On Fri 04 Aug 07:50 PDT 2017, Rob Herring wrote: > On Thu, Aug 3, 2017 at 6:31 PM, Bjorn Andersson > <bjorn.andersson@xxxxxxxxxx> wrote: > > On Thu 03 Aug 10:45 PDT 2017, Rob Herring wrote: > > > >> On Wed, Aug 2, 2017 at 9:57 PM, Bjorn Andersson > >> <bjorn.andersson@xxxxxxxxxx> wrote: > >> > In some cases drivers referencing a reserved-memory region might want to > >> > remap the entire region, but when defining the reserved-memory by "size" > >> > the client driver has no means to know the associated base address of > >> > the reserved memory region. > >> > > >> > This patch adds an accessor for such drivers to acquire a handle to > >> > their associated reserved-memory for this purpose. > >> > > >> > A complicating factor for the implementation is that the reserved_mem > >> > objects are created from the flattened DeviceTree, as such we can't > >> > use the device_node address for comparison. Fortunately the name of the > >> > node will be used as "name" of the reserved_mem and will be used when > >> > building the full_name, so we can compare the "name" with the basename > >> > of the full_name to find the match. > >> > >> Maybe we should add the device_node pointer when we unflatten? > >> > > > > It did try to figure something sane out in that direction. > > > > The solution I came up with was to amend populate_node() to in a !dryrun > > block check if the "dad" full_name is /reserved-memory and if so > > call call a new accessor in of_reserved_mem.c to add the "np" to the > > reserved_mem object with fdt_node equal offset. > > I was thinking doing it with the unflattened tree just after it has > been unflattened rather than during unflattening. > The problem is that the fdt_node of the reserved_mem is the offset in the flat tree, but we don't carry this information with us when we create the individual device_nodes. So, AFAICT, to fill out this information at any point after returning from the particular populate_node() call we will have to use some sort of heuristics in matching the two nodes. > > This code path is already cluttered due to the version differences when > > it comes to building full_name and we would end up checking for each > > node in the entire tree if the parent happens to be "/reserved-mem". > > > > So I went for the less intrusive and more straight forward comparison > > with basename(full_name) instead. > > That's good, because full_name is about to become just the basename. > I'll update patch 1/5 and resend the series. Thanks, Bjorn -- 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
