Hello,
This is another approach to finish support for reserved memory regions defined in device tree. Previous attempts (http://lists.linaro.org/pipermail/linaro-mm-sig/2014-February/003738.html and https://lkml.org/lkml/2014/7/14/108) ended in merging parts of the code and documentation. Merged patches allow to reserve memory, but there is still no reserved memory drivers nor any code that actually uses reserved memory regions.
The final conclusion from the above mentioned threads is that there is no automated reserved memory initialization. All drivers that want to use reserved memory, should initialize it on their own.
This patch series provides two driver for reserved memory regions (one based on CMA and one based on dma_coherent allocator). The main improvement comparing to the previous version is removal of automated reserved memory for every device and support for named memory regions.
Support for more than one reserved memory region can be considered as a separate DMA address space, so support for more than one region per device has been implemented the same way as support for separate IO/DMA address spaces in my Exynos IOMMU dma-mapping proposal: http://thread.gmane.org/gmane.linux.kernel.samsung-soc/36079
Best regards Marek Szyprowski Samsung R&D Institute Poland
Changes since '[PATCH v2 RESEND 0/4] CMA & device tree, once again' version: (https://lkml.org/lkml/2014/7/14/108) - added return error value to of_reserved_mem_device_init() - added support for named memory regions (so more than one region can be defined per device) - added usage example - converted custom reserved memory code used by s5p-mfc driver to the generic reserved memory handling code
Patch summary:
Marek Szyprowski (7): drivers: of: add return value to of_reserved_mem_device_init drivers: of: add support for named memory regions drivers: dma-coherent: add initialization from device tree drivers: dma-contiguous: add initialization from device tree media: s5p-mfc: replace custom reserved memory init code with generic one ARM: Exynos: convert MFC to generic reserved memory bindings ARM: DTS: exynos4412-odroid*: enable MFC device
.../devicetree/bindings/media/s5p-mfc.txt | 16 +-- .../bindings/reserved-memory/reserved-memory.txt | 6 +- arch/arm/boot/dts/exynos4210-origen.dts | 22 +++- arch/arm/boot/dts/exynos4210-smdkv310.dts | 22 +++- arch/arm/boot/dts/exynos4412-odroid-common.dtsi | 24 ++++ arch/arm/boot/dts/exynos4412-origen.dts | 22 +++- arch/arm/boot/dts/exynos4412-smdk4412.dts | 22 +++- arch/arm/boot/dts/exynos5250-arndale.dts | 22 +++- arch/arm/boot/dts/exynos5250-smdk5250.dts | 22 +++- arch/arm/boot/dts/exynos5420-arndale-octa.dts | 22 +++- arch/arm/boot/dts/exynos5420-smdk5420.dts | 22 +++- arch/arm/mach-exynos/exynos.c | 18 --- arch/arm/mach-exynos/mfc.h | 16 --- arch/arm/plat-samsung/Kconfig | 5 - arch/arm/plat-samsung/Makefile | 1 - arch/arm/plat-samsung/s5p-dev-mfc.c | 94 -------------- drivers/base/dma-coherent.c | 138 ++++++++++++++++++--- drivers/base/dma-contiguous.c | 71 +++++++++++ drivers/media/platform/s5p-mfc/s5p_mfc.c | 102 ++++++--------- drivers/of/of_reserved_mem.c | 102 ++++++++++----- include/linux/cma.h | 3 + include/linux/of_reserved_mem.h | 9 +- mm/cma.c | 62 +++++++-- 23 files changed, 552 insertions(+), 291 deletions(-) delete mode 100644 arch/arm/mach-exynos/mfc.h delete mode 100644 arch/arm/plat-samsung/s5p-dev-mfc.c