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authorTobias Klauser <tklauser@distanz.ch>2017-04-02 20:09:04 -0700
committerLey Foon Tan <ley.foon.tan@intel.com>2017-05-08 16:59:19 +0800
commit44a4ed42576da5f3387005a1667cb3e7aedfd687 (patch)
treed1963ca7e55fc9a21178bd42e30de1a11f3a5b28 /arch/nios2
parent57ac76ed6c0daf02c520e09e0af421f02ee2de8b (diff)
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nios2: enable earlycon support
Enable generic earlycon support for nios2. This e.g. allows to use a 8250/16650 UART as earlycon. In order to get the earlycon, we just need to call parse_early_param() in early_init_devtree() as soon as the device tree is initially scanned. By adding an stdout-path property to the dts (done in this patch for 10m50_devboard), the earlycon can be used. In order to provide early printk support, we need to provide a dummy implementation of early_console_write(), so that arch/nios2/kernel/early_printk.c can still be compiled if neither SERIAL_ALTERA_JTAGUART_CONSOLE nor SERIAL_ALTERA_UART_CONSOLE is selected. As soon as the altera_uart and altera_jtaguart support earlycon, the entire file can be removed. Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com>
Diffstat (limited to 'arch/nios2')
-rw-r--r--arch/nios2/Kconfig.debug1
-rw-r--r--arch/nios2/boot/dts/10m50_devboard.dts3
-rw-r--r--arch/nios2/kernel/early_printk.c7
-rw-r--r--arch/nios2/kernel/setup.c2
4 files changed, 9 insertions, 4 deletions
diff --git a/arch/nios2/Kconfig.debug b/arch/nios2/Kconfig.debug
index 2fd08cbfdddb..55105220370c 100644
--- a/arch/nios2/Kconfig.debug
+++ b/arch/nios2/Kconfig.debug
@@ -18,7 +18,6 @@ config EARLY_PRINTK
bool "Activate early kernel debugging"
default y
select SERIAL_CORE_CONSOLE
- depends on SERIAL_ALTERA_JTAGUART_CONSOLE || SERIAL_ALTERA_UART_CONSOLE
help
Enable early printk on console
This is useful for kernel debugging when your machine crashes very
diff --git a/arch/nios2/boot/dts/10m50_devboard.dts b/arch/nios2/boot/dts/10m50_devboard.dts
index f362b2224ee7..4bb4dc1b52e9 100644
--- a/arch/nios2/boot/dts/10m50_devboard.dts
+++ b/arch/nios2/boot/dts/10m50_devboard.dts
@@ -244,6 +244,7 @@
};
chosen {
- bootargs = "debug console=ttyS0,115200";
+ bootargs = "debug earlycon console=ttyS0,115200";
+ stdout-path = &a_16550_uart_0;
};
};
diff --git a/arch/nios2/kernel/early_printk.c b/arch/nios2/kernel/early_printk.c
index c08e4c1486fc..4a7bb98f744c 100644
--- a/arch/nios2/kernel/early_printk.c
+++ b/arch/nios2/kernel/early_printk.c
@@ -81,8 +81,11 @@ static void early_console_write(struct console *con, const char *s, unsigned n)
}
#else
-# error Neither SERIAL_ALTERA_JTAGUART_CONSOLE nor SERIAL_ALTERA_UART_CONSOLE \
-selected
+
+static void early_console_write(struct console *con, const char *s, unsigned n)
+{
+}
+
#endif
static struct console early_console_prom = {
diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
index 6044d9be28b4..8b5146082e3e 100644
--- a/arch/nios2/kernel/setup.c
+++ b/arch/nios2/kernel/setup.c
@@ -137,6 +137,8 @@ asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
#endif
#endif
+
+ parse_early_param();
}
void __init setup_arch(char **cmdline_p)