esp-idf/components/log
Michael (XIAO Xufeng) 562af8f65e global: move the soc component out of the common list
This MR removes the common dependency from every IDF components to the SOC component.

Currently, in the ``idf_functions.cmake`` script, we include the header path of SOC component by default for all components.
But for better code organization (or maybe also benifits to the compiling speed), we may remove the dependency to SOC components for most components except the driver and kernel related components.

In CMAKE, we have two kinds of header visibilities (set by include path visibility):

(Assume component A --(depends on)--> B, B is the current component)

1. public (``COMPONENT_ADD_INCLUDEDIRS``): means this path is visible to other depending components (A) (visible to A and B)
2. private (``COMPONENT_PRIV_INCLUDEDIRS``): means this path is only visible to source files inside the component (visible to B only)

and we have two kinds of depending ways:

(Assume component A --(depends on)--> B --(depends on)--> C, B is the current component)

1. public (```COMPONENT_REQUIRES```): means B can access to public include path of C. All other components rely on you (A) will also be available for the public headers. (visible to A, B)
2. private (``COMPONENT_PRIV_REQUIRES``): means B can access to public include path of C, but don't propagate this relation to other components (A). (visible to B)

1. remove the common requirement in ``idf_functions.cmake``, this makes the SOC components invisible to all other components by default.
2. if a component (for example, DRIVER) really needs the dependency to SOC, add a private dependency to SOC for it.
3. some other components that don't really depends on the SOC may still meet some errors saying "can't find header soc/...", this is because it's depended component (DRIVER) incorrectly include the header of SOC in its public headers. Moving all this kind of #include into source files, or private headers
4. Fix the include requirements for some file which miss sufficient #include directives. (Previously they include some headers by the long long long header include link)

This is a breaking change. Previous code may depends on the long include chain.
You may need to include the following headers for some files after this commit:

- soc/soc.h
- soc/soc_memory_layout.h
- driver/gpio.h
- esp_sleep.h

The major broken include chain includes:

1. esp_system.h no longer includes esp_sleep.h. The latter includes driver/gpio.h and driver/touch_pad.h.
2. ets_sys.h no longer includes soc/soc.h
3. freertos/portmacro.h no longer includes soc/soc_memory_layout.h

some peripheral headers no longer includes their hw related headers, e.g. rom/gpio.h no longer includes soc/gpio_pins.h and soc/gpio_reg.h

BREAKING CHANGE
2019-04-16 13:21:15 +08:00
..
include separate rom from esp32 component to esp_rom 2019-03-21 18:51:45 +08:00
CMakeLists.txt global: move the soc component out of the common list 2019-04-16 13:21:15 +08:00
component.mk remove executable permission from source files 2018-05-29 20:07:45 +08:00
Kconfig Correct Kconfigs according to the coding style 2019-01-29 13:37:01 +01:00
log.c separate rom from esp32 component to esp_rom 2019-03-21 18:51:45 +08:00
README.rst Review log.rst and index.rst files in api-reference/system 2019-04-11 15:33:38 +08:00

Logging library
===============

Overview
--------

The logging library provides two ways for setting log verbosity:

- **At compile time**: in menuconfig, set the verbosity level using the option :envvar:`CONFIG_LOG_DEFAULT_LEVEL`. All logging statements for verbosity levels higher than :envvar:`CONFIG_LOG_DEFAULT_LEVEL` will be removed by the preprocessor.
- **At runtime**: all logs for verbosity levels lower than :envvar:`CONFIG_LOG_DEFAULT_LEVEL` are enabled by default. The function :cpp:func:`esp_log_level_set` can be used to set a logging level on a per module basis. Modules are identified by their tags, which are human-readable ASCII zero-terminated strings.

There are the following verbosity levels:

- Error (lowest)
- Warning
- Info
- Debug
- Verbose (highest)

.. note::

    The function :cpp:func:`esp_log_level_set` cannot set logging levels higher than specified by :envvar:`CONFIG_LOG_DEFAULT_LEVEL`. To increase log level for a specific file at compile time, use the macro `LOG_LOCAL_LEVEL` (see the details below).


How to use this library
-----------------------

In each C file that uses logging functionality, define the TAG variable as shown below:

.. code-block:: c

   static const char* TAG = "MyModule";

Then use one of logging macros to produce output, e.g:

.. code-block:: c

   ESP_LOGW(TAG, "Baud rate error %.1f%%. Requested: %d baud, actual: %d baud", error * 100, baud_req, baud_real);

Several macros are available for different verbosity levels:

* ``ESP_LOGE`` - error (lowest)
* ``ESP_LOGW`` - warning
* ``ESP_LOGI`` - info
* ``ESP_LOGD`` - debug
* ``ESP_LOGV`` - verbose (highest)

Additionally, there are ``ESP_EARLY_LOGx`` versions for each of these macros, e.g., :c:macro:`ESP_EARLY_LOGE`. These versions have to be used explicitly in the early startup code only, before heap allocator and syscalls have been initialized. Normal ``ESP_LOGx`` macros can also be used while compiling the bootloader, but they will fall back to the same implementation as ``ESP_EARLY_LOGx`` macros.

To override default verbosity level at file or component scope, define the ``LOG_LOCAL_LEVEL`` macro.

At file scope, define it before including ``esp_log.h``, e.g.:

.. code-block:: c

   #define LOG_LOCAL_LEVEL ESP_LOG_VERBOSE
   #include "esp_log.h"

At component scope, define it in the component makefile:

.. code-block:: make

   CFLAGS += -D LOG_LOCAL_LEVEL=ESP_LOG_DEBUG

To configure logging output per module at runtime, add calls to the function :cpp:func:`esp_log_level_set` as follows:

.. code-block:: c

   esp_log_level_set("*", ESP_LOG_ERROR);        // set all components to ERROR level
   esp_log_level_set("wifi", ESP_LOG_WARN);      // enable WARN logs from WiFi stack
   esp_log_level_set("dhcpc", ESP_LOG_INFO);     // enable INFO logs from DHCP client

Logging to Host via JTAG
^^^^^^^^^^^^^^^^^^^^^^^^

By default, the logging library uses the vprintf-like function to write formatted output to the dedicated UART. By calling a simple API, all log output may be routed to JTAG instead, making logging several times faster. For details, please refer to Section :ref:`app_trace-logging-to-host`.