diff options
| author | James Hogan <james.hogan@imgtec.com> | 2015-01-29 11:14:13 +0000 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2015-03-31 12:04:12 +0200 |
| commit | e934945db7625716f9cc469e31fc5da8666c8024 (patch) | |
| tree | ec3381a503bb92b2d40ee656e8b9b4b222add244 /drivers/tty | |
| parent | 4cebec609aea6dff23e67a42b6516d852fa87d07 (diff) | |
MIPS, ttyFDC: Add early FDC console support
Add support for early console of MIPS Fast Debug Channel (FDC) on
channel 1 with a call very early from the MIPS setup_arch().
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/9145/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/tty/mips_ejtag_fdc.c | 20 |
2 files changed, 33 insertions, 0 deletions
diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig index 39469ca4231c..e0c18e5b7057 100644 --- a/drivers/tty/Kconfig +++ b/drivers/tty/Kconfig @@ -437,4 +437,17 @@ config MIPS_EJTAG_FDC_TTY If unsure, say N. +config MIPS_EJTAG_FDC_EARLYCON + bool "Early FDC console" + depends on MIPS_EJTAG_FDC_TTY + help + This registers a console on FDC channel 1 very early during boot (from + MIPS arch code). This is useful for bring-up and debugging early boot + issues. + + Do not enable unless there is a debug probe attached to drain the FDC + TX FIFO. + + If unsure, say N. + endif # TTY diff --git a/drivers/tty/mips_ejtag_fdc.c b/drivers/tty/mips_ejtag_fdc.c index 51672cfe7e45..8d9bf6f90110 100644 --- a/drivers/tty/mips_ejtag_fdc.c +++ b/drivers/tty/mips_ejtag_fdc.c @@ -69,6 +69,9 @@ #define REG_FDSTAT_TXE BIT(1) /* Tx Empty */ #define REG_FDSTAT_TXF BIT(0) /* Tx Full */ +/* Default channel for the early console */ +#define CONSOLE_CHANNEL 1 + #define NUM_TTY_CHANNELS 16 #define RX_BUF_SIZE 1024 @@ -1124,3 +1127,20 @@ static int __init mips_ejtag_fdc_init_console(void) return mips_ejtag_fdc_console_init(&mips_ejtag_fdc_con); } console_initcall(mips_ejtag_fdc_init_console); + +#ifdef CONFIG_MIPS_EJTAG_FDC_EARLYCON +static struct mips_ejtag_fdc_console mips_ejtag_fdc_earlycon = { + .cons = { + .name = "early_fdc", + .write = mips_ejtag_fdc_console_write, + .flags = CON_PRINTBUFFER | CON_BOOT, + .index = CONSOLE_CHANNEL, + }, + .lock = __RAW_SPIN_LOCK_UNLOCKED(mips_ejtag_fdc_earlycon.lock), +}; + +int __init setup_early_fdc_console(void) +{ + return mips_ejtag_fdc_console_init(&mips_ejtag_fdc_earlycon); +} +#endif |