Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> writes:
> On Fri, 13 Jan 2023, Sergey Organov wrote:
>
>> We perform soft reset in 2 places, slightly differently for no sufficient
>> reasons, so move more generic variant to a function, and re-use the code.
>>
>> Out of 2 repeat counters, 10 and 100, select 10, as the code works at
>> interrupts disabled, and in practice the reset happens immediately.
>>
>> Signed-off-by: Sergey Organov <sorganov@xxxxxxxxx>
>> ---
>> drivers/tty/serial/imx.c | 73 ++++++++++++++++++++--------------------
>> 1 file changed, 37 insertions(+), 36 deletions(-)
>>
>> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
>> index 757825edb0cd..bf222d8568a9 100644
>> --- a/drivers/tty/serial/imx.c
>> +++ b/drivers/tty/serial/imx.c
>> @@ -397,6 +397,39 @@ static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
>> hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
>> }
>>
>> +/* called with port.lock taken and irqs off */
>> +static void imx_uart_soft_reset(struct imx_port *sport)
>> +{
>> + int i = 10;
>> + u32 ucr2, ubir, ubmr, uts;
>> +
>> + /*
>> + * According to the Reference Manual description of the UART SRST bit:
>> + *
>> + * "Reset the transmit and receive state machines,
>> + * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD
>> + * and UTS[6-3]".
>> + *
>> + * We don't need to restore the old values from USR1, USR2, URXD and
>> + * UTXD. UBRC is read only, so only save/restore the other three
>> + * registers.
>> + */
>> + ubir = imx_uart_readl(sport, UBIR);
>> + ubmr = imx_uart_readl(sport, UBMR);
>> + uts = imx_uart_readl(sport, IMX21_UTS);
>> +
>> + ucr2 = imx_uart_readl(sport, UCR2);
>> + imx_uart_writel(sport, ucr2 & ~UCR2_SRST, UCR2);
>> +
>> + while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0))
>> + udelay(1);
>
> This could use read_poll_timeout_atomic().
As this is just a factor-out of existing code that uses the loop, I'm not
sure if it's a good idea to change this along the way.
Do you want me to add yet another patch to the series? I'd rather not,
as I won't be able to test it on my outdated kernel anyway.
Thanks,
-- Sergey Organov
