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-rw-r--r--drivers/acpi/nfit.c33
-rw-r--r--drivers/acpi/nfit.h5
2 files changed, 37 insertions, 1 deletions
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index 11aa513f2fda..628a42c41ab1 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,
@@ -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,
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index 815cb561cdba..79b6d83875c1 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -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 {