/* keyboard.c — PS/2 keyboard driver for KHY OS * @pattern Adapter * * Reads scancode set 1 from the i8042 controller on IRQ1, translates make * codes to ASCII honoring Shift/CapsLock/Ctrl, and pushes the result into a * lock-free single-producer/single-consumer ring buffer. The IRQ handler is * the sole producer; the shell task is the sole consumer. */ #include "keyboard.h" #include "pic.h" #include "process.h" /* PS/2 controller I/O ports */ #define PS2_DATA 0x60 /* read: scancode / write: device command */ #define PS2_STATUS 0x64 /* read: status register */ /* Scancode set 1 make codes for the modifier keys we track */ #define SC_LSHIFT 0x2A #define SC_RSHIFT 0x36 #define SC_CTRL 0x1D #define SC_CAPS 0x3A #define SC_EXTENDED 0xE0 /* prefix byte for extended (E0) keys */ #define SC_BREAK 0x80 /* bit set on break (key-release) codes */ /* Input ring buffer. Size must be a power of two for the cheap mask wrap. */ #define KBD_BUF_SIZE 128 #define KBD_BUF_MASK (KBD_BUF_SIZE - 1) static char kbd_buf[KBD_BUF_SIZE]; static volatile uint32_t kbd_head; /* producer (IRQ) write index */ static volatile uint32_t kbd_tail; /* consumer (shell) read index */ /* Modifier state */ static int shift_down; static int ctrl_down; static int caps_lock; static int extended; /* set after an 0xE0 prefix, consumed by next byte */ static inline uint8_t inb(uint16_t port) { uint8_t ret; __asm__ volatile("inb %1, %0" : "=a"(ret) : "Nd"(port)); return ret; } /* US QWERTY scancode set 1 → ASCII, unshifted. 0 = no printable mapping. */ static const char scancode_ascii[128] = { 0, 27, '1', '2', '3', '4', '5', '6', '7', '8', /* 0x00-0x09 */ '9', '0', '-', '=', '\b', '\t', 'q', 'w', 'e', 'r', /* 0x0A-0x13 */ 't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n', 0, /* 0x14-0x1D (0x1D=Ctrl) */ 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', /* 0x1E-0x27 */ '\'', '`', 0, '\\', 'z', 'x', 'c', 'v', 'b', 'n', /* 0x28-0x31 (0x2A=LShift) */ 'm', ',', '.', '/', 0, '*', 0, ' ', 0, 0, /* 0x32-0x3B (0x36=RShift,0x3A=Caps) */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x3C-0x45 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x46-0x4F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50-0x59 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x5A-0x63 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x64-0x6D */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x6E-0x77 */ 0, 0, 0, 0, 0, 0, 0, 0, /* 0x78-0x7F */ }; /* US QWERTY scancode set 1 → ASCII, shifted. 0 = no printable mapping. */ static const char scancode_ascii_shift[128] = { 0, 27, '!', '@', '#', '$', '%', '^', '&', '*', /* 0x00-0x09 */ '(', ')', '_', '+', '\b', '\t', 'Q', 'W', 'E', 'R', /* 0x0A-0x13 */ 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n', 0, /* 0x14-0x1D */ 'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', /* 0x1E-0x27 */ '"', '~', 0, '|', 'Z', 'X', 'C', 'V', 'B', 'N', /* 0x28-0x31 */ 'M', '<', '>', '?', 0, '*', 0, ' ', 0, 0, /* 0x32-0x3B */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x3C-0x45 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x46-0x4F */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x50-0x59 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x5A-0x63 */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x64-0x6D */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 0x6E-0x77 */ 0, 0, 0, 0, 0, 0, 0, 0, /* 0x78-0x7F */ }; static int is_alpha(char c) { return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); } static void kbd_push(char c) { uint32_t next = (kbd_head + 1) & KBD_BUF_MASK; if (next == kbd_tail) return; /* buffer full → drop, never block the IRQ */ kbd_buf[kbd_head] = c; kbd_head = next; } /* Push a NUL-terminated byte sequence. Used to emit VT100/ANSI escape * sequences for the extended navigation keys so the shell's line editor sees * the exact same input a real serial terminal would send (e.g. ESC [ A for * Up). On a full buffer the tail bytes are dropped by kbd_push; worst case is * a truncated escape, which the shell parser harmlessly discards. */ static void kbd_push_str(const char *s) { while (*s) kbd_push(*s++); } /* Translate an extended (0xE0-prefixed) make code to a VT100 escape sequence. * Returns NULL for codes we don't map (e.g. PgUp/PgDn/keypad). */ static const char *extended_escape(uint8_t code) { switch (code) { case 0x48: return "\x1b[A"; /* Up */ case 0x50: return "\x1b[B"; /* Down */ case 0x4D: return "\x1b[C"; /* Right */ case 0x4B: return "\x1b[D"; /* Left */ case 0x47: return "\x1b[H"; /* Home */ case 0x4F: return "\x1b[F"; /* End */ case 0x53: return "\x1b[3~";/* Delete*/ default: return 0; } } void keyboard_init(void) { kbd_head = 0; kbd_tail = 0; shift_down = 0; ctrl_down = 0; caps_lock = 0; extended = 0; } void keyboard_handler(void) { /* Always drain the data port exactly once, even if we end up ignoring the * byte — leaving it unread wedges the controller and stops further IRQs. */ uint8_t sc = inb(PS2_DATA); /* Extended-key prefix: remember it and skip translation of this byte. The * following byte (arrows / keypad / right-ctrl etc.) is consumed but not * mapped to ASCII in this pass. */ if (sc == SC_EXTENDED) { extended = 1; pic_send_eoi(1); return; } if (extended) { extended = 0; /* Only navigation make codes emit a sequence; break codes (0x80 bit) * and unmapped keys are consumed silently. */ if (!(sc & SC_BREAK)) { const char *esc = extended_escape(sc & 0x7F); if (esc) kbd_push_str(esc); } pic_send_eoi(1); return; } int is_break = (sc & SC_BREAK) != 0; uint8_t code = sc & 0x7F; /* Modifier key state tracking */ if (code == SC_LSHIFT || code == SC_RSHIFT) { shift_down = !is_break; pic_send_eoi(1); return; } if (code == SC_CTRL) { ctrl_down = !is_break; pic_send_eoi(1); return; } if (code == SC_CAPS) { if (!is_break) caps_lock = !caps_lock; /* toggle on make only */ pic_send_eoi(1); return; } /* Only make codes produce characters */ if (is_break) { pic_send_eoi(1); return; } /* CapsLock affects letters only: for alpha keys the effective shift is * (shift XOR caps); for every other key only the real shift applies. */ int effective_shift = shift_down; if (caps_lock && is_alpha(scancode_ascii[code])) effective_shift = shift_down ^ 1; char ch = effective_shift ? scancode_ascii_shift[code] : scancode_ascii[code]; if (ch) { /* Ctrl combines with letters to yield control codes (Ctrl-A=0x01 …). */ if (ctrl_down && is_alpha(ch)) { char upper = (ch >= 'a' && ch <= 'z') ? (char)(ch - 'a' + 'A') : ch; ch = (char)(upper - 'A' + 1); } /* Ctrl-C (0x03) is the terminal INTR character: raise SIGINT on the * foreground program so even a CPU-bound loop that never calls read() is * interrupted (delivered on the IRQ return-to-user path). The byte is * still buffered so a program blocked in read() returns promptly and the * signal is delivered on its syscall return; the pending bit is * idempotent, so the two paths cannot double-deliver. With no foreground * program (shell at its prompt) the byte is left for the line editor. */ if (ch == 0x03) { uint32_t fg = process_foreground(); if (fg != 0) process_raise_signal(fg, PROCESS_SIGINT); } kbd_push(ch); } pic_send_eoi(1); } int keyboard_getchar_nonblock(char *out) { if (!out) return 0; if (kbd_tail == kbd_head) return 0; /* empty */ *out = kbd_buf[kbd_tail]; kbd_tail = (kbd_tail + 1) & KBD_BUF_MASK; return 1; }