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authorGerald Baeza <gerald.baeza@st.com>2017-07-27 19:50:20 +0300
committerOlof Johansson <olof@lixom.net>2018-11-12 21:20:41 +0300
commitd88bb418b7cc0525254cb1723a40b7b4133bad01 (patch)
tree824e07c884530059fcd56ee8a63c4eaf6715d20e /arch/arm/include/debug
parentccda4af0f4b92f7b4c308d3acc262f4a7e3affad (diff)
downloadlinux-d88bb418b7cc0525254cb1723a40b7b4133bad01.tar.xz
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>
Diffstat (limited to 'arch/arm/include/debug')
-rw-r--r--arch/arm/include/debug/stm32.S41
1 files changed, 41 insertions, 0 deletions
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 <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