On 6 July 2012 02:56, Peter Crosthwaite <peter.crosthwa...@petalogix.com> wrote: > Can we generalise and get functionality for reading cells with offsets > as well? Your function assumes (and asserts) that the property is a > single cell, but can we add a index parameter for reading a non-0th > property out of a multi-cell prop? Needed for reading things like > ranges, regs and interrupt properties.
I was playing about with this and I'm really not sure that we should be providing a "read a single u32 from a u32 array property" at the device_tree.c layer. For example, for handling the ranges property what you really want to do is treat it as a list of tuples (including doing something sensible if it doesn't have the right length to be a complete list), so the code that knows the structure of the ranges property is better off calling qemu_devtree_getprop to get a uint32_t* for the whole array. Then it has the whole thing as a straightforward C array which will be much easier and more efficient to handle than constantly bouncing back into the fdt layer to read each uint32_t. I've also just realised that I'm assuming that the pointer returned by fdt_getprop() is naturally aligned for a 32 bit integer if the property is a 32 bit integer -- is that valid? -- PMM
