From 87680a246429d24e99b7b477b743c357f73b752c Mon Sep 17 00:00:00 2001 From: Julius Werner Date: Mon, 2 Jun 2014 20:13:51 -0700 Subject: [PATCH] libpayload: Add ability to unregister output driver This patch adds a console_kill_output_driver() function, which can remove a previously registered output driver. This is mostly useful when you overlay some output channel over another, such as when the GDB stub takes direct control of the UART (and thus has to get rid of the existing serial output driver). BUG=chrome-os-partner:18390 TEST=None Change-Id: I6fce95c22fd15cd321ca6b2d6fbc4e3902b1eac3 Signed-off-by: Julius Werner Reviewed-on: https://chromium-review.googlesource.com/202561 Reviewed-by: Stefan Reinauer --- payloads/libpayload/include/libpayload.h | 1 + payloads/libpayload/libc/console.c | 17 +++++++++++++++++ 2 files changed, 18 insertions(+) diff --git a/payloads/libpayload/include/libpayload.h b/payloads/libpayload/include/libpayload.h index 7f220787d1..819dcf36fc 100644 --- a/payloads/libpayload/include/libpayload.h +++ b/payloads/libpayload/include/libpayload.h @@ -282,6 +282,7 @@ struct console_output_driver { void console_add_output_driver(struct console_output_driver *out); void console_add_input_driver(struct console_input_driver *in); +int console_remove_output_driver(void *function); #define havechar havekey /** @} */ diff --git a/payloads/libpayload/libc/console.c b/payloads/libpayload/libc/console.c index 8c0664d125..827da792b9 100644 --- a/payloads/libpayload/libc/console.c +++ b/payloads/libpayload/libc/console.c @@ -48,6 +48,23 @@ void console_add_input_driver(struct console_input_driver *in) console_in = in; } +/* + * For when you really need to silence an output driver (e.g. to avoid ugly + * recursions). Takes the pointer of either of the two output functions, since + * the struct console_output_driver itself is often static and inaccessible. + */ +int console_remove_output_driver(void *function) +{ + struct console_output_driver **out; + for (out = &console_out; *out; out = &(*out)->next) + if ((*out)->putchar == function || (*out)->write == function) { + *out = (*out)->next; + return 1; + } + + return 0; +} + void console_init(void) { #ifdef CONFIG_LP_VIDEO_CONSOLE