Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/arm/include/debug/stm32.S b/arch/arm/include/debug/stm32.S
new file mode 100644
index 0000000..1abb32f
--- /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