Re: [PATCH v8 4/4] serial: pl011: add console matching function
From: Yury Norov <hidden>
Date: 2016-06-22 12:18:29
Also in:
linux-acpi, linux-arm-kernel, lkml
On Fri, May 20, 2016 at 04:03:23PM +0300, Aleksey Makarov wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Reviewed-by: Peter Hurley <redacted> --- 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?
+
+ 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