Commit 1811fff2 authored by ZhongYao Luo's avatar ZhongYao Luo Committed by Kumar Gala
Browse files

console: Add semihosting console 



Many chips have only one serial port. When the serial port is occupied
by other devices, there is a lack of a console to output debugging
information. Semihosting can provide a console. The disadvantage of
semihosting is that a debugger must be connected, so it can only be
used for online debugging.

Signed-off-by: default avatarZhongYao Luo <LuoZhongYao@gmail.com>
Signed-off-by: default avatarCarles Cufi <carles.cufi@nordicsemi.no>
parent 8c051f08

CODEOWNERS

+1 −0
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@@ -139,6 +139,7 @@ 
/drivers/can/*mcp2515*                    @karstenkoenig

/drivers/clock_control/*nrf*              @nordic-krch

/drivers/counter/                         @nordic-krch

/drivers/console/semihost_console.c       @luozhongyao

/drivers/counter/counter_cmos.c           @andrewboie

/drivers/counter/maxim_ds3231.c           @pabigot

/drivers/crypto/*nrf_ecb*                 @maciekfabia @anangl

drivers/console/CMakeLists.txt

+1 −0
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@@ -11,3 +11,4 @@ zephyr_sources_if_kconfig(xtensa_sim_console.c) 
zephyr_sources_if_kconfig(native_posix_console.c)

zephyr_sources_if_kconfig(uart_mux.c)

zephyr_sources_if_kconfig(gsm_mux.c)

zephyr_sources_if_kconfig(semihost_console.c)

drivers/console/Kconfig

+14 −0
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@@ -291,6 +291,20 @@ config NATIVE_POSIX_CONSOLE_INIT_PRIORITY 
	help

	  Device driver initialization priority.



config SEMIHOST_CONSOLE

	bool "Use semihosting for console"

	select CONSOLE_HAS_DRIVER

	depends on CPU_CORTEX_M

	help

	  Enable this option to use semihosting for console.

	  Semihosting is a mechanism that enables code running on an ARM target

	  to communicate and use the Input/Output facilities on a host computer

	  that is running a debugger.

	  Additional information can be found in:

	  https://developer.arm.com/docs/dui0471/k/what-is-semihosting/what-is-semihosting

	  This option is compatible with hardware and with QEMU, through the

	  (automatic) use of the -semihosting-config switch when invoking it.



module = UART_CONSOLE

module-str = UART console

source "subsys/logging/Kconfig.template.log_config"

drivers/console/semihost_console.c

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/*

 * Copyright (c) 2019 LuoZhongYao

 * SPDX-License-Identifier: Apache-2.0

 */



#include <kernel.h>

#include <device.h>

#include <init.h>

#include <sys/printk.h>



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

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



static int semihost_console_out(int ch)

{

	static unsigned char c;



	c = ch;

	__asm__ __volatile__ (

		"movs	r1, %0\n"

		"movs	r0, #3\n"

		"bkpt	0xab\n"

		:

		: "r" (&c)

		: "r0", "r1");

	return ch;

}



static int semihost_console_init(struct device *dev)

{

	ARG_UNUSED(dev);



	__printk_hook_install(semihost_console_out);

	__stdout_hook_install(semihost_console_out);



	return 0;

}



SYS_INIT(semihost_console_init, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

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