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2023-01-07soc: qcom: dcc: rewrite description of dcc sysfs filesBagas Sanjaya1-66/+76
The description of dcc sysfs files is somewhat confusing and not effective. Rewrite it to be clear. While at it, also use literal code block for config sysfs examples and remove redundant examples that are obvious. Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20221230135030.17002-3-bagasdotme@gmail.com
2023-01-07soc: qcom: dcc: Fix examples list on ↵Bagas Sanjaya1-22/+41
/sys/kernel/debug/dcc/.../[list-number]/config documentation kernel test robot reported htmldocs warnings: Documentation/ABI/testing/debugfs-driver-dcc:34: WARNING: Unexpected indentation. Documentation/ABI/testing/debugfs-driver-dcc:34: WARNING: Block quote ends without a blank line; unexpected unindent. Fix these by fixing numbered list syntax on description of /sys/kernel/debug/dcc/.../[list-number]/config, including adding blank line separators as appropriate. Link: https://lore.kernel.org/linux-doc/202212300426.eMLsZsvA-lkp@intel.com/ Fixes: 4cbe60cf5ad622 ("soc: qcom: dcc: Add driver support for Data Capture and Compare unit(DCC)") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com> Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/20221230135030.17002-2-bagasdotme@gmail.com
2022-12-28soc: qcom: dcc: Add driver support for Data Capture and Compare unit(DCC)Souradeep Chowdhury1-0/+98
The DCC is a DMA Engine designed to capture and store data during system crash or software triggers. The DCC operates based on user inputs via the debugfs interface. The user gives addresses as inputs and these addresses are stored in the dcc sram. In case of a system crash or a manual software trigger by the user through the debugfs interface, the dcc captures and stores the values at these addresses. This patch contains the driver which has all the methods pertaining to the debugfs interface, auxiliary functions to support all the four fundamental operations of dcc namely read, write, read/modify/write and loop. The probe method here instantiates all the resources necessary for dcc to operate mainly the dedicated dcc sram where it stores the values. The DCC driver can be used for debugging purposes without going for a reboot since it can perform software triggers as well based on user inputs. Also add the documentation for debugfs entries which explains the functionalities of each debugfs file that has been created for dcc. The following is the justification of using debugfs interface over the other alternatives like sysfs/ioctls i) As can be seen from the debugfs attribute descriptions, some of the debugfs attribute files here contains multiple arguments which needs to be accepted from the user. This goes against the design style of sysfs. ii) The user input patterns have been made simple and convenient in this case with the use of debugfs interface as user doesn't need to shuffle between different files to execute one instruction as was the case on using other alternatives. Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com> Reviewed-by: Alex Elder <elder@linaro.org> [bjorn: Fixed up a few indents and line wraps] Signed-off-by: Bjorn Andersson <andersson@kernel.org> Link: https://lore.kernel.org/r/644b4f66a358492a8a6738454035c3b120092fe7.1672148732.git.quic_schowdhu@quicinc.com