libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option
We currently register a platform device for e820 type-12 memory and
register a nvdimm bus beneath it. Registering the platform device
triggers the device-core machinery to probe for a driver, but that
search currently comes up empty. Building the nvdimm-bus registration
into the e820_pmem platform device registration in this way forces
libnvdimm to be built-in. Instead, convert the built-in portion of
CONFIG_X86_PMEM_LEGACY to simply register a platform device and move the
rest of the logic to the driver for e820_pmem, for the following
reasons:
1/ Letting e820_pmem support be a module allows building and testing
libnvdimm.ko changes without rebooting
2/ All the normal policy around modules can be applied to e820_pmem
(unbind to disable and/or blacklisting the module from loading by
default)
3/ Moving the driver to a generic location and converting it to scan
"iomem_resource" rather than "e820.map" means any other architecture can
take advantage of this simple nvdimm resource discovery mechanism by
registering a resource named "Persistent Memory (legacy)"
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b3a1a5d..76c6115 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1426,10 +1426,14 @@
source "mm/Kconfig"
+config X86_PMEM_LEGACY_DEVICE
+ bool
+
config X86_PMEM_LEGACY
- bool "Support non-standard NVDIMMs and ADR protected memory"
+ tristate "Support non-standard NVDIMMs and ADR protected memory"
depends on PHYS_ADDR_T_64BIT
depends on BLK_DEV
+ select X86_PMEM_LEGACY_DEVICE
select LIBNVDIMM
help
Treat memory marked using the non-standard e820 type of 12 as used