From 470ca0de69feaba5df215ad804cec1859883a5ed Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 9 Mar 2015 16:27:21 -0400 Subject: 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 Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- include/asm-generic/vmlinux.lds.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/asm-generic/vmlinux.lds.h') diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ac78910d7416..87e5b6f8f4fc 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -150,6 +150,14 @@ #define TRACE_SYSCALLS() #endif +#ifdef CONFIG_SERIAL_EARLYCON +#define EARLYCON_TABLE() . = ALIGN(8); \ + VMLINUX_SYMBOL(__earlycon_table) = .; \ + *(__earlycon_table) \ + *(__earlycon_table_end) +#else +#define EARLYCON_TABLE() +#endif #define ___OF_TABLE(cfg, name) _OF_TABLE_##cfg(name) #define __OF_TABLE(cfg, name) ___OF_TABLE(cfg, name) @@ -503,6 +511,7 @@ CPU_METHOD_OF_TABLES() \ KERNEL_DTB() \ IRQCHIP_OF_MATCH_TABLE() \ + EARLYCON_TABLE() \ EARLYCON_OF_TABLES() #define INIT_TEXT \ -- cgit v1.2.3