From d88bb418b7cc0525254cb1723a40b7b4133bad01 Mon Sep 17 00:00:00 2001 From: Gerald Baeza Date: Thu, 27 Jul 2017 16:50:20 +0000 Subject: 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: Gerald Baeza Signed-off-by: Bich Hemon Acked-by: Alexandre TORGUE Signed-off-by: Olof Johansson --- arch/arm/include/debug/stm32.S | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 arch/arm/include/debug/stm32.S (limited to 'arch/arm/include') diff --git a/arch/arm/include/debug/stm32.S b/arch/arm/include/debug/stm32.S new file mode 100644 index 000000000000..1abb32f685fd --- /dev/null +++ b/arch/arm/include/debug/stm32.S @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) STMicroelectronics SA 2017 - All Rights Reserved + * Author: Gerald Baeza 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 -- cgit v1.2.3