Commit f0f2c072 authored by Ross Zwisler's avatar Ross Zwisler Committed by Dan Williams
Browse files

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: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent c2ad2954

drivers/acpi/nfit.c

+32 −1
Original line number Diff line number Diff line
@@ -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,

drivers/acpi/nfit.h

+5 −0
Original line number Diff line number Diff line
@@ -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 {

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