Adding upstream version 2.8.0+dfsg.upstream/2.8.0+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 700 insertions, 0 deletions

diff --git a/drivers/st/uart/aarch32/stm32_console.S b/drivers/st/uart/aarch32/stm32_console.S
new file mode 100644
index 0000000..e3e0e67
--- /dev/null
+++ b/drivers/st/uart/aarch32/stm32_console.S
@@ -0,0 +1,261 @@
+/*
+ * Copyright (c) 2018-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include <asm_macros.S>
+#include <assert_macros.S>
+#include <console_macros.S>
+#include <drivers/st/stm32_console.h>
+#include <drivers/st/stm32_uart_regs.h>
+
+#define USART_TIMEOUT		0x1000
+
+	/*
+	 * "core" functions are low-level implementations that don't require
+	 * writeable memory and are thus safe to call in BL1 crash context.
+	 */
+	.globl	console_stm32_core_init
+	.globl	console_stm32_core_putc
+	.globl	console_stm32_core_getc
+	.globl	console_stm32_core_flush
+
+	.globl	console_stm32_putc
+	.globl	console_stm32_flush
+
+
+
+	/* -----------------------------------------------------------------
+	 * int console_core_init(uintptr_t base_addr,
+	 *			 unsigned int uart_clk,
+	 *			 unsigned int baud_rate)
+	 *
+	 * Function to initialize the console without a C Runtime to print
+	 * debug information. This function will be accessed by console_init
+	 * and crash reporting.
+	 *
+	 * In: r0 - console base address
+	 *     r1 - Uart clock in Hz
+	 *     r2 - Baud rate
+	 * Out: return 1 on success else 0 on error
+	 * Clobber list : r1, r2, r3
+	 * -----------------------------------------------------------------
+	 */
+func console_stm32_core_init
+	/* Check the input base address */
+	cmp	r0, #0
+	beq	core_init_fail
+#if !defined(IMAGE_BL2)
+#if STM32MP_RECONFIGURE_CONSOLE
+	/* UART clock rate is set to 0 in BL32, skip init in that case */
+	cmp	r1, #0
+	beq	1f
+#else /* STM32MP_RECONFIGURE_CONSOLE */
+	/* Skip UART initialization if it is already enabled */
+	ldr	r3, [r0, #USART_CR1]
+	ands	r3, r3, #USART_CR1_UE
+	bne	1f
+#endif /* STM32MP_RECONFIGURE_CONSOLE */
+#endif /* IMAGE_BL2 */
+	/* Check baud rate and uart clock for sanity */
+	cmp	r1, #0
+	beq	core_init_fail
+	cmp	r2, #0
+	beq	core_init_fail
+	/* Disable UART */
+	ldr	r3, [r0, #USART_CR1]
+	bic	r3, r3, #USART_CR1_UE
+	str	r3, [r0, #USART_CR1]
+	/* Configure UART */
+	orr	r3, r3, #(USART_CR1_TE | USART_CR1_FIFOEN)
+	str	r3, [r0, #USART_CR1]
+	ldr	r3, [r0, #USART_CR2]
+	bic	r3, r3, #USART_CR2_STOP
+	str	r3, [r0, #USART_CR2]
+	/* Divisor =  (Uart clock + (baudrate / 2)) / baudrate */
+	lsr	r3, r2, #1
+	add	r3, r1, r3
+	udiv	r3, r3, r2
+	cmp	r3, #16
+	bhi	2f
+	/* Oversampling 8 */
+	/* Divisor =  (2 * Uart clock + (baudrate / 2)) / baudrate */
+	lsr	r3, r2, #1
+	add	r3, r3, r1, lsl #1
+	udiv	r3, r3, r2
+	and	r1, r3, #USART_BRR_DIV_FRACTION
+	lsr	r1, r1, #1
+	bic	r3, r3, #USART_BRR_DIV_FRACTION
+	orr	r3, r3, r1
+	ldr	r1, [r0, #USART_CR1]
+	orr	r1, r1, #USART_CR1_OVER8
+	str	r1, [r0, #USART_CR1]
+2:
+	str	r3, [r0, #USART_BRR]
+	/* Enable UART */
+	ldr	r3, [r0, #USART_CR1]
+	orr	r3, r3, #USART_CR1_UE
+	str	r3, [r0, #USART_CR1]
+	/* Check TEACK bit */
+	mov	r2, #USART_TIMEOUT
+teack_loop:
+	subs	r2, r2, #1
+	beq	core_init_fail
+	ldr	r3, [r0, #USART_ISR]
+	tst	r3, #USART_ISR_TEACK
+	beq	teack_loop
+1:
+	mov	r0, #1
+	bx	lr
+core_init_fail:
+	mov	r0, #0
+	bx	lr
+endfunc console_stm32_core_init
+
+	.globl console_stm32_register
+
+	/* -------------------------------------------------------
+	 * int console_stm32_register(uintptr_t baseaddr,
+	 *     uint32_t clock, uint32_t baud,
+	 *     console_t *console);
+	 * Function to initialize and register a new STM32
+	 * console. Storage passed in for the console struct
+	 * *must* be persistent (i.e. not from the stack).
+	 * In: r0 - UART register base address
+	 *     r1 - UART clock in Hz
+	 *     r2 - Baud rate
+	 *     r3 - pointer to empty console_t struct
+	 * Out: return 1 on success, 0 on error
+	 * Clobber list : r0, r1, r2
+	 * -------------------------------------------------------
+	 */
+func console_stm32_register
+	push	{r4, lr}
+	mov	r4, r3
+	cmp	r4, #0
+	beq	register_fail
+	str	r0, [r4, #CONSOLE_T_BASE]
+
+	bl console_stm32_core_init
+	cmp	r0, #0
+	beq	register_fail
+
+	mov	r0, r4
+	pop	{r4, lr}
+	finish_console_register stm32 putc=1, getc=0, flush=1
+
+register_fail:
+	pop	{r4, pc}
+endfunc console_stm32_register
+
+	/* ---------------------------------------------------------------
+	 * int console_core_putc(int c, uintptr_t base_addr)
+	 *
+	 * Function to output a character over the console. It returns the
+	 * character printed on success or -1 on error.
+	 *
+	 * In : r0 - character to be printed
+	 *      r1 - console base address
+	 * Out : return -1 on error else return character.
+	 * Clobber list : r2
+	 * ---------------------------------------------------------------
+	 */
+func console_stm32_core_putc
+	/* Check the input parameter */
+	cmp	r1, #0
+	beq	putc_error
+
+	/* Check Transmit Data Register Empty */
+txe_loop:
+	ldr	r2, [r1, #USART_ISR]
+	tst	r2, #USART_ISR_TXE
+	beq	txe_loop
+	str	r0, [r1, #USART_TDR]
+	/* Check transmit complete flag */
+tc_loop:
+	ldr	r2, [r1, #USART_ISR]
+	tst	r2, #USART_ISR_TC
+	beq	tc_loop
+	bx	lr
+putc_error:
+	mov	r0, #-1
+	bx	lr
+endfunc console_stm32_core_putc
+
+	/* ------------------------------------------------------------
+	 * int console_stm32_putc(int c, console_t *console)
+	 * Function to output a character over the console. It
+	 * returns the character printed on success or -1 on error.
+	 * In: r0 - character to be printed
+	 *     r1 - pointer to console_t structure
+	 * Out : return -1 on error else return character.
+	 * Clobber list: r2
+	 * ------------------------------------------------------------
+	 */
+func console_stm32_putc
+#if ENABLE_ASSERTIONS
+	cmp	r1, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	ldr	r1, [r1, #CONSOLE_T_BASE]
+	b	console_stm32_core_putc
+endfunc console_stm32_putc
+
+	/* -----------------------------------------------------------
+	 * int console_core_getc(uintptr_t base_addr)
+	 *
+	 * Function to get a character from the console.
+	 * It returns the character grabbed on success or -1 on error.
+	 *
+	 * In : r0 - console base address
+	 * Out : return -1.
+	 * Clobber list : r0, r1
+	 * -----------------------------------------------------------
+	 */
+func console_stm32_core_getc
+	/* Not supported */
+	mov	r0, #-1
+	bx	lr
+endfunc console_stm32_core_getc
+
+	/* ---------------------------------------------------------------
+	 * void console_core_flush(uintptr_t base_addr)
+	 *
+	 * Function to force a write of all buffered data that hasn't been
+	 * output.
+	 *
+	 * In : r0 - console base address
+	 * Out : void.
+	 * Clobber list : r0, r1
+	 * ---------------------------------------------------------------
+	 */
+func console_stm32_core_flush
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	/* Check Transmit Data Register Empty */
+txe_loop_3:
+	ldr	r1, [r0, #USART_ISR]
+	tst	r1, #USART_ISR_TXE
+	beq	txe_loop_3
+	bx	lr
+endfunc console_stm32_core_flush
+
+	/* ------------------------------------------------------
+	 * void console_stm32_flush(console_t *console)
+	 * Function to force a write of all buffered
+	 * data that hasn't been output.
+	 * In : r0 - pointer to console_t structure
+	 * Out : void.
+	 * Clobber list: r0, r1
+	 * ------------------------------------------------------
+	 */
+func console_stm32_flush
+#if ENABLE_ASSERTIONS
+	cmp	r0, #0
+	ASM_ASSERT(ne)
+#endif /* ENABLE_ASSERTIONS */
+	ldr	r0, [r0, #CONSOLE_T_BASE]
+	b	console_stm32_core_flush
+endfunc console_stm32_flush
diff --git a/drivers/st/uart/stm32_uart.c b/drivers/st/uart/stm32_uart.c
new file mode 100644
index 0000000..63970c7
--- /dev/null
+++ b/drivers/st/uart/stm32_uart.c
@@ -0,0 +1,439 @@
+/*
+ * Copyright (c) 2021-2022, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <string.h>
+
+#include <common/bl_common.h>
+#include <drivers/clk.h>
+#include <drivers/delay_timer.h>
+#include <drivers/st/stm32_gpio.h>
+#include <drivers/st/stm32_uart.h>
+#include <drivers/st/stm32_uart_regs.h>
+#include <drivers/st/stm32mp_clkfunc.h>
+#include <lib/mmio.h>
+
+#include <platform_def.h>
+
+/* UART time-out value */
+#define STM32_UART_TIMEOUT_US	20000U
+
+/* Mask to clear ALL the configuration registers */
+
+#define STM32_UART_CR1_FIELDS \
+		(USART_CR1_M | USART_CR1_PCE | USART_CR1_PS | USART_CR1_TE | \
+		 USART_CR1_RE | USART_CR1_OVER8 | USART_CR1_FIFOEN)
+
+#define STM32_UART_CR2_FIELDS \
+		(USART_CR2_SLVEN | USART_CR2_DIS_NSS | USART_CR2_ADDM7 | \
+		 USART_CR2_LBDL | USART_CR2_LBDIE | USART_CR2_LBCL | \
+		 USART_CR2_CPHA | USART_CR2_CPOL | USART_CR2_CLKEN | \
+		 USART_CR2_STOP | USART_CR2_LINEN | USART_CR2_SWAP | \
+		 USART_CR2_RXINV | USART_CR2_TXINV | USART_CR2_DATAINV | \
+		 USART_CR2_MSBFIRST | USART_CR2_ABREN | USART_CR2_ABRMODE | \
+		 USART_CR2_RTOEN | USART_CR2_ADD)
+
+#define STM32_UART_CR3_FIELDS \
+		(USART_CR3_EIE | USART_CR3_IREN | USART_CR3_IRLP | \
+		 USART_CR3_HDSEL | USART_CR3_NACK | USART_CR3_SCEN | \
+		 USART_CR3_DMAR | USART_CR3_DMAT | USART_CR3_RTSE | \
+		 USART_CR3_CTSE | USART_CR3_CTSIE | USART_CR3_ONEBIT | \
+		 USART_CR3_OVRDIS | USART_CR3_DDRE | USART_CR3_DEM | \
+		 USART_CR3_DEP | USART_CR3_SCARCNT | USART_CR3_WUS | \
+		 USART_CR3_WUFIE | USART_CR3_TXFTIE | USART_CR3_TCBGTIE | \
+		 USART_CR3_RXFTCFG | USART_CR3_RXFTIE | USART_CR3_TXFTCFG)
+
+#define STM32_UART_ISR_ERRORS	 \
+		(USART_ISR_ORE | USART_ISR_NE |  USART_ISR_FE | USART_ISR_PE)
+
+static const uint16_t presc_table[STM32_UART_PRESCALER_NB] = {
+	1U, 2U, 4U, 6U, 8U, 10U, 12U, 16U, 32U, 64U, 128U, 256U
+};
+
+/* @brief  BRR division operation to set BRR register in 8-bit oversampling
+ * mode.
+ * @param  clockfreq: UART clock.
+ * @param  baud_rate: Baud rate set by the user.
+ * @param  prescaler: UART prescaler value.
+ * @retval Division result.
+ */
+static uint32_t uart_div_sampling8(unsigned long clockfreq,
+				   uint32_t baud_rate,
+				   uint32_t prescaler)
+{
+	uint32_t scaled_freq = clockfreq / presc_table[prescaler];
+
+	return ((scaled_freq * 2) + (baud_rate / 2)) / baud_rate;
+
+}
+
+/* @brief  BRR division operation to set BRR register in 16-bit oversampling
+ * mode.
+ * @param  clockfreq: UART clock.
+ * @param  baud_rate: Baud rate set by the user.
+ * @param  prescaler: UART prescaler value.
+ * @retval Division result.
+ */
+static uint32_t uart_div_sampling16(unsigned long clockfreq,
+				    uint32_t baud_rate,
+				    uint32_t prescaler)
+{
+	uint32_t scaled_freq = clockfreq / presc_table[prescaler];
+
+	return (scaled_freq + (baud_rate / 2)) / baud_rate;
+
+}
+
+/*
+ * @brief  Return the UART clock frequency.
+ * @param  huart: UART handle.
+ * @retval Frequency value in Hz.
+ */
+static unsigned long uart_get_clock_freq(struct stm32_uart_handle_s *huart)
+{
+	return fdt_get_uart_clock_freq((uintptr_t)huart->base);
+}
+
+/*
+ * @brief  Configure the UART peripheral.
+ * @param  huart: UART handle.
+ * @retval UART status.
+ */
+static int uart_set_config(struct stm32_uart_handle_s *huart,
+			   const struct stm32_uart_init_s *init)
+{
+	uint32_t tmpreg;
+	unsigned long clockfreq;
+	unsigned long int_div;
+	uint32_t brrtemp;
+	uint32_t over_sampling;
+
+	/*---------------------- USART BRR configuration --------------------*/
+	clockfreq = uart_get_clock_freq(huart);
+	if (clockfreq == 0UL) {
+		return -ENODEV;
+	}
+
+	int_div = clockfreq / init->baud_rate;
+	if (int_div < 16U) {
+		uint32_t usartdiv = uart_div_sampling8(clockfreq,
+						       init->baud_rate,
+						       init->prescaler);
+
+		brrtemp = (usartdiv & USART_BRR_DIV_MANTISSA) |
+			  ((usartdiv & USART_BRR_DIV_FRACTION) >> 1);
+		over_sampling = USART_CR1_OVER8;
+	} else {
+		brrtemp = uart_div_sampling16(clockfreq,
+					      init->baud_rate,
+					      init->prescaler) &
+			  (USART_BRR_DIV_FRACTION | USART_BRR_DIV_MANTISSA);
+		over_sampling = 0x0U;
+	}
+	mmio_write_32(huart->base + USART_BRR, brrtemp);
+
+	/*
+	 * ---------------------- USART CR1 Configuration --------------------
+	 * Clear M, PCE, PS, TE, RE and OVER8 bits and configure
+	 * the UART word length, parity, mode and oversampling:
+	 * - set the M bits according to init->word_length value,
+	 * - set PCE and PS bits according to init->parity value,
+	 * - set TE and RE bits according to init->mode value,
+	 * - set OVER8 bit according baudrate and clock.
+	 */
+	tmpreg = init->word_length |
+		 init->parity |
+		 init->mode |
+		 over_sampling |
+		 init->fifo_mode;
+	mmio_clrsetbits_32(huart->base + USART_CR1, STM32_UART_CR1_FIELDS, tmpreg);
+
+	/*
+	 * --------------------- USART CR2 Configuration ---------------------
+	 * Configure the UART Stop Bits: Set STOP[13:12] bits according
+	 * to init->stop_bits value.
+	 */
+	mmio_clrsetbits_32(huart->base + USART_CR2, STM32_UART_CR2_FIELDS,
+			   init->stop_bits);
+
+	/*
+	 * --------------------- USART CR3 Configuration ---------------------
+	 * Configure:
+	 * - UART HardWare Flow Control: set CTSE and RTSE bits according
+	 *   to init->hw_flow_control value,
+	 * - one-bit sampling method versus three samples' majority rule
+	 *   according to init->one_bit_sampling (not applicable to
+	 *   LPUART),
+	 * - set TXFTCFG bit according to init->tx_fifo_threshold value,
+	 * - set RXFTCFG bit according to init->rx_fifo_threshold value.
+	 */
+	tmpreg = init->hw_flow_control | init->one_bit_sampling;
+
+	if (init->fifo_mode == USART_CR1_FIFOEN) {
+		tmpreg |= init->tx_fifo_threshold |
+			  init->rx_fifo_threshold;
+	}
+
+	mmio_clrsetbits_32(huart->base + USART_CR3, STM32_UART_CR3_FIELDS, tmpreg);
+
+	/*
+	 * --------------------- USART PRESC Configuration -------------------
+	 * Configure UART Clock Prescaler : set PRESCALER according to
+	 * init->prescaler value.
+	 */
+	assert(init->prescaler < STM32_UART_PRESCALER_NB);
+	mmio_clrsetbits_32(huart->base + USART_PRESC, USART_PRESC_PRESCALER,
+			   init->prescaler);
+
+	return 0;
+}
+
+/*
+ * @brief  Handle UART communication timeout.
+ * @param  huart: UART handle.
+ * @param  flag: Specifies the UART flag to check.
+ * @retval UART status.
+ */
+static int stm32_uart_wait_flag(struct stm32_uart_handle_s *huart, uint32_t flag)
+{
+	uint64_t timeout_ref = timeout_init_us(STM32_UART_TIMEOUT_US);
+
+	while ((mmio_read_32(huart->base + USART_ISR) & flag) == 0U) {
+		if (timeout_elapsed(timeout_ref)) {
+			return -ETIMEDOUT;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * @brief  Check the UART idle State.
+ * @param  huart: UART handle.
+ * @retval UART status.
+ */
+static int stm32_uart_check_idle(struct stm32_uart_handle_s *huart)
+{
+	int ret;
+
+	/* Check if the transmitter is enabled */
+	if ((mmio_read_32(huart->base + USART_CR1) & USART_CR1_TE) == USART_CR1_TE) {
+		ret = stm32_uart_wait_flag(huart, USART_ISR_TEACK);
+		if (ret != 0) {
+			return ret;
+		}
+	}
+
+	/* Check if the receiver is enabled */
+	if ((mmio_read_32(huart->base + USART_CR1) & USART_CR1_RE) == USART_CR1_RE) {
+		ret = stm32_uart_wait_flag(huart, USART_ISR_REACK);
+		if (ret != 0) {
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * @brief  Compute RDR register mask depending on word length.
+ * @param  huart: UART handle.
+ * @retval Mask value.
+ */
+static unsigned int stm32_uart_rdr_mask(const struct stm32_uart_init_s *init)
+{
+	unsigned int mask = 0U;
+
+	switch (init->word_length) {
+	case STM32_UART_WORDLENGTH_9B:
+		mask = GENMASK(8, 0);
+		break;
+	case STM32_UART_WORDLENGTH_8B:
+		mask = GENMASK(7, 0);
+		break;
+	case STM32_UART_WORDLENGTH_7B:
+		mask = GENMASK(6, 0);
+		break;
+	default:
+		break; /* not reached */
+	}
+
+	if (init->parity != STM32_UART_PARITY_NONE) {
+		mask >>= 1;
+	}
+
+	return mask;
+}
+
+/*
+ * @brief  Check interrupt and status errors.
+ * @retval True if error detected, false otherwise.
+ */
+static bool stm32_uart_error_detected(struct stm32_uart_handle_s *huart)
+{
+	return (mmio_read_32(huart->base + USART_ISR) & STM32_UART_ISR_ERRORS) != 0U;
+}
+
+/*
+ * @brief  Clear status errors.
+ */
+static void stm32_uart_error_clear(struct stm32_uart_handle_s *huart)
+{
+	mmio_write_32(huart->base + USART_ICR, STM32_UART_ISR_ERRORS);
+}
+
+/*
+ * @brief  Stop the UART.
+ * @param  base: UART base address.
+ */
+void stm32_uart_stop(uintptr_t base)
+{
+	mmio_clrbits_32(base + USART_CR1, USART_CR1_UE);
+}
+
+/*
+ * @brief  Initialize UART.
+ * @param  huart: UART handle.
+ * @param  base_addr: base address of UART.
+ * @param  init: UART initialization parameter.
+ * @retval UART status.
+ */
+int stm32_uart_init(struct stm32_uart_handle_s *huart,
+		    uintptr_t base_addr,
+		    const struct stm32_uart_init_s *init)
+{
+	int ret;
+	int uart_node;
+	int clk;
+	void *fdt = NULL;
+
+	if (huart == NULL || init == NULL || base_addr == 0U) {
+		return -EINVAL;
+	}
+
+	huart->base = base_addr;
+
+	/* Search UART instance in DT */
+	if (fdt_get_address(&fdt) == 0) {
+		return -FDT_ERR_NOTFOUND;
+	}
+
+	if (fdt == NULL) {
+		return -FDT_ERR_NOTFOUND;
+	}
+
+	uart_node = dt_match_instance_by_compatible(DT_UART_COMPAT, base_addr);
+	if (uart_node == -FDT_ERR_NOTFOUND) {
+		return -FDT_ERR_NOTFOUND;
+	}
+
+	/* Pinctrl initialization */
+	if (dt_set_pinctrl_config(uart_node) != 0) {
+		return -FDT_ERR_BADVALUE;
+	}
+
+	/* Clock initialization */
+	clk = fdt_get_clock_id(uart_node);
+	if (clk < 0) {
+		return -FDT_ERR_NOTFOUND;
+	}
+	clk_enable(clk);
+
+	/* Disable the peripheral */
+	stm32_uart_stop(huart->base);
+
+	/* Computation of UART mask to apply to RDR register */
+	huart->rdr_mask = stm32_uart_rdr_mask(init);
+
+	/* Init the peripheral */
+	ret = uart_set_config(huart, init);
+	if (ret != 0) {
+		return ret;
+	}
+
+	/* Enable the peripheral */
+	mmio_setbits_32(huart->base + USART_CR1, USART_CR1_UE);
+
+	/* TEACK and/or REACK to check */
+	return stm32_uart_check_idle(huart);
+}
+
+/*
+ * @brief  Transmit one data in no blocking mode.
+ * @param  huart: UART handle.
+ * @param  c: data to sent.
+ * @retval UART status.
+ */
+int stm32_uart_putc(struct stm32_uart_handle_s *huart, int c)
+{
+	int ret;
+
+	if (huart == NULL) {
+		return -EINVAL;
+	}
+
+	ret = stm32_uart_wait_flag(huart, USART_ISR_TXE);
+	if (ret != 0) {
+		return ret;
+	}
+
+	mmio_write_32(huart->base + USART_TDR, c);
+	if (stm32_uart_error_detected(huart)) {
+		stm32_uart_error_clear(huart);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+/*
+ * @brief  Flush TX Transmit fifo
+ * @param  huart: UART handle.
+ * @retval UART status.
+ */
+int stm32_uart_flush(struct stm32_uart_handle_s *huart)
+{
+	int ret;
+
+	if (huart == NULL) {
+		return -EINVAL;
+	}
+
+	ret = stm32_uart_wait_flag(huart, USART_ISR_TXE);
+	if (ret != 0) {
+		return ret;
+	}
+
+	return stm32_uart_wait_flag(huart, USART_ISR_TC);
+}
+
+/*
+ * @brief  Receive a data in no blocking mode.
+ * @retval value if >0 or UART status.
+ */
+int stm32_uart_getc(struct stm32_uart_handle_s *huart)
+{
+	uint32_t data;
+
+	if (huart == NULL) {
+		return -EINVAL;
+	}
+
+	/* Check if data is available */
+	if ((mmio_read_32(huart->base + USART_ISR) & USART_ISR_RXNE) == 0U) {
+		return -EAGAIN;
+	}
+
+	data = mmio_read_32(huart->base + USART_RDR) & huart->rdr_mask;
+
+	if (stm32_uart_error_detected(huart)) {
+		stm32_uart_error_clear(huart);
+		return -EFAULT;
+	}
+
+	return (int)data;
+}