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linux-stable/arch/arm/include/debug/stm32.S

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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 <gerald.baeza@st.com> Signed-off-by: Bich Hemon <bich.hemon@st.com> Acked-by: Alexandre TORGUE <alexandre.torgue@st.com> Signed-off-by: Olof Johansson <olof@lixom.net>
2017-07-27 16:50:20 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) STMicroelectronics SA 2017 - All Rights Reserved
* Author: Gerald Baeza <gerald.baeza@st.com> for STMicroelectronics.
*/
#ifdef CONFIG_STM32F4_DEBUG_UART
#define STM32_USART_SR_OFF 0x00
#define STM32_USART_TDR_OFF 0x04
#endif
ARM: debug: stm32: add UART early console support for STM32MP1 Add support of early console for STM32MP1. Default UART instance is UART4, but other UART instances can be configured by setting physical and virtual base addresses in menuconfig. Signed-off-by: Erwan Le Ray <erwan.leray@st.com> Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
2020-02-03 14:04:25 +00:00
#if defined(CONFIG_STM32F7_DEBUG_UART) || defined(CONFIG_STM32H7_DEBUG_UART) || \
defined(CONFIG_STM32MP1_DEBUG_UART)
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 <gerald.baeza@st.com> Signed-off-by: Bich Hemon <bich.hemon@st.com> Acked-by: Alexandre TORGUE <alexandre.torgue@st.com> Signed-off-by: Olof Johansson <olof@lixom.net>
2017-07-27 16:50:20 +00:00
#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
ARM: debug: stm32: add UART early console configuration for STM32F4 Early console is hardcoded on USART1 in current implementation. With this patch, default UART instance is USART1, but other UART instances can be configured by setting physical and virtual base addresses in menuconfig. Signed-off-by: Erwan Le Ray <erwan.leray@st.com> Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>
2020-02-03 14:04:22 +00:00
ldr \rp, =CONFIG_DEBUG_UART_PHYS @ physical base
ldr \rv, =CONFIG_DEBUG_UART_VIRT @ virt base
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 <gerald.baeza@st.com> Signed-off-by: Bich Hemon <bich.hemon@st.com> Acked-by: Alexandre TORGUE <alexandre.torgue@st.com> Signed-off-by: Olof Johansson <olof@lixom.net>
2017-07-27 16:50:20 +00:00
.endm
.macro senduart,rd,rx
strb \rd, [\rx, #STM32_USART_TDR_OFF]
.endm
ARM: 9004/1: debug: Split waituart to CTS and TXRDY This patch was triggered by a remark from Russell that introducing a call to the waituart (needed to fix debug prints on the Qualcomm platforms) was dangerous because in some cases this will involve waiting for a modem CTS (clear to send) signal, and debug messages would maybe not work on platforms with no modem connected to the UART port: they will just hang waiting for the modem to assert CTS and this might never happen. Looking through all UART debug drivers implementing the waituart macro I discovered that all users except two actually use this macro to check if the UART is ready for TX, let's call this TXRDY. Only two debug UART drivers actually check for CTS: - arch/arm/include/debug/8250.S - arch/arm/include/debug/tegra.S The former is very significant since the 8250 is possibly the most common UART on the planet. We have the following problem: the semantics of waituart are ambiguous making it dangerous to introduce the macro to debug code fixing debug prints for Qualcomm. To start to pry this problem apart, this patch does the following: - Convert all debug UART drivers to define two macros: - waituartcts with the clear semantic to wait for CTS to be asserted - waituarttxrdy with the clear semantic to wait for the TX capability of the UART to be ready - When doing this take care to assign the right function to each drivers macro, so they now do exactly the above. - Update the three sites in the kernel invoking the waituart macro to call waituartcts/waituarttxrdy in sequence, so that the functional impact on the kernel should be zero. After this we can start to change the code sites using this code to do the right thing. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2020-08-27 22:25:37 +00:00
.macro waituartcts,rd,rx
.endm
.macro waituarttxrdy,rd,rx
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 <gerald.baeza@st.com> Signed-off-by: Bich Hemon <bich.hemon@st.com> Acked-by: Alexandre TORGUE <alexandre.torgue@st.com> Signed-off-by: Olof Johansson <olof@lixom.net>
2017-07-27 16:50:20 +00:00
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
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