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nfit: add support for NVDIMM "latch" flag 

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@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Ross Zwisler 2015-07-10 11:06:14 -06:00 committed by Dan Williams
parent c2ad29540c
commit f0f2c072cf
2 changed files with 37 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/acpi/nfit.c
View File

@ -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,
@ -1266,6 +1268,28 @@ 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 && flags.status == 0)
nfit_blk->dimm_flags = flags.flags;
else if (rc == -ENOTTY) {
/* fall back to a conservative default */
nfit_blk->dimm_flags = ND_BLK_DCR_LATCH;
rc = 0;
} else
rc = -ENXIO;
return rc;
}
static int acpi_nfit_blk_region_enable(struct nvdimm_bus *nvdimm_bus,
struct device *dev)
{
@ -1340,6 +1364,13 @@ 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) {
nfit_blk->nvdimm_flush = devm_ioremap_nocache(dev,

5
drivers/acpi/nfit.h
View File

@ -40,6 +40,10 @@ enum nfit_uuids {
NFIT_UUID_MAX,
};
enum {
ND_BLK_DCR_LATCH = 2,
};
struct nfit_spa {
struct acpi_nfit_system_address *spa;
struct list_head list;
@ -131,6 +135,7 @@ struct nfit_blk {
u64 stat_offset;
u64 cmd_offset;
void __iomem *nvdimm_flush;
u32 dimm_flags;
};
enum spa_map_type {