Message ID | cover.1672148732.git.quic_schowdhu@quicinc.com |
---|---|
Headers | show |
Series | soc: qcom: dcc: Add driver support for Data Capture and Compare unit(DCC) | expand |
On Tue, Dec 27, 2022 at 08:52:46PM +0530, Souradeep Chowdhury wrote: > 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. > I would have preferred to get some more input from users of the debugfs interface, but it's after all not ABI. So let's get this merged and if people has concerns/objections/suggestions we'll improve it as necessary. Thanks for pushing this Souradeep! > Signed-off-by: Souradeep Chowdhury <quic_schowdhu@quicinc.com> > Reviewed-by: Alex Elder <elder@linaro.org> Thanks Alex. Regards, Bjorn
On Tue, 27 Dec 2022 20:52:44 +0530, Souradeep Chowdhury wrote: > DCC(Data Capture and Compare) is a DMA engine designed for debugging purposes. > In case of a system crash or manual software triggers by the user the DCC hardware > stores the value at the register addresses which can be used for debugging purposes. > The DCC driver provides the user with debugfs interface to configure the register > addresses. The options that the DCC hardware provides include reading from registers, > writing to registers, first reading and then writing to registers and looping > through the values of the same register. > > [...] Applied, thanks! [4/7] arm64: dts: qcom: sm8150: Add Data Capture and Compare(DCC) support node commit: d4b94c8244919742417c3a165ef73081de37ef3b [5/7] arm64: dts: qcom: sc7280: Add Data Capture and Compare(DCC) support node commit: 029d6586dc2d1d10e9df3962633e29e145d764ec [6/7] arm64: dts: qcom: sc7180: Add Data Capture and Compare(DCC) support node commit: add74cad7c9d1bf59d41b229852f3ebe0be4a84f [7/7] arm64: dts: qcom: sdm845: Add Data Capture and Compare(DCC) support node commit: 91269c425649baad9758dbe269e7069ad7fa05fc Best regards,