usbkbd.c

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/*
 * Copyright (C) 2015 Michael Brown <mbrown@fensystems.co.uk>.
 *
 * This program 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 of the
 * License, or (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/console.h>
#include <ipxe/keys.h>
#include <ipxe/keymap.h>
#include <ipxe/usb.h>
#include "usbkbd.h"

/** @file
 *
 * USB keyboard driver
 *
 */

/** List of USB keyboards */
static LIST_HEAD ( usb_keyboards );

/******************************************************************************
 *
 * Keyboard map
 *
 ******************************************************************************
 */

/**
 * Map USB keycode to iPXE key
 *
 * @v keycode           Keycode
 * @v modifiers         Modifiers
 * @v leds              LED state
 * @ret key             iPXE key
 *
 * Key codes are defined in the USB HID Usage Tables Keyboard/Keypad
 * page.
 */
static unsigned int usbkbd_map ( unsigned int keycode, unsigned int modifiers,
                                 unsigned int leds ) {
        unsigned int key;

        if ( keycode < USBKBD_KEY_A ) {
                /* Not keys */
                key = 0;
        } else if ( keycode <= USBKBD_KEY_Z ) {
                /* Alphabetic keys */
                key = ( keycode - USBKBD_KEY_A + 'a' );
                if ( modifiers & USBKBD_SHIFT ) {
                        key -= ( 'a' - 'A' );
                }
        } else if ( keycode <= USBKBD_KEY_0 ) {
                /* Numeric key row */
                if ( modifiers & USBKBD_SHIFT ) {
                        key = "!@#$%^&*()" [ keycode - USBKBD_KEY_1 ];
                } else {
                        key = ( ( ( keycode - USBKBD_KEY_1 + 1 ) % 10 ) + '0' );
                }
        } else if ( keycode <= USBKBD_KEY_SPACE ) {
                /* Unmodifiable keys */
                static const uint8_t unmodifable[] =
                        { LF, ESC, BACKSPACE, TAB, ' ' };
                key = unmodifable[ keycode - USBKBD_KEY_ENTER ];
        } else if ( keycode <= USBKBD_KEY_SLASH ) {
                /* Punctuation keys */
                if ( modifiers & USBKBD_SHIFT ) {
                        key = "_+{}|~:\"~<>?" [ keycode - USBKBD_KEY_MINUS ];
                } else {
                        key = "-=[]\\#;'`,./" [ keycode - USBKBD_KEY_MINUS ];
                }
        } else if ( keycode <= USBKBD_KEY_UP ) {
                /* Special keys */
                static const uint16_t special[] = {
                        0, 0, 0, 0, 0, KEY_F5, KEY_F6, KEY_F7, KEY_F8, KEY_F9,
                        KEY_F10, KEY_F11, KEY_F12, 0, 0, 0, KEY_IC, KEY_HOME,
                        KEY_PPAGE, KEY_DC, KEY_END, KEY_NPAGE, KEY_RIGHT,
                        KEY_LEFT, KEY_DOWN, KEY_UP
                };
                key = special[ keycode - USBKBD_KEY_CAPS_LOCK ];
        } else if ( keycode <= USBKBD_KEY_PAD_ENTER ) {
                /* Keypad (unaffected by Num Lock) */
                key = "\0/*-+\n" [ keycode - USBKBD_KEY_NUM_LOCK ];
        } else if ( keycode <= USBKBD_KEY_PAD_DOT ) {
                /* Keypad (affected by Num Lock) */
                if ( leds & USBKBD_LED_NUM_LOCK ) {
                        key = "1234567890." [ keycode - USBKBD_KEY_PAD_1 ];
                } else {
                        static const uint16_t keypad[] = {
                                KEY_END, KEY_DOWN, KEY_NPAGE, KEY_LEFT, 0,
                                KEY_RIGHT, KEY_HOME, KEY_UP, KEY_PPAGE,
                                KEY_IC, KEY_DC
                        };
                        key = keypad[ keycode - USBKBD_KEY_PAD_1 ];
                };
        } else if ( keycode == USBKBD_KEY_NON_US ) {
                /* Non-US \ and | */
                key = ( ( modifiers & USBKBD_SHIFT ) ?
                        ( KEYMAP_PSEUDO | '|' ) : ( KEYMAP_PSEUDO | '\\' ) );
        } else {
                key = 0;
        }

        /* Remap key if applicable */
        if ( ( keycode < USBKBD_KEY_CAPS_LOCK ) ||
             ( keycode == USBKBD_KEY_NON_US ) ) {

                /* Apply modifiers */
                if ( modifiers & USBKBD_CTRL )
                        key |= KEYMAP_CTRL;
                if ( modifiers & USBKBD_ALT_RIGHT )
                        key |= KEYMAP_ALTGR;
                if ( leds & USBKBD_LED_CAPS_LOCK )
                        key |= KEYMAP_CAPSLOCK;

                /* Remap key */
                key = key_remap ( key );
        }

        return key;
}

/******************************************************************************
 *
 * Keyboard buffer
 *
 ******************************************************************************
 */

/**
 * Insert keypress into keyboard buffer
 *
 * @v kbd               USB keyboard
 * @v keycode           Keycode
 * @v modifiers         Modifiers
 */
static void usbkbd_produce ( struct usb_keyboard *kbd, unsigned int keycode,
                             unsigned int modifiers ) {
        unsigned int leds = 0;
        unsigned int key;

        /* Check for LED-modifying keys */
        if ( keycode == USBKBD_KEY_CAPS_LOCK ) {
                leds = USBKBD_LED_CAPS_LOCK;
        } else if ( keycode == USBKBD_KEY_NUM_LOCK ) {
                leds = USBKBD_LED_NUM_LOCK;
        }

        /* Handle LED-modifying keys */
        if ( leds ) {
                kbd->leds ^= leds;
                kbd->leds_changed = 1;
                return;
        }

        /* Map to iPXE key */
        key = usbkbd_map ( keycode, modifiers, kbd->leds );

        /* Do nothing if this keycode has no corresponding iPXE key */
        if ( ! key ) {
                DBGC ( kbd, "KBD %s has no key for keycode %#02x:%#02x\n",
                       kbd->name, modifiers, keycode );
                return;
        }

        /* Check for buffer overrun */
        if ( usbkbd_fill ( kbd ) >= USBKBD_BUFSIZE ) {
                DBGC ( kbd, "KBD %s buffer overrun (key %#02x)\n",
                       kbd->name, key );
                return;
        }

        /* Insert into buffer */
        kbd->key[ ( kbd->prod++ ) % USBKBD_BUFSIZE ] = key;
        DBGC2 ( kbd, "KBD %s key %#02x produced\n", kbd->name, key );
}

/**
 * Consume character from keyboard buffer
 *
 * @v kbd               USB keyboard
 * @ret character       Character
 */
static unsigned int usbkbd_consume ( struct usb_keyboard *kbd ) {
        static char buf[] = "\x1b[xx~";
        char *tmp = &buf[2];
        unsigned int key;
        unsigned int character;
        unsigned int ansi_n;
        unsigned int len;

        /* Sanity check */
        assert ( usbkbd_fill ( kbd ) > 0 );

        /* Get current keypress */
        key = kbd->key[ kbd->cons % USBKBD_BUFSIZE ];

        /* If this is a straightforward key, just consume and return it */
        if ( key < KEY_MIN ) {
                kbd->cons++;
                DBGC2 ( kbd, "KBD %s key %#02x consumed\n", kbd->name, key );
                return key;
        }

        /* Construct ANSI sequence */
        ansi_n = KEY_ANSI_N ( key );
        if ( ansi_n )
                tmp += sprintf ( tmp, "%d", ansi_n );
        *(tmp++) = KEY_ANSI_TERMINATOR ( key );
        *tmp = '\0';
        len = ( tmp - buf );
        assert ( len < sizeof ( buf ) );
        if ( kbd->subcons == 0 ) {
                DBGC2 ( kbd, "KBD %s key %#02x consumed as ^[%s\n",
                        kbd->name, key, &buf[1] );
        }

        /* Extract character from ANSI sequence */
        assert ( kbd->subcons < len );
        character = buf[ kbd->subcons++ ];

        /* Consume key if applicable */
        if ( kbd->subcons == len ) {
                kbd->cons++;
                kbd->subcons = 0;
        }

        return character;
}

/******************************************************************************
 *
 * Keyboard report
 *
 ******************************************************************************
 */

/**
 * Check for presence of keycode in report
 *
 * @v report            Keyboard report
 * @v keycode           Keycode (must be non-zero)
 * @ret has_keycode     Keycode is present in report
 */
static int usbkbd_has_keycode ( struct usb_keyboard_report *report,
                                unsigned int keycode ) {
        unsigned int i;

        /* Check for keycode */
        for ( i = 0 ; i < ( sizeof ( report->keycode ) /
                            sizeof ( report->keycode[0] ) ) ; i++ ) {
                if ( report->keycode[i] == keycode )
                        return keycode;
        }

        return 0;
}

/**
 * Handle keyboard report
 *
 * @v kbd               USB keyboard
 * @v new               New keyboard report
 */
static void usbkbd_report ( struct usb_keyboard *kbd,
                            struct usb_keyboard_report *new ) {
        struct usb_keyboard_report *old = &kbd->report;
        unsigned int keycode;
        unsigned int i;

        /* Check if current key has been released */
        if ( kbd->keycode && ! usbkbd_has_keycode ( new, kbd->keycode ) ) {
                DBGC2 ( kbd, "KBD %s keycode %#02x released\n",
                        kbd->name, kbd->keycode );
                kbd->keycode = 0;
        }

        /* Decrement auto-repeat hold-off timer, if applicable */
        if ( kbd->holdoff )
                kbd->holdoff--;

        /* Check if a new key has been pressed */
        for ( i = 0 ; i < ( sizeof ( new->keycode ) /
                            sizeof ( new->keycode[0] ) ) ; i++ ) {

                /* Ignore keys present in the previous report */
                keycode = new->keycode[i];
                if ( ( keycode == 0 ) || usbkbd_has_keycode ( old, keycode ) )
                        continue;
                DBGC2 ( kbd, "KBD %s keycode %#02x pressed\n",
                        kbd->name, keycode );

                /* Insert keypress into keyboard buffer */
                usbkbd_produce ( kbd, keycode, new->modifiers );

                /* Record as most recent keycode */
                kbd->keycode = keycode;

                /* Start auto-repeat hold-off timer */
                kbd->holdoff = USBKBD_HOLDOFF;
        }

        /* Insert auto-repeated keypress into keyboard buffer, if applicable */
        if ( kbd->keycode && ! kbd->holdoff )
                usbkbd_produce ( kbd, kbd->keycode, new->modifiers );

        /* Record report */
        memcpy ( old, new, sizeof ( *old ) );
}

/******************************************************************************
 *
 * Interrupt endpoint
 *
 ******************************************************************************
 */

/**
 * Complete interrupt transfer
 *
 * @v ep                USB endpoint
 * @v iobuf             I/O buffer
 * @v rc                Completion status code
 */
static void usbkbd_complete ( struct usb_endpoint *ep,
                              struct io_buffer *iobuf, int rc ) {
        struct usb_keyboard *kbd = container_of ( ep, struct usb_keyboard,
                                                  hid.in );
        struct usb_keyboard_report *report;

        /* Ignore packets cancelled when the endpoint closes */
        if ( ! ep->open )
                goto drop;

        /* Ignore packets with errors */
        if ( rc != 0 ) {
                DBGC ( kbd, "KBD %s interrupt IN failed: %s\n",
                       kbd->name, strerror ( rc ) );
                goto drop;
        }

        /* Ignore underlength packets */
        if ( iob_len ( iobuf ) < sizeof ( *report ) ) {
                DBGC ( kbd, "KBD %s underlength report:\n", kbd->name );
                DBGC_HDA ( kbd, 0, iobuf->data, iob_len ( iobuf ) );
                goto drop;
        }
        report = iobuf->data;

        /* Handle keyboard report */
        usbkbd_report ( kbd, report );

 drop:
        /* Recycle I/O buffer */
        usb_recycle ( &kbd->hid.in, iobuf );
}

/** Interrupt endpoint operations */
static struct usb_endpoint_driver_operations usbkbd_operations = {
        .complete = usbkbd_complete,
};

/******************************************************************************
 *
 * Keyboard LEDs
 *
 ******************************************************************************
 */

/**
 * Set keyboard LEDs
 *
 * @v kbd               USB keyboard
 * @ret rc              Return status code
 */
static int usbkbd_set_leds ( struct usb_keyboard *kbd ) {
        struct usb_function *func = kbd->hid.func;
        int rc;

        DBGC2 ( kbd, "KBD %s setting LEDs to %#02x\n", kbd->name, kbd->leds );

        /* Set keyboard LEDs */
        if ( ( rc = usbhid_set_report ( func->usb, func->interface[0],
                                        USBHID_REPORT_OUTPUT, 0, &kbd->leds,
                                        sizeof ( kbd->leds ) ) ) != 0 ) {
                DBGC ( kbd, "KBD %s could not set LEDs to %#02x: %s\n",
                       kbd->name, kbd->leds, strerror ( rc ) );
                return rc;
        }

        return 0;
}

/******************************************************************************
 *
 * USB interface
 *
 ******************************************************************************
 */

/**
 * Probe device
 *
 * @v func              USB function
 * @v config            Configuration descriptor
 * @ret rc              Return status code
 */
static int usbkbd_probe ( struct usb_function *func,
                          struct usb_configuration_descriptor *config ) {
        struct usb_device *usb = func->usb;
        struct usb_keyboard *kbd;
        int rc;

        /* Allocate and initialise structure */
        kbd = zalloc ( sizeof ( *kbd ) );
        if ( ! kbd ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        kbd->name = func->name;
        kbd->bus = usb->port->hub->bus;
        usbhid_init ( &kbd->hid, func, &usbkbd_operations, NULL );
        usb_refill_init ( &kbd->hid.in, 0, sizeof ( kbd->report ),
                          USBKBD_INTR_MAX_FILL );

        /* Describe USB human interface device */
        if ( ( rc = usbhid_describe ( &kbd->hid, config ) ) != 0 ) {
                DBGC ( kbd, "KBD %s could not describe: %s\n",
                       kbd->name, strerror ( rc ) );
                goto err_describe;
        }
        DBGC ( kbd, "KBD %s using %s (len %zd)\n",
               kbd->name, usb_endpoint_name ( &kbd->hid.in ), kbd->hid.in.mtu );

        /* Set boot protocol */
        if ( ( rc = usbhid_set_protocol ( usb, func->interface[0],
                                          USBHID_PROTOCOL_BOOT ) ) != 0 ) {
                DBGC ( kbd, "KBD %s could not set boot protocol: %s\n",
                       kbd->name, strerror ( rc ) );
                goto err_set_protocol;
        }

        /* Set idle time */
        if ( ( rc = usbhid_set_idle ( usb, func->interface[0], 0,
                                      USBKBD_IDLE_DURATION ) ) != 0 ) {
                DBGC ( kbd, "KBD %s could not set idle time: %s\n",
                       kbd->name, strerror ( rc ) );
                goto err_set_idle;
        }

        /* Open USB human interface device */
        if ( ( rc = usbhid_open ( &kbd->hid ) ) != 0 ) {
                DBGC ( kbd, "KBD %s could not open: %s\n",
                       kbd->name, strerror ( rc ) );
                goto err_open;
        }

        /* Add to list of USB keyboards */
        list_add_tail ( &kbd->list, &usb_keyboards );

        /* Set initial LED state */
        usbkbd_set_leds ( kbd );

        usb_func_set_drvdata ( func, kbd );
        return 0;

        usbhid_close ( &kbd->hid );
 err_open:
 err_set_idle:
 err_set_protocol:
 err_describe:
        free ( kbd );
 err_alloc:
        return rc;
}

/**
 * Remove device
 *
 * @v func              USB function
 */
static void usbkbd_remove ( struct usb_function *func ) {
        struct usb_keyboard *kbd = usb_func_get_drvdata ( func );

        /* Remove from list of USB keyboards */
        list_del ( &kbd->list );

        /* Close USB human interface device */
        usbhid_close ( &kbd->hid );

        /* Free device */
        free ( kbd );
}

/** USB keyboard device IDs */
static struct usb_device_id usbkbd_ids[] = {
        {
                .name = "kbd",
                .vendor = USB_ANY_ID,
                .product = USB_ANY_ID,
        },
};

/** USB keyboard driver */
struct usb_driver usbkbd_driver __usb_driver = {
        .ids = usbkbd_ids,
        .id_count = ( sizeof ( usbkbd_ids ) / sizeof ( usbkbd_ids[0] ) ),
        .class = USB_CLASS_ID ( USB_CLASS_HID, USB_SUBCLASS_HID_BOOT,
                                USBKBD_PROTOCOL ),
        .score = USB_SCORE_NORMAL,
        .probe = usbkbd_probe,
        .remove = usbkbd_remove,
};

/******************************************************************************
 *
 * Console interface
 *
 ******************************************************************************
 */

/**
 * Read a character from the console
 *
 * @ret character       Character read
 */
static int usbkbd_getchar ( void ) {
        struct usb_keyboard *kbd;

        /* Consume first available key */
        list_for_each_entry ( kbd, &usb_keyboards, list ) {
                if ( usbkbd_fill ( kbd ) )
                        return usbkbd_consume ( kbd );
        }

        return 0;
}

/**
 * Check for available input
 *
 * @ret is_available    Input is available
 */
static int usbkbd_iskey ( void ) {
        struct usb_keyboard *kbd;
        unsigned int fill;

        /* Poll USB keyboards, refill endpoints, and set LEDs if applicable */
        list_for_each_entry ( kbd, &usb_keyboards, list ) {

                /* Poll keyboard */
                usb_poll ( kbd->bus );

                /* Refill endpoints */
                usb_refill ( &kbd->hid.in );

                /* Update keyboard LEDs, if applicable */
                if ( kbd->leds_changed ) {
                        usbkbd_set_leds ( kbd );
                        kbd->leds_changed = 0;
                }
        }

        /* Check for a non-empty keyboard buffer */
        list_for_each_entry ( kbd, &usb_keyboards, list ) {
                fill = usbkbd_fill ( kbd );
                if ( fill )
                        return fill;
        }

        return 0;
}

/** USB keyboard console */
struct console_driver usbkbd_console __console_driver = {
        .getchar = usbkbd_getchar,
        .iskey = usbkbd_iskey,
};