Commit e7748305 authored by Dan Williams's avatar Dan Williams
Browse files

cxl/acpi: Minimize granularity for x1 interleaves 



The kernel enforces that region granularity is >= to the top-level
interleave-granularity for the given CXL window. However, when the CXL
window interleave is x1, i.e. non-interleaved at the host bridge level,
then the specified granularity does not matter. Override the window
specified granularity to the CXL minimum so that any valid region
granularity is >= to the root granularity.

Reported-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Reviewed-by: default avatarAlison Schofield <alison.schofield@intel.com>
Link: https://lore.kernel.org/r/165853776917.2430596.16823264262010844458.stgit@dwillia2-xfh.jf.intel.com


[djbw: add CXL_DECODER_MIN_GRANULARITY per vishal]
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2bde6dbe

drivers/cxl/acpi.c

+6 −0
Original line number Diff line number Diff line
@@ -140,6 +140,12 @@ static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg, 
		.end = res->end,

	};

	cxld->interleave_ways = ways;

	/*

	 * Minimize the x1 granularity to advertise support for any

	 * valid region granularity

	 */

	if (ways == 1)

		ig = CXL_DECODER_MIN_GRANULARITY;

	cxld->interleave_granularity = ig;



	rc = cxl_decoder_add(cxld, target_map);

drivers/cxl/cxl.h

+2 −0
Original line number Diff line number Diff line
@@ -248,6 +248,8 @@ enum cxl_decoder_type { 
 */

#define CXL_DECODER_MAX_INTERLEAVE 16



#define CXL_DECODER_MIN_GRANULARITY 256



/**

 * struct cxl_decoder - Common CXL HDM Decoder Attributes

 * @dev: this decoder's device