Commit 1cd37f21 authored by Hou Zhiqiang's avatar Hou Zhiqiang Committed by David Leach
Browse files

drivers: ram_console: add option to link console buffer to given section 



Currently, the ram_console buffer is defined as a global var, its
address is determined during the building and may be changed when
code update. This is not a problem if the ram_console is just used
in debug purpose.

While in the heterogeneous SoCs, there can be multiple MPU Cores
and several MCU cores, it can run multiple OS/bare-metal instances
on these cores, but the UART ports may be not enough, so the
ram_console can be leveraged. To make it easy to use, it's better
make the console buffer fixed and predefined.

This patch adds a option to link the console buffer to a given
section, through the "zephyr,memory-region" device tree node, then
the address can be known from the device tree node and easy to
check from other cores running Linux/U-Boot.

To use this option, the chosen property 'zephyr,ram-console' must
be added, the following is a example:

	chosen {
		zephyr,ram-console = &ram_console;
	};

	ram_console: memory@93d00000 {
		compatible = "zephyr,memory-region";
		reg = <0x93d00000 DT_SIZE_K(4)>;
		zephyr,memory-region = "RAM_CONSOLE";
	};

Signed-off-by: default avatarHou Zhiqiang <Zhiqiang.Hou@nxp.com>
parent 209568ea

drivers/console/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -95,16 +95,30 @@ config JAILHOUSE_DEBUG_CONSOLE 
	  Useful in board bring-up if there aren't any working serial

	  drivers.



# Workaround for not being able to have commas in macro arguments

DT_CHOSEN_Z_RAM_CONSOLE := zephyr,ram-console



config RAM_CONSOLE

	bool "Use RAM console"

	select CONSOLE_HAS_DRIVER

	select RAM_CONSOLE_BUFFER_SECTION if $(dt_chosen_enabled,$(DT_CHOSEN_Z_RAM_CONSOLE))

	help

	  Emit console messages to a RAM buffer "ram_console" which can

	  be examined at runtime with a debugger. Useful in board bring-up

	  if there aren't any working serial drivers.



config RAM_CONSOLE_BUFFER_SECTION

	bool "Use dedicated section as RAM console buffer"

	depends on RAM_CONSOLE && $(dt_chosen_enabled,$(DT_CHOSEN_Z_RAM_CONSOLE))

	select KERNEL_DIRECT_MAP if MMU

	help

	  Use a dedicated section as the RAM console buffer, whose address is

	  known before build so that the console output messages can be easily

	  examined by a debugger or software tool from a parallel-running OS.



config RAM_CONSOLE_BUFFER_SIZE

	int "Ram Console buffer size"

	default $(dt_chosen_reg_size_int,$(DT_CHOSEN_Z_RAM_CONSOLE)) if RAM_CONSOLE_BUFFER_SECTION

	default 1024

	depends on RAM_CONSOLE

	help

drivers/console/ram_console.c

+26 −1
Original line number Diff line number Diff line
@@ -2,6 +2,7 @@ 


/*

 * Copyright (c) 2015 Intel Corporation

 * Copyright 2024 NXP

 *

 * SPDX-License-Identifier: Apache-2.0

 */
@@ -11,11 +12,26 @@ 
#include <zephyr/sys/printk.h>

#include <zephyr/device.h>

#include <zephyr/init.h>

#include <zephyr/linker/devicetree_regions.h>



#ifdef CONFIG_RAM_CONSOLE_BUFFER_SECTION

#if !DT_HAS_CHOSEN(zephyr_ram_console)

#error "Lack of chosen property zephyr,ram_console!"

#elif (CONFIG_RAM_CONSOLE_BUFFER_SIZE > DT_REG_SIZE(DT_CHOSEN(zephyr_ram_console)))

#error "Custom RAM console buffer exceeds the section size!"

#endif



#define RAM_CONSOLE_BUF_ATTR	\

	__attribute__((__section__(LINKER_DT_NODE_REGION_NAME(DT_CHOSEN(zephyr_ram_console)))))

#else

#define RAM_CONSOLE_BUF_ATTR

#endif



extern void __printk_hook_install(int (*fn)(int));

extern void __stdout_hook_install(int (*fn)(int));



char ram_console[CONFIG_RAM_CONSOLE_BUFFER_SIZE];

char ram_console_buf[CONFIG_RAM_CONSOLE_BUFFER_SIZE] RAM_CONSOLE_BUF_ATTR;

char *ram_console;

static int pos;



static int ram_console_out(int character)
@@ -28,6 +44,15 @@ static int ram_console_out(int character) 


static int ram_console_init(void)

{

#ifdef CONFIG_RAM_CONSOLE_BUFFER_SECTION

	mm_reg_t ram_console_va;



	device_map((mm_reg_t *)&ram_console_va, DT_REG_ADDR(DT_CHOSEN(zephyr_ram_console)),

		   CONFIG_RAM_CONSOLE_BUFFER_SIZE, K_MEM_CACHE_NONE | K_MEM_DIRECT_MAP);

	ram_console = (char *)ram_console_va,

#else

	ram_console = ram_console_buf,

#endif

	__printk_hook_install(ram_console_out);

	__stdout_hook_install(ram_console_out);

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