On Wed, Apr 29, 2015 at 10:10 AM, Dan Williams <dan.j.willi...@intel.com> wrote: > On Tue, Apr 28, 2015 at 4:06 PM, Andy Lutomirski <l...@amacapital.net> wrote: >> On Tue, Apr 28, 2015 at 3:30 PM, Dan Williams <dan.j.willi...@intel.com> >> wrote: >>> On Tue, Apr 28, 2015 at 2:10 PM, Andy Lutomirski <l...@amacapital.net> >>> wrote: >>>> On Tue, Apr 28, 2015 at 11:26 AM, Dan Williams <dan.j.willi...@intel.com> >>>> wrote: >>>>> From: Ross Zwisler <ross.zwis...@linux.intel.com> >>>>> >>>>> The libnd implementation handles allocating dimm address space (DPA) >>>>> between PMEM and BLK mode interfaces. After DPA has been allocated from >>>>> a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O >>>>> as a struct bio based block device. Unlike PMEM, BLK is required to >>>>> handle platform specific details like mmio register formats and memory >>>>> controller interleave. For this reason the libnd generic nd_blk driver >>>>> calls back into the bus provider to carry out the I/O. >>>>> >>>>> This initial implementation handles the BLK interface defined by the >>>>> ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from >>>>> DCR (dimm control region), BDW (block data window), IDT (interleave >>>>> descriptor) NFIT structures and the hardware register format. >>>>> [1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf >>>>> [2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf >>>>> >>>>> Cc: Andy Lutomirski <l...@amacapital.net> >>>>> Cc: Boaz Harrosh <b...@plexistor.com> >>>>> Cc: H. Peter Anvin <h...@zytor.com> >>>>> Cc: Jens Axboe <ax...@fb.com> >>>>> Cc: Ingo Molnar <mi...@kernel.org> >>>>> Cc: Christoph Hellwig <h...@lst.de> >>>>> Signed-off-by: Ross Zwisler <ross.zwis...@linux.intel.com> >>>>> Signed-off-by: Dan Williams <dan.j.willi...@intel.com> >>>>> --- >>>>> drivers/block/nd/Kconfig | 12 + >>>>> drivers/block/nd/Makefile | 3 >>>>> drivers/block/nd/acpi.c | 422 >>>>> +++++++++++++++++++++++++++++++++++-- >>>>> drivers/block/nd/acpi_nfit.h | 47 ++++ >>>>> drivers/block/nd/blk.c | 264 +++++++++++++++++++++++ >>>>> drivers/block/nd/libnd.h | 11 + >>>>> drivers/block/nd/namespace_devs.c | 47 ++++ >>>>> drivers/block/nd/nd-private.h | 3 >>>>> drivers/block/nd/nd.h | 16 + >>>>> drivers/block/nd/region.c | 8 + >>>>> drivers/block/nd/region_devs.c | 65 +++++- >>>>> drivers/block/nd/test/nfit.c | 29 +++ >>>>> drivers/block/nd/test/nfit_test.h | 2 >>>>> 13 files changed, 891 insertions(+), 38 deletions(-) >>>>> create mode 100644 drivers/block/nd/blk.c >>>>> >>>>> diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig >>>>> index 612bf2b14283..bac4290129fc 100644 >>>>> --- a/drivers/block/nd/Kconfig >>>>> +++ b/drivers/block/nd/Kconfig >>>>> @@ -95,6 +95,18 @@ config BLK_DEV_PMEM >>>>> >>>>> Say Y if you want to use a NVDIMM described by ACPI, E820, >>>>> etc... >>>>> >>>>> +config ND_BLK >>>>> + tristate "BLK: Block data window (aperture) device support" >>>>> + depends on LIBND >>>>> + default ND_ACPI >>>>> + help >>>>> + This driver performs I/O using a set of mmio windows on a >>>>> + dimm. The set of apertures will all access the one DIMM. >>>>> + Multiple windows allow multiple threads to have a different >>>>> + portions of the dimm open at one time. >>>>> + >>>>> + Say Y if you want to use a NVDIMM with BLK-mode capability >>>>> + >>>> >>>> This describes how it works, not what it is. How about: >>>> >>>> This driver exposes NVDIMM BLK regions as block devices. BLK regions >>>> are regions of NVDIMM storage that are sector-addressable, not >>>> byte-addressible, and do not support DAX. >>> >>> They *are* byte-addressable albeit through an indirection window. The >>> indirection windows are too small for DAX to be a viable access mode. >> >> Right, I was assuming incorrectly that the sector-atomic thing was a >> necessary part of BLK, or at least of this implementation. >> >> Anyway, I think my point stands: let's describe what these drivers do >> from a user's perspective, not how they work. > > Agreed. How about: > > "Support NVDIMMs, or other devices, that implement a BLK-mode access > capability. BLK-mode access uses memory-mapped-i/o apertures to > access persistent media. > > Say Y if your platform firmware emits an ACPI.NFIT table > (CONFIG_ND_ACPI), or otherwise exposes BLK-mode capabilities."
Sure. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
