Detect recovery key combination

Check if ESC+Power+Refresh is pressed at startup, if the recovery
combination is detected, record it to allow U-Boot to go into recovery.

The status of the keyboard recovery can be read from the response of the
EC_CMD_MKBP_INFO command.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BUG=chrome-os-partner:9916
TEST=On Snow, do a recovery reset by pressing ESC+Refresh+Power and see
the trace, try other resets and don't see it.

Change-Id: I0e1a8214781a6e74bd90bf8313887a9dcf4df56d

3 files changed, 79 insertions, 22 deletions

diff --git a/chip/stm32/keyboard_scan.c b/chip/stm32/keyboard_scan.c
index b8051539d5..2b7b894dd6 100644
--- a/chip/stm32/keyboard_scan.c
+++ b/chip/stm32/keyboard_scan.c
@@ -17,6 +17,7 @@
 #include "keyboard.h"
 #include "keyboard_scan.h"
 #include "registers.h"
+#include "system.h"
 #include "task.h"
 #include "timer.h"
 #include "util.h"
@@ -41,6 +42,9 @@ enum COL_INDEX {
 /* The keyboard state from the last read */
 static uint8_t raw_state[KB_OUTPUTS];
 
+/* status of keyboard related switches */
+static uint8_t switches;
+
 /* Mask with 1 bits only for keys that actually exist */
 static const uint8_t *actual_key_mask;
 
@@ -55,6 +59,12 @@ static const uint8_t actual_key_masks[4][KB_OUTPUTS] = {
 	{0},
 	};
 
+/* Key masks for special boot keys */
+#define MASK_INDEX_ESC     1
+#define MASK_VALUE_ESC     0x02
+#define MASK_INDEX_REFRESH 2
+#define MASK_VALUE_REFRESH 0x04
+
 struct kbc_gpio {
 	int num;		/* logical row or column number */
 	uint32_t port;
@@ -187,26 +197,6 @@ static void select_column(int col)
 }
 
 
-int keyboard_scan_init(void)
-{
-	int i;
-
-	/* Tri-state (put into Hi-Z) the outputs */
-	select_column(COL_TRI_STATE_ALL);
-
-	/* initialize raw state since host may request it before
-	 * a key has been pressed (e.g. during keyboard driver init) */
-	for (i = 0; i < ARRAY_SIZE(raw_state); i++)
-		raw_state[i] = 0x00;
-
-	/* TODO: method to set which keyboard we have, so we set the actual
-	 * key mask properly */
-	actual_key_mask = actual_key_masks[0];
-
-	return EC_SUCCESS;
-}
-
-
 void wait_for_interrupt(void)
 {
 	uint32_t pr_before, pr_after;
@@ -316,6 +306,58 @@ static int check_keys_changed(void)
 }
 
 
+/* Returns non-zero if the user has triggered a recovery reset by pushing
+ * Power + Refresh + ESC. */
+static int check_recovery_key(void)
+{
+	int c;
+
+	/* check the recovery key only if we're booting due to a
+	 * reset-pin-caused reset. */
+	if (system_get_reset_cause() != SYSTEM_RESET_RESET_PIN)
+		return 0;
+
+	/* cold boot : Power + Refresh were pressed,
+	 * check if ESC is also pressed for recovery. */
+	if (!(raw_state[MASK_INDEX_ESC] & MASK_VALUE_ESC))
+		return 0;
+
+	/* Make sure only other allowed keys are pressed.  This protects
+	 * against accidentally triggering the special key when a cat sits on
+	 * your keyboard.  Currently, only the requested key and ESC are
+	 * allowed. */
+	for (c = 0; c < KB_OUTPUTS; c++) {
+		if (raw_state[c] &&
+		(c != MASK_INDEX_ESC || raw_state[c] != MASK_VALUE_ESC) &&
+		(c != MASK_INDEX_REFRESH || raw_state[c] != MASK_VALUE_REFRESH))
+			return 0;  /* Additional disallowed key pressed */
+	}
+
+	CPRINTF("Keyboard RECOVERY detected !\n");
+	return 1;
+}
+
+
+int keyboard_scan_init(void)
+{
+	/* Tri-state (put into Hi-Z) the outputs */
+	select_column(COL_TRI_STATE_ALL);
+
+	/* TODO: method to set which keyboard we have, so we set the actual
+	 * key mask properly */
+	actual_key_mask = actual_key_masks[0];
+
+	/* Initialize raw state */
+	check_keys_changed();
+
+	/* is recovery key pressed on cold startup ? */
+	switches |= check_recovery_key() ?
+			EC_SWITCH_KEYBOARD_RECOVERY : 0;
+
+	return EC_SUCCESS;
+}
+
+
 void keyboard_scan_task(void)
 {
 	int key_press_timer = 0;
@@ -376,8 +418,7 @@ void keyboard_put_char(uint8_t chr, int send_irq)
 
 int keyboard_scan_recovery_pressed(void)
 {
-	/* TODO: (crosbug.com/p/8573) needs to be implemented */
-	return 0;
+	return switches & EC_SWITCH_KEYBOARD_RECOVERY;
 }
 
 static int keyboard_get_scan(uint8_t *data, int *resp_size)
@@ -397,6 +438,7 @@ static int keyboard_get_info(uint8_t *data, int *resp_size)
 
 	r->rows = 8;
 	r->cols = KB_OUTPUTS;
+	r->switches = switches;
 
 	*resp_size = sizeof(struct ec_response_mkbp_info);
 	return EC_RES_SUCCESS;
diff --git a/common/gaia_power.c b/common/gaia_power.c
index 519099d0eb..841135fc48 100644
--- a/common/gaia_power.c
+++ b/common/gaia_power.c
@@ -27,6 +27,7 @@
 #include "chipset.h"  /* This module implements chipset functions too */
 #include "console.h"
 #include "gpio.h"
+#include "keyboard_scan.h"
 #include "task.h"
 #include "timer.h"
 #include "util.h"
@@ -96,6 +97,9 @@ static int pwron_released;
 /* time where we will release GPIO_PMIC_PWRON_L */
 static timestamp_t pwron_deadline;
 
+/* force AP power on (used for recovery keypress) */
+static int auto_power_on;
+
 /*
  * Wait for GPIO "signal" to reach level "value".
  * Returns EC_ERROR_TIMEOUT if timeout before reaching the desired state.
@@ -189,6 +193,10 @@ int gaia_power_init(void)
 	gpio_enable_interrupt(GPIO_PP1800_LDO2);
 	gpio_enable_interrupt(GPIO_SOC1V8_XPSHOLD);
 
+	/* auto power on if the recovery combination was pressed */
+	if (keyboard_scan_recovery_pressed())
+		auto_power_on = 1;
+
 	return EC_SUCCESS;
 }
 
@@ -233,6 +241,12 @@ static int check_for_power_on_event(void)
 	if (gpio_get_level(GPIO_EN_PP3300))
 		return 1;
 
+	/* power on requested at EC startup for recovery */
+	if (auto_power_on) {
+		auto_power_on = 0;
+		return 1;
+	}
+
 	/* wait for Power button press */
 	wait_in_signal(GPIO_KB_PWR_ON_L, 0, -1);
 
diff --git a/include/ec_commands.h b/include/ec_commands.h
index 4599cf4475..805398e1fb 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -533,6 +533,7 @@ struct ec_response_mkbp_state {
 struct ec_response_mkbp_info {
 	uint32_t rows;
 	uint32_t cols;
+	uint8_t switches;
 } __attribute__ ((packed));
 
 /* Simulate key press */