From e77483055c325fa629c5835913b07f3dce3ac7fd Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 22 Jul 2022 17:56:09 -0700 Subject: [PATCH] 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: Jonathan Cameron Reviewed-by: Vishal Verma Reviewed-by: Alison Schofield 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: Dan Williams --- drivers/cxl/acpi.c | 6 ++++++ drivers/cxl/cxl.h | 2 ++ 2 files changed, 8 insertions(+) diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c index eb43626..fb64968 100644 --- a/drivers/cxl/acpi.c +++ b/drivers/cxl/acpi.c @@ -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); diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index 969953c..bc604b7 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -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 -- 2.7.4