From: Ben Widawsky <ben.widawsky@intel.com>
To: linux-cxl@vger.kernel.org, Dan Williams <dan.j.williams@intel.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>,
Ira Weiny <ira.weiny@intel.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>
Subject: [PATCH v2] cxl/hdm: Fix decoder count calculation
Date: Fri, 11 Jun 2021 12:01:11 -0700 [thread overview]
Message-ID: <20210611190111.121295-1-ben.widawsky@intel.com> (raw)
In-Reply-To: <20210610215332.991905-1-ben.widawsky@intel.com>
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 <ira.weiny@intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
v2:
- Minor whitespace cleanup in commit message.
- Move value decoder to inline function. (Dan)
- Rework value decoding logic to be more concise.
---
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 6db660249cea..49744ad885de 100644
--- a/drivers/cxl/core.c
+++ b/drivers/cxl/core.c
@@ -603,7 +603,7 @@ 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 3f9a6f7b05db..f1e52487c644 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -42,6 +42,13 @@
#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
--
2.32.0
next prev parent reply other threads:[~2021-06-11 19:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-10 21:53 [PATCH] cxl/hdm: Fix decoder count calculation Ben Widawsky
2021-06-10 22:00 ` Dan Williams
2021-06-11 10:37 ` Jonathan Cameron
2021-06-11 19:01 ` Ben Widawsky [this message]
2021-06-11 19:08 ` [PATCH v2] " Dan Williams
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