From 1250ed7114a977cdc2a67a0c09d6cdda63970eb9 Mon Sep 17 00:00:00 2001 From: Fabrice Gasnier Date: Thu, 21 Nov 2019 09:10:49 +0100 Subject: serial: stm32: fix clearing interrupt error flags The interrupt clear flag register is a "write 1 to clear" register. So, only writing ones allows to clear flags: - Replace buggy stm32_clr_bits() by a simple write to clear error flags - Replace useless read/modify/write stm32_set_bits() routine by a simple write to clear TC (transfer complete) flag. Fixes: 4f01d833fdcd ("serial: stm32: fix rx error handling") Signed-off-by: Fabrice Gasnier Cc: stable Link: https://lore.kernel.org/r/1574323849-1909-1-git-send-email-fabrice.gasnier@st.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/stm32-usart.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index df90747ee3a8..2f72514d63ed 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -240,8 +240,8 @@ static void stm32_receive_chars(struct uart_port *port, bool threaded) * cleared by the sequence [read SR - read DR]. */ if ((sr & USART_SR_ERR_MASK) && ofs->icr != UNDEF_REG) - stm32_clr_bits(port, ofs->icr, USART_ICR_ORECF | - USART_ICR_PECF | USART_ICR_FECF); + writel_relaxed(sr & USART_SR_ERR_MASK, + port->membase + ofs->icr); c = stm32_get_char(port, &sr, &stm32_port->last_res); port->icount.rx++; @@ -435,7 +435,7 @@ static void stm32_transmit_chars(struct uart_port *port) if (ofs->icr == UNDEF_REG) stm32_clr_bits(port, ofs->isr, USART_SR_TC); else - stm32_set_bits(port, ofs->icr, USART_ICR_TCCF); + writel_relaxed(USART_ICR_TCCF, port->membase + ofs->icr); if (stm32_port->tx_ch) stm32_transmit_chars_dma(port); -- cgit