cbmk/config/coreboot/default/patches/0006-ec-dell-mec5035-Add-S3-suspend-SMI-handler.patch

From f20c476a9358865d347c83d15f1943e4e238fe88 Mon Sep 17 00:00:00 2001
From: Nicholas Chin <nic.c3.14@gmail.com>
Date: Fri, 3 May 2024 11:03:32 -0600
Subject: [PATCH 06/18] ec/dell/mec5035: Add S3 suspend SMI handler

This is necessary for S3 resume to work on SNB and newer Dell Latitude
laptops. If a command isn't sent, the EC cuts power to the DIMMs,
preventing the system from resuming. These commands were found using an
FPGA to log all LPC bus transactions between the host and the EC and
then narrowing down which ones were actually necessary.

Interestingly, the command IDs appear to be identical to those in
ec/google/wilco, the EC used on Dell Latitude Chromebooks, and that EC
implements a similar S3 SMI handler as the one implemented in this
commit. The Wilco EC Kconfig does suggest that its firmware is a
modified version of Dell's usual Latitude EC firmware, so the
similarities seem to be intentional.

These similarities also identified a command to enable or disable wake
sources like the power button and lid switch, and this was added to the
SMI handler to disable lid wake as the system does not yet resume
properly from a like wake with coreboot.

Tested on the Latitude E6430 (Ivy Bridge) and the Precision M6800
(Haswell, not yet pushed).

Change-Id: I655868aba46911d128f6c24f410dc6fdf83f3070
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
---
 src/ec/dell/mec5035/Makefile.mk  |  1 +
 src/ec/dell/mec5035/mec5035.c    | 14 ++++++++++++++
 src/ec/dell/mec5035/mec5035.h    | 22 ++++++++++++++++++++++
 src/ec/dell/mec5035/smihandler.c | 17 +++++++++++++++++
 4 files changed, 54 insertions(+)
 create mode 100644 src/ec/dell/mec5035/smihandler.c

diff --git a/src/ec/dell/mec5035/Makefile.mk b/src/ec/dell/mec5035/Makefile.mk
index 4ebdd811f9..be557e4599 100644
--- a/src/ec/dell/mec5035/Makefile.mk
+++ b/src/ec/dell/mec5035/Makefile.mk
@@ -5,5 +5,6 @@ ifeq ($(CONFIG_EC_DELL_MEC5035),y)
 bootblock-y += mec5035.c
 romstage-y += mec5035.c
 ramstage-y += mec5035.c
+smm-y += mec5035.c smihandler.c
 
 endif
diff --git a/src/ec/dell/mec5035/mec5035.c b/src/ec/dell/mec5035/mec5035.c
index dffbb7960c..85c2ab0140 100644
--- a/src/ec/dell/mec5035/mec5035.c
+++ b/src/ec/dell/mec5035/mec5035.c
@@ -94,6 +94,20 @@ void mec5035_control_radio(enum ec_radio_dev dev, enum ec_radio_state state)
 	ec_command(CMD_RADIO_CTRL);
 }
 
+void mec5035_change_wake(u8 source, enum ec_wake_change change)
+{
+	u8 buf[ACPI_WAKEUP_NUM_ARGS] = {change, source, 0, 0x40};
+	write_mailbox_regs(buf, 2, ACPI_WAKEUP_NUM_ARGS);
+	ec_command(CMD_ACPI_WAKEUP_CHANGE);
+}
+
+void mec5035_sleep_enable(void)
+{
+	u8 buf[SLEEP_EN_NUM_ARGS] = {3, 0};
+	write_mailbox_regs(buf, 2, SLEEP_EN_NUM_ARGS);
+	ec_command(CMD_SLEEP_ENABLE);
+}
+
 void mec5035_early_init(void)
 {
 	/* If this isn't sent the EC shuts down the system after about 15
diff --git a/src/ec/dell/mec5035/mec5035.h b/src/ec/dell/mec5035/mec5035.h
index 32f791cb01..8d4fded28b 100644
--- a/src/ec/dell/mec5035/mec5035.h
+++ b/src/ec/dell/mec5035/mec5035.h
@@ -4,12 +4,15 @@
 #define _EC_DELL_MEC5035_H_
 
 #include <stdint.h>
+#include <types.h>
 
 #define NUM_REGISTERS	32
 
 enum mec5035_cmd {
 	CMD_MOUSE_TP = 0x1a,
 	CMD_RADIO_CTRL = 0x2b,
+	CMD_ACPI_WAKEUP_CHANGE = 0x4a,
+	CMD_SLEEP_ENABLE = 0x64,
 	CMD_CPU_OK = 0xc2,
 };
 
@@ -33,9 +36,28 @@ enum ec_radio_state {
 	RADIO_ON
 };
 
+#define ACPI_WAKEUP_NUM_ARGS 4
+enum ec_wake_change {
+	WAKE_OFF = 0,
+	WAKE_ON
+};
+
+/* Copied from ec/google/wilco/commands.h. Not sure if these all apply */
+enum ec_acpi_wake_events {
+	EC_ACPI_WAKE_PWRB = BIT(0),     /* Wake up by power button */
+	EC_ACPI_WAKE_LID = BIT(1),      /* Wake up by lid switch */
+	EC_ACPI_WAKE_RTC = BIT(5),      /* Wake up by RTC */
+};
+
+#define SLEEP_EN_NUM_ARGS 2
+
 u8 mec5035_mouse_touchpad(enum ec_mouse_setting setting);
 void mec5035_cpu_ok(void);
 void mec5035_early_init(void);
 void mec5035_control_radio(enum ec_radio_dev device, enum ec_radio_state state);
+void mec5035_change_wake(u8 source, enum ec_wake_change change);
+void mec5035_sleep_enable(void);
+
+void mec5035_smi_sleep(int slp_type);
 
 #endif /* _EC_DELL_MEC5035_H_ */
diff --git a/src/ec/dell/mec5035/smihandler.c b/src/ec/dell/mec5035/smihandler.c
new file mode 100644
index 0000000000..958733bf97
--- /dev/null
+++ b/src/ec/dell/mec5035/smihandler.c
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <acpi/acpi.h>
+#include <console/console.h>
+#include <ec/acpi/ec.h>
+#include "mec5035.h"
+
+void mec5035_smi_sleep(int slp_type)
+{
+	switch (slp_type) {
+	case ACPI_S3:
+		/* System does not yet resume properly if woken by lid */
+		mec5035_change_wake(EC_ACPI_WAKE_LID, WAKE_OFF);
+		mec5035_sleep_enable();
+		break;
+	}
+}
-- 
2.39.5