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Commit d88bb418 authored by Gerald Baeza's avatar Gerald Baeza Committed by Olof Johansson
Browse files

ARM: stm32: debug: add low-level debug support 



This adds low-level debug support on USART1 for STM32F4
and STM32F7.
Compiled via 'CONFIG_DEBUG_LL' and 'CONFIG_EARLY_PRINTK'.
Enabled via 'earlyprintk' in bootargs.

Signed-off-by: default avatarGerald Baeza <gerald.baeza@st.com>
Signed-off-by: default avatarBich Hemon <bich.hemon@st.com>
Acked-by: default avatarAlexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
parent ccda4af0

arch/arm/Kconfig.debug

+27 −0
Original line number Diff line number Diff line
@@ -1192,6 +1192,28 @@ choice 


		  If unsure, say N.



	config STM32F4_DEBUG_UART

		bool "Use STM32F4 UART for low-level debug"

		depends on ARCH_STM32

		select DEBUG_STM32_UART

		help

		  Say Y here if you want kernel low-level debugging support

		  on STM32F4 based platforms, which default UART is wired on

		  USART1.



		  If unsure, say N.



	config STM32F7_DEBUG_UART

		bool "Use STM32F7 UART for low-level debug"

		depends on ARCH_STM32

		select DEBUG_STM32_UART

		help

		  Say Y here if you want kernel low-level debugging support

		  on STM32F7 based platforms, which default UART is wired on

		  USART1.



		  If unsure, say N.



	config TEGRA_DEBUG_UART_AUTO_ODMDATA

		bool "Kernel low-level debugging messages via Tegra UART via ODMDATA"

		depends on ARCH_TEGRA
@@ -1476,6 +1498,10 @@ config DEBUG_STI_UART 
	bool

	depends on ARCH_STI



config DEBUG_STM32_UART

	bool

	depends on ARCH_STM32



config DEBUG_SIRFSOC_UART

	bool

	depends on ARCH_SIRF
@@ -1525,6 +1551,7 @@ config DEBUG_LL_INCLUDE 
	default "debug/s5pv210.S" if DEBUG_S5PV210_UART

	default "debug/sirf.S" if DEBUG_SIRFSOC_UART

	default "debug/sti.S" if DEBUG_STI_UART

	default "debug/stm32.S" if DEBUG_STM32_UART

	default "debug/tegra.S" if DEBUG_TEGRA_UART

	default "debug/ux500.S" if DEBUG_UX500_UART

	default "debug/vexpress.S" if DEBUG_VEXPRESS_UART0_DETECT

arch/arm/include/debug/stm32.S

0 → 100644
+41 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) STMicroelectronics SA 2017 - All Rights Reserved

 * Author:   Gerald Baeza <gerald.baeza@st.com> for STMicroelectronics.

 */



#define STM32_UART_BASE			0x40011000	/* USART1 */



#ifdef CONFIG_STM32F4_DEBUG_UART

#define STM32_USART_SR_OFF		0x00

#define STM32_USART_TDR_OFF		0x04

#endif



#ifdef CONFIG_STM32F7_DEBUG_UART

#define STM32_USART_SR_OFF		0x1C

#define STM32_USART_TDR_OFF		0x28

#endif



#define STM32_USART_TC			(1 << 6)	/* Tx complete       */

#define STM32_USART_TXE			(1 << 7)	/* Tx data reg empty */



.macro	addruart, rp, rv, tmp

	ldr	\rp,      =STM32_UART_BASE	@ physical base

	ldr	\rv,      =STM32_UART_BASE      @ virt base /* NoMMU */

.endm



.macro  senduart,rd,rx

	strb    \rd, [\rx, #STM32_USART_TDR_OFF]

.endm



.macro  waituart,rd,rx

1001:	ldr	\rd, [\rx, #(STM32_USART_SR_OFF)]	@ Read Status Register

	tst	\rd, #STM32_USART_TXE			@ TXE = 1 = tx empty

	beq	1001b

.endm



.macro  busyuart,rd,rx

1001:	ldr	\rd, [\rx, #(STM32_USART_SR_OFF)]	@ Read Status Register

	tst	\rd, #STM32_USART_TC			@ TC = 1 = tx complete

	beq	1001b

.endm