Re: [PATCH v4 9/9] Documentation: ABI: Add sysfs ABI documentation for DDR training data

[Kishore Batta <kishore.batta@oss.qualcomm.com>]

On 4/13/2026 5:29 PM, Manivannan Sadhasivam wrote:
> On Thu, Mar 19, 2026 at 12:01:49PM +0530, Kishore Batta wrote:
>> Add ABI documentation for the DDR training data sysfs attribute exposed by
>> the sahara MHI driver.
>>
>> The documented sysfs node provides read-only access to the DDR training
>> data captured during sahara command mode and exposed via the MHI
>> controller device. This allows userspace to read the training data and
>> manage it as needed outside the kernel.
>>
>> Signed-off-by: Kishore Batta <kishore.batta@oss.qualcomm.com>
> Ah, this should be squashed with previous patch.
>
> - Mani
Sure. I will do it.
>> ---
>>   .../ABI/testing/sysfs-bus-mhi-ddr_training_data       | 19 +++++++++++++++++++
>>   1 file changed, 19 insertions(+)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-mhi-ddr_training_data b/Documentation/ABI/testing/sysfs-bus-mhi-ddr_training_data
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..810b487b5a5fdba133d81255f9879844e3938a10
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-bus-mhi-ddr_training_data
>> @@ -0,0 +1,19 @@
>> +What:                   /sys/bus/mhi/devices/<mhi-cntrl>/ddr_training_data
>> +
>> +Date:                   March 2026
>> +
>> +Contact:                Kishore Batta <kishore.batta@oss.qualcomm.com>
>> +
>> +Description:            Contains the DDR training data for the Qualcomm device
>> +                        connected. MHI driver populates different controller
>> +                        nodes for each device. The DDR training data is exposed
>> +                        to userspace to read and save the training data file to
>> +                        the filesystem. In the subsequent boot up of the device,
>> +                        the training data is restored from host to device
>> +                        optimizing the boot up time of the device.
>> +
>> +Usage:                  Example for reading DDR training data:
>> +                        cat /sys/bus/mhi/devices/mhi0/ddr_training_data
>> +
>> +Permissions:            The file permissions are set to 0444 allowing read
>> +                        access.
>>
>> -- 
>> 2.34.1
>>