On Wed, Dec 09, 2015 at 03:52:59PM +0900, Masahiro Yamada wrote: > The UniPhier System Bus is an external bus that connects on-board > devices to the UniPhier SoC. Each bank (chip select) is dynamically > mapped to the CPU-viewed address base via the bus controller. The > bus controller must be configured before any access to the bus. > > This driver parses the "ranges" property of the System Bus node and > initialized the bus controller. After the bus becomes ready, devices > below it are populated. > > Note: > Each bank can be mapped anywhere in the supported address space; > there is nothing preventing us from assigning bank 0 on 0x42000000, > 0x43000000, or anywhere as long as such region is not used by others. > So, the "ranges" is just one possible software configuration, which > does not seem to fit in device tree because device tree is a hardware > description language. However, of_translate_address() requires > "ranges" in every bus node between CPUs and device mapped on the CPU > address space. In other words, "ranges" properties must be statically > defined in device tree. After some discussion, I decided the dynamic > address reassignment by the driver is too bothersome. Instead, the > device tree should provide a reasonable translation setup that the OS > can rely on. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > Acked-by: Rob Herring <robh@xxxxxxxxxx> > Acked-by: Arnd Bergmann <arnd@xxxxxxxx> Thanks, applied to next/drivers. -Olof -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
