[PATCH v8 4/4] serial: pl011: add console matching function

Peter Hurley
2016-06-22T14:08:33Z

> On Jun 22, 2016, at 5:18 AM, Yury Norov <ynorov@caviumnetworks.com> wrote:
>
>> On Fri, May 20, 2016 at 04:03:23PM +0300, Aleksey Makarov wrote:
>> 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@linaro.org>
>> Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
>> ---
>> 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;
>
> So it looks like iotype is constant inside the loop, and UPIO_MEM
> and UPIO_MEM32 too, of course. It means you can move this check out of
> cycle and avoid ports traversing at all in specific case. Am I wrong?
>

No you're not wrong but I'd prefer if we don't use assumptions like that in port enumeration.

>> +
>> + 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,
>> --
>> 2.8.2