mkpb: Add MKBP support over ACPI

Add a host event to support MKPB:
When sent, the ACPI code will send a notification to the kernel
cros-ec-lpcs driver that will issue EC_CMD_GET_NEXT_EVENT.
We can allow code (sensor stack for instance) that uses MKBP to work
on ACPI based architecture.

Obviously, host event over MKPB is not supported.

BRANCH=none
BUG=b:27849483
TEST=Check we get sensor events on Cyan through the sensor ring.
(cyan branch)

Change-Id: Iadc9c852b410cf69ef15bcbbb1b086c36687c687
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/353634
Reviewed-by: Randall Spangler <rspangler@chromium.org>

4 files changed, 21 insertions, 7 deletions

diff --git a/common/host_event_commands.c b/common/host_event_commands.c
index feb1d93552..4b9320c9ce 100644
--- a/common/host_event_commands.c
+++ b/common/host_event_commands.c
@@ -51,11 +51,13 @@ void host_set_events(uint32_t mask)
 	lpc_set_host_event_state(events);
 #else
 	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) = events;
-#endif
-
 #ifdef CONFIG_MKBP_EVENT
-	mkbp_send_event(EC_MKBP_EVENT_HOST_EVENT);
+#ifdef CONFIG_MKBP_USE_HOST_EVENT
+#error "Config error: MKBP must not be on top of host event"
 #endif
+	mkbp_send_event(EC_MKBP_EVENT_HOST_EVENT);
+#endif  /* CONFIG_MKBP_EVENT */
+#endif  /* !CONFIG_LPC */
 }
 
 void host_clear_events(uint32_t mask)
@@ -70,11 +72,10 @@ void host_clear_events(uint32_t mask)
 	lpc_set_host_event_state(events);
 #else
 	*(uint32_t *)host_get_memmap(EC_MEMMAP_HOST_EVENTS) = events;
-#endif
-
 #ifdef CONFIG_MKBP_EVENT
 	mkbp_send_event(EC_MKBP_EVENT_HOST_EVENT);
 #endif
+#endif  /* !CONFIG_LPC */
 }
 
 static int host_get_next_event(uint8_t *out)
diff --git a/common/mkbp_event.c b/common/mkbp_event.c
index 95bb4fd3f5..60ca19d645 100644
--- a/common/mkbp_event.c
+++ b/common/mkbp_event.c
@@ -36,7 +36,12 @@ static int event_is_set(uint8_t event_type)
 static void set_host_interrupt(int active)
 {
 	/* interrupt host by using active low EC_INT signal */
+#ifdef CONFIG_MKBP_USE_HOST_EVENT
+	if (active)
+		host_set_single_event(EC_HOST_EVENT_MKBP);
+#else
 	gpio_set_level(GPIO_EC_INT_L, !active);
+#endif
 }
 
 void mkbp_send_event(uint8_t event_type)
diff --git a/include/config.h b/include/config.h
index c432d25c6c..fca9942f62 100644
--- a/include/config.h
+++ b/include/config.h
@@ -1395,6 +1395,9 @@
 /* Support MKBP event */
 #undef CONFIG_MKBP_EVENT
 
+/* MKBP events are sent using host event */
+#undef CONFIG_MKBP_USE_HOST_EVENT
+
 /*
  * With this option, we can define the MKBP wakeup events in this mask (as a
  * white list) in board level, those events allow to interrupt AP during S3.
diff --git a/include/ec_commands.h b/include/ec_commands.h
index e17a784215..66c8f61077 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -437,6 +437,9 @@ enum host_event_code {
 	/* EC RTC event occurred */
 	EC_HOST_EVENT_RTC = 26,
 
+	/* Emulate MKBP event */
+	EC_HOST_EVENT_MKBP = 27,
+
 	/*
 	 * The high bit of the event mask is not used as a host event code.  If
 	 * it reads back as set, then the entire event mask should be
@@ -3198,8 +3201,10 @@ struct ec_params_entering_mode {
 #define VBOOT_MODE_RECOVERY  2
 
 /*****************************************************************************/
-/* I2C passthru protection command: Protects I2C tunnels against access on
- * certain addresses (board-specific). */
+/*
+ * I2C passthru protection command: Protects I2C tunnels against access on
+ * certain addresses (board-specific).
+ */
 #define EC_CMD_I2C_PASSTHRU_PROTECT 0xb7
 
 enum ec_i2c_passthru_protect_subcmd {