Re: [PATCH 6/8] serial: imx: stop using USR2 in FIFO reading loop

[Sergey Organov <sorganov@gmail.com>]

Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> writes:

> On Fri, 13 Jan 2023, Sergey Organov wrote:
>
>> The chip provides all the needed bits in the URXD0 register that we read
>> anyway for data, so get rid of reading USR2 and use only URXD0 bits
>> instead.
>> 
>> Signed-off-by: Sergey Organov <sorganov@gmail.com>
>> ---
>>  drivers/tty/serial/imx.c | 18 ++++++------------
>>  1 file changed, 6 insertions(+), 12 deletions(-)
>> 
>> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
>> index c44a7293c013..be00362b8b67 100644
>> --- a/drivers/tty/serial/imx.c
>> +++ b/drivers/tty/serial/imx.c
>> @@ -892,27 +892,21 @@ static irqreturn_t __imx_uart_rxint(int irq, void *dev_id)
>>  	struct tty_port *port = &sport->port.state->port;
>>  	u32 usr2;
>>  
>> -	usr2 = imx_uart_readl(sport, USR2);
>> -
>>  	/* If we received something, check for 0xff flood */
>> +	usr2 = imx_uart_readl(sport, USR2);
>
> Please just place the read into the correct place in 2/8 rather than 
> moving it needlessly here again.

Well, this I considered and rejected already, before publishing the
patches.

In 2/8 this read was an initialization for the entire FIFO reading loop,
the value being re-used for flood check at the beginning as well, and
with this patch it becomes just a local read for subsequent 2 lines of
code that perform flood check, not used in the FIFO loop anymore, so I
moved it in this patch to where it now belongs.

Thanks,
-- Sergey Organov