From 391d677e7e955455133256a255ccbc9380680ef2 Mon Sep 17 00:00:00 2001 From: Etienne Carriere Date: Mon, 17 Dec 2018 16:54:14 +0100 Subject: stm32_uart: timeout to escape waiting loops Add a timeout in output console waiting loops. This is useful if the secure world relies on a non-secure UART that may be suspended or disabled from the non-secure world. Signed-off-by: Etienne Carriere Reviewed-by: Jerome Forissier Reviewed-by: Jens Wiklander --- core/drivers/stm32_uart.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'core/drivers') diff --git a/core/drivers/stm32_uart.c b/core/drivers/stm32_uart.c index 1febd841..53d9c1e6 100644 --- a/core/drivers/stm32_uart.c +++ b/core/drivers/stm32_uart.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #define UART_REG_CR1 0x00 /* Control register 1 */ @@ -21,6 +22,9 @@ #define UART_REG_TDR 0x28 /* Transmit data register */ #define UART_REG_PRESC 0x2c /* Prescaler register */ +#define PUTC_TIMEOUT_US 1000 +#define FLUSH_TIMEOUT_US 16000 + /* * Uart Interrupt & status register bits * @@ -45,17 +49,21 @@ static vaddr_t loc_chip_to_base(struct serial_chip *chip) static void loc_flush(struct serial_chip *chip) { vaddr_t base = loc_chip_to_base(chip); + uint64_t timeout = timeout_init_us(FLUSH_TIMEOUT_US); while (!(read32(base + UART_REG_ISR) & USART_ISR_TXFE)) - ; + if (timeout_elapsed(timeout)) + return; } static void loc_putc(struct serial_chip *chip, int ch) { vaddr_t base = loc_chip_to_base(chip); + uint64_t timeout = timeout_init_us(PUTC_TIMEOUT_US); while (!(read32(base + UART_REG_ISR) & USART_ISR_TXE_TXFNF)) - ; + if (timeout_elapsed(timeout)) + return; write32(ch, base + UART_REG_TDR); } -- cgit v1.2.3