device-dax: Add a driver for "hmem" devices

[linux-2.6-microblaze.git] / drivers / dax / Kconfig

diff --git a/drivers/dax/Kconfig b/drivers/dax/Kconfig
index f33c73e..3b6c06f 100644 (file)
--- a/drivers/dax/Kconfig
+++ b/drivers/dax/Kconfig
@@ -32,19 +32,36 @@ config DEV_DAX_PMEM
 
          Say M if unsure
 
+config DEV_DAX_HMEM
+       tristate "HMEM DAX: direct access to 'specific purpose' memory"
+       depends on EFI_SOFT_RESERVE
+       default DEV_DAX
+       help
+         EFI 2.8 platforms, and others, may advertise 'specific purpose'
+         memory. For example, a high bandwidth memory pool. The
+         indication from platform firmware is meant to reserve the
+         memory from typical usage by default. This driver creates
+         device-dax instances for these memory ranges, and that also
+         enables the possibility to assign them to the DEV_DAX_KMEM
+         driver to override the reservation and add them to kernel
+         "System RAM" pool.
+
+         Say M if unsure.
+
 config DEV_DAX_KMEM
        tristate "KMEM DAX: volatile-use of persistent memory"
        default DEV_DAX
        depends on DEV_DAX
        depends on MEMORY_HOTPLUG # for add_memory() and friends
        help
-         Support access to persistent memory as if it were RAM.  This
-         allows easier use of persistent memory by unmodified
-         applications.
+         Support access to persistent, or other performance
+         differentiated memory as if it were System RAM. This allows
+         easier use of persistent memory by unmodified applications, or
+         adds core kernel memory services to heterogeneous memory types
+         (HMEM) marked "reserved" by platform firmware.
 
          To use this feature, a DAX device must be unbound from the
-         device_dax driver (PMEM DAX) and bound to this kmem driver
-         on each boot.
+         device_dax driver and bound to this kmem driver on each boot.
 
          Say N if unsure.