On Wed, Jul 8, 2015 at 9:00 AM, Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> wrote: > 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 <ross.zwisler@xxxxxxxxxxxxxxx> > Cc: linux-nvdimm@xxxxxxxxxxxx > Cc: linux-acpi@xxxxxxxxxxxxxxx > Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx> > Cc: Len Brown <lenb@xxxxxxxxxx> > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Jeff Moyer <jmoyer@xxxxxxxxxx> > Cc: Toshi Kani <toshi.kani@xxxxxx> > --- > 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; Subjective nit, I tend to prefer the form (flags.status == 0) for positive cases. (!flags.status) reads like an error handling case to me. > + else if (flags.status == ND_DSM_STATUS_NOT_SUPPORTED) > + nfit_blk->dimm_flags = 0; /* as per the _DSM spec */ The spec says if command is "not implemented", I would treat "not supported" like any other non-zero flags.status value and return a failure. > + else > + rc = -EINVAL; s/EINVAL/ENXIO/ as it is a failure to run the command, not necessarily bad parameters. > + } > + > + return rc; This ends up treating -ENOTTY as an error when it is really just an indication that the flags DSM is not implemented. We should return zero in that case. > +} > + > 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, Unless it becomes clear that we need this for debug I'd prefer to not implement the error status flags at this point and just treat non-zero status flags generically as -ENXIO. > +}; > + > 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-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
