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authorPeter Hurley <peter@hurleysoftware.com>2015-03-09 16:27:21 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-26 17:25:27 +0100
commit470ca0de69feaba5df215ad804cec1859883a5ed (patch)
treef6881a136d161bb131d56b9b68860568756b53eb /include/linux/serial_core.h
parent7c53cb3de493573dc3b7f2468a542a9f11cc5079 (diff)
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serial: earlycon: Enable earlycon without command line param
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>
Diffstat (limited to 'include/linux/serial_core.h')
-rw-r--r--include/linux/serial_core.h19
1 files changed, 11 insertions, 8 deletions
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 980170e5a982..8aeec4913a9c 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -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 *)