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-rw-r--r--Documentation/kernel-parameters.txt18
-rw-r--r--drivers/tty/serial/8250/8250_core.c5
2 files changed, 18 insertions, 5 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bfcb1a62a7b4..1facf0bebb31 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -713,10 +713,18 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
+ uart[8250],mmio32,<addr>[,options]
+ uart[8250],0x<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address,
- switching to the matching ttyS device later. The
- options are the same as for ttyS, above.
+ switching to the matching ttyS device later.
+ MMIO inter-register address stride is either 8-bit
+ (mmio) or 32-bit (mmio32).
+ If none of [io|mmio|mmio32], <addr> is assumed to be
+ equivalent to 'mmio'. 'options' are specified in the
+ same format described for ttyS above; if unspecified,
+ the h/w is not re-initialized.
+
hvc<n> Use the hypervisor console device <n>. This is for
both Xen and PowerPC hypervisors.
@@ -944,11 +952,15 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
uart[8250],mmio32,<addr>[,options]
+ uart[8250],0x<addr>[,options]
Start an early, polled-mode console on the 8250/16550
UART at the specified I/O port or MMIO address.
MMIO inter-register address stride is either 8-bit
(mmio) or 32-bit (mmio32).
- The options are the same as for ttyS, above.
+ If none of [io|mmio|mmio32], <addr> is assumed to be
+ equivalent to 'mmio'. 'options' are specified in the
+ same format described for "console=ttyS<n>"; if
+ unspecified, the h/w is not initialized.
pl011,<addr>
Start an early, polled-mode console on a pl011 serial
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 18142ee3c013..422ebea96a64 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -3471,12 +3471,13 @@ static int univ8250_console_setup(struct console *co, char *options)
* @options: ptr to option string from console command line
*
* Only attempts to match console command lines of the form:
- * console=uart<>,io|mmio|mmio32,<addr>,<options>
- * console=uart<>,<addr>,options
+ * console=uart[8250],io|mmio|mmio32,<addr>[,<options>]
+ * console=uart[8250],0x<addr>[,<options>]
* This form is used to register an initial earlycon boot console and
* replace it with the serial8250_console at 8250 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
*/