info *si = di->si;
        uint32  tmpUlong;
        pci_info *pcii = &(di->pcii);

        /* disable memory mapped IO */
        tmpUlong = get_pci(PCI_command, 4);
        tmpUlong &= 0xfffffffc;
        set_pci(PCI_command, 4, tmpUlong);
        /* delete the areas */
        if (si->regs_area >= 0) delete_area(si->regs_area);
        if (si->fb_area >= 0) delete_area(si->fb_area);
        si->regs_area = si->fb_area = -1;
        si->framebuffer = NULL;
        di->regs = NULL;
}

static void probe_devices(void) {
        uint32 pci_index = 0;
        uint32 count = 0;
        device_info *di = pd->di;

        /* while there are more pci devices */
        while ((count < MAX_DEVICES) && ((*pci_bus->get_nth_pci_info)(pci_index, &(di->pcii)) == B_NO_ERROR)) {
                int vendor = 0;

                /* if we match a supported vendor */
                while (SupportedDevices[vendor].vendor) {
                        if (SupportedDevices[vendor].vendor == di->pcii.vendor_id) {
                                uint16 *devices = SupportedDevices[vendor].devices;
                                /* while there are more supported devices */
                                while (*devices) {
                                        /* if we match a supported device */
                                        if (*devices == di->pcii.device_id ) {
                                                /* publish the device name */
                                                sprintf(di->name, "graphics/" DEVICE_FORMAT,
                                                        di->pcii.vendor_id, di->pcii.device_id,
                                                        di->pcii.bus, di->pcii.device, di->pcii.function);

                                                /* remember the name */
                                                pd->device_names[count] = di->name;
                                                /* mark the driver as available for R/W open */
                                                di->is_open = 0;
                                                /* mark areas as not yet created */
                                                di->shared_area = -1;
                                                /* mark pointer to shared data as invalid */
                                                di->si = NULL;
                                                /* inc pointer to device info */
                                                di++;
                                                /* inc count */
                                                count++;
                                                /* break out of these while loops */
                                                goto next_device;
                                        }
                                        /* next supported device */
                                        devices++;
                                }
                        }
                        vendor++;
                }
next_device:
                /* next pci_info struct, please */
                pci_index++;
        }
        /* propagate count */
        pd->count = count;
        /* terminate list of device names with a null pointer */
        pd->device_names[pd->count] = NULL;
}

static uint32 thread_interrupt_work(int32 *flags, vuint32 *regs, shared_info *si) {
        uint32 handled = B_HANDLED_INTERRUPT;
        /* release the vblank semaphore */
        if (si->vblank >= 0) {
                int32 blocked;
                if ((get_sem_count(si->vblank, &blocked) == B_OK) && (blocked < 0)) {
                        release_sem_etc(si->vblank, -blocked, B_DO_NOT_RESCHEDULE);
                        handled = B_INVOKE_SCHEDULER;
                }
        }
        return handled;
}

static int32
eng_interrupt(void *data)
{
        int32 handled = B_UNHANDLED_INTERRUPT;
        device_info *di = (device_info *)data;
        shared_info *si = di->si;
        int32 *flags = (int32*)&(si->flags);
        vuint32 *regs;

        /* is someone already handling an interrupt for this device? */
        if (atomic_or(flags, SKD_HANDLER_INSTALLED) & SKD_HANDLER_INSTALLED) {
                goto exit0;
        }
        /* get regs */
        regs = di->regs;

        /* was it a VBI? */
        if (caused_vbi(regs)) {
                /*clear the interrupt*/
                clear_vbi(regs);
                /*release the semaphore*/
                handled = thread_interrupt_work(flags, regs, si);
        }

        /* note that we're not in the handler any more */
        atomic_and(flags, ~SKD_HANDLER_INSTALLED);

exit0:
        return handled;
}

static status_t open_hook (const char* name, uint32 flags, void** cookie) {
        int32 index = 0;
        device_info *di;
        shared_info *si;
        thread_id       thid;
        thread_info     thinfo;
        status_t        result = B_OK;
        vuint32         *regs;
        char shared_name[B_OS_NAME_LENGTH];

        /* find the device name in the list of devices */
        /* we're never passed a name we didn't publish */
        while (pd->device_names[index] && (strcmp(name, pd->device_names[index]) != 0)) index++;

        /* for convienience */
        di = &(pd->di[index]);

        /* make sure no one else has write access to the common data */
        AQUIRE_BEN(pd->kernel);

        /* if it's already open for writing */
        if (di->is_open) {
                /* mark it open another time */
                goto mark_as_open;
        }
        /* create the shared area */
        sprintf(shared_name, DEVICE_FORMAT " shared",
                di->pcii.vendor_id, di->pcii.device_id,
                di->pcii.bus, di->pcii.device, di->pcii.function);
        /* create this area with NO user-space read or write permissions, to prevent accidental dammage */
        di->shared_area = create_area(shared_name, (void **)&(di->si), B_ANY_KERNEL_ADDRESS, ((sizeof(shared_info) + (B_PAGE_SIZE - 1)) & ~(B_PAGE_SIZE - 1)), B_FULL_LOCK,
                B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA | B_CLONEABLE_AREA);
        if (di->shared_area < 0) {
                /* return the error */
                result = di->shared_area;
                goto done;
        }

        /* save a few dereferences */
        si = di->si;

        /* save the vendor and device IDs */
        si->vendor_id = di->pcii.vendor_id;
        si->device_id = di->pcii.device_id;
        si->revision = di->pcii.revision;
        si->bus = di->pcii.bus;
        si->device = di->pcii.device;
        si->function = di->pcii.function;

        /* device at bus #0, device #0, function #0 holds byte value at byte-index 0xf6 */
        si->ps.chip_rev = ((*pci_bus->read_pci_config)(0, 0, 0, 0xf6, 1));

        /* map the device */
        result = map_device(di);
        if (result < 0) goto free_shared;
        result = B_OK;

        /* create a semaphore for vertical blank management */
        si->vblank = create_sem(0, di->name);
        if (si->vblank < 0) {
                result = si->vblank;
                goto unmap;
        }

        /* change the owner of the semaphores to the opener's team */
        /* this is required because apps can't aquire kernel semaphores */
        thid = find_thread(NULL);
        get_thread_info(thid, &thinfo);
        set_sem_owner(si->vblank, thinfo.team);

        /* assign local regs pointer for SAMPLExx() macros */
        regs = di->regs;

        /* disable and clear any pending interrupts */
        disable_vbi(regs);

        /* If there is a valid interrupt line assigned then set up interrupts */
        if ((di->pcii.u.h0.interrupt_pin == 0x00) ||
            (di->pcii.u.h0.interrupt_line == 0xff) || /* no IRQ assigned */
            (di->pcii.u.h0.interrupt_line <= 0x02))   /* system IRQ assigned */
        {
                /* we are aborting! */
                /* Note: the R4 graphics driver kit lacks this statement!! */
                result = B_ERROR;
                /* interrupt does not exist so exit without installing our handler */
                goto delete_the_sem;
        }
        else
        {
                /* otherwise install our interrupt handler */
                result = install_io_interrupt_handler(di->pcii.u.h0.interrupt_line, eng_interrupt, (void *)di, 0);
                /* bail if we couldn't install the handler */
                if (result != B_OK) goto delete_the_sem;
        }

mark_as_open:
        /* mark the device open */
        di->is_open++;

        /* send the cookie to the opener */
        *cookie = di;

        goto done;


delete_the_sem:
        delete_sem(si->vblank);

unmap:
        unmap_device(di);

free_shared:
        /* clean up our shared area */
        delete_area(di->shared_area);
        di->shared_area = -1;
        di->si = NULL;

done:
        /* end of critical section */
        RELEASE_BEN(pd->kernel);

        /* all done, return the status */
        return result;
}

/* ----------
        read_hook - does nothing, gracefully
----- */
static status_t
read_hook (void* dev, off_t pos, void* buf, size_t* len)
{
        *len = 0;
        return B_NOT_ALLOWED;
}

/* ----------
        write_hook - does nothing, gracefully
----- */
static status_t
write_hook (void* dev, off_t pos, const void* buf, size_t* len)
{
        *len = 0;
        return B_NOT_ALLOWED;
}

/* ----------
        close_hook - does nothing, gracefully
----- */
static status_t
close_hook (void* dev)
{
        /* we don't do anything on close: there might be dup'd fd */
        return B_NO_ERROR;
}

/* -----------
        free_hook - close down the device
----------- */
static status_t
free_hook (void* dev) {
        device_info *di = (device_info *)dev;
        shared_info     *si = di->si;
        vuint32 *regs = di->regs;

        /* lock the driver */
        AQUIRE_BEN(pd->kernel);

        /* if opened multiple times, decrement the open count and exit */
        if (di->is_open > 1)
                goto unlock_and_exit;

        /* disable and clear any pending interrupts */
        disable_vbi(regs);

        /* remove interrupt handler */
        remove_io_interrupt_handler(di->pcii.u.h0.interrupt_line, eng_interrupt, di);

        /* delete the semaphores, ignoring any errors ('cause the owning team may have died on us) */
        delete_sem(si->vblank);
        si->vblank = -1;

        /* free regs and framebuffer areas */
        unmap_device(di);

        /* clean up our shared area */
        delete_area(di->shared_area);
        di->shared_area = -1;
        di->si = NULL;

unlock_and_exit:
        /* mark the device available */
        di->is_open--;
        /* unlock the driver */
        RELEASE_BEN(pd->kernel);
        /* all done */
        return B_OK;
}

/* -----------
        control_hook - where the real work is done
----------- */
static status_t
control_hook (void* dev, uint32 msg, void *buf, size_t len) {
        device_info *di = (device_info *)dev;
        status_t result = B_DEV_INVALID_IOCTL;
        uint32 tmpUlong;

        switch (msg) {
                /* the only PUBLIC ioctl */
                case B_GET_ACCELERANT_SIGNATURE: {
                        char *sig = (char *)buf;
                        strcpy(sig, current_settings.accelerant);
                        result = B_OK;
                } break;

                /* PRIVATE ioctl from here on */
                case ENG_GET_PRIVATE_DATA: {
                        eng_get_private_data *gpd = (eng_get_private_data *)buf;
                        if (gpd->magic == VIA_PRIVATE_DATA_MAGIC) {
                                gpd->shared_info_area = di->shared_area;
                                result = B_OK;
                        }
                } break;
                case ENG_GET_PCI: {
                        eng_get_set_pci *gsp = (eng_get_set_pci *)buf;
                        if (gsp->magic == VIA_PRIVATE_DATA_MAGIC) {
                                pci_info *pcii = &(di->pcii);
                                gsp->value = get_pci(gsp->offset, gsp->size);
                                result = B_OK;
                        }
                } break;
                case ENG_SET_PCI: {
                        eng_get_set_pci *gsp = (eng_get_set_pci *)buf;
                        if (gsp->magic == VIA_PRIVATE_DATA_MAGIC) {
                                pci_info *pcii = &(di->pcii);
                                set_pci(gsp->offset, gsp->size, gsp->value);
                                result = B_OK;
                        }
                } break;
                case ENG_DEVICE_NAME: { // apsed
                        eng_device_name *dn = (eng_device_name *)buf;
                        if (dn->magic == VIA_PRIVATE_DATA_MAGIC) {
                                strcpy(dn->name, di->name);
                                result = B_OK;
                        }
                } break;
                case ENG_RUN_INTERRUPTS: {
                        eng_set_bool_state *ri = (eng_set_bool_state *)buf;
                        if (ri->magic == VIA_PRIVATE_DATA_MAGIC) {
                                vuint32 *regs = di->regs;
                                if (ri->do_it) {
                                        enable_vbi(regs);
                                } else {
                                        disable_vbi(regs);
                                }
                                result = B_OK;
                        }
                } break;
                case ENG_GET_NTH_AGP_INFO: {
                        eng_nth_agp_info *nai = (eng_nth_agp_info *)buf;
                        if (nai->magic == VIA_PRIVATE_DATA_MAGIC) {
                                nai->exist = false;
                                nai->agp_bus = false;
                                if (agp_bus) {
                                        nai->agp_bus = true;
                                        if ((*agp_bus->get_nth_agp_info)(nai->index, &(nai->agpi)) == B_NO_ERROR) {
                                                nai->exist = true;
                                        }
                                }
                                result = B_OK;
                        }
                } break;
                case ENG_ENABLE_AGP: {
                        eng_cmd_agp *nca = (eng_cmd_agp *)buf;
                        if (nca->magic == VIA_PRIVATE_DATA_MAGIC) {
                                if (agp_bus) {
                                        nca->agp_bus = true;
                                        nca->cmd = agp_bus->set_agp_mode(nca->cmd);
                                } else {
                                        nca->agp_bus = false;
                                        nca->cmd = 0;
                                }
                                result = B_OK;
                        }
                } break;
                case ENG_ISA_OUT: {
                        eng_in_out_isa *io_isa = (eng_in_out_isa *)buf;
                        if (io_isa->magic == VIA_PRIVATE_DATA_MAGIC) {
                                pci_info *pcii = &(di->pcii);

                                /* lock the driver:
                                 * no other graphics card may have ISA I/O enabled when we enter */
                                AQUIRE_BEN(pd->kernel);

                                /* enable ISA I/O access */
                                tmpUlong = get_pci(PCI_command, 2);
                                tmpUlong |= PCI_command_io;
                                set_pci(PCI_command, 2, tmpUlong);

                                if (io_isa->size == 1)
                                        isa_bus->write_io_8(io_isa->adress, (uint8)io_isa->data);
                                else
                                        isa_bus->write_io_16(io_isa->adress, io_isa->data);
                                result = B_OK;

                                /* disable ISA I/O access */
                                tmpUlong = get_pci(PCI_command, 2);
                                tmpUlong &= ~PCI_command_io;
                                set_pci(PCI_command, 2, tmpUlong);

                                /* end of critical section */
                                RELEASE_BEN(pd->kernel);
                        }
                } break;
                case ENG_ISA_IN: {
                        eng_in_out_isa *io_isa = (eng_in_out_isa *)buf;
                        if (io_isa->magic == VIA_PRIVATE_DATA_MAGIC) {
                                pci_info *pcii = &(di->pcii);

                                /* lock the driver:
                                 * no other graphics card may have ISA I/O enabled when we enter */
                                AQUIRE_BEN(pd->kernel);

                                /* enable ISA I/O access */
                                tmpUlong = get_pci(PCI_command, 2);
                                tmpUlong |= PCI_command_io;
                                set_pci(PCI_command, 2, tmpUlong);

                                if (io_isa->size == 1)
                                        io_isa->data = isa_bus->read_io_8(io_isa->adress);
                                else
                                        io_isa->data = isa_bus->read_io_16(io_isa->adress);
                                result = B_OK;

                                /* disable ISA I/O access */
                                tmpUlong = get_pci(PCI_command, 2);
                                tmpUlong &= ~PCI_command_io;
                                set_pci(PCI_command, 2, tmpUlong);

                                /* end of critical section */
                                RELEASE_BEN(pd->kernel);
                        }
                } break;
        }
        return result;
}