From c5cb3cfd2187c82b11bb1f12d644e77ecd807efc Mon Sep 17 00:00:00 2001 From: Lorenz Meier Date: Fri, 24 Jan 2014 17:34:42 +0100 Subject: Make the IO mixer upload report not only a global success / fail flag, but on transfer basis. Also use a crude lock to avoid updating the mixer while it runs (we have no proper mutexes on IO, and this is a pure read/write locking case with two locks, which should make the execution even with this crude approach thread-safe). --- src/modules/px4iofirmware/mixer.cpp | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) (limited to 'src/modules/px4iofirmware/mixer.cpp') diff --git a/src/modules/px4iofirmware/mixer.cpp b/src/modules/px4iofirmware/mixer.cpp index e55ef784a..2e79f0ac6 100644 --- a/src/modules/px4iofirmware/mixer.cpp +++ b/src/modules/px4iofirmware/mixer.cpp @@ -1,6 +1,6 @@ /**************************************************************************** * - * Copyright (C) 2012 PX4 Development Team. All rights reserved. + * Copyright (c) 2012-2014 PX4 Development Team. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions @@ -71,6 +71,7 @@ extern "C" { static bool mixer_servos_armed = false; static bool should_arm = false; static bool should_always_enable_pwm = false; +static volatile bool in_mixer = false; /* selected control values and count for mixing */ enum mixer_source { @@ -95,6 +96,7 @@ static void mixer_set_failsafe(); void mixer_tick(void) { + /* check that we are receiving fresh data from the FMU */ if (hrt_elapsed_time(&system_state.fmu_data_received_time) > FMU_INPUT_DROP_LIMIT_US) { @@ -199,13 +201,17 @@ mixer_tick(void) } - } else if (source != MIX_NONE) { + } else if (source != MIX_NONE && (r_status_flags & PX4IO_P_STATUS_FLAGS_MIXER_OK)) { float outputs[PX4IO_SERVO_COUNT]; unsigned mixed; /* mix */ + + /* poor mans mutex */ + in_mixer = true; mixed = mixer_group.mix(&outputs[0], PX4IO_SERVO_COUNT); + in_mixer = false; pwm_limit_calc(should_arm, mixed, r_page_servo_disarmed, r_page_servo_control_min, r_page_servo_control_max, outputs, r_page_servos, &pwm_limit); @@ -297,12 +303,17 @@ mixer_callback(uintptr_t handle, static char mixer_text[256]; /* large enough for one mixer */ static unsigned mixer_text_length = 0; -void +int mixer_handle_text(const void *buffer, size_t length) { /* do not allow a mixer change while safety off */ if ((r_status_flags & PX4IO_P_STATUS_FLAGS_SAFETY_OFF)) { - return; + return 1; + } + + /* abort if we're in the mixer */ + if (in_mixer) { + return 1; } px4io_mixdata *msg = (px4io_mixdata *)buffer; @@ -310,7 +321,7 @@ mixer_handle_text(const void *buffer, size_t length) isr_debug(2, "mix txt %u", length); if (length < sizeof(px4io_mixdata)) - return; + return 0; unsigned text_length = length - sizeof(px4io_mixdata); @@ -328,13 +339,16 @@ mixer_handle_text(const void *buffer, size_t length) case F2I_MIXER_ACTION_APPEND: isr_debug(2, "append %d", length); + /* disable mixing during the update */ + r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK; + /* check for overflow - this would be really fatal */ if ((mixer_text_length + text_length + 1) > sizeof(mixer_text)) { r_status_flags &= ~PX4IO_P_STATUS_FLAGS_MIXER_OK; - return; + return 0; } - /* append mixer text and nul-terminate */ + /* append mixer text and nul-terminate, guard against overflow */ memcpy(&mixer_text[mixer_text_length], msg->text, text_length); mixer_text_length += text_length; mixer_text[mixer_text_length] = '\0'; @@ -369,6 +383,8 @@ mixer_handle_text(const void *buffer, size_t length) break; } + + return 0; } static void -- cgit v1.2.3