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author | Erwan Le Ray <erwan.leray@foss.st.com> | 2021-03-04 17:23:01 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-10 09:34:10 +0100 |
commit | 12761869f0efa524348e2ae31827fd52eebf3f0d (patch) | |
tree | b245931290011257006ed424bed902abe2566be5 /drivers/tty/serial/stm32-usart.c | |
parent | ad7676812437a00a4c6be155fc17926069f99084 (diff) | |
download | linux-stable-12761869f0efa524348e2ae31827fd52eebf3f0d.tar.gz linux-stable-12761869f0efa524348e2ae31827fd52eebf3f0d.tar.bz2 linux-stable-12761869f0efa524348e2ae31827fd52eebf3f0d.zip |
serial: stm32: fix wake-up flag handling
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>
Diffstat (limited to 'drivers/tty/serial/stm32-usart.c')
-rw-r--r-- | drivers/tty/serial/stm32-usart.c | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 370141445780..326f300dd410 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -218,9 +218,6 @@ 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 @@ -463,6 +460,7 @@ 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; @@ -473,9 +471,14 @@ 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); @@ -901,6 +904,12 @@ 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); @@ -1476,23 +1485,20 @@ 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); } } |