From: Erwan Le Ray erwan.leray@foss.st.com
[ Upstream commit 12761869f0efa524348e2ae31827fd52eebf3f0d ]
This patch fixes several issue with wake-up handling: - the WUF irq is handled several times at wake-up - the USART is disabled / enabled at suspend to set wake-up flag. It can cause glitches during RX.
This patch fix those issues: - clear wake-up flag and disable wake-up irq in WUF irq handling - enable wake-up from low power on start bit detection at port configuration - Unmask the wake-up flag irq at suspend and mask it at resume
In addition, pm_wakeup_event handling is moved from receice_chars to WUF irq handling.
Fixes: 270e5a74fe4c ("serial: stm32: add wakeup mechanism") Signed-off-by: Erwan Le Ray erwan.leray@foss.st.com Link: https://lore.kernel.org/r/20210304162308.8984-7-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/stm32-usart.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 5ae3841a4a08..85e9a4d4e91d 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -217,9 +217,6 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) u32 sr; char flag;
- if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) - pm_wakeup_event(tport->tty->dev, 0); - if (threaded) spin_lock_irqsave(&port->lock, flags); else @@ -462,6 +459,7 @@ static void stm32_usart_transmit_chars(struct uart_port *port) static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) { struct uart_port *port = ptr; + struct tty_port *tport = &port->state->port; struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; u32 sr; @@ -472,9 +470,14 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr) writel_relaxed(USART_ICR_RTOCF, port->membase + ofs->icr);
- if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) + if ((sr & USART_SR_WUF) && ofs->icr != UNDEF_REG) { + /* Clear wake up flag and disable wake up interrupt */ writel_relaxed(USART_ICR_WUCF, port->membase + ofs->icr); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); + if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) + pm_wakeup_event(tport->tty->dev, 0); + }
if ((sr & USART_SR_RXNE) && !(stm32_port->rx_ch)) stm32_usart_receive_chars(port, false); @@ -899,6 +902,12 @@ static void stm32_usart_set_termios(struct uart_port *port, cr1 &= ~(USART_CR1_DEDT_MASK | USART_CR1_DEAT_MASK); }
+ /* Configure wake up from low power on start bit detection */ + if (stm32_port->wakeirq > 0) { + cr3 &= ~USART_CR3_WUS_MASK; + cr3 |= USART_CR3_WUS_START_BIT; + } + writel_relaxed(cr3, port->membase + ofs->cr3); writel_relaxed(cr2, port->membase + ofs->cr2); writel_relaxed(cr1, port->membase + ofs->cr1); @@ -1466,23 +1475,20 @@ static void __maybe_unused stm32_usart_serial_en_wakeup(struct uart_port *port, { struct stm32_port *stm32_port = to_stm32_port(port); const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; - const struct stm32_usart_config *cfg = &stm32_port->info->cfg; - u32 val;
if (stm32_port->wakeirq <= 0) return;
+ /* + * Enable low-power wake-up and wake-up irq if argument is set to + * "enable", disable low-power wake-up and wake-up irq otherwise + */ if (enable) { - stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); stm32_usart_set_bits(port, ofs->cr1, USART_CR1_UESM); - val = readl_relaxed(port->membase + ofs->cr3); - val &= ~USART_CR3_WUS_MASK; - /* Enable Wake up interrupt from low power on start bit */ - val |= USART_CR3_WUS_START_BIT | USART_CR3_WUFIE; - writel_relaxed(val, port->membase + ofs->cr3); - stm32_usart_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit)); + stm32_usart_set_bits(port, ofs->cr3, USART_CR3_WUFIE); } else { stm32_usart_clr_bits(port, ofs->cr1, USART_CR1_UESM); + stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_WUFIE); } }