libpayload/keyboard: Implement self-test

The keyboard self-test is required for some devices. At least one
device (integrated keyboard in a ThinkPad X201) actually starts the
test automatically leading to spurious output and no response for
the first seconds.

We wait up to 5s for the self-test result. On failure or timeout,
the command will be repeated until the 30s init timer runs out. This
happens all in the background of the UI polling loop.

To not unnecessarily delay the boot process, we first try an oppor-
tunistic initialization which skips the self-test.

Change-Id: Ie07b31e74d06e116ac81e76309621eed39a19b49
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47088
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 47 insertions, 2 deletions

diff --git a/payloads/libpayload/drivers/i8042/keyboard.c b/payloads/libpayload/drivers/i8042/keyboard.c
index 114e18bc40..14089bd51e 100644
--- a/payloads/libpayload/drivers/i8042/keyboard.c
+++ b/payloads/libpayload/drivers/i8042/keyboard.c
@@ -233,9 +233,12 @@ static bool set_scancode_set(const unsigned char set)
 
 static enum keyboard_state {
 	STATE_INIT = 0,
+	STATE_SIMPLIFIED_INIT,
 	STATE_DISABLE_SCAN,
 	STATE_DRAIN_INPUT,
 	STATE_DISABLE_TRANSLATION,
+	STATE_START_SELF_TEST,
+	STATE_SELF_TEST,
 	STATE_CONFIGURE,
 	STATE_CONFIGURE_SET1,
 	STATE_ENABLE_TRANSLATION,
@@ -258,6 +261,15 @@ static void keyboard_poll(void)
 		/* Wait until keyboard_init() has been called. */
 		break;
 
+	case STATE_SIMPLIFIED_INIT:
+		/* On the first try, start opportunistically, do
+		   the first steps at once and skip the self-test. */
+		(void)keyboard_cmd(I8042_KBCMD_DEFAULT_DIS);
+		keyboard_drain_input();
+		(void)i8042_set_kbd_translation(false);
+		next_state = STATE_CONFIGURE;
+		break;
+
 	case STATE_DISABLE_SCAN:
 		(void)keyboard_cmd(I8042_KBCMD_DEFAULT_DIS);
 		next_state = STATE_DRAIN_INPUT;
@@ -274,7 +286,40 @@ static void keyboard_poll(void)
 	case STATE_DISABLE_TRANSLATION:
 		/* Be opportunistic and assume it's disabled on failure. */
 		(void)i8042_set_kbd_translation(false);
-		next_state = STATE_CONFIGURE;
+		next_state = STATE_START_SELF_TEST;
+		break;
+
+	case STATE_START_SELF_TEST:
+		if (!keyboard_cmd(I8042_KBCMD_RESET))
+			printf("ERROR: Keyboard self-test couldn't be started.\n");
+		/* We ignore errors and always move to the self-test state
+		   which will simply try again if necessary. */
+		next_state = STATE_SELF_TEST;
+		break;
+
+	case STATE_SELF_TEST:
+		if (!i8042_data_ready_ps2()) {
+			if (timer_us(state_time) > 5*1000*1000)
+				next_state = STATE_DISABLE_SCAN;
+			break;
+		}
+
+		const uint8_t self_test_result = i8042_read_data_ps2();
+		switch (self_test_result) {
+		case 0xaa:
+			/* Success! */
+			next_state = STATE_CONFIGURE;
+			break;
+		case 0xfc:
+		case 0xfd:
+			/* Failure. Try again. */
+			next_state = STATE_START_SELF_TEST;
+			break;
+		default:
+			printf("WARNING: Keyboard self-test received spurious 0x%02x\n",
+			       self_test_result);
+			break;
+		}
 		break;
 
 	case STATE_CONFIGURE:
@@ -491,7 +536,7 @@ void keyboard_init(void)
 	/* Enable first PS/2 port */
 	i8042_cmd(I8042_CMD_EN_KB);
 
-	keyboard_state = STATE_DISABLE_SCAN;
+	keyboard_state = STATE_SIMPLIFIED_INIT;
 	keyboard_time = state_time = timer_us(0);
 
 	console_add_input_driver(&cons);