On 4/14/25 2:28 PM, Dmitry Baryshkov wrote: > On Fri, Apr 11, 2025 at 12:52:32PM +0200, Konrad Dybcio wrote: >> On 4/11/25 12:50 PM, Dmitry Baryshkov wrote: >>> On Fri, Apr 11, 2025 at 12:03:03PM +0200, Konrad Dybcio wrote: >>>> On 4/11/25 11:57 AM, Dmitry Baryshkov wrote: >>>>> On Fri, 11 Apr 2025 at 12:49, Konrad Dybcio >>>>> <konrad.dyb...@oss.qualcomm.com> wrote: >>>>>> >>>>>> On 4/9/25 5:49 PM, Konrad Dybcio wrote: >>>>>>> On 4/9/25 5:44 PM, Dmitry Baryshkov wrote: >>>>>>>> On 09/04/2025 17:47, Konrad Dybcio wrote: >>>>>>>>> SMEM allows the OS to retrieve information about the DDR memory. >>>>>>>>> Among that information, is a semi-magic value called 'HBB', or Highest >>>>>>>>> Bank address Bit, which multimedia drivers (for hardware like Adreno >>>>>>>>> and MDSS) must retrieve in order to program the IP blocks correctly. >>>>>>>>> >>>>>>>>> This series introduces an API to retrieve that value, uses it in the >>>>>>>>> aforementioned programming sequences and exposes available DDR >>>>>>>>> frequencies in debugfs (to e.g. pass to aoss_qmp debugfs). More >>>>>>>>> information can be exposed in the future, as needed. >>>>>>>> >>>>>>>> I know that for some platforms HBB differs between GPU and DPU (as >>>>>>>> it's being programmed currently). Is there a way to check, which >>>>>>>> values are we going to program: >>>>>>>> >>>>>>>> - SM6115, SM6350, SM6375 (13 vs 14) >>>>>> >>>>>> SM6350 has INFO_V3 >>>>>> SM6375 has INFO_V3_WITH_14_FREQS >>>>> >>>>> I'm not completely sure what you mean here. I pointed out that these >>>>> platforms disagreed upon the HBB value between the DPU/msm_mdss.c and >>>>> a6xx_gpu.c. >>>>> In some cases (a610/SM6115 and a619/SM6350) that was intentional to >>>>> fix screen corruption issues. I don't remember if it was the case for >>>>> QCM2290 or not. >>>> >>>> As I said below, I couldn't get a good answer yet, as the magic value >>>> is not provided explicitly and I'll hopefully be able to derive it from >>>> the available data >>> >>> I see... >>> Is this data even supposed to be poked into? The foo_WITH_bar types >>> doesn't sound like a very stable API. >> >> Yeah, it was designed with both the producer and consumer being part >> of a single codebase, always having the data structures in sync.. > > I feel somewhat worried about parsing those structures then. But... the > only viable alternative is to have an in-kernel list of possible > platform configurations and parse the /memory@foo/ddr_device_type > property.
Well, this is where that property's value comes from.. Konrad
