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The following commit(s) were added to refs/heads/master by this push:
new 2b1b82c73b7 arch/arm/src/stm32n6: disable the USART while changing the
line format
2b1b82c73b7 is described below
commit 2b1b82c73b742634220df0e60dceff83197d641f
Author: Swatantra Yadav <[email protected]>
AuthorDate: Mon Nov 2 19:25:20 2026 +0530
arch/arm/src/stm32n6: disable the USART while changing the line format
stm32serial_setformat() writes BRR, CR2 STOP bits, and the PCE, PS,
and M0/M1 bits of CR1 with the USART enabled. They can only be written
while UE = 0 per the ST Reference Manual (RM0486), so a run-time
tcsetattr() that changes baud rate, parity, or word length returned
success but left the hardware USART registers unchanged.
Clear UE around the update and restore it inside a critical section,
matching the approved STM32L4 (commit 47180bf5ea), STM32WB (PR #21334),
STM32WL5 (PR #21336), STM32H7, and F7 implementations.
Also fix pre-existing nxstyle alignment, declaration, and brace issues
in stm32serial_pm_setsuspend, stm32serial_setapbclock, stm32serial_detach,
stm32serial_interrupt, stm32serial_ioctl, and stm32serial_pmprepare.
Fixes #21377
Signed-off-by: Swatantra Yadav <[email protected]>
Assisted-by: Google Gemini
---
arch/arm/src/stm32n6/stm32_serial.c | 272 ++++++++++++++++++++----------------
1 file changed, 148 insertions(+), 124 deletions(-)
diff --git a/arch/arm/src/stm32n6/stm32_serial.c
b/arch/arm/src/stm32n6/stm32_serial.c
index df0dcd199b0..783c613abb4 100644
--- a/arch/arm/src/stm32n6/stm32_serial.c
+++ b/arch/arm/src/stm32n6/stm32_serial.c
@@ -435,9 +435,22 @@ static void stm32serial_setformat(struct uart_dev_s *dev)
struct stm32_serial_s *priv =
(struct stm32_serial_s *)dev->priv;
uint32_t regval;
+ uint32_t cr1_ue;
uint32_t brr;
uint32_t cr1;
uint32_t usartdiv8;
+ irqstate_t flags;
+
+ flags = enter_critical_section();
+
+ /* Disable UE: the baud rate, parity and word length bits can not be
+ * written while UE = 1.
+ */
+
+ regval = stm32serial_getreg(priv, STM32_USART_CR1_OFFSET);
+ cr1_ue = regval & USART_CR1_UE;
+ stm32serial_putreg(priv, STM32_USART_CR1_OFFSET,
+ regval & ~USART_CR1_UE);
/* In case of oversampling by 8, the equation is:
*
@@ -557,6 +570,13 @@ static void stm32serial_setformat(struct uart_dev_s *dev)
#endif
stm32serial_putreg(priv, STM32_USART_CR3_OFFSET, regval);
+
+ /* Restore UE */
+
+ regval = stm32serial_getreg(priv, STM32_USART_CR1_OFFSET);
+ stm32serial_putreg(priv, STM32_USART_CR1_OFFSET, regval | cr1_ue);
+
+ leave_critical_section(flags);
}
#endif /* CONFIG_SUPPRESS_UART_CONFIG */
@@ -635,7 +655,9 @@ static void stm32serial_pm_setsuspend(bool suspend)
/* Already in desired state? */
if (suspend == g_serialpm.serial_suspended)
- return;
+ {
+ return;
+ }
g_serialpm.serial_suspended = suspend;
@@ -677,14 +699,14 @@ static void stm32serial_setapbclock(struct uart_dev_s
*dev, bool on)
switch (priv->usartbase)
{
- default:
- return;
+ default:
+ return;
#ifdef CONFIG_STM32_USART1_SERIALDRIVER
- case STM32_USART1_BASE:
- rcc_en = RCC_APB2ENR_USART1EN;
- regaddr_set = STM32_RCC_APB2ENSR;
- regaddr_clr = STM32_RCC_APB2ENCR;
- break;
+ case STM32_USART1_BASE:
+ rcc_en = RCC_APB2ENR_USART1EN;
+ regaddr_set = STM32_RCC_APB2ENSR;
+ regaddr_clr = STM32_RCC_APB2ENCR;
+ break;
#endif
}
@@ -942,6 +964,7 @@ static void stm32serial_detach(struct uart_dev_s *dev)
{
struct stm32_serial_s *priv =
(struct stm32_serial_s *)dev->priv;
+
up_disable_irq(priv->irq);
irq_detach(priv->irq);
}
@@ -961,8 +984,9 @@ static void stm32serial_detach(struct uart_dev_s *dev)
static int stm32serial_interrupt(int irq, void *context, void *arg)
{
struct stm32_serial_s *priv = (struct stm32_serial_s *)arg;
- int passes;
+ int passes;
bool handled;
+
DEBUGASSERT(priv != NULL);
/* Report serial activity to the power management logic */
@@ -1076,120 +1100,120 @@ static int stm32serial_ioctl(struct file *filep, int
cmd,
switch (cmd)
{
#ifdef CONFIG_SERIAL_TIOCSERGSTRUCT
- case TIOCSERGSTRUCT:
- {
- struct stm32_serial_s *user;
+ case TIOCSERGSTRUCT:
+ {
+ struct stm32_serial_s *user;
- user = (struct stm32_serial_s *)arg;
+ user = (struct stm32_serial_s *)arg;
- if (!user)
- {
- ret = -EINVAL;
- }
- else
- {
- memcpy(user, dev, sizeof(struct stm32_serial_s));
- }
- }
- break;
+ if (!user)
+ {
+ ret = -EINVAL;
+ }
+ else
+ {
+ memcpy(user, dev, sizeof(struct stm32_serial_s));
+ }
+ }
+ break;
#endif
#ifdef CONFIG_SERIAL_TERMIOS
- case TCGETS:
- {
- struct termios *termiosp = (struct termios *)arg;
+ case TCGETS:
+ {
+ struct termios *termiosp = (struct termios *)arg;
- if (!termiosp)
- {
- ret = -EINVAL;
- break;
- }
+ if (!termiosp)
+ {
+ ret = -EINVAL;
+ break;
+ }
- cfsetispeed(termiosp, priv->baud);
+ cfsetispeed(termiosp, priv->baud);
- /* Note that since we only support 8/9 bit modes and
- * there is no way to report 9-bit mode, we always claim 8.
- */
+ /* Note that since we only support 8/9 bit modes and
+ * there is no way to report 9-bit mode, we always claim 8.
+ */
- termiosp->c_cflag =
- ((priv->parity != 0) ? PARENB : 0) |
- ((priv->parity == 1) ? PARODD : 0) |
- ((priv->stopbits2) ? CSTOPB : 0) |
+ termiosp->c_cflag =
+ ((priv->parity != 0) ? PARENB : 0) |
+ ((priv->parity == 1) ? PARODD : 0) |
+ ((priv->stopbits2) ? CSTOPB : 0) |
#ifdef CONFIG_SERIAL_OFLOWCONTROL
- ((priv->oflow) ? CCTS_OFLOW : 0) |
+ ((priv->oflow) ? CCTS_OFLOW : 0) |
#endif
#ifdef CONFIG_SERIAL_IFLOWCONTROL
- ((priv->iflow) ? CRTS_IFLOW : 0) |
+ ((priv->iflow) ? CRTS_IFLOW : 0) |
#endif
- CS8;
- }
- break;
+ CS8;
+ }
+ break;
- case TCSETS:
- {
- struct termios *termiosp = (struct termios *)arg;
+ case TCSETS:
+ {
+ struct termios *termiosp = (struct termios *)arg;
- if (!termiosp)
- {
- ret = -EINVAL;
- break;
- }
+ if (!termiosp)
+ {
+ ret = -EINVAL;
+ break;
+ }
- /* Perform some sanity checks before accepting any changes */
+ /* Perform some sanity checks before accepting any changes */
- if (((termiosp->c_cflag & CSIZE) != CS8)
+ if (((termiosp->c_cflag & CSIZE) != CS8)
#ifdef CONFIG_SERIAL_OFLOWCONTROL
- || ((termiosp->c_cflag & CCTS_OFLOW) && (priv->cts_gpio == 0))
+ || ((termiosp->c_cflag & CCTS_OFLOW) && (priv->cts_gpio == 0))
#endif
#ifdef CONFIG_SERIAL_IFLOWCONTROL
- || ((termiosp->c_cflag & CRTS_IFLOW) && (priv->rts_gpio == 0))
+ || ((termiosp->c_cflag & CRTS_IFLOW) && (priv->rts_gpio == 0))
#endif
- )
- {
- ret = -EINVAL;
- break;
- }
+ )
+ {
+ ret = -EINVAL;
+ break;
+ }
- if (termiosp->c_cflag & PARENB)
- {
- priv->parity = (termiosp->c_cflag & PARODD) ? 1 : 2;
- }
- else
- {
- priv->parity = 0;
- }
+ if (termiosp->c_cflag & PARENB)
+ {
+ priv->parity = (termiosp->c_cflag & PARODD) ? 1 : 2;
+ }
+ else
+ {
+ priv->parity = 0;
+ }
- priv->stopbits2 = (termiosp->c_cflag & CSTOPB) != 0;
+ priv->stopbits2 = (termiosp->c_cflag & CSTOPB) != 0;
#ifdef CONFIG_SERIAL_OFLOWCONTROL
- priv->oflow = (termiosp->c_cflag & CCTS_OFLOW) != 0;
+ priv->oflow = (termiosp->c_cflag & CCTS_OFLOW) != 0;
#endif
#ifdef CONFIG_SERIAL_IFLOWCONTROL
- priv->iflow = (termiosp->c_cflag & CRTS_IFLOW) != 0;
+ priv->iflow = (termiosp->c_cflag & CRTS_IFLOW) != 0;
#endif
- /* Note that since there is no way to request 9-bit mode
- * and no way to support 5/6/7-bit modes, we ignore them
- * all here.
- */
+ /* Note that since there is no way to request 9-bit mode
+ * and no way to support 5/6/7-bit modes, we ignore them
+ * all here.
+ */
- /* Note that only cfgetispeed is used because we have knowledge
- * that only one speed is supported.
- */
+ /* Note that only cfgetispeed is used because we have knowledge
+ * that only one speed is supported.
+ */
- priv->baud = cfgetispeed(termiosp);
+ priv->baud = cfgetispeed(termiosp);
- /* Effect the changes immediately - note that we do not implement
- * TCSADRAIN / TCSAFLUSH
- */
+ /* Effect the changes immediately - note that we do not implement
+ * TCSADRAIN / TCSAFLUSH
+ */
- stm32serial_setformat(dev);
- }
- break;
+ stm32serial_setformat(dev);
+ }
+ break;
#endif /* CONFIG_SERIAL_TERMIOS */
- default:
- ret = -ENOTTY;
- break;
+ default:
+ ret = -ENOTTY;
+ break;
}
return ret;
@@ -1547,54 +1571,54 @@ static int stm32serial_pmprepare(struct pm_callback_s
*cb, int domain,
switch (pmstate)
{
- case PM_NORMAL:
- case PM_IDLE:
- break;
+ case PM_NORMAL:
+ case PM_IDLE:
+ break;
- case PM_STANDBY:
- case PM_SLEEP:
+ case PM_STANDBY:
+ case PM_SLEEP:
- /* Check if any of the active ports have data pending on Tx/Rx
- * buffers.
- */
+ /* Check if any of the active ports have data pending on Tx/Rx
+ * buffers.
+ */
- for (n = 0; n < STM32_NUSART; n++)
- {
- struct stm32_serial_s *priv = g_uart_devs[n];
+ for (n = 0; n < STM32_NUSART; n++)
+ {
+ struct stm32_serial_s *priv = g_uart_devs[n];
- if (!priv || !priv->initialized)
- {
- /* Not active, skip. */
+ if (!priv || !priv->initialized)
+ {
+ /* Not active, skip. */
- continue;
- }
+ continue;
+ }
- if (priv->suspended)
- {
- /* Port already suspended, skip. */
+ if (priv->suspended)
+ {
+ /* Port already suspended, skip. */
- continue;
- }
+ continue;
+ }
- /* Check if port has data pending (Rx & Tx). */
+ /* Check if port has data pending (Rx & Tx). */
- if (priv->dev.xmit.head != priv->dev.xmit.tail)
- {
- return ERROR;
- }
+ if (priv->dev.xmit.head != priv->dev.xmit.tail)
+ {
+ return ERROR;
+ }
- if (priv->dev.recv.head != priv->dev.recv.tail)
- {
- return ERROR;
- }
- }
- break;
+ if (priv->dev.recv.head != priv->dev.recv.tail)
+ {
+ return ERROR;
+ }
+ }
+ break;
- default:
+ default:
- /* Should not get here */
+ /* Should not get here */
- break;
+ break;
}
return OK;
