Hi,
On 1/8/26 15:21, 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.
Patch 3 should really be merged after 1&2
While trying it, I got the following warning:
In function ‘smem_dram_parse_v3_data’,
inlined from ‘smem_dram_parse’ at drivers/soc/qcom/smem_dramc.c:380:3:
drivers/soc/qcom/smem_dramc.c:216:31: warning: iteration 13 invokes undefined
behavior [-Waggressive-loop-optimizations]
216 | if (freq_entry->freq_khz && freq_entry->enabled)
| ~~~~~~~~~~^~~~~~~~~~
drivers/soc/qcom/smem_dramc.c:213:27: note: within this loop
213 | for (int i = 0; i < num_freq_entries; i++) {
| ~~^~~~~~~~~~~~~~~~~~
Neil
Signed-off-by: Konrad Dybcio <[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]
---
Konrad Dybcio (3):
soc: qcom: smem: Expose DDR data from SMEM
soc: qcom: ubwc: Get HBB from SMEM
drm/msm/adreno: Trust the SSoT UBWC config
drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 11 +-
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 82 +------
drivers/gpu/drm/msm/adreno/adreno_gpu.h | 5 -
drivers/soc/qcom/Makefile | 3 +-
drivers/soc/qcom/smem.c | 14 +-
drivers/soc/qcom/smem.h | 9 +
drivers/soc/qcom/smem_dramc.c | 408 ++++++++++++++++++++++++++++++++
drivers/soc/qcom/ubwc_config.c | 69 ++++--
include/linux/soc/qcom/smem.h | 4 +
9 files changed, 485 insertions(+), 120 deletions(-)
---
base-commit: fc4e91c639c0af93d63c3d5bc0ee45515dd7504a
change-id: 20250409-topic-smem_dramc-6467187ac865
Best regards,
