ec/lenovo: Add support for MEC1653 EC

Add support for the MEC1653 EC as used by the Thinkpad T480/480s.

Change-Id: If82a7d27eb3163f51565c0c6e60cab60753611a7
Signed-off-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88395
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: David Hendricks <david.hendricks@gmail.com>
Reviewed-by: Filip Lewiński <filip.lewinski@3mdeb.com>
Reviewed-by: Máté Kukri <km@mkukri.xyz>

src/ec/lenovo/mec1653/Kconfig

@@ -0,0 +1,24 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+config EC_LENOVO_MEC1653
+	bool
+
+if EC_LENOVO_MEC1653
+
+config MEC1653_HAS_DEBUG_UNLOCK
+	bool
+
+config MEC1653_DEBUG_UNLOCK_KEY
+	string
+	depends on MEC1653_HAS_DEBUG_UNLOCK
+	help
+	  Debug unlock key necessary to enable the UART.
+
+config MEC1653_ENABLE_UART
+	bool "Enable EC UART"
+	depends on MEC1653_HAS_DEBUG_UNLOCK
+	help
+	  The EC UART physical interface is board-specific and requires
+	  a board-specific debug unlock key.
+
+endif

src/ec/lenovo/mec1653/Makefile.mk

@@ -0,0 +1,9 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+ifeq ($(CONFIG_EC_LENOVO_MEC1653),y)
+
+bootblock-y += mec1653.c
+bootblock-$(CONFIG_MEC1653_ENABLE_UART) += debug.c
+bootblock-$(CONFIG_MEC1653_ENABLE_UART) += uart.c
+
+endif

src/ec/lenovo/mec1653/debug.c

@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/io.h>
+#include <ec/acpi/ec.h>
+#include "debug.h"
+#include "mec1653.h"
+
+
+static void debug_cmd(uint8_t cmd)
+{
+	ec_set_ports(EC_SC, EC_DATA);
+	ec_write(EC_DEBUG_CMD, cmd);
+	while (ec_read(EC_DEBUG_CMD) & 0x80)
+		;
+}
+
+uint32_t debug_read_dword(uint32_t addr)
+{
+	ec_set_ports(EC3_CMD, EC3_DATA);
+	ec_clear_out_queue();
+	ec_ready_send(EC_SEND_TIMEOUT_US);
+	outl(addr << 8 | 0xE2, EC3_DATA);
+	ec_ready_recv(EC_SEND_TIMEOUT_US);
+	return inl(EC3_DATA);
+}
+
+void debug_write_dword(uint32_t addr, uint32_t val)
+{
+	ec_set_ports(EC3_CMD, EC3_DATA);
+	ec_clear_out_queue();
+	ec_ready_send(EC_SEND_TIMEOUT_US);
+	outl(addr << 8 | 0xEA, EC3_DATA);
+	ec_ready_send(EC_SEND_TIMEOUT_US);
+	outl(val, EC3_DATA);
+}
+
+// Helper function to convert hex character to byte
+static uint8_t hex_char_to_byte(char c)
+{
+	if (c >= '0' && c <= '9')
+		return c - '0';
+	if (c >= 'a' && c <= 'f')
+		return c - 'a' + 10;
+	if (c >= 'A' && c <= 'F')
+		return c - 'A' + 10;
+	return 0; // Invalid character
+}
+
+// Helper function to convert 16-char hex string to 8 bytes
+static void hex_string_to_bytes(const char *hex_str, uint8_t *bytes)
+{
+	for (int i = 0; i < 8; ++i) {
+		bytes[i] = (hex_char_to_byte(hex_str[i * 2]) << 4) |
+			   hex_char_to_byte(hex_str[i * 2 + 1]);
+	}
+}
+
+void debug_write_key(uint8_t i, const char *hex_key)
+{
+	uint8_t key_bytes[8];
+
+	ec_set_ports(EC_SC, EC_DATA);
+	hex_string_to_bytes(hex_key, key_bytes);
+
+	for (int j = 0; j < 8; ++j)
+		ec_write(0x3e + j, key_bytes[j]);
+	debug_cmd(0xc0 |  (i & 0xf));
+}
+
+void debug_read_key(uint8_t i, uint8_t *key)
+{
+	debug_cmd(0x80 | (i & 0xf));
+	for (int j = 0; j < 8; ++j)
+		key[j] = ec_read(0x3e + j);
+}
+
+uint16_t debug_loaded_keys(void)
+{
+	ec_set_ports(EC_SC, EC_DATA);
+	return (uint16_t) ec_read(0x87) << 8 | (uint16_t) ec_read(0x86);
+}

src/ec/lenovo/mec1653/debug.h

@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef EC_LENOVO_MEC1653_DEBUG_H
+#define EC_LENOVO_MEC1653_DEBUG_H
+
+// The following location (via either EC0 or EC1) can be used to interact with the debug interface
+#define EC_DEBUG_CMD		0x3d
+
+// RW unlock key index
+#define DEBUG_RW_KEY_IDX	1
+
+#define EC_SEND_TIMEOUT_US	20000	// 20ms
+#define EC_RECV_TIMEOUT_US	320000	// 320ms
+
+#define EC0_CMD		0x0066
+#define EC0_DATA	0x0062
+#define EC1_CMD		0x1604
+#define EC1_DATA	0x1600
+#define EC2_CMD		0x1634
+#define EC2_DATA	0x1630
+#define EC3_CMD		0x161c
+#define EC3_DATA	0x1618
+
+
+// Read loaded debug key mask
+uint16_t debug_loaded_keys(void);
+
+void debug_read_key(uint8_t i, uint8_t *key);
+
+void debug_write_key(uint8_t i, const char *hex_key);
+
+uint32_t debug_read_dword(uint32_t addr);
+
+void debug_write_dword(uint32_t addr, uint32_t val);
+
+#endif /* EC_LENOVO_MEC1653_DEBUG_H */

src/ec/lenovo/mec1653/mec1653.c

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <ec/acpi/ec.h>
+#include <arch/io.h>
+#include "mec1653.h"
+#include "uart.h"
+
+void bootblock_ec_init(void)
+{
+	// Tell EC via BIOS Debug Port 1 that the world isn't on fire
+
+	// Let the EC know that BIOS code is running
+	outb(0x11, 0x86);
+	outb(0x6e, 0x86);
+
+	// Enable accesses to EC1 interface
+	ec_set_ports(EC_SC, EC_DATA);
+	ec_clear_out_queue();
+	ec_write(ec_read(0), 0x20);
+
+	// Reset LEDs to power on state
+	// (Without this warm reboot leaves LEDs off)
+	ec_write(0x0c, 0x80);
+	ec_write(0x0c, 0x07);
+	ec_write(0x0c, 0x8a);
+
+	// Setup debug UART
+	if (CONFIG(MEC1653_ENABLE_UART))
+		mec1653_configure_uart();
+}

src/ec/lenovo/mec1653/mec1653.h

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef EC_LENOVO_MEC1653_H
+#define EC_LENOVO_MEC1653_H
+
+void bootblock_ec_init(void);
+
+#endif /* EC_LENOVO_MEC1653_H */

src/ec/lenovo/mec1653/uart.c

@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <device/pnp_ops.h>
+#include <ec/lenovo/mec1653/mec1653.h>
+#include "debug.h"
+#include "uart.h"
+
+static void pnp_write_config32(pnp_devfn_t dev, uint8_t offset, uint32_t value)
+{
+	pnp_write_config(dev, offset, value & 0xff);
+	pnp_write_config(dev, offset + 1, (value >> 8) & 0xff);
+	pnp_write_config(dev, offset + 2, (value >> 16) & 0xff);
+	pnp_write_config(dev, offset + 3, (value >> 24) & 0xff);
+}
+
+void mec1653_configure_uart(void)
+{
+	pnp_devfn_t lpc_dev = PNP_DEV(EC_CFG_PORT, LDN_LPCIF);
+	pnp_devfn_t uart_dev = PNP_DEV(EC_CFG_PORT, LDN_UART);
+
+	// Enter PNP conf state
+	outb(MEC_CFG_ENTRY_KEY, EC_CFG_PORT);
+
+	// Select LPC I/F LDN
+	pnp_set_logical_device(lpc_dev);
+
+	// Write UART BAR
+	pnp_write_config32(lpc_dev, LPCIF_BAR_UART, (uint32_t) UART_PORT << 16 | 0x8707);
+
+	// Set SIRQ4 to UART
+	pnp_write_config(lpc_dev, LPCIF_SIRQ(UART_IRQ), LDN_UART);
+
+	// Enable and configure UART LDN
+	pnp_set_logical_device(uart_dev);
+	pnp_set_enable(uart_dev, 1);
+	pnp_write_config(uart_dev, UART_CONFIG_SELECT, 0);
+
+	// Exit PNP conf state
+	outb(MEC_CFG_EXIT_KEY, EC_CFG_PORT);
+
+	// Supply debug unlock key
+	debug_write_key(DEBUG_RW_KEY_IDX, CONFIG_MEC1653_DEBUG_UNLOCK_KEY);
+
+	// Use debug writes to set UART_TX and UART_RX GPIOs
+	debug_write_dword(MEC1653_CFG_REG + MEC1653_CFG_TX_GPIO_OFFSET, 0x1000);
+	debug_write_dword(MEC1653_CFG_REG + MEC1653_CFG_RX_GPIO_OFFSET, 0x1000);
+}

src/ec/lenovo/mec1653/uart.h

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef EC_LENOVO_MEC1653_UART_H
+#define EC_LENOVO_MEC1653_UART_H
+
+#define MEC_CFG_ENTRY_KEY		0x55
+#define MEC_CFG_EXIT_KEY		0xaa
+
+#define UART_PORT			0x3f8
+#define UART_IRQ			4
+
+#define MEC1653_CFG_REG			0xf0c400
+#define  MEC1653_CFG_TX_GPIO_OFFSET	0x110
+#define  MEC1653_CFG_RX_GPIO_OFFSET	0x114
+
+// EC configuration base address
+#define EC_CFG_PORT			0x4e
+
+// Chip global registers
+#define PNP_LDN_SELECT			0x07
+# define LDN_UART			0x07
+# define LDN_LPCIF			0x0c
+
+// LPC I/F registers
+#define LPCIF_SIRQ(i)			(0x40 + (i))
+
+#define LPCIF_BAR_UART			0x80
+
+// UART registers
+#define UART_ACTIVATE			0x30
+#define UART_CONFIG_SELECT		0xf0
+
+void mec1653_configure_uart(void);
+
+#endif /* EC_LENOVO_MEC1653_UART_H */