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| author | Valentin Caron <valentin.caron@foss.st.com> | 2022-04-19 10:53:28 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-22 16:36:23 +0200 |
| commit | 28fb1a92a00706d4e008ab24fbd8e4642df46ca5 (patch) | |
| tree | 323c8bd551a8aa70adf5a7ecfb0a6d5a4faae4d5 | |
| parent | ec66b8cf03e5a63de6332c989b0ceebe4ba2937e (diff) | |
| download | linux-28fb1a92a00706d4e008ab24fbd8e4642df46ca5.tar.gz linux-28fb1a92a00706d4e008ab24fbd8e4642df46ca5.tar.bz2 linux-28fb1a92a00706d4e008ab24fbd8e4642df46ca5.zip | |
serial: stm32: remove infinite loop possibility in putchar function
Rework stm32_usart_console_putchar() function in order to anticipate
the case where the character can never be sent.
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220419085330.1178925-2-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/stm32-usart.c | 12 | ||||
| -rw-r--r-- | drivers/tty/serial/stm32-usart.h | 2 |
2 files changed, 11 insertions, 3 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index f886976daef6..9910a18779af 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -1640,10 +1640,16 @@ static void stm32_usart_console_putchar(struct uart_port *port, unsigned char ch { struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; + u32 isr; + int ret; - while (!(readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE)) - cpu_relax(); - + ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, isr, + (isr & USART_SR_TXE), 100, + STM32_USART_TIMEOUT_USEC); + if (ret != 0) { + dev_err(port->dev, "Error while sending data in UART TX : %d\n", ret); + return; + } writel_relaxed(ch, port->membase + ofs->tdr); } diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h index feab952aec16..d734c4a5fd24 100644 --- a/drivers/tty/serial/stm32-usart.h +++ b/drivers/tty/serial/stm32-usart.h @@ -251,6 +251,8 @@ struct stm32_usart_info stm32h7_info = { #define RX_BUF_P (RX_BUF_L / 2) /* dma rx buffer period */ #define TX_BUF_L RX_BUF_L /* dma tx buffer length */ +#define STM32_USART_TIMEOUT_USEC USEC_PER_SEC /* 1s timeout in µs */ + struct stm32_port { struct uart_port port; struct clk *clk; |