Commit a15797f4 authored Aug 31, 2017 by Dan Williams

libnvdimm, nfit: export an 'ecc_unit_size' sysfs attribute

When the nfit driver initializes it runs an ARS (Address Range Scrub)
operation across every pmem range. Part of that process involves
determining the ARS capabilities of a given address range. One of the
capabilities that is reported is the 'Clear Uncorrectable Error Range
Length Unit Size' (see: ACPI 6.2 section 9.20.7.4 Function Index 1 -
Query ARS Capabilities). This property is of interest to userspace
software as it indicates the boundary at which the NVDIMM may need to
perform read-modify-write cycles to maintain ECC blocks.

Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

parent ed36b4db

drivers/acpi/nfit/core.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -1674,8 +1674,19 @@ static ssize_t range_index_show(struct device *dev,
		}
		static DEVICE_ATTR_RO(range_index);

		static ssize_t ecc_unit_size_show(struct device *dev,
		struct device_attribute attr, char buf)
		{
		struct nd_region *nd_region = to_nd_region(dev);
		struct nfit_spa *nfit_spa = nd_region_provider_data(nd_region);

		return sprintf(buf, "%d\n", nfit_spa->clear_err_unit);
		}
		static DEVICE_ATTR_RO(ecc_unit_size);

		static struct attribute *acpi_nfit_region_attributes[] = {
		&dev_attr_range_index.attr,
		&dev_attr_ecc_unit_size.attr,
		NULL,
		};

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