On 09/19/2018 07:19 PM, Ard Biesheuvel wrote: > On 19 September 2018 at 07:31, Jim Quinlan <jim2101024@xxxxxxxxx> wrote: >> The Broadcom STB PCIe host controller is intimately related to the >> memory subsystem. This close relationship adds complexity to how cpu >> system memory is mapped to PCIe memory. Ideally, this mapping is an >> identity mapping, or an identity mapping off by a constant. Not so in >> this case. >> >> Consider the Broadcom reference board BCM97445LCC_4X8 which has 6 GB >> of system memory. Here is how the PCIe controller maps the >> system memory to PCIe memory: >> >> memc0-a@[ 0....3fffffff] <=> pci@[ 0....3fffffff] >> memc0-b@[100000000...13fffffff] <=> pci@[ 40000000....7fffffff] >> memc1-a@[ 40000000....7fffffff] <=> pci@[ 80000000....bfffffff] >> memc1-b@[300000000...33fffffff] <=> pci@[ c0000000....ffffffff] >> memc2-a@[ 80000000....bfffffff] <=> pci@[100000000...13fffffff] >> memc2-b@[c00000000...c3fffffff] <=> pci@[140000000...17fffffff] >> > > So is describing this as > > dma-ranges = <0x0 0x0 0x0 0x0 0x0 0x40000000>, > <0x0 0x40000000 0x1 0x0 0x0 0x40000000>, > <0x0 0x80000000 0x0 0x40000000 0x0 0x40000000>, > <0x0 0xc0000000 0x3 0x0 0x0 0x40000000>, > <0x1 0x0 0x0 0x80000000 0x0 0x40000000>, > <0x1 0x40000000 0x0 0xc0000000 0x0 0x40000000>; > > not working for you? I haven't tried this myself, but since DT permits > describing the inbound mappings this way, we should fix the code if it > doesn't work at the moment. You mean encoding the memory controller index in the first cell? If that works, that's indeed a much cleaner solution, though is it standard compliant in any form? -- Florian
