cxl/region: Translate DPA->HPA in unaligned MOD3 regions

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The CXL driver implementation of DPA->HPA address translation depends
on a region's starting address always being aligned to Host Bridge
Interleave Ways * 256MB. The driver follows the decode methods
defined in the CXL Spec[1] and expanded upon in the CXL Driver Writers
Guide[2], which describe bit manipulations based on power-of-2
alignment to translate a DPA to an HPA.

With the introduction of MOD3 interleave way support, platforms may
create regions at starting addresses that are not power-of-2 aligned.
This allows platforms to avoid gaps in the memory map, but addresses
within those regions cannot be translated using the existing bit
manipulation method.

Introduce an unaligned translation method for DPA->HPA that
reconstructs an HPA by restoring the address first at the port level
and then at the host bridge level.

[1] CXL Spec 4.0 8.2.4.20.13 Implementation Note Device Decoder Logic
[2] CXL Type 3 Memory Software Guide 1.1 2.13.25 DPA to HPA Translation

Suggested-by: Qing Huang <qing.huang@intel.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Link: https://patch.msgid.link/e7c53215bf69f2ff1ae7e58bcc49ca387b7b0299.1768538962.git.alison.schofield@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

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Alison Schofield 2026-01-15 20:58:36 -08:00 • committed by Dave Jiang

parent 4ed7952b9e

commit e639055f1f

1 changed files with 155 additions and 5 deletions

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drivers/cxl/core/region.c

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