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→Implementation example for GNU/Linux o.s.
Below is an example of how the TRACE32-based log method can be applied to a Linux system. The solution is based on light instrumentation of the <code>mmc_start_request()</code> and <code>mmc_request_done()</code> functions defined in the Linux <code>drivers/mmc/core/core.c</code> source code file. Relevant eMMC device accesses are captured through the instrumentation code and they are written to a static data structure making them immediately traceable if data trace is available in the SoC. If data tracing is not possible, the instrumentation code writes the data to the Arm®/Cortex® Context ID register.
The solution was successfully tested on the aforementioned embedded platform. The instrumentation code is provided in [[#Appendix 1: source code example|Appendix 1]]. The zero initialization of the <code>T32_mmc</code> structure is guaranteed by Linux, since this variable is allocated in the bss section. The instrumentation is normally disabled but can be enabled by writing the value "1" into the <code>enable</code> field of the <code>T32_mmc</code> structure. The identifier of the eMMC device to be traced must be written into the <code>dev</code> field. Both of these operations can be performed from a TRACE32 script with the following commands:
<pre class="workstation-terminal">
