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//=============================================================================

//

//      ps2kbdmou_ecos.c

//

//      eCos support for a PS/2 keyboard and mouse.

//

//=============================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//=============================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    bartv

// Date:         2002-04-04

// Purpose:      Implement basic keyboard and mouse support for microwindows

//               only, interacting directly with the hardware.

//

//####DESCRIPTIONEND####

//=============================================================================

#include <pkgconf/system.h>

#include <cyg/infra/cyg_ass.h>

#include <cyg/infra/diag.h>

#include <cyg/hal/hal_io.h>

#include <cyg/hal/hal_intr.h>

#include <cyg/hal/drv_api.h>

#include <cyg/kernel/kapi.h>

#include <microwin/device.h>

#ifdef CYGPKG_KERNEL

# include <cyg/kernel/kapi.h>

#endif

// ----------------------------------------------------------------------------

// Configuration options. For now local to this file.

#define CYGDBG_DEVS_PS2KBDMOUSE_VERBOSE         1

#ifdef CYGDBG_DEVS_PS2KBDMOUSE_VERBOSE

# define DBG(format, args...)       diag_printf(format, ## args)

#else

# define DBG(format, args...)

#endif

// ----------------------------------------------------------------------------

// The hardware.

//

// On PC's with PS/2 hardware both the mouse and the keyboard are

// handled through a single keyboard controller chip. There are four

// registers: status, control, input and output. There are also 8-bit

// input and output ports which can be manipulated by writing certain

// control messages. The registers are accessed via the I/O bus.

//

// Output means keyboard controller -> cpu.

// Input means cpu -> keyboard controller.

//

// So you need to do a HAL_READ_UINT() to the output register,

// and a HAL_WRITE_UINT8 to the input register. They are actually

// at the same address...

//

// The following information was extracted from "The Indispensable

// PC Hardware Book" by Messmer, third edition, chapter 34. 

#define KC_OUTPUT       0x060

#define KC_INPUT        0x060

#define KC_CONTROL      0x064

#define KC_STATUS       0x064

// Bits in the status register.

#define KC_STATUS_PARE  (0x01 << 7)

#define KC_STATUS_TIM   (0x01 << 6)

#define KC_STATUS_AUXB  (0x01 << 5)

#define KC_STATUS_KEYL  (0x01 << 4)

#define KC_STATUS_CD    (0x01 << 3)

#define KC_STATUS_SYSF  (0x01 << 2)

#define KC_STATUS_INPB  (0x01 << 1)

#define KC_STATUS_OUTB  (0x01 << 0)

// Commands that can be written to the control register,

// plus for some the results that would come back.

#define KC_CONTROL_NULL                 -1

#define KC_CONTROL_DISABLE_AUX          0x00A7

#define KC_CONTROL_ENABLE_AUX           0x00A8

#define KC_CONTROL_CHECK_AUX            0x00A9

#define KC_CONTROL_CHECK_AUX_OK             0x000

#define KC_CONTROL_CHECK_AUX_CLOCK_LOW      0x001

#define KC_CONTROL_CHECK_AUX_CLOCK_HIGH     0x002

#define KC_CONTROL_CHECK_AUX_DATA_LOW       0x003

#define KC_CONTROL_CHECK_AUX_DATA_HIGH      0x004

#define KC_CONTROL_CHECK_AUX_NONE           0x0FF

#define KC_CONTROL_SELF_TEST            0x00AA

#define KC_CONTROL_SELF_TEST_OK             0x055

#define KC_CONTROL_CHECK_KBD            0x00AB

#define KC_CONTROL_CHECK_KBD_OK             0x000

#define KC_CONTROL_CHECK_KBD_CLOCK_LOW      0x001

#define KC_CONTROL_CHECK_KBD_CLOCK_HIGH     0x002

#define KC_CONTROL_CHECK_KBD_DATA_LOW       0x003

#define KC_CONTROL_CHECK_KBD_DATA_HIGH      0x004

#define KC_CONTROL_CHECK_KBD_ERROR          0x0FF

#define KC_CONTROL_DISABLE_KBD          0x00AD

#define KC_CONTROL_ENABLE_KBD           0x00AE

#define KC_CONTROL_READ_INPUT_PORT      0x00C0

#define KC_CONTROL_READ_INPUT_PORT_LOW  0x00C1

#define KC_CONTROL_READ_INPUT_PORT_HIGH 0x00C2

#define KC_CONTROL_READ_OUTPUT_PORT     0x00D0

#define KC_CONTROL_WRITE_OUTPUT_PORT    0x00D1

#define KC_CONTROL_WRITE_KBD_OUTPUT     0x00D2

#define KC_CONTROL_WRITE_AUX_OUTPUT     0x00D3

#define KC_CONTROL_WRITE_AUX            0x00D4

#define KC_CONTROL_READ_TEST_INPUT      0x00E0

#define KC_CONTROL_PULSE                0x00F0

// Additional commands, not from the book...

#define KC_CONTROL_READ_MODE            0x0020

#define KC_CONTROL_WRITE_MODE           0x0060

#define KC_MODE_KBD_INT                 (0x01 << 0)

#define KC_MODE_MOU_INT                 (0x01 << 1)

#define KC_MODE_SYS                     (0x01 << 2)

#define KC_MODE_NO_KEYLOCK              (0x01 << 3)

#define KC_MODE_DISABLE_KBD             (0x01 << 4)

#define KC_MODE_ENABLE_KBD              (0x01 << 5)

#define KC_MODE_KCC                     (0x01 << 6)

#define KC_MODE_RFU                     (0x01 << 7)

// The input port

#define KC_INPUT_LOCK       (0x01 << 7)

#define KC_INPUT_CM         (0x01 << 6)

#define KC_INPUT_CM_MONO    (0x01 << 6)

#define KC_INPUT_CM_COLOR   (0x00 << 6)

#define KC_INPUT_CM_COLOUR  (0x00 << 6)

#define KC_INPUT_AUX        (0x01 << 1)

#define KC_INPUT_KBD        (0x01 << 0)

// And the output port

#define KC_OUTPUT_KBDO      (0x01 << 7)

#define KC_OUTPUT_KCLK      (0x01 << 6)

#define KC_OUTPUT_AUXB      (0x01 << 5)

#define KC_OUTPUT_OUTB      (0x01 << 4)

#define KC_OUTPUT_ACLK      (0x01 << 3)

#define KC_OUTPUT_AXDO      (0x01 << 2)

#define KC_OUTPUT_GA20      (0x01 << 1)

#define KC_OUTPUT_SYSR      (0x01 << 0)

// Data from the keyboard

#define KC_KBD_OVERFLOW     0x000

#define KC_KBD_KEY_ERROR    0x0FF

#define KC_KBD_MFII_ID      0x0041AB

#define KC_KBD_BAT_COMPLETE 0x0AA

#define KC_KBD_ECHO         0x0EE

#define KC_KBD_ACK          0x0FA

#define KC_KBD_BAT_ERROR    0x0FC

#define KC_KBD_RESEND       0x0FE

#define KC_KBD_SCANCODE_MIN 0x001

// Likely to be incorrect for some modern keyboards

#define KC_KBD_SCANCODE_MAX 0x058

// Commands that can be sent to the keyboard. These

// are just written to the input register. Some of

// them will be followed by additional data.

#define KC_KBDC_LED_ONOFF           0x0ED

#define KC_KBDC_ECHO                0x0EE

#define KC_KBDC_SETSCAN             0x0F0

#define KC_KBDC_IDENTIFY            0x0F2

#define KC_KBDC_SETREPEAT           0x0F3

#define KC_KBDC_ENABLE              0x0F4

#define KC_KBDC_STANDARD_DISABLE    0x0F5

#define KC_KBDC_STANDARD_ENABLE     0x0F6

#define KC_KBDC_RESEND              0x0FE

#define KC_KBDC_RESET               0x0FF

// And commands that can be sent to the mouse. These

// involve a controller write followed by another

// write to the input register.

#define KC_MOUSEC_RESET_SCALING     0x0E6

#define KC_MOUSEC_SET_SCALING       0x0E7

#define KC_MOUSEC_SET_RESOLUTION    0x0E8

#define KC_MOUSEC_STATUS            0x0E9

#define KC_MOUSEC_SET_STREAM_MODE   0x0EA

#define KC_MOUSEC_READ_DATA         0x0EB

#define KC_MOUSEC_RESET_WRAP_MODE   0x0EC

#define KC_MOUSEC_SET_WRAP_MODE     0x0EE

#define KC_MOUSEC_SET_REMOTE_MODE   0x0F0

#define KC_MOUSEC_IDENTIFY          0x0F2

#define KC_MOUSEC_SET_SAMPLE_RATE   0x0F3

#define KC_MOUSEC_ENABLE            0x0F4

#define KC_MOUSEC_DISABLE           0x0F5

#define KC_MOUSEC_SET_STANDARD      0x0F6

#define KC_MOUSEC_RESEND            0x0FE

#define KC_MOUSEC_RESET             0x0FF

// Data back from the mouse. Some special characters.

#define KC_MOUSE_ACK                0x0FA

#define KC_MOUSE_RESEND             0x0FE

// ----------------------------------------------------------------------------

// The low-level stuff. Managing the PS/2 hardware is actually quite

// messy if you want a robust implementation because of the various

// ack's, resend requests, etc.

// The keyboard device. The interrupt handler is responsible for storing

// key press and release events in a circular buffer. The poll and read code

// will then try to convert these events into something closer to what

// microwindows expects. There is an assumption that the poll() and read()

// code will be called often enough that there is no risk of overflow.

// A circular buffer of scancodes.

#define PS2KBD_SCANCODE_BUFSIZE    64

static unsigned char    ps2kbd_scancode_buffer[PS2KBD_SCANCODE_BUFSIZE];

static volatile int     ps2kbd_scancode_buffer_head = 0;    // new data written here

static volatile int     ps2kbd_scancode_buffer_tail = 0;    // old data extracted from here

// The current mouse state. Just maintain the current X and Y deltas,

// button state,, and a delta flag. The hardware will generate

// eight-byte mouse data packets, and when a complete packet has been

// received the interrupt handler will update the values and set the

// delta flag.

#define PS2MOU_DATA_BUFSIZE 12

static MWCOORD          ps2mou_dx       = 0;

static MWCOORD          ps2mou_dy       = 0;

static int              ps2mou_buttons  = 0;

static volatile int     ps2mou_changed  = 0;

static unsigned char    ps2mou_buffer[PS2MOU_DATA_BUFSIZE];

static int              ps2mou_buffer_index = 0;

// Sending commands. In theory there are a number of variations of

// these.

//

// 1) commands to be sent directly to the controller. The control byte

//    goes to KC_CONTROL, and any additional bytes go to KC_INPUT.

//    The hardware will either ACK the additional bytes or request

//    a resend.  Any replies can be read from KC_OUTPUT, and errors

//    are possible.

//

//    For replies, it is not clear how to distinguish between keyboard

//    events that happen at just the wrong moment and the reply data.

//

// 2) commands for the keyboard. These just get written directly to

//    the input buffer, one character at a time with ACKs or resends

//    in between.

//

// 3) commands for the mouse. These involve a write of 0xD4 to the

//    control port followed by a write to the input buffer. The latter

//    results in ACKs or resends.

static unsigned char*   ps2_command             = NULL;

static int              ps2_command_mouse       = 0;

static int              ps2_command_index       = 0;

static int              ps2_command_length      = 0;

static volatile int     ps2_command_ack         = 0;

static int              ps2_command_mouse_waiting_for_ack   = 0;

// ----------------------------------------------------------------------------

// Decoding of mouse packets. There are lots of different rodent or

// rodent-like devices out there, all implementing subtly different

// protocols. A general-purpose solution would try to cope with all

// of them. The eCos approach would be to allow just one to be

// configured statically.

// Support for Synaptics touchpads and compatible. This assumes

// default relative format. Byte 0 contains various flags and

// the button state. Byte 1 contains X-offset, byte 2 contains

// the y-offset.

static int              ps2mou_packet_size  = 3;

static void

ps2mou_synaptics_translate(void)

{

    int new_buttons = 0;

    int dx, dy;

    // The packet consists of six bytes. Bit 3 of the first packet

    // should be set. If that condition is not satisfied then we

    // are in trouble and we may need to perform some sort of reset.

    if (0 == (ps2mou_buffer[0] & 0x08)) {

        // FIXME: perform some sort of reset to get the world

        // back in sync.

        return;

    }

    // Byte 0 holds the button flags.

    if (0 != (ps2mou_buffer[0] & (0x01 << 0))) {

        new_buttons = MWBUTTON_L;

    }

    if (0 != (ps2mou_buffer[0] & (0x01 << 1))) {

        new_buttons |= MWBUTTON_R;

    }

    ps2mou_buttons  = new_buttons;

    dx = ps2mou_buffer[1];

    if (0 != (ps2mou_buffer[0] & (0x001 << 4))) {

        // Negative number.

        if (0 != (ps2mou_buffer[0] & (0x01 << 6))) {

            // -ve overflow

            dx = -256;

        } else {

            dx = 0 - (256 - dx);

        }

    } else if (0 != (ps2mou_buffer[0] & (0x01 << 6))) {

        // +ve overflow

        dx = 256;

    }

    ps2mou_dx += dx;

    dy = ps2mou_buffer[2];

    if (0 != (ps2mou_buffer[0] & (0x01 << 5))) {

        // Negative number.

        if (0 != (ps2mou_buffer[0] & (0x01 << 7))) {

            // -ve overflow

            dy = -256;

        } else {

            // -ve signed, bottom byte only

            dy = 0 - (256 - dy);

        }

    } else if (0 != (ps2mou_buffer[0] & (0x01 << 7))) {

        // +ve overflow

        dy = 256;

    }

    ps2mou_dy += dy;

    ps2mou_changed      = 1;

}

// Mouse data. A PS/2 mouse sends events in the form of

// eight-byte packets. Some of the fields are officially

// reserved and ignored for now.

#define KC_MOUSE_DATA_FLAGS         0x00

#define KC_MOUSE_DATA_FLAGS_YOV     (0x01 << 7)

#define KC_MOUSE_DATA_FLAGS_XOV     (0x01 << 6)

#define KC_MOUSE_DATA_FLAGS_YNG     (0x01 << 5)

#define KC_MOUSE_DATA_FLAGS_XNG     (0x01 << 4)

#define KC_MOUSE_DATA_FLAGS_RIG     (0x01 << 1)

#define KC_MOUSE_DATA_FLAGS_LEF     (0x01 << 0)

#define KC_MOUSE_DATA_X             0x02

#define KC_MOUSE_DATA_Y             0x04

#define KC_MOUSE_DATA_SIZE          0x08

// ----------------------------------------------------------------------------

// An interrupt has occurred. Usually this means that there is data

// in the output register, although errors are possible as well. The

// data can be keyboard scancodes, parts of a mouse packet, or

// replies to control messages.

//

// For now errors are ignored, including parity and timeout errors. In

// theory these are supposed to be handled by requesting a resend. In

// practice that seems to cause as many complications as it might

// solve. For example what should happen if there is already a command

// being sent?

//

// The controller interrupts at two separate vectors, one for keyboard

// and another for mouse. If nested interrupts are enabled this could

// cause problems with nested calls to ps2_isr() updating the global

// data in the wrong order. It may be necessary to have a volatile flag

// to detect nesting, accompanied by an early acknowledge and return to

// the interrupted interrupt handler.

static cyg_uint32

ps2_isr(cyg_vector_t isr_vector, cyg_addrword_t isr_data)

{

    int             status;

    unsigned char   data;

    CYG_UNUSED_PARAM(cyg_addrword_t, isr_data);

    HAL_READ_UINT8(KC_STATUS, status);

    while (status & KC_STATUS_OUTB) {

        HAL_READ_UINT8(KC_OUTPUT, data);

        if (status & KC_STATUS_AUXB) {

            // Data from the mouse. This will be either an ACK for a

            // command, a resend request, or a byte for the current

            // packet. When a complete 8-byte packet has been received

            // it can be processed. When an ACK is received the next

            // byte for the current command should get sent, or on

            // completion the sending code can be woken up.

            //

            // The mouse can also send back other data, e.g. in response

            // to a determine-status request. These are disallowed

            // because there is no obvious way of separating out such

            // data from a current mouse packet being transferred.

            //

            // There may also be special bytes sent for disconnect and

            // reconnect. It is not clear how to distinguish those

            // from packet data either.

            if (ps2_command_mouse_waiting_for_ack && ((KC_MOUSE_ACK == data) || (KC_MOUSE_RESEND == data))) {

                int tmp;

                if (KC_MOUSE_ACK == data) {

                    // Is there another byte to be sent?

                    ps2_command_index++;

                    if (ps2_command_index < ps2_command_length) {

                        // Send the next byte for the current command

                        do {

                            HAL_READ_UINT8(KC_STATUS, tmp);

                        } while (tmp & KC_STATUS_INPB);

                        HAL_WRITE_UINT8(KC_CONTROL, KC_CONTROL_WRITE_AUX);

                        do {

                            HAL_READ_UINT8(KC_STATUS, tmp);

                        } while (tmp & KC_STATUS_INPB);

                        HAL_WRITE_UINT8(KC_INPUT, ps2_command[ps2_command_index]);

                    } else {

                        // The whole command has been sent and acknowledged.

                        // Allow the polling thread to resume.

                        ps2_command_index   = 0;

                        ps2_command_length  = 0;

                        ps2_command         = NULL;

                        ps2_command_ack     = 1;

                        ps2_command_mouse_waiting_for_ack = 0;

                    }

                } else {

                    // A resend request for the current byte.

                    do {

                        HAL_READ_UINT8(KC_STATUS, tmp);

                    } while (tmp & KC_STATUS_INPB);

                    HAL_WRITE_UINT8(KC_CONTROL, KC_CONTROL_WRITE_AUX);

                    do {

                        HAL_READ_UINT8(KC_STATUS, tmp);

                    } while (tmp & KC_STATUS_INPB);

                    HAL_WRITE_UINT8(KC_INPUT, ps2_command[ps2_command_index]);

                }

            } else {

                ps2mou_buffer[ps2mou_buffer_index++] = data;

                if (ps2mou_packet_size == ps2mou_buffer_index) {

                    // A complete packet has been received.

                    ps2mou_synaptics_translate();

                    ps2mou_buffer_index = 0;    // Ready for the next packet

                }

            }

        } else {

            // Data from the keyboard. Usually this will be a scancode.

            // There are a number of other possibilities such as

            // echo replies, resend requests, and acks.

            if ((KC_KBD_ACK == data) && (NULL != ps2_command) && !ps2_command_mouse_waiting_for_ack) {

                // Send the next byte for the current command, or

                // else we have completed.

                ps2_command_index++;

                if (ps2_command_index < ps2_command_length) {

                    int tmp;

                    do {

                        HAL_READ_UINT8(KC_STATUS, tmp);

                    } while (tmp & KC_STATUS_INPB);

                    HAL_WRITE_UINT8(KC_INPUT, ps2_command[ps2_command_index]);

                } else {

                    ps2_command_index   = 0;

                    ps2_command_length  = 0;

                    ps2_command         = NULL;

                    ps2_command_ack     = 1;

                }

            } else if ((KC_KBD_RESEND == data) && (NULL != ps2_command) && !ps2_command_mouse_waiting_for_ack) {

                int tmp;

                do {

                    HAL_READ_UINT8(KC_STATUS, tmp);

                } while (tmp & KC_STATUS_INPB);

                HAL_WRITE_UINT8(KC_INPUT, ps2_command[ps2_command_index]);

            } else {

                if (((ps2kbd_scancode_buffer_head + 1) % PS2KBD_SCANCODE_BUFSIZE) == ps2kbd_scancode_buffer_tail) {

                    // Already full. The data has to be discarded.

                } else {

                    ps2kbd_scancode_buffer[ps2kbd_scancode_buffer_head] = data;

                    ps2kbd_scancode_buffer_head = (ps2kbd_scancode_buffer_head + 1) % PS2KBD_SCANCODE_BUFSIZE;

                }

            }

        }

        // Just in case the keyboard controller is fast enough to send another byte,

        // go around again.

        HAL_READ_UINT8(KC_STATUS, status);

    }

    // The interrupt has been fully handled. For now there is no point

    // in running a DSR.

    cyg_drv_interrupt_acknowledge(isr_vector);

    return CYG_ISR_HANDLED;

}

// For now the DSR does nothing. 

static void

ps2_dsr(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)

{

    CYG_UNUSED_PARAM(cyg_vector_t, vector);

    CYG_UNUSED_PARAM(cyg_ucount32, count);

    CYG_UNUSED_PARAM(cyg_addrword_t, data);

}

// Sending out a command. The controller command, if any, gets sent here.

// This is followed by the first byte for the keyboard or mouse. The

// remaining bytes and any retransmits will be handled by the interrupt

// handler.

static void

ps2_send_command(int controller_command, unsigned char* command, int length, int mouse)

{

    int     status;

    CYG_PRECONDITION(NULL == ps2_command, "Only one send command is allowed at a time");

    CYG_PRECONDITION((KC_CONTROL_NULL != controller_command) || (NULL != command), "no-op");

    CYG_PRECONDITION(!mouse || (KC_CONTROL_NULL == controller_command), "cannot combine controller and mouse commands");

    ps2_command         = command;

    ps2_command_index   = 0;

    ps2_command_length  = length;

    ps2_command_mouse   = 0;

    ps2_command_ack     = 0;

    if (KC_CONTROL_NULL != controller_command) {

        do {

            HAL_READ_UINT8(KC_STATUS, status);

        } while (status & KC_STATUS_INPB);

        HAL_WRITE_UINT8(KC_CONTROL, controller_command);

    }

    if (length > 0) {

        if (mouse) {

            do {

                HAL_READ_UINT8(KC_STATUS, status);

            } while (status & KC_STATUS_INPB);

            HAL_WRITE_UINT8(KC_CONTROL, KC_CONTROL_WRITE_AUX);

        }

        do {

            HAL_READ_UINT8(KC_STATUS, status);

        } while (status & KC_STATUS_INPB);

        HAL_WRITE_UINT8(KC_INPUT, command[0]);

    }

}

// For now there is little difference between polled and non-polled

// mode, they both just spin until the ACK byte is received. The

// polled version just calls the interrupt handler as well. This is

// probably acceptable for now because commands only get sent during

// initialization, but eventually the non-polled version should be

// using a synch primitive signalled by the dsr.

//

// ACKs are only generated when there is data to be sent, not for

// operations on the control register.

//

// For keyboard commands there is no real problem because the ACK

// character 0xFA does not match a valid scancode. For the mouse

// things are more difficult because 0xFA could be present in the

// data, e.g. as a fairly large movement. Therefore the interrupt

// handler needs to know whether or not a mouse ACK is expected.

// It is assumed that the ACK and any actual 0xFA data get sent

// within a byte of each other so that the 0xFA still ends up in

// the right place in the buffer.

//

// A couple of commands do not result in an ACK. For the mouse this

// includes reset-wrap-mode and reset. For the keyboard this includes

// echo. These commands are not currently used, so there is no need

// to worry about the special cases.

static void

ps2_send_command_poll(int controller_command, unsigned char* command, int length, int mouse)

{

    if ((NULL != command) && mouse) {

        ps2_command_mouse_waiting_for_ack = 1;

    }

    ps2_send_command(controller_command, command, length, mouse);

    if (NULL != command) {

        for ( ; !ps2_command_ack; ) {

            ps2_isr( CYGNUM_HAL_INTERRUPT_KEYBOARD, 0);

        }

        ps2_command_ack = 0;

    }

}

static void

ps2_send_command_wait(int controller_command, unsigned char* command, int length, int mouse)

{

    if ((NULL != command) && mouse) {

        ps2_command_mouse_waiting_for_ack = 1;

    }

    ps2_send_command(controller_command, command, length, mouse);

    if (NULL != command) {

        for ( ; !ps2_command_ack; )

            ;

        ps2_command_ack = 0;

    }

}

// ----------------------------------------------------------------------------

// Hardware initialization and the interrupt handling.

static cyg_handle_t     ps2kbd_interrupt_handle;

static cyg_interrupt    ps2kbd_interrupt_data;

static cyg_handle_t     ps2mouse_interrupt_handle;

static cyg_interrupt    ps2mouse_interrupt_data;

static void

ps2_initialize(void)

{

    unsigned char   buf[2];

    int             status, data;

    // Only perform initialization once, not for both kbd and mouse.

    static int  initialized = 0;

    if (initialized) {

        return;

    }

    initialized++;

    // Start by masking out the interrupts. Other code such as the HAL

    // or RedBoot may think it currently owns the keyboard, and I do

    // not want any interference from them while setting up the

    // interrupt handlers.

    cyg_drv_interrupt_mask_intunsafe(CYGNUM_HAL_INTERRUPT_KEYBOARD);

    cyg_drv_interrupt_mask_intunsafe(CYGNUM_HAL_INTERRUPT_IRQ12);

    // Install my own interrupt handler, overwriting anything that might

    // be there already.

    cyg_drv_interrupt_create(CYGNUM_HAL_INTERRUPT_KEYBOARD, 0, 0,

                             &ps2_isr, &ps2_dsr, &ps2kbd_interrupt_handle, &ps2kbd_interrupt_data);

    cyg_drv_interrupt_attach(ps2kbd_interrupt_handle);

    cyg_drv_interrupt_create(CYGNUM_HAL_INTERRUPT_IRQ12, 0, 0,

                             &ps2_isr, &ps2_dsr, &ps2mouse_interrupt_handle, &ps2mouse_interrupt_data);

    cyg_drv_interrupt_attach(ps2mouse_interrupt_handle);

    // Get the device into a known state.

    ps2_send_command(KC_CONTROL_DISABLE_AUX, NULL, 0, 0);

    ps2_send_command(KC_CONTROL_DISABLE_KBD, NULL, 0, 0);

    // Discard any current data.

    HAL_READ_UINT8(KC_STATUS, status);

    while (status & KC_STATUS_OUTB) {

        HAL_READ_UINT8(KC_OUTPUT, data);

        HAL_READ_UINT8(KC_STATUS, status);

    }

    // Now restart and reset the keyboard.

    ps2_send_command(KC_CONTROL_ENABLE_KBD, NULL, 0, 0);

    buf[0] = KC_KBDC_STANDARD_DISABLE;

    ps2_send_command_poll(KC_CONTROL_NULL, buf, 1, 0);

    buf[0] = KC_KBDC_LED_ONOFF;

    buf[1] = 0;

    ps2_send_command_poll(KC_CONTROL_NULL, buf, 2, 0);

    // The keyboard-specific initialization can now reenable the keyboard

    // using enable

    // Similarly for a mouse

    // Standard mode means 100 samples/s, 1:1 scaling, stream mode, 4 counts/mm resolution,

    // and transferdisabled. Stream mode is important, that means mouse data will

    // be immediately available rather than requiring separate control messages to

    // read a packet.

    ps2_send_command(KC_CONTROL_ENABLE_AUX, NULL, 0, 0);

    buf[0] = KC_MOUSEC_SET_STANDARD;

    ps2_send_command_poll(KC_CONTROL_NULL, buf, 1, 1);

    buf[0] = KC_MOUSEC_SET_SAMPLE_RATE;

    buf[1] = 0x0A;

    ps2_send_command_poll(KC_CONTROL_NULL, buf, 2, 1);

    // WRITE_MODE does not appear to involve an ACK

    ps2_send_command_poll(KC_CONTROL_WRITE_MODE, NULL, 0, 0);

    do {

        HAL_READ_UINT8(KC_STATUS, status);

    } while (status & KC_STATUS_INPB);

    HAL_WRITE_UINT8(KC_INPUT, KC_MODE_KBD_INT | KC_MODE_MOU_INT | KC_MODE_SYS | KC_MODE_KCC);

    cyg_drv_interrupt_unmask_intunsafe(CYGNUM_HAL_INTERRUPT_KEYBOARD);

    cyg_drv_interrupt_unmask_intunsafe(CYGNUM_HAL_INTERRUPT_IRQ12);

}

// ----------------------------------------------------------------------------

static int

PS2Mouse_Open(MOUSEDEVICE* pmd)

{

    unsigned char buf[1];

    ps2_initialize();

    buf[0] = KC_MOUSEC_ENABLE;

    ps2_send_command_wait(KC_CONTROL_NULL, buf, 1, 1);

}

// Closing the mouse is equivalent to disabling. It is assumed that we

// are not in the middle of a packet transfer, which could really

// confuse things.

static void

PS2Mouse_Close(void)

{

    unsigned char buf[1];

    buf[0] = KC_MOUSEC_SET_STANDARD;

    ps2_send_command_wait(KC_CONTROL_NULL, buf, 1, 1);

    ps2mou_buffer_index = 0;

}

static int

PS2Mouse_GetButtonInfo(void)

{