On Sun, 24 Mar 2024 at 16:57, Arnaud Minier
<arnaud.min...@telecom-paris.fr> wrote:
>
> Add a function to change the settings of the
> serial connection.
>
> Signed-off-by: Arnaud Minier <arnaud.min...@telecom-paris.fr>
> Signed-off-by: Inès Varhol <ines.var...@telecom-paris.fr>
> ---
> hw/char/stm32l4x5_usart.c | 98 +++++++++++++++++++++++++++++++++++++++
> hw/char/trace-events | 1 +
> 2 files changed, 99 insertions(+)
>
> diff --git a/hw/char/stm32l4x5_usart.c b/hw/char/stm32l4x5_usart.c
> index ec8c2f6e63..b4d11dd826 100644
> --- a/hw/char/stm32l4x5_usart.c
> +++ b/hw/char/stm32l4x5_usart.c
> @@ -267,6 +267,92 @@ static void
> usart_cancel_transmit(Stm32l4x5UsartBaseState *s)
> }
> }
>
> +static void stm32l4x5_update_params(Stm32l4x5UsartBaseState *s)
> +{
> + int speed, parity, data_bits, stop_bits;
> + uint32_t value, usart_div;
> + QEMUSerialSetParams ssp;
> +
> + /* Select the parity type */
> + if (s->cr1 & R_CR1_PCE_MASK) {
> + if (s->cr1 & R_CR1_PS_MASK) {
> + parity = 'O';
> + } else {
> + parity = 'E';
> + }
> + } else {
> + parity = 'N';
> + }
> +
> + /* Select the number of stop bits */
> + switch (FIELD_EX32(s->cr2, CR2, STOP)) {
> + case 0:
> + stop_bits = 1;
> + break;
> + case 2:
> + stop_bits = 2;
> + break;
> + default:
> + qemu_log_mask(LOG_UNIMP,
> + "UNIMPLEMENTED: fractionnal stop bits; CR2[13:12] = %x",
%x without a leading 0x is a bit odd. In this case since
the possible values are 0-3 it doesn't make a difference,
but maybe better to use %u ?
> + FIELD_EX32(s->cr2, CR2, STOP));
> + return;
> + }
> +
> + /* Select the length of the word */
> + switch ((FIELD_EX32(s->cr1, CR1, M1) << 1) | FIELD_EX32(s->cr1, CR1,
> M0)) {
> + case 0:
> + data_bits = 8;
> + break;
> + case 1:
> + data_bits = 9;
> + break;
> + case 2:
> + data_bits = 7;
> + break;
> + default:
> + qemu_log_mask(LOG_GUEST_ERROR,
> + "UNDEFINED: invalid word length, CR1.M = 0b11");
> + return;
> + }
> +
> + /* Select the baud rate */
> + value = FIELD_EX32(s->brr, BRR, BRR);
> + if (value < 16) {
> + qemu_log_mask(LOG_GUEST_ERROR,
> + "UNDEFINED: BRR lesser than 16: %u", value);
"less than"
> + return;
> + }
> +
> + if (FIELD_EX32(s->cr1, CR1, OVER8) == 0) {
> + /*
> + * Oversampling by 16
> + * BRR = USARTDIV
> + */
> + usart_div = value;
> + } else {
> + /*
> + * Oversampling by 8
> + * - BRR[2:0] = USARTDIV[3:0] shifted 1 bit to the right.
> + * - BRR[3] must be kept cleared.
> + * - BRR[15:4] = USARTDIV[15:4]
> + * - The frequency is multiplied by 2
> + */
> + usart_div = ((value & 0xFFF0) | ((value & 0x0007) << 1)) / 2;
> + }
> +
> + speed = clock_get_hz(s->clk) / usart_div;
> +
> + ssp.speed = speed;
> + ssp.parity = parity;
> + ssp.data_bits = data_bits;
> + ssp.stop_bits = stop_bits;
> +
> + qemu_chr_fe_ioctl(&s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
> +
> + trace_stm32l4x5_usart_update_params(speed, parity, data_bits, stop_bits);
> +}
Otherwise
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
thanks
-- PMM
