[PATCH] bsps/arm/stm32f4: Enable USART RX interrupts

Kinsey Moore kinsey.moore at oarcorp.com
Thu Dec 14 17:27:22 UTC 2023


This looks good to me.

A minor nit for future patches: Try to keep unrelated whitespace changes
out of functional patches unless you're already touching the code in
question.

Thanks for the contribution!

Kinsey

On Wed, Dec 13, 2023 at 6:49 PM Jacob Killelea <jkillelea344 at gmail.com>
wrote:

> Hi all,
>
> A quick bump, is anyone able to take a look at this?
>
> Best,
> Jacob
>
> On Thu, Dec 7, 2023, 9:00 PM Jacob Killelea <jkillelea344 at gmail.com>
> wrote:
>
>> From: Jacob Killelea <jkillelea344 at gmail.com>
>>
>> Hi all, this is my first email patch submission and my first contribution
>> to RTEMS, so please give any feedback you have!
>>
>> This patch enables interrupt driven data reception on USART ports on
>> STM32F4 series chips. This feature is gated behind the config flag
>> BSP_CONSOLE_USE_INTERRUPTS. If this flag is not set to True, the older
>> polling implementation will be used. I tested this feature on STM32F401CE
>> (blackpill) and STM32 Nucleo F411RE boards, with both capable of keeping
>> up with a 115200 baud continous data stream. With the older polling
>> implementation, both would drop bytes at 9600 baud. In addition, I
>> updated the implementation of usart_set_attributes to support changing
>> the baud rate of the USART port based on the input speed.
>> ---
>>  bsps/arm/stm32f4/console/usart.c    | 81 ++++++++++++++++++++++++-----
>>  spec/build/bsps/arm/stm32f4/grp.yml |  2 +
>>  2 files changed, 69 insertions(+), 14 deletions(-)
>>
>> diff --git a/bsps/arm/stm32f4/console/usart.c
>> b/bsps/arm/stm32f4/console/usart.c
>> index 37566ef9d7..129249dc29 100644
>> --- a/bsps/arm/stm32f4/console/usart.c
>> +++ b/bsps/arm/stm32f4/console/usart.c
>> @@ -14,6 +14,8 @@
>>  #include <bsp/irq.h>
>>  #include <bsp/usart.h>
>>  #include <bsp/stm32f4.h>
>> +#include <termios.h>
>> +#include <string.h>
>>
>>  static volatile stm32f4_usart *usart_get_regs(const console_tbl *ct)
>>  {
>> @@ -27,6 +29,24 @@ static rtems_vector_number usart_get_irq_number(const
>> console_tbl *ct)
>>  }
>>  #endif
>>
>> +#ifdef BSP_CONSOLE_USE_INTERRUPTS
>> +/**
>> + * Read characters in an interrupt
>> + */
>> +static void stm32f4_usart_interrupt(void *arg)
>> +{
>> +  rtems_termios_tty *tty = (rtems_termios_tty *) arg;
>> +  const console_tbl *ct = Console_Port_Tbl [tty->minor];
>> +  volatile stm32f4_usart *usart = usart_get_regs(ct);
>> +
>> +  while ((usart->sr & STM32F4_USART_SR_RXNE) == STM32F4_USART_SR_RXNE)
>> +  {
>> +    char data = STM32F4_USART_DR_GET(usart->dr);
>> +    rtems_termios_enqueue_raw_characters(tty, &data, sizeof(data));
>> +  }
>> +}
>> +#endif
>> +
>>  static const stm32f4_rcc_index usart_rcc_index [] = {
>>    STM32F4_RCC_USART1,
>>    STM32F4_RCC_USART2,
>> @@ -128,29 +148,50 @@ static void usart_initialize(int minor)
>>    usart->cr2 = 0;
>>    usart->cr3 = 0;
>>    usart->bbr = usart_get_bbr(usart, pclk, baud);
>> -  usart->cr1 = STM32F4_USART_CR1_UE
>> -    | STM32F4_USART_CR1_TE
>> -    | STM32F4_USART_CR1_RE;
>> +  usart->cr1 = STM32F4_USART_CR1_UE // UART enable
>> +#ifdef BSP_CONSOLE_USE_INTERRUPTS
>> +    | STM32F4_USART_CR1_RXNEIE // RX interrupt
>> +#endif
>> +    | STM32F4_USART_CR1_TE  // TX enable
>> +    | STM32F4_USART_CR1_RE; // RX enable
>>  }
>>
>>  static int usart_first_open(int major, int minor, void *arg)
>>  {
>> +  rtems_status_code sc = RTEMS_SUCCESSFUL;
>>    rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *)
>> arg;
>> -  struct rtems_termios_tty *tty = (struct rtems_termios_tty *)
>> oc->iop->data1;
>> +  rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
>>    const console_tbl *ct = Console_Port_Tbl [minor];
>>    console_data *cd = &Console_Port_Data [minor];
>>
>>    cd->termios_data = tty;
>>    rtems_termios_set_initial_baud(tty, ct->ulClock);
>>
>> -  return 0;
>> +#ifdef BSP_CONSOLE_USE_INTERRUPTS
>> +  sc = rtems_interrupt_handler_install(ct->ulIntVector,
>> +      ct->sDeviceName,
>> +      RTEMS_INTERRUPT_UNIQUE,
>> +      stm32f4_usart_interrupt,
>> +      tty);
>> +#endif
>> +
>> +  return sc;
>>  }
>>
>>  static int usart_last_close(int major, int minor, void *arg)
>>  {
>> -  return 0;
>> +  rtems_status_code sc = RTEMS_SUCCESSFUL;
>> +#ifdef BSP_CONSOLE_USE_INTERRUPTS
>> +  rtems_libio_open_close_args_t *oc = (rtems_libio_open_close_args_t *)
>> arg;
>> +  rtems_termios_tty *tty = (struct rtems_termios_tty *) oc->iop->data1;
>> +  const console_tbl *ct = Console_Port_Tbl [minor];
>> +
>> +  sc = rtems_interrupt_handler_remove(ct->ulIntVector,
>> stm32f4_usart_interrupt, tty);
>> +#endif
>> +  return sc;
>>  }
>>
>> +#ifndef BSP_CONSOLE_USE_INTERRUPTS
>>  static int usart_read_polled(int minor)
>>  {
>>    const console_tbl *ct = Console_Port_Tbl [minor];
>> @@ -162,6 +203,7 @@ static int usart_read_polled(int minor)
>>      return -1;
>>    }
>>  }
>> +#endif
>>
>>  static void usart_write_polled(int minor, char c)
>>  {
>> @@ -175,11 +217,7 @@ static void usart_write_polled(int minor, char c)
>>    usart->dr = STM32F4_USART_DR(c);
>>  }
>>
>> -static ssize_t usart_write_support_polled(
>> -  int minor,
>> -  const char *s,
>> -  size_t n
>> -)
>> +static ssize_t usart_write_support_polled(int minor, const char *s,
>> size_t n)
>>  {
>>    ssize_t i = 0;
>>
>> @@ -190,19 +228,34 @@ static ssize_t usart_write_support_polled(
>>    return n;
>>  }
>>
>> +/**
>> + * Configure settings from a termios call to tcsetattr()
>> + */
>>  static int usart_set_attributes(int minor, const struct termios *term)
>>  {
>> -  return -1;
>> +  console_tbl *ct = Console_Port_Tbl[minor];
>> +  volatile stm32f4_usart *usart = usart_get_regs(ct);
>> +  uint32_t pclk = usart_get_pclk(ct);
>> +  uint32_t baud = term->c_ispeed;
>> +
>> +  ct->ulClock = baud;
>> +  usart->bbr = usart_get_bbr(usart, pclk, baud);
>> +  return 0;
>>  }
>>
>> -const console_fns stm32f4_usart_fns = {
>> +const console_fns stm32f4_usart_fns =
>> +{
>>    .deviceProbe = libchip_serial_default_probe,
>>    .deviceFirstOpen = usart_first_open,
>>    .deviceLastClose = usart_last_close,
>> +#ifdef BSP_CONSOLE_USE_INTERRUPTS
>> +  .deviceRead = NULL,
>> +#else
>>    .deviceRead = usart_read_polled,
>> +#endif
>>    .deviceWrite = usart_write_support_polled,
>>    .deviceInitialize = usart_initialize,
>>    .deviceWritePolled = usart_write_polled,
>>    .deviceSetAttributes = usart_set_attributes,
>> -  .deviceOutputUsesInterrupts = false
>> +  .deviceOutputUsesInterrupts = false,
>>  };
>> diff --git a/spec/build/bsps/arm/stm32f4/grp.yml
>> b/spec/build/bsps/arm/stm32f4/grp.yml
>> index 2257fdf015..27e2197e46 100644
>> --- a/spec/build/bsps/arm/stm32f4/grp.yml
>> +++ b/spec/build/bsps/arm/stm32f4/grp.yml
>> @@ -50,6 +50,8 @@ links:
>>    uid: optsysclk
>>  - role: build-dependency
>>    uid: optusartbaud
>> +- role: build-dependency
>> +  uid: ../../optconsoleirq
>>  - role: build-dependency
>>    uid: ../../linkcmds
>>  - role: build-dependency
>> --
>> 2.34.1
>>
>> _______________________________________________
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