From 6423035fd26c1ecb72f90ecab909e9afa36942b8 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Fri, 11 Jun 2021 12:01:11 -0700 Subject: [PATCH] cxl/hdm: Fix decoder count calculation MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The decoder count in the HDM decoder capability structure is an encoded field. As defined in the spec: Decoder Count: Reports the number of memory address decoders implemented by the component. 0 – 1 Decoder 1 – 2 Decoders 2 – 4 Decoders 3 – 6 Decoders 4 – 8 Decoders 5 – 10 Decoders All other values are reserved Nothing is actually fixed by this as nothing actually used this mapping yet. Cc: Ira Weiny Fixes: 08422378c4ad ("cxl/pci: Add HDM decoder capabilities") Acked-by: Jonathan Cameron Signed-off-by: Ben Widawsky Link: https://lore.kernel.org/r/20210611190111.121295-1-ben.widawsky@intel.com Signed-off-by: Dan Williams --- drivers/cxl/core.c | 2 +- drivers/cxl/cxl.h | 7 +++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/cxl/core.c b/drivers/cxl/core.c index 1b9ee0b08384..b134b29923ca 100644 --- a/drivers/cxl/core.c +++ b/drivers/cxl/core.c @@ -595,7 +595,7 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base, hdr = readl(register_block); - decoder_cnt = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, hdr); + decoder_cnt = cxl_hdm_decoder_count(hdr); length = 0x20 * decoder_cnt + 0x10; map->hdm_decoder.valid = true; diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h index b988ea288f53..97a273ae3947 100644 --- a/drivers/cxl/cxl.h +++ b/drivers/cxl/cxl.h @@ -41,6 +41,13 @@ #define CXL_HDM_DECODER0_SIZE_HIGH_OFFSET 0x1c #define CXL_HDM_DECODER0_CTRL_OFFSET 0x20 +static inline int cxl_hdm_decoder_count(u32 cap_hdr) +{ + int val = FIELD_GET(CXL_HDM_DECODER_COUNT_MASK, cap_hdr); + + return val ? val * 2 : 1; +} + /* CXL 2.0 8.2.8.1 Device Capabilities Array Register */ #define CXLDEV_CAP_ARRAY_OFFSET 0x0 #define CXLDEV_CAP_ARRAY_CAP_ID 0 -- 2.20.1