linux-kernel - Re: [PATCH v8 4/4] serial: pl011: add console matching function

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Date:	Mon, 20 Jun 2016 15:26:39 +0300
From:	Aleksey Makarov <aleksey.makarov@...aro.org>
To:	Russell King <linux@....linux.org.uk>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Aleksey Makarov <aleksey.makarov@...aro.org>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	linux-serial@...r.kernel.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Len Brown <lenb@...nel.org>,
	Leif Lindholm <leif.lindholm@...aro.org>,
	Graeme Gregory <graeme.gregory@...aro.org>,
	Al Stone <ahs3@...hat.com>,
	Christopher Covington <cov@...eaurora.org>,
	Yury Norov <ynorov@...iumnetworks.com>,
	Peter Hurley <peter@...leysoftware.com>,
	Andy Shevchenko <andy.shevchenko@...il.com>,
	"Zheng, Lv" <lv.zheng@...el.com>, Mark Salter <msalter@...hat.com>,
	Kefeng Wang <wangkefeng.wang@...wei.com>,
	Russell King <linux@...linux.org.uk>,
	Jiri Slaby <jslaby@...e.com>
Subject: Re: [PATCH v8 4/4] serial: pl011: add console matching function


On 06/02/2016 09:02 PM, Aleksey Makarov wrote:
> 
> On 05/20/2016 04:03 PM, Aleksey Makarov wrote:

Hi Russell,

Can you review this patch please?

Thank you
Aleksey Makarov

>> This patch adds function pl011_console_match() that implements
>> method match of struct console.  It allows to match consoles against
>> data specified in a string, for example taken from command line or
>> compiled by ACPI SPCR table handler.
>>
>> Signed-off-by: Aleksey Makarov <aleksey.makarov@...aro.org>
>> Reviewed-by: Peter Hurley <peter@...leysoftware.com>
> 
> Hi Greg, Russell,
> 
> Can you review this patch and consider ACKing it please?
> It had an ACK from Greg in v7 but since then I changed it a bit.
> 
> The patch by Christopher Covington [1] specifies that SBSA uart 
> does 32-bit access to registers and this breaks the match function.  
> In this series the function was changed to match when SPCR specifies
> both mmio32 and mmio access.  I removed Acked-by: Greg from this
> patch because of these changes.
> 
> The difference between v7 and v8:
> 
> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
> index 4139b64..388edc8 100644
> --- a/drivers/tty/serial/amba-pl011.c
> +++ b/drivers/tty/serial/amba-pl011.c
> @@ -2328,10 +2329,10 @@ static int __init pl011_console_match(struct console *co, char *name, int idx,
>  
>                 port = &amba_ports[i]->port;
>  
> -               if (port->iotype != iotype)
> +               if (iotype != UPIO_MEM && iotype != UPIO_MEM32)
>                         continue;
> -               if ((iotype == UPIO_MEM || iotype == UPIO_MEM32) &&
> -                   (port->mapbase != addr))
> +
> +               if (port->mapbase != addr)
>                         continue;
>  
>                 co->index = i;
> 
> [1] https://lkml.kernel.org/g/1457415800-8799-1-git-send-email-cov@codeaurora.org
> 
> Thank you
> Aleksey Makarov
> 
>> ---
>>  drivers/tty/serial/amba-pl011.c | 56 +++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 56 insertions(+)
>>
>> diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
>> index a2aa655..388edc8 100644
>> --- a/drivers/tty/serial/amba-pl011.c
>> +++ b/drivers/tty/serial/amba-pl011.c
>> @@ -2288,12 +2288,68 @@ static int __init pl011_console_setup(struct console *co, char *options)
>>  	return uart_set_options(&uap->port, co, baud, parity, bits, flow);
>>  }
>>  
>> +/**
>> + *	pl011_console_match - non-standard console matching
>> + *	@co:	  registering console
>> + *	@name:	  name from console command line
>> + *	@idx:	  index from console command line
>> + *	@options: ptr to option string from console command line
>> + *
>> + *	Only attempts to match console command lines of the form:
>> + *	    console=pl011,mmio|mmio32,<addr>[,<options>]
>> + *	    console=pl011,0x<addr>[,<options>]
>> + *	This form is used to register an initial earlycon boot console and
>> + *	replace it with the amba_console at pl011 driver init.
>> + *
>> + *	Performs console setup for a match (as required by interface)
>> + *	If no <options> are specified, then assume the h/w is already setup.
>> + *
>> + *	Returns 0 if console matches; otherwise non-zero to use default matching
>> + */
>> +static int __init pl011_console_match(struct console *co, char *name, int idx,
>> +				      char *options)
>> +{
>> +	char match[] = "pl011";	/* pl011-specific earlycon name */
>> +	unsigned char iotype;
>> +	unsigned long addr;
>> +	int i;
>> +
>> +	if (strncmp(name, match, 5) != 0)
>> +		return -ENODEV;
>> +
>> +	if (uart_parse_earlycon(options, &iotype, &addr, &options))
>> +		return -ENODEV;
>> +
>> +	/* try to match the port specified on the command line */
>> +	for (i = 0; i < ARRAY_SIZE(amba_ports); i++) {
>> +		struct uart_port *port;
>> +
>> +		if (!amba_ports[i])
>> +			continue;
>> +
>> +		port = &amba_ports[i]->port;
>> +
>> +		if (iotype != UPIO_MEM && iotype != UPIO_MEM32)
>> +			continue;
>> +
>> +		if (port->mapbase != addr)
>> +			continue;
>> +
>> +		co->index = i;
>> +		port->cons = co;
>> +		return pl011_console_setup(co, options);
>> +	}
>> +
>> +	return -ENODEV;
>> +}
>> +
>>  static struct uart_driver amba_reg;
>>  static struct console amba_console = {
>>  	.name		= "ttyAMA",
>>  	.write		= pl011_console_write,
>>  	.device		= uart_console_device,
>>  	.setup		= pl011_console_setup,
>> +	.match		= pl011_console_match,
>>  	.flags		= CON_PRINTBUFFER,
>>  	.index		= -1,
>>  	.data		= &amba_reg,
>>