ec/starlabs/merlin: Add support for the ITE mirror flag

When enabled, the EC will mirror the firmware contained inside the
coreboot ROM. This allows it to be updated at the same time as
coreboot.

Enable the mirror flag if the installed EC firmware does not match
the target version or if a CMOS option, "manual_mirror_flag" is
set.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I377abbb37dc4d3e535e518a73e73969b25967daa
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73044
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/ec/starlabs/merlin/Kconfig

@@ -64,6 +64,20 @@ config EC_STARLABS_MAX_CHARGE
 	help
 	  Select if the mainboard supports limiting the maximum charge of the battery.
 
+config EC_STARLABS_MIRROR_SUPPORT
+	bool "Enable mirror flag support"
+	default n
+	depends on EC_STARLABS_ITE
+	help
+	  Select if the EC should mirror the EC firmware contained in the coreboot ROM.
+
+config EC_STARLABS_MIRROR_VERSION
+	hex "Version of the EC firmware that should be installed."
+	depends on EC_STARLABS_MIRROR_SUPPORT
+	help
+	  The version of the EC that should be installed. The mirror flag will be activated
+	  if this Kconfig option is set and it does not match the current EC version.
+
 config EC_STARLABS_MERLIN
 	bool "Use open-source Merlin EC Firmware"
 	default n

src/ec/starlabs/merlin/ec.h

@@ -98,6 +98,13 @@
 #define KBL_DISABLED		0x00
 #define KBL_ENABLED		0xdd
 
+/* Mirror Flag */
+#define MIRROR_DISABLED		0x00
+#define MIRROR_ENABLED		0xaa
+
+#define MIRROR_ATTEMPTS		1
+
 uint16_t ec_get_version(void);
+void ec_mirror_flag(void);
 
 #endif

src/ec/starlabs/merlin/ite.c

@@ -6,6 +6,7 @@
 #include <ec/acpi/ec.h>
 #include <option.h>
 #include <pc80/keyboard.h>
+#include <halt.h>
 
 #include "ec.h"
 #include "ecdefs.h"
@@ -26,6 +27,66 @@ static uint8_t get_ec_value_from_option(const char *name,
 	return lut[index];
 }
 
+static void ec_mirror_with_count(void)
+{
+	unsigned int cmos_mirror_flag_counter = get_uint_option("mirror_flag_counter", UINT_MAX);
+
+	if (cmos_mirror_flag_counter != UINT_MAX) {
+		printk(BIOS_DEBUG, "ITE: mirror_flag_counter = %u\n", cmos_mirror_flag_counter);
+
+		/* Avoid boot loops by only trying a state change once */
+		if (cmos_mirror_flag_counter < MIRROR_ATTEMPTS) {
+			cmos_mirror_flag_counter++;
+			set_uint_option("mirror_flag_counter", cmos_mirror_flag_counter);
+			printk(BIOS_DEBUG, "ITE: Mirror attempt %u/%u.\n", cmos_mirror_flag_counter,
+				MIRROR_ATTEMPTS);
+
+			/* Write the EC mirror flag */
+			ec_write(ECRAM_MIRROR_FLAG, MIRROR_ENABLED);
+
+			/* Check what has been written */
+			if (ec_read(ECRAM_MIRROR_FLAG) == MIRROR_ENABLED)
+				poweroff();
+		} else {
+			/*
+			 * If the mirror flags fails after 1 attempt, it will
+			 * likely need a cold boot, or recovering.
+			 */
+			printk(BIOS_ERR, "ITE: Failed to mirror the EC in %u attempts!\n",
+				MIRROR_ATTEMPTS);
+		}
+	} else {
+		printk(BIOS_DEBUG, "ITE: Powering Off");
+		/* Write the EC mirror flag */
+		ec_write(ECRAM_MIRROR_FLAG, MIRROR_ENABLED);
+
+		/* Check what has been written */
+		if (ec_read(ECRAM_MIRROR_FLAG) == MIRROR_ENABLED)
+			poweroff();
+	}
+}
+
+
+void ec_mirror_flag(void)
+{
+	/*
+	 * For the mirror flag to work, the status of the EC pin must be known
+	 * at all times, which means external power. This can be either a DC
+	 * charger, or PD with CCG6. PD with an ANX7447 requires configuration
+	 * from the EC, so the update will interrupt this.
+	 *
+	 * This means we can unconditionally apply the mirror flag to devices
+	 * that have CCG6, present on devices with TBT, but have a manual
+	 * flag for devices without it.
+	 */
+	if (CONFIG(EC_STARLABS_MIRROR_SUPPORT) &&
+		(CONFIG(SOC_INTEL_COMMON_BLOCK_TCSS) || get_uint_option("mirror_flag", 0)) &&
+		(ec_get_version() != CONFIG_EC_STARLABS_MIRROR_VERSION))	{
+		printk(BIOS_ERR, "ITE: System and EC ROM version mismatch.\n");
+		ec_mirror_with_count();
+	}
+}
+
 static uint16_t ec_get_chip_id(unsigned int port)
 {
 	return (pnp_read_index(port, ITE_CHIPID1) << 8) |
@@ -57,6 +118,8 @@ static void merlin_init(struct device *dev)
 		return;
 	}
 
+	ec_mirror_flag();
+
 	pc_keyboard_init(NO_AUX_DEVICE);
 
 	/*

src/ec/starlabs/merlin/variants/adl/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	0x1a
 #define ECRAM_FAN_MODE		0x1b
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x05
 
 #endif

src/ec/starlabs/merlin/variants/apl/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x04
 
 #endif

src/ec/starlabs/merlin/variants/cezanne/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_KBL_BRIGHTNESS	0x36
 #define ECRAM_FN_LOCK_STATE	0x70
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x05
 
 #endif

src/ec/starlabs/merlin/variants/cml/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_KBL_BRIGHTNESS	0x19
 #define ECRAM_FN_LOCK_STATE	0x2c
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x04
 
 #endif

src/ec/starlabs/merlin/variants/glk/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x04
 
 #endif

src/ec/starlabs/merlin/variants/glkr/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAN_MODE		dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE       0x18
+#define ECRAM_MIRROR_FLAG	dead_code_t(uint8_t)
 
 #endif

src/ec/starlabs/merlin/variants/kbl/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_FN_CTRL_REVERSE	0x43
 #define ECRAM_MAX_CHARGE	dead_code_t(uint8_t)
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x04
 
 #endif

src/ec/starlabs/merlin/variants/merlin/ecdefs.h

@@ -20,5 +20,6 @@
 #define ECRAM_FAN_MODE		0x50
 #define ECRAM_MAX_CHARGE	0x51
 #define ECRAM_FAST_CHARGE       0x52
+#define ECRAM_MIRROR_FLAG	0x05
 
 #endif

src/ec/starlabs/merlin/variants/tgl/ecdefs.h

@@ -23,5 +23,6 @@
 #define ECRAM_MAX_CHARGE	0x1a
 #define ECRAM_FAN_MODE		0x1b
 #define ECRAM_FAST_CHARGE	dead_code_t(uint8_t)
+#define ECRAM_MIRROR_FLAG	0x05
 
 #endif