Add support in the NFIT BLK I/O path for the "latch" flag defined in the "Get Block NVDIMM Flags" _DSM function:
http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf This flag requires the driver to read back the command register after it is written in the block I/O path. This ensures that the hardware has fully processed the new command and moved the aperture appropriately. Signed-off-by: Ross Zwisler <[email protected]> Cc: [email protected] Cc: [email protected] Cc: "Rafael J. Wysocki" <[email protected]> Cc: Dan Williams <[email protected]> Cc: Len Brown <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Jeff Moyer <[email protected]> Cc: Toshi Kani <[email protected]> --- drivers/acpi/nfit.c | 33 ++++++++++++++++++++++++++++++++- drivers/acpi/nfit.h | 6 ++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c index b3c446412f61..9062c11c1062 100644 --- a/drivers/acpi/nfit.c +++ b/drivers/acpi/nfit.c @@ -1059,7 +1059,9 @@ static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw, writeq(cmd, mmio->base + offset); wmb_blk(nfit_blk); - /* FIXME: conditionally perform read-back if mandated by firmware */ + + if (nfit_blk->dimm_flags & ND_BLK_DCR_LATCH) + readq(mmio->base + offset); } static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk, @@ -1258,6 +1260,28 @@ static int nfit_blk_init_interleave(struct nfit_blk_mmio *mmio, return 0; } +static int acpi_nfit_blk_get_flags(struct nvdimm_bus_descriptor *nd_desc, + struct nvdimm *nvdimm, struct nfit_blk *nfit_blk) +{ + struct nd_cmd_dimm_flags flags; + int rc; + + memset(&flags, 0, sizeof(flags)); + rc = nd_desc->ndctl(nd_desc, nvdimm, ND_CMD_DIMM_FLAGS, &flags, + sizeof(flags)); + + if (rc >= 0) { + if (!flags.status) + nfit_blk->dimm_flags = flags.flags; + else if (flags.status == ND_DSM_STATUS_NOT_SUPPORTED) + nfit_blk->dimm_flags = 0; /* as per the _DSM spec */ + else + rc = -EINVAL; + } + + return rc; +} + static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus, struct device *dev) { @@ -1333,6 +1357,13 @@ static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus, return rc; } + rc = acpi_nfit_blk_get_flags(nd_desc, nvdimm, nfit_blk); + if (rc < 0) { + dev_dbg(dev, "%s: %s failed get DIMM flags\n", + __func__, nvdimm_name(nvdimm)); + return rc; + } + nfit_flush = nfit_mem->nfit_flush; if (nfit_flush && nfit_flush->flush->hint_count != 0) { struct acpi_nfit_flush_address *flush = nfit_flush->flush; diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h index d284729cc37c..98e36ca0dfc2 100644 --- a/drivers/acpi/nfit.h +++ b/drivers/acpi/nfit.h @@ -40,6 +40,11 @@ enum nfit_uuids { NFIT_UUID_MAX, }; +enum { + ND_BLK_DCR_LATCH = 2, + ND_DSM_STATUS_NOT_SUPPORTED = 1, +}; + struct nfit_spa { struct acpi_nfit_system_address *spa; struct list_head list; @@ -131,6 +136,7 @@ struct nfit_blk { u64 stat_offset; u64 cmd_offset; void __iomem *nvdimm_flush; + u32 dimm_flags; }; struct nfit_spa_mapping { -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
