Split x86 power button logic out of switch.c

Power button logic is common across all platforms and is not
LM4-specific, so move it to its own module.  Switch.c will eventually
be moving to common/ and will common across all platforms (not just
x86), and splitting out the x86 power button logic is needed before
that too.

BUG=chrome-os-partner:18343
BRANCH=none
TEST=manual
     1) power on system with both lid and power button.
     2) power+refresh -> reboots
     3) power+refresh+esc -> recovery mode
     4) power+refresh+downarrow -> reboots, AP stays off
     5) toggling recovery GPIO via servo should generate SW debug output
        showing bit 0x10 toggling

Change-Id: I07714e2c035dceece66f90407983397d2697e7d5
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/61780

1 files changed, 399 insertions, 0 deletions

diff --git a/common/power_button_x86.c b/common/power_button_x86.c
new file mode 100644
index 0000000000..2d353b74ed
--- /dev/null
+++ b/common/power_button_x86.c
@@ -0,0 +1,399 @@
+/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Power button state machine for x86 platforms */
+
+#include "charge_state.h"
+#include "chipset.h"
+#include "common.h"
+#include "console.h"
+#include "gpio.h"
+#include "hooks.h"
+#include "host_command.h"
+#include "keyboard_scan.h"
+#include "lid_switch.h"
+#include "power_button.h"
+#include "switch.h"
+#include "system.h"
+#include "task.h"
+#include "timer.h"
+#include "util.h"
+
+/* Console output macros */
+#define CPUTS(outstr) cputs(CC_SWITCH, outstr)
+#define CPRINTF(format, args...) cprintf(CC_SWITCH, format, ## args)
+
+/*
+ * When chipset is on, we stretch the power button signal to it so chipset
+ * hard-reset is triggered at ~8 sec, not ~4 sec:
+ *
+ *   PWRBTN#   ---                      ----
+ *     to EC     |______________________|
+ *
+ *
+ *   PWRBTN#   ---  ---------           ----
+ *    to PCH     |__|       |___________|
+ *                t0    t1    held down
+ *
+ *   scan code   |                      |
+ *    to host    v                      v
+ *     @S0   make code             break code
+ */
+/* TODO: link to full power button / lid switch state machine description. */
+#define PWRBTN_DELAY_T0    (32 * MSEC)  /* 32ms (PCH requires >16ms) */
+#define PWRBTN_DELAY_T1    (4 * SECOND - PWRBTN_DELAY_T0)  /* 4 secs - t0 */
+/*
+ * Length of time to stretch initial power button press to give chipset a
+ * chance to wake up (~100ms) and react to the press (~16ms).  Also used as
+ * pulse length for simulated power button presses when the system is off.
+ */
+#define PWRBTN_INITIAL_US  (200 * MSEC)
+
+enum power_button_state {
+	/* Button up; state machine idle */
+	PWRBTN_STATE_IDLE = 0,
+	/* Button pressed; debouncing done */
+	PWRBTN_STATE_PRESSED,
+	/* Button down, chipset on; sending initial short pulse */
+	PWRBTN_STATE_T0,
+	/* Button down, chipset on; delaying until we should reassert signal */
+	PWRBTN_STATE_T1,
+	/* Button down, signal asserted to chipset */
+	PWRBTN_STATE_HELD,
+	/* Force pulse due to lid-open event */
+	PWRBTN_STATE_LID_OPEN,
+	/* Button released; debouncing done */
+	PWRBTN_STATE_RELEASED,
+	/* Ignore next button release */
+	PWRBTN_STATE_EAT_RELEASE,
+	/*
+	 * Need to power on system after init, but waiting to find out if
+	 * sufficient battery power.
+	 */
+	PWRBTN_STATE_INIT_ON,
+	/* Forced pulse at EC boot due to keyboard controlled reset */
+	PWRBTN_STATE_BOOT_KB_RESET,
+	/* Power button pressed when chipset was off; stretching pulse */
+	PWRBTN_STATE_WAS_OFF,
+};
+static enum power_button_state pwrbtn_state = PWRBTN_STATE_IDLE;
+
+static const char * const state_names[] = {
+	"idle",
+	"pressed",
+	"t0",
+	"t1",
+	"held",
+	"lid-open",
+	"released",
+	"eat-release",
+	"init-on",
+	"recovery",
+	"was-off",
+};
+
+/*
+ * Time for next state transition of power button state machine, or 0 if the
+ * state doesn't have a timeout.
+ */
+static uint64_t tnext_state;
+
+static void set_pwrbtn_to_pch(int high)
+{
+	/*
+	 * If the battery is discharging and low enough we'd shut down the
+	 * system, don't press the power button.
+	 */
+	if (!high && charge_want_shutdown()) {
+		CPRINTF("[%T PB PCH pwrbtn ignored due to battery level\n");
+		high = 1;
+	}
+
+	CPRINTF("[%T PB PCH pwrbtn=%s]\n", high ? "HIGH" : "LOW");
+	gpio_set_level(GPIO_PCH_PWRBTN_L, high);
+}
+
+/**
+ * Handle debounced power button down.
+ */
+static void power_button_pressed(uint64_t tnow)
+{
+	CPRINTF("[%T PB pressed]\n");
+	pwrbtn_state = PWRBTN_STATE_PRESSED;
+	tnext_state = tnow;
+}
+
+/**
+ * Handle debounced power button up.
+ */
+static void power_button_released(uint64_t tnow)
+{
+	CPRINTF("[%T PB released]\n");
+	pwrbtn_state = PWRBTN_STATE_RELEASED;
+	tnext_state = tnow;
+}
+
+/**
+ * Set initial power button state.
+ */
+static void set_initial_pwrbtn_state(void)
+{
+	uint32_t reset_flags = system_get_reset_flags();
+
+	if (system_jumped_to_this_image() &&
+	    chipset_in_state(CHIPSET_STATE_ON)) {
+		/*
+		 * Jumped to this image while the chipset was already on, so
+		 * simply reflect the actual power button state.
+		 */
+		if (power_button_is_pressed()) {
+			CPRINTF("[%T PB init-jumped-held]\n");
+			set_pwrbtn_to_pch(0);
+		} else {
+			CPRINTF("[%T PB init-jumped]\n");
+		}
+	} else if ((reset_flags & RESET_FLAG_AP_OFF) ||
+		   (keyboard_scan_get_boot_key() == BOOT_KEY_DOWN_ARROW)) {
+		/*
+		 * Reset triggered by keyboard-controlled reset, and down-arrow
+		 * was held down.  Or reset flags request AP off.
+		 *
+		 * Leave the main processor off.  This is a fail-safe
+		 * combination for debugging failures booting the main
+		 * processor.
+		 *
+		 * Don't let the PCH see that the power button was pressed.
+		 * Otherwise, it might power on.
+		 */
+		CPRINTF("[%T PB init-off]\n");
+		set_pwrbtn_to_pch(1);
+		if (power_button_is_pressed())
+			pwrbtn_state = PWRBTN_STATE_EAT_RELEASE;
+		else
+			pwrbtn_state = PWRBTN_STATE_IDLE;
+	} else {
+		/*
+		 * All other EC reset conditions power on the main processor so
+		 * it can verify the EC.
+		 */
+		CPRINTF("[%T PB init-on]\n");
+		pwrbtn_state = PWRBTN_STATE_INIT_ON;
+	}
+}
+
+/**
+ * Power button state machine.
+ *
+ * @param tnow		Current time from usec counter
+ */
+static void state_machine(uint64_t tnow)
+{
+	/* Not the time to move onto next state */
+	if (tnow < tnext_state)
+		return;
+
+	/* States last forever unless otherwise specified */
+	tnext_state = 0;
+
+	switch (pwrbtn_state) {
+	case PWRBTN_STATE_PRESSED:
+		if (chipset_in_state(CHIPSET_STATE_ANY_OFF)) {
+			/*
+			 * Chipset is off, so wake the chipset and send it a
+			 * long enough pulse to wake up.  After that we'll
+			 * reflect the true power button state.  If we don't
+			 * stretch the pulse here, the user may release the
+			 * power button before the chipset finishes waking from
+			 * hard off state.
+			 */
+			chipset_exit_hard_off();
+			tnext_state = tnow + PWRBTN_INITIAL_US;
+			pwrbtn_state = PWRBTN_STATE_WAS_OFF;
+		} else {
+			/* Chipset is on, so send the chipset a pulse */
+			tnext_state = tnow + PWRBTN_DELAY_T0;
+			pwrbtn_state = PWRBTN_STATE_T0;
+		}
+		set_pwrbtn_to_pch(0);
+		break;
+	case PWRBTN_STATE_T0:
+		tnext_state = tnow + PWRBTN_DELAY_T1;
+		pwrbtn_state = PWRBTN_STATE_T1;
+		set_pwrbtn_to_pch(1);
+		break;
+	case PWRBTN_STATE_T1:
+		/*
+		 * If the chipset is already off, don't tell it the power
+		 * button is down; it'll just cause the chipset to turn on
+		 * again.
+		 */
+		if (chipset_in_state(CHIPSET_STATE_ANY_OFF))
+			CPRINTF("[%T PB chipset already off]\n");
+		else
+			set_pwrbtn_to_pch(0);
+		pwrbtn_state = PWRBTN_STATE_HELD;
+		break;
+	case PWRBTN_STATE_RELEASED:
+	case PWRBTN_STATE_LID_OPEN:
+		set_pwrbtn_to_pch(1);
+		pwrbtn_state = PWRBTN_STATE_IDLE;
+		break;
+	case PWRBTN_STATE_INIT_ON:
+		/*
+		 * Don't do anything until the charger knows the battery level.
+		 * Otherwise we could power on the AP only to shut it right
+		 * back down due to insufficient battery.
+		 */
+#ifdef HAS_TASK_CHARGER
+		if (charge_get_state() == PWR_STATE_INIT)
+			break;
+#endif
+
+		/*
+		 * Power the system on if possible.  Gating due to insufficient
+		 * battery is handled inside set_pwrbtn_to_pch().
+		 */
+		chipset_exit_hard_off();
+		set_pwrbtn_to_pch(0);
+		tnext_state = get_time().val + PWRBTN_INITIAL_US;
+
+		if (power_button_is_pressed()) {
+			if (system_get_reset_flags() & RESET_FLAG_RESET_PIN)
+				pwrbtn_state = PWRBTN_STATE_BOOT_KB_RESET;
+			else
+				pwrbtn_state = PWRBTN_STATE_WAS_OFF;
+		} else {
+			pwrbtn_state = PWRBTN_STATE_RELEASED;
+		}
+
+		break;
+
+	case PWRBTN_STATE_BOOT_KB_RESET:
+		/* Initial forced pulse is done.  Ignore the actual power
+		 * button until it's released, so that holding down the
+		 * recovery combination doesn't cause the chipset to shut back
+		 * down. */
+		set_pwrbtn_to_pch(1);
+		if (power_button_is_pressed())
+			pwrbtn_state = PWRBTN_STATE_EAT_RELEASE;
+		else
+			pwrbtn_state = PWRBTN_STATE_IDLE;
+		break;
+	case PWRBTN_STATE_WAS_OFF:
+		/* Done stretching initial power button signal, so show the
+		 * true power button state to the PCH. */
+		if (power_button_is_pressed()) {
+			/* User is still holding the power button */
+			pwrbtn_state = PWRBTN_STATE_HELD;
+		} else {
+			/* Stop stretching the power button press */
+			power_button_released(tnow);
+		}
+		break;
+	case PWRBTN_STATE_IDLE:
+	case PWRBTN_STATE_HELD:
+	case PWRBTN_STATE_EAT_RELEASE:
+		/* Do nothing */
+		break;
+	}
+}
+
+void power_button_task(void)
+{
+	uint64_t t;
+	uint64_t tsleep;
+
+	while (1) {
+		t = get_time().val;
+
+		/* Update state machine */
+		CPRINTF("[%T PB task %d = %s]\n", pwrbtn_state,
+			state_names[pwrbtn_state]);
+
+		state_machine(t);
+
+		/* Sleep until our next timeout */
+		tsleep = -1;
+		if (tnext_state && tnext_state < tsleep)
+			tsleep = tnext_state;
+		t = get_time().val;
+		if (tsleep > t) {
+			unsigned d = tsleep == -1 ? -1 : (unsigned)(tsleep - t);
+			/*
+			 * (Yes, the conversion from uint64_t to unsigned could
+			 * theoretically overflow if we wanted to sleep for
+			 * more than 2^32 us, but our timeouts are small enough
+			 * that can't happen - and even if it did, we'd just go
+			 * back to sleep after deciding that we woke up too
+			 * early.)
+			 */
+			CPRINTF("[%T PB task %d = %s, wait %d]\n", pwrbtn_state,
+			state_names[pwrbtn_state], d);
+			task_wait_event(d);
+		}
+	}
+}
+
+/*****************************************************************************/
+/* Hooks */
+
+static void powerbtn_x86_init(void)
+{
+	set_initial_pwrbtn_state();
+}
+DECLARE_HOOK(HOOK_INIT, powerbtn_x86_init, HOOK_PRIO_DEFAULT);
+
+/**
+ * Handle switch changes based on lid event.
+ */
+static void powerbtn_x86_lid_change(void)
+{
+	/* If chipset is off, pulse the power button on lid open to wake it. */
+	if (lid_is_open() && chipset_in_state(CHIPSET_STATE_ANY_OFF)) {
+		chipset_exit_hard_off();
+		set_pwrbtn_to_pch(0);
+		pwrbtn_state = PWRBTN_STATE_LID_OPEN;
+		tnext_state = get_time().val + PWRBTN_INITIAL_US;
+		task_wake(TASK_ID_POWERBTN);
+	}
+}
+DECLARE_HOOK(HOOK_LID_CHANGE, powerbtn_x86_lid_change, HOOK_PRIO_DEFAULT);
+
+/**
+ * Handle debounced power button changing state.
+ */
+static void powerbtn_x86_changed(void)
+{
+	if (pwrbtn_state == PWRBTN_STATE_BOOT_KB_RESET ||
+	    pwrbtn_state == PWRBTN_STATE_INIT_ON ||
+	    pwrbtn_state == PWRBTN_STATE_LID_OPEN ||
+	    pwrbtn_state == PWRBTN_STATE_WAS_OFF) {
+		/* Ignore all power button changes during an initial pulse */
+		CPRINTF("[%T PB ignoring change]\n");
+		return;
+	}
+
+	if (power_button_is_pressed()) {
+		/* Power button pressed */
+		power_button_pressed(get_time().val);
+	} else {
+		/* Power button released */
+		if (pwrbtn_state == PWRBTN_STATE_EAT_RELEASE) {
+			/*
+			 * Ignore the first power button release if we already
+			 * told the PCH the power button was released.
+			 */
+			CPRINTF("[%T PB ignoring release]\n");
+			pwrbtn_state = PWRBTN_STATE_IDLE;
+			return;
+		}
+
+		power_button_released(get_time().val);
+	}
+
+	/* Wake the power button task */
+	task_wake(TASK_ID_POWERBTN);
+}
+DECLARE_HOOK(HOOK_POWER_BUTTON_CHANGE, powerbtn_x86_changed, HOOK_PRIO_DEFAULT);