This patchset adds three secure heaps: 1) secure_mtk_cm: secure chunk memory for MediaTek SVP (Secure Video Path). The buffer is reserved for the secure world after bootup and it is used for vcodec's ES/working buffer; 2) secure_mtk_cma: secure CMA memory for MediaTek SVP. This buffer is dynamically reserved for the secure world and will be got when we start playing secure videos, Once the security video playing is complete, the CMA will be released. This heap is used for the vcodec's frame buffer. 3) secure_cma: Use the kerne CMA ops as the allocation ops. currently it is a draft version for Vijay and Jaskaran.
For the first two MediaTek heaps will be used v4l2[1] and drm[2], thus we cannot put it in v4l2 or drm, and create a common heap for them. Meanwhile We have a limited number of hardware entries to protect memory, we cannot protect memory arbitrarily, thus the secure memory management is actually inside OPTEE. The kernel just tells the TEE what size I want and the TEE will return a "secure handle".
[1] https://lore.kernel.org/linux-mediatek/20231106120423.23364-1-yunfei.dong@me... [2] https://lore.kernel.org/linux-mediatek/20231023044549.21412-1-jason-jh.lin@m...
Change note: v2: 1) Move John's patches into the vcodec patchset since they use the new dma heap interface directly. https://lore.kernel.org/linux-mediatek/20231106120423.23364-1-yunfei.dong@me... 2) Reword the dt-binding description. 3) Rename the heap name from mtk_svp to secure_mtk_cm. This means the current vcodec/DRM upstream code doesn't match this. 4) Add a normal CMA heap. currently it should be a draft version. 5) Regarding the UUID, I still use hard code, but put it in a private data which allow the others could set their own UUID. What's more, UUID is necessary for the session with TEE. If we don't have it, we can't communicate with the TEE, including the get_uuid interface, which tries to make uuid more generic, not working. If there is other way to make UUID more general, please free to tell me.
v1: https://lore.kernel.org/linux-mediatek/20230911023038.30649-1-yong.wu@mediat... Base on v6.6-rc1.
Yong Wu (8): dma-buf: heaps: Initialize a secure heap dma-buf: heaps: secure_heap: Add private heap ops dma-buf: heaps: secure_heap: Initialize tee session dma-buf: heaps: secure_heap: Add tee memory service call dma-buf: heaps: secure_heap: Add dma_ops dt-bindings: reserved-memory: Add secure CMA reserved memory range dma_buf: heaps: secure_heap: Add a new MediaTek CMA heap dma-buf: heaps: secure_heap: Add normal CMA heap
.../reserved-memory/secure_cma_region.yaml | 44 ++ drivers/dma-buf/heaps/Kconfig | 7 + drivers/dma-buf/heaps/Makefile | 1 + drivers/dma-buf/heaps/secure_heap.c | 602 ++++++++++++++++++ 4 files changed, 654 insertions(+) create mode 100644 Documentation/devicetree/bindings/reserved-memory/secure_cma_region.yaml create mode 100644 drivers/dma-buf/heaps/secure_heap.c