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. Signed-off-by: Konrad Dybcio <[email protected]> --- Changes in v4: - Rebase on top of Dmitry's cleanups to ubwc_config - Mark and consume the shared data as little-endian - Fix compiler optimizing out what it thinks is impossible (odd v3_14freq case) - Rework qcom_ubwc_config_get_data() per discussion to not alter hardcoded data - Remove some unnecessary comments and assignments - Return -ENODATA instead of -EINVAL for out-of-sensible-range HBB - Cosmetic/line wrapping fixups - Drop applied drm/msm patch - Link to v3: https://lore.kernel.org/r/[email protected] Changes in v3: - Support v6 and v7 DDRInfo (v7 is used on e.g. Hamoa) - Handle rare cases of DDRInfo v5 with additional trailing data - Rebase/adjust to SSoT UBWC - Expose hbb value in debugfs - cosmetic changes - Link to v2: https://lore.kernel.org/r/[email protected] Changes in v2: - Avoid checking for < 0 on unsigned types - Overwrite Adreno UBWC data to keep the data shared with userspace coherent with what's programmed into the hardware - Call get_hbb() in msm_mdss_enable() instead of all UBWC setup branches separately - Pick up Bjorn's rb on patch 1 - Link to v1: https://lore.kernel.org/r/[email protected] To: Bjorn Andersson <[email protected]> To: Konrad Dybcio <[email protected]> To: Kees Cook <[email protected]> To: "Gustavo A. R. Silva" <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] --- Konrad Dybcio (2): soc: qcom: smem: Expose DDR data from SMEM soc: qcom: ubwc: Get HBB from SMEM drivers/soc/qcom/Makefile | 3 +- drivers/soc/qcom/smem.c | 14 +- drivers/soc/qcom/smem.h | 9 + drivers/soc/qcom/smem_dramc.c | 430 +++++++++++++++++++++++++++++++++++++++++ drivers/soc/qcom/ubwc_config.c | 40 +++- include/linux/soc/qcom/smem.h | 2 + 6 files changed, 495 insertions(+), 3 deletions(-) --- base-commit: 3fe08b9796f36ef437ab9328e7dd1e5ff2d66603 change-id: 20250409-topic-smem_dramc-6467187ac865 Best regards, -- Konrad Dybcio <[email protected]>
