[coreboot-gerrit] Change in coreboot[master]: ec/system76: Add console support

[Jeremy Soller (Code Review)]

Jeremy Soller has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/43718 )

Change subject: ec/system76: Add console support
......................................................................

ec/system76: Add console support

This adds support for line-buffered console output to System76 EC firmware.

Tested on system76/lemp9 with CONSOLE_SYSTEM76_EC enabled.

Signed-off-by: Jeremy Soller 
Change-Id: I861bf3e22f40dd6c3ec7ba1d73711b399358e332
---
M src/console/Kconfig
M src/console/console.c
A src/ec/system76/ec/Makefile.inc
A src/ec/system76/ec/system76_ec.c
A src/include/console/system76_ec.h
5 files changed, 102 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/18/43718/1

diff --git a/src/console/Kconfig b/src/console/Kconfig
index 7c6e9bc..bad6c56 100644
--- a/src/console/Kconfig
+++ b/src/console/Kconfig
@@ -302,6 +302,13 @@
      This is currently working only in ramstage due to how the spi
      drivers are written.

+config CONSOLE_SYSTEM76_EC
+	bool "System76 EC console output"
+	default n
+	depends on EC_SYSTEM76_EC
+	help
+	  Send coreboot debug output to a System76 embedded controller.
+
 config CONSOLE_OVERRIDE_LOGLEVEL
    bool
    help
diff --git a/src/console/console.c b/src/console/console.c
index bc9d918..2f544a8 100644
--- a/src/console/console.c
+++ b/src/console/console.c
@@ -9,6 +9,7 @@
 #include <console/usb.h>
 #include <console/spi.h>
 #include <console/flash.h>
+#include <console/system76_ec.h>

void console_hw_init(void)
 {
@@ -21,6 +22,7 @@
    __usbdebug_init();
    __spiconsole_init();
    __flashconsole_init();
+	__system76_ec_init();
 }

void console_tx_byte(unsigned char byte)
@@ -42,6 +44,7 @@
    __usb_tx_byte(byte);
    __spiconsole_tx_byte(byte);
    __flashconsole_tx_byte(byte);
+	__system76_ec_tx_byte(byte);
 }

void console_tx_flush(void)
@@ -50,6 +53,7 @@
    __ne2k_tx_flush();
    __usb_tx_flush();
    __flashconsole_tx_flush();
+	__system76_ec_tx_flush();
 }

void console_write_line(uint8_t *buffer, size_t number_of_bytes)
diff --git a/src/ec/system76/ec/Makefile.inc b/src/ec/system76/ec/Makefile.inc
new file mode 100644
index 0000000..382daa6
--- /dev/null
+++ b/src/ec/system76/ec/Makefile.inc
@@ -0,0 +1,6 @@
+ifeq ($(CONFIG_EC_SYSTEM76_EC),y)
+
+all-y += system76_ec.c
+smm-$(CONFIG_DEBUG_SMI) += system76_ec.c
+
+endif
diff --git a/src/ec/system76/ec/system76_ec.c b/src/ec/system76/ec/system76_ec.c
new file mode 100644
index 0000000..238e630
--- /dev/null
+++ b/src/ec/system76/ec/system76_ec.c
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <arch/io.h>
+#include <console/system76_ec.h>
+#include <timer.h>
+
+#define SYSTEM76_EC_BASE 0x0E00
+
+static inline uint8_t system76_ec_read(uint8_t addr)
+{
+	return inb(SYSTEM76_EC_BASE + (uint16_t)addr);
+}
+
+static inline void system76_ec_write(uint8_t addr, uint8_t data)
+{
+	outb(data, SYSTEM76_EC_BASE + (uint16_t)addr);
+}
+
+void system76_ec_init(void)
+{
+	// Clear entire command region
+	for (int i = 0; i < 256; i++)
+		system76_ec_write((uint8_t)i, 0);
+}
+
+void system76_ec_flush(void)
+{
+	// Send command
+	system76_ec_write(0, 4);
+
+	// Wait for command completion, for up to 10 milliseconds
+	wait_us(10000, system76_ec_read(0) == 0);
+
+	// Clear length
+	system76_ec_write(3, 0);
+}
+
+void system76_ec_print(uint8_t byte)
+{
+	// Read length
+	uint8_t len = system76_ec_read(3);
+	// Write data at offset
+	system76_ec_write(len + 4, byte);
+	// Update length
+	system76_ec_write(3, len + 1);
+
+	// If we hit the end of the buffer, or were given a newline, flush
+	if (byte == '\n' || len >= 128)
+		system76_ec_flush();
+}
diff --git a/src/include/console/system76_ec.h b/src/include/console/system76_ec.h
new file mode 100644
index 0000000..616e46f
--- /dev/null
+++ b/src/include/console/system76_ec.h
@@ -0,0 +1,35 @@
+#ifndef CONSOLE_SYSTEM76_EC_H
+#define CONSOLE_SYSTEM76_EC_H 1
+
+#include <stddef.h>
+#include <stdint.h>
+
+void system76_ec_init(void);
+void system76_ec_flush(void);
+void system76_ec_print(uint8_t byte);
+
+#define __CONSOLE_SYSTEM76_EC_ENABLE__	(CONFIG(CONSOLE_SYSTEM76_EC) && \
+	(ENV_BOOTBLOCK || ENV_ROMSTAGE || ENV_RAMSTAGE \
+	 || ENV_SEPARATE_VERSTAGE || ENV_POSTCAR \
+	 || (ENV_SMM && CONFIG(DEBUG_SMI))))
+
+#if __CONSOLE_SYSTEM76_EC_ENABLE__
+static inline void __system76_ec_init(void)
+{
+	system76_ec_init();
+}
+static inline void __system76_ec_tx_flush(void)
+{
+	system76_ec_flush();
+}
+static inline void __system76_ec_tx_byte(unsigned char byte)
+{
+	system76_ec_print(byte);
+}
+#else
+static inline void __system76_ec_init(void) {}
+static inline void __system76_ec_tx_flush(void) {}
+static inline void __system76_ec_tx_byte(unsigned char byte) {}
+#endif
+
+#endif