[M] Change in coreboot[main]: [WIP] src/console: Add read-only flash console

[J. Neuschäfer (Code Review)]

J. Neuschäfer has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/84214?usp=email )

Change subject: [WIP] src/console: Add read-only flash console
......................................................................

[WIP] src/console: Add read-only flash console

Change-Id: Ie2f7a48e0cc6f7e91129bea9f15a5b7de3bbdfab
Signed-off-by: J. Neuschäfer 
---
M src/console/Kconfig
M src/console/console.c
M src/drivers/spi/Makefile.mk
A src/drivers/spi/ro_flashconsole.c
A src/include/console/ro_flash.h
5 files changed, 66 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/14/84214/1

diff --git a/src/console/Kconfig b/src/console/Kconfig
index db71204..c90c083 100644
--- a/src/console/Kconfig
+++ b/src/console/Kconfig
@@ -300,6 +300,22 @@
      value (128K or 0x20000 bytes) is large enough to accommodate
      even the BIOS_SPEW level.

+config CONSOLE_RO_FLASH
+	bool "Read-only flash console"
+	default n
+	help
+	  Read-only flash console. (TODO)
+
+if CONSOLE_RO_FLASH
+
+config CONSOLE_RO_FLASH_OFFSET
+	hex "Base offset into flash"
+
+config CONSOLE_RO_FLASH_SHIFT
+	int "Bit shift"
+
+endif # CONSOLE_RO_FLASH
+
 config CONSOLE_I2C_SMBUS
    bool "SMBus console output"
    depends on SOUTHBRIDGE_INTEL_COMMON_SMBUS
diff --git a/src/console/console.c b/src/console/console.c
index bb9d374..cec3c43 100644
--- a/src/console/console.c
+++ b/src/console/console.c
@@ -12,6 +12,7 @@
 #include <console/system76_ec.h>
 #include <console/uart.h>
 #include <console/usb.h>
+#include <console/ro_flash.h>
 #include <types.h>

/* Note: when adding a new console, make sure you update the definition of
@@ -27,6 +28,7 @@
    __usbdebug_init();
    __spiconsole_init();
    __flashconsole_init();
+	__ro_flashconsole_init();
    __system76_ec_init();
    __i2c_smbus_console_init();
    __simnow_console_init();
@@ -47,6 +49,7 @@
    __ne2k_tx_byte(byte);
    __usb_tx_byte(byte);
    __spiconsole_tx_byte(byte);
+	__ro_flashconsole_tx_byte(byte);
    __system76_ec_tx_byte(byte);
    __i2c_smbus_console_tx_byte(byte);
    __simnow_console_tx_byte(byte);
diff --git a/src/drivers/spi/Makefile.mk b/src/drivers/spi/Makefile.mk
index 97c3d63..6724cd1 100644
--- a/src/drivers/spi/Makefile.mk
+++ b/src/drivers/spi/Makefile.mk
@@ -20,6 +20,7 @@
 $(1)-$(CONFIG_SPI_SDCARD) += spi_sdcard.c
 $(1)-$(CONFIG_BOOT_DEVICE_SPI_FLASH_RW_NOMMAP$(2)) += boot_device_rw_nommap.c
 $(1)-$(CONFIG_CONSOLE_SPI_FLASH) += flashconsole.c
+$(1)-$(CONFIG_CONSOLE_RO_FLASH) += ro_flashconsole.c
 $(1)-$(CONFIG_SPI_FLASH_ADESTO) += adesto.c
 $(1)-$(CONFIG_SPI_FLASH_AMIC) += amic.c
 $(1)-$(CONFIG_SPI_FLASH_ATMEL) += atmel.c
diff --git a/src/drivers/spi/ro_flashconsole.c b/src/drivers/spi/ro_flashconsole.c
new file mode 100644
index 0000000..14a12d0
--- /dev/null
+++ b/src/drivers/spi/ro_flashconsole.c
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <console/ro_flash.h>
+#include <commonlib/region.h>
+#include <boot_device.h>
+
+void ro_flashconsole_init(void)
+{
+}
+
+void ro_flashconsole_tx_byte(unsigned char c)
+{
+	const struct region_device *rdev = boot_device_ro();
+	uint32_t offset = CONFIG_CONSOLE_RO_FLASH_OFFSET + (c << CONFIG_CONSOLE_RO_FLASH_SHIFT);
+
+	char buf[1];
+	rdev_readat(rdev, buf, offset, 1);
+}
diff --git a/src/include/console/ro_flash.h b/src/include/console/ro_flash.h
new file mode 100644
index 0000000..c5858b5
--- /dev/null
+++ b/src/include/console/ro_flash.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef CONSOLE_RO_FLASH_H
+#define CONSOLE_RO_FLASH_H
+
+#include <stdint.h>
+
+void ro_flashconsole_init(void);
+void ro_flashconsole_tx_byte(unsigned char data);
+
+#define __RO_FLASHCONSOLE_ENABLE__	CONFIG(CONSOLE_RO_FLASH)
+
+#if __RO_FLASHCONSOLE_ENABLE__
+static inline void __ro_flashconsole_init(void)
+{
+	ro_flashconsole_init();
+}
+
+static inline void __ro_flashconsole_tx_byte(u8 data)
+{
+	ro_flashconsole_tx_byte(data);
+}
+#else
+static inline void __ro_flashconsole_init(void)	{}
+static inline void __ro_flashconsole_tx_byte(u8 data)	{}
+#endif
+
+#endif /* CONSOLE_RO_FLASH_H */