apfs/linux-apfs
0
0
Fork 0
mirror of https://github.com/linux-apfs/linux-apfs.git synced 2026-05-01 15:00:59 -07:00
Code Issues Packages Projects Releases Wiki Activity

serial: earlycon: Enable earlycon without command line param

Browse Source 
Earlycon matching can only be triggered if 'earlycon=...' has been
specified on the kernel command line. To workaround this limitation
requires tight coupling between arches and specific serial drivers
in order to start an earlycon. Devicetree avoids this limitation
with a link table that contains the required data to match earlycons.

Mirror this approach for earlycon match by name. Re-purpose
EARLYCON_DECLARE to generate a table entry which associates name with
setup() function. Re-purpose setup_earlycon() to scan this table for
an earlycon match, which is registered if found.

Declare one "earlycon" early_param, which calls setup_earlycon().

This design allows setup_earlycon() to be called directly with a
param string (as if 'earlycon=...' had been set on the command line).
Re-registration (either directly or by early_param) is prevented.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Peter Hurley
2015-03-09 16:27:21 -04:00
committed by Greg Kroah-Hartman
parent 7c53cb3de4
commit 470ca0de69
4 changed files with 94 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/serial_core.h
+11 -8
View File
@@ -337,18 +337,21 @@ struct earlycon_device {
char options[16]; /* e.g., 115200n8 */
unsigned int baud;
};
int setup_earlycon(char *buf, const char *match,
int (*setup)(struct earlycon_device *, const char *));
struct earlycon_id {
char name[16];
int (*setup)(struct earlycon_device *, const char *options);
};
extern int setup_earlycon(char *buf);
extern int of_setup_earlycon(unsigned long addr,
int (*setup)(struct earlycon_device *, const char *));
#define EARLYCON_DECLARE(name, func) \
static int __init name ## _setup_earlycon(char *buf) \
{ \
return setup_earlycon(buf, __stringify(name), func); \
} \
early_param("earlycon", name ## _setup_earlycon);
#define EARLYCON_DECLARE(_name, func) \
static const struct earlycon_id __earlycon_##_name \
__used __section(__earlycon_table) \
= { .name = __stringify(_name), \
.setup = func }
#define OF_EARLYCON_DECLARE(name, compat, fn) \
_OF_DECLARE(earlycon, name, compat, fn, void *)