serial: pl011: add console matching function

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>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Tested-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index e2c33b9528d8..cd5d1ee3b8b6 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -2315,12 +2315,67 @@ 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)
+{
+        unsigned char iotype;
+        unsigned long addr;
+        int i;
+
+        if (strcmp(name, "pl011") != 0)
+                return -ENODEV;
+
+        if (uart_parse_earlycon(options, &iotype, &addr, &options))
+                return -ENODEV;
+
+        if (iotype != UPIO_MEM && iotype != UPIO_MEM32)
+                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 (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,