Quantcast
Viewing all articles
Browse latest Browse all 4872

Device Tree • Re: Modify dma-ranges in custom device tree

Code:

dma-ranges = <0xc0000000 0x00 0x40000000 0x400000000x7c000000 0x00 0xfc000000 0x3800000>;
This used to say:

Code:

dma-ranges = <0xc0000000 0x00 0x00000000 0x400000000x7c000000 0x00 0xfc000000 0x3800000>;
Why did you change it? The VPU and most of the bus masters in its domain cannot access more than the first 1GB, i.e. 0x40000000 bytes rooted at 0x0_00000000.

It's a similar story with the CMA declaration:

Code:

linux,cma {linux,cma-default;compatible = "shared-dma-pool";alloc-ranges = <0x00 0x40000000 0xbc000000>; // Entire 3 GBsize = <0x20000000>; // 512 MBreusable;};
We want the DMA pool to be accessible by the DMA controller, otherwise there's no point, but here you've put it out of reach above the 1GB boundary.

Statistics: Posted by PhilE — Thu Nov 28, 2024 11:02 pm



Viewing all articles
Browse latest Browse all 4872

Trending Articles