On Wed, 2016-02-17 at 11:34 -0800, Dan Williams wrote: > On Wed, Feb 17, 2016 at 10:00 AM, Toshi Kani <toshi.kani@xxxxxxx> wrote: > > On Tue, 2016-02-16 at 19:00 -0700, Toshi Kani wrote: > > > On Fri, 2016-02-12 at 15:32 -0800, Dan Williams wrote: > > > > On Fri, Feb 12, 2016 at 2:30 PM, Toshi Kani <toshi.kani@xxxxxxx> > > > > wrote: : > > > Here are three options I can think of. > > > > > > 1) Set pmem type to "reserved" (This patch-set) > > > - Add a new iomem_set_desc(), which sets a given type to a top-level > > > entry. Change the ACPI NFIT driver to call it to set pmem type to > > > "reserved" entry. > > > - region_intersects() finds a pmem entry by checking top-level > > > entries (no change). > > > > > > 2) Change region_intersects() to check children's type > > > - Add a new request_region_ext(), which is an extension to > > > request_region() to allow specifying a type of resource. It puts a > > > new child entry under "reserved". Change the pmem driver to call > > > this func. > > > - Change region_intersects() to check children's type for finding > > > this child pmem entry. > > > > > > 3) Pmem driver to call insert_resource() > > > - Change the pmem driver to call insert_resource(), which puts a new > > > pmem entry as the parent of "reserved". > > > - region_intersects() finds a pmem entry by checking top-level > > > entries (no change). > > > - Add a new release_resource_self(), which releases a given entry > > > and keeps its children if any. Change the pmem driver to call it for > > > release. > > > > Thinking further, 3) needs to be modified as follows. insert_resource( > > ) should only be allowed for producers of resource (ex. nfit), not > > consumers (ex. pmem). It also needs to export insert_resource(). > > > > 3) NFIT driver to call insert_resource() > > - Change the ACPI nfit driver to call insert_resource() when a target > > range is not marked as PMEM (i.e. "reserved") or not present in iomem. > > This puts a new PMEM entry as the parent of "reserved". > > - region_intersects() finds a pmem entry by checking top-level entries > > (no change). > > - Add a new release_resource_self(), which releases a given entry and > > keeps its children if any. Change the nfit driver to call it for > > release. > > > > > This patch-set implements 1). The pmem type is set to "reserved" for > > > its life-cycle. This option is simplest. > > > > > > For 2), the changes to region_intersects() may be too complex for > > > maintenance. > > > > I should have said "region_intersects() may be overly complicated for > > this purpose and maintenance". > > > > > Here are a few examples when region_intersects() is called > > > with addr [1-10] where iomem has entry P and its children. > > > > > > Case A: P is fully covered by children C1 & C2. region_intersects() > > > ignores P's type, but checks C1 and C2's. > > > > > > P [1-10] + C1 [1-5] > > > + C2 [6-10] > > > > > > Case B: C2 is fully covered by C3, but P is not. region_intersects() > > > ignores C2's type, but checks P, C1, C3's. > > > > > > P [1-10] + C1 [1-2] > > > + C2 [6-10] + C3 [6-10] > > > > > > I think region_intersects() will need to construct a flat table from > > > the tree while making recursive calls to walk thru all children. > > > > > > 3) is similar to 2), but avoids the changes to region_intersects() > > > since insert_resource() inserts a new entry as the parent to > > > "reserved". > > > > 3) is actually similar to 1) as both options change the producer side. > > > > > However, a new interface is necessary to put "reserved" back to top- > > > level when releasing the added entry. > > > > > > My recommendation is go with either 1) or 3). What do you think? > > > > I think we should modify the producer side, so 1) or 3) are still my > > recommendation. > > > > I think 3 is the most promising option. It aligns the acpi/nfit > driver closer with the acpi/pci_root driver that is also doing > insert_resource() for each root bridge, and removing those resources > when the bridge is disabled/removed. > > I'd still want to maintain the ability of nfit to be built as a > module, so we would need to split the resource registration into a > separate built-in object file from nfit.ko. Sounds good. I will implement 3), and add an ACPI built-in wrapper function to call insert_resource(). Thanks! -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
