init: primitive ps2 driver

2 files changed, 88 insertions, 0 deletions

diff --git a/src/init/driver/driver.h b/src/init/driver/driver.h
index e854c65..dc21573 100644
--- a/src/init/driver/driver.h
+++ b/src/init/driver/driver.h
@@ -1,3 +1,4 @@
 #pragma once
 
 void ansiterm_drv(void);
+void ps2_drv(void);
diff --git a/src/init/driver/ps2.c b/src/init/driver/ps2.c
new file mode 100644
index 0000000..55869f5
--- /dev/null
+++ b/src/init/driver/ps2.c
@@ -0,0 +1,87 @@
+#include <init/driver/driver.h>
+#include <shared/syscalls.h>
+#include <stdbool.h>
+
+
+static const char keymap_lower[] = {
+	'\0', '\0', '1',  '2',  '3',  '4',  '5',  '6',  '7',  '8',  '9',  '0',  '-',  '=',  '\b', '\t',
+	'q',  'w',  'e',  'r',  't',  'y',  'u',  'i',  'o',  'p',  '[',  ']',  '\r', '\0', 'a',  's',
+	'd',  'f',  'g',  'h',  'j',  'k',  'l',  '\0', '\'', '`',  '\0', '\\', 'z',  'x',  'c',  'v',
+	'b',  'n',  'm',  ',',  '.',  '/',  '\0', '*',  '\0', ' ',  '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '7',  '8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',
+	'2',  '3',  '0',  '.',  '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+};
+
+static const char keymap_upper[] = {
+	'\0', '\0', '!',  '@',  '#',  '$',  '%',  '^',  '&',  '*',  '(',  ')',  '_',  '+',  '\b', '\t',
+	'Q',  'W',  'E',  'R',  'T',  'Y',  'U',  'I',  'O',  'P',  '{',  '}',  '\r', '\0', 'A',  'S',
+	'D',  'F',  'G',  'H',  'J',  'K',  'L',  ':',  '"',  '~',  '\0', '|',  'Z',  'X',  'C',  'V',
+	'B',  'N',  'M',  '<',  '>',  '?',  '\0', '*',  '\0', ' ',  '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '7',  '8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',
+	'2',  '3',  '0',  '.',  '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+	'\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
+};
+
+
+#define BACKLOG_CAPACITY 16
+static char backlog[BACKLOG_CAPACITY] = {};
+static size_t backlog_size = 0;
+
+static handle_t fd;
+
+static bool keys[0x80] = {0};
+
+static void parse_scancode(uint8_t s) {
+	bool shift = keys[0x2A] || keys[0x36];
+	bool down = !(s & 0x80);
+	s &= 0x7f;
+	keys[s] = down;
+
+	char c = shift ? keymap_upper[s] : keymap_lower[s];
+
+	if (backlog_size >= BACKLOG_CAPACITY) return;
+	if (down && c)
+		backlog[backlog_size++] = c;
+}
+
+static void main_loop(void) {
+	static char buf[512];
+	struct fs_wait_response res;
+	while (!_syscall_fs_wait(buf, sizeof buf, &res)) {
+		switch (res.op) {
+			case VFSOP_OPEN:
+				_syscall_fs_respond(NULL, 1);
+				break;
+
+			case VFSOP_READ:
+				while (backlog_size == 0) {
+					/* read raw input until we have something to output */
+					int len = _syscall_read(fd, buf, sizeof buf, 0);
+					if (len == 0) break;
+					for (size_t i = 0; i < len; i++)
+						parse_scancode(buf[i]);
+				}
+				if (res.capacity > backlog_size)
+					res.capacity = backlog_size;
+				// TODO don't discard chars past what was read
+				backlog_size = 0;
+				_syscall_fs_respond(backlog, res.capacity);
+				break;
+
+			default:
+				_syscall_fs_respond(NULL, -1);
+				break;
+		}
+	}
+}
+
+void ps2_drv(void) {
+	fd = _syscall_open("/ps2", 4);
+	if (fd < 0) _syscall_exit(1);
+
+	main_loop();
+	_syscall_exit(0);
+}