Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752700AbdLKKod (ORCPT ); Mon, 11 Dec 2017 05:44:33 -0500 Received: from mx07-00178001.pphosted.com ([62.209.51.94]:13471 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752624AbdLKKo2 (ORCPT ); Mon, 11 Dec 2017 05:44:28 -0500 From: Ludovic Barre To: Russell King CC: Maxime Coquelin , Alexandre Torgue , , , Ludovic Barre , "Gerald Baeza" Subject: [PATCH V2 1/1] ARM: debug: add stm32 low-level debug support Date: Mon, 11 Dec 2017 11:43:39 +0100 Message-ID: <1512989019-26874-1-git-send-email-ludovic.Barre@st.com> X-Mailer: git-send-email 2.7.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.48.0.237] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-12-11_05:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3483 Lines: 114 From: Ludovic Barre 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: Ludovic Barre Acked-by: Alexandre TORGUE --- arch/arm/Kconfig.debug | 25 +++++++++++++++++++++++++ arch/arm/include/debug/stm32.S | 41 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 66 insertions(+) create mode 100644 arch/arm/include/debug/stm32.S diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index 17685e1..9469c58 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -1140,6 +1140,26 @@ 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 STM32 based platforms. + + 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 STM32 based platforms. + + 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 @@ -1424,6 +1444,10 @@ 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 @@ -1472,6 +1496,7 @@ 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 diff --git a/arch/arm/include/debug/stm32.S b/arch/arm/include/debug/stm32.S new file mode 100644 index 0000000..3f1a970 --- /dev/null +++ b/arch/arm/include/debug/stm32.S @@ -0,0 +1,41 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) STMicroelectronics 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 -- 2.7.4