linux-kernel - Re: [PATCH v4 09/10] tty: serial: use uart_port

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Date:   Tue, 20 Sep 2022 10:56:10 +0200
From:   Jiri Slaby <jirislaby@...nel.org>
To:     Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-serial <linux-serial@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Tobias Klauser <tklauser@...tanz.ch>,
        Richard Genoud <richard.genoud@...il.com>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Claudiu Beznea <claudiu.beznea@...rochip.com>,
        Vladimir Zapolskiy <vz@...ia.com>,
        Liviu Dudau <liviu.dudau@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Andreas Färber <afaerber@...e.de>,
        Manivannan Sadhasivam <mani@...nel.org>
Subject: Re: [PATCH v4 09/10] tty: serial: use uart_port_tx() helper

On 20. 09. 22, 10:54, Ilpo Järvinen wrote:
> On Tue, 20 Sep 2022, Jiri Slaby wrote:
> 
>> uart_port_tx() is a new helper to send characters to the device. Use it
>> in these drivers.
>>
>> Cc: Tobias Klauser <tklauser@...tanz.ch>
>> Cc: Richard Genoud <richard.genoud@...il.com>
>> Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>
>> Cc: Alexandre Belloni <alexandre.belloni@...tlin.com>
>> Cc: Claudiu Beznea <claudiu.beznea@...rochip.com>
>> Cc: Vladimir Zapolskiy <vz@...ia.com>
>> Cc: Liviu Dudau <liviu.dudau@....com>
>> Cc: Sudeep Holla <sudeep.holla@....com>
>> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
>> Cc: Shawn Guo <shawnguo@...nel.org>
>> Cc: Sascha Hauer <s.hauer@...gutronix.de>
>> Cc: Pengutronix Kernel Team <kernel@...gutronix.de>
>> Cc: Fabio Estevam <festevam@...il.com>
>> Cc: NXP Linux Team <linux-imx@....com>
>> Cc: "Andreas Färber" <afaerber@...e.de>
>> Cc: Manivannan Sadhasivam <mani@...nel.org>
>> Signed-off-by: Jiri Slaby <jslaby@...e.cz>
>> ---
> 
>> diff --git a/drivers/tty/serial/mcf.c b/drivers/tty/serial/mcf.c
>> index b1cd9a76dd93..53b642ea46ba 100644
>> --- a/drivers/tty/serial/mcf.c
>> +++ b/drivers/tty/serial/mcf.c
>> @@ -327,29 +327,13 @@ static void mcf_rx_chars(struct mcf_uart *pp)
>>   static void mcf_tx_chars(struct mcf_uart *pp)
>>   {
>>   	struct uart_port *port = &pp->port;
>> -	struct circ_buf *xmit = &port->state->xmit;
>> -
>> -	if (port->x_char) {
>> -		/* Send special char - probably flow control */
>> -		writeb(port->x_char, port->membase + MCFUART_UTB);
>> -		port->x_char = 0;
>> -		port->icount.tx++;
>> -		return;
>> -	}
>> -
>> -	while (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY) {
>> -		if (uart_circ_empty(xmit))
>> -			break;
>> -		writeb(xmit->buf[xmit->tail], port->membase + MCFUART_UTB);
>> -		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE -1);
>> -		port->icount.tx++;
>> -	}
>> -
>> -	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
>> -		uart_write_wakeup(port);
>> +	unsigned int pending;
>> +	u8 ch;
>>   
>> -	if (uart_circ_empty(xmit)) {
>> -		mcf_stop_tx(port);
>> +	pending = uart_port_tx(port, ch,
>> +		readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY,
>> +		writeb(ch, port->membase + MCFUART_UTB));
>> +	if (!pending) {
> 
> Why unsigned int pending here and bool pending in the other cases?

Right, I somehow omitted that pending is not used anywhere else. This 
should be bool too, of course.

> Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>

thanks,
-- 
js
suse labs