[PATCH v2 01/15] cxl: Modify address translation callback for generic use

Robert Richter
2025-02-18T13:24:37Z

The root decoder address translation callback could be reused for
other decoders too. For generic use of the callback, change the
function interface to use a decoder argument instead of the root
decoder.

Note that a root decoder's HPA is equal to its SPA, but else it may be
different. Thus, change the name of the function type to
cxl_to_hpa_fn.

Signed-off-by: Robert Richter <rrichter@amd.com>
---
drivers/cxl/acpi.c | 4 ++--
drivers/cxl/core/region.c | 7 +++++--
drivers/cxl/cxl.h | 5 ++---
3 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 93c73b163c28..48ad90025d77 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -22,9 +22,9 @@ static const guid_t acpi_cxl_qtg_id_guid =
GUID_INIT(0xF365F9A6, 0xA7DE, 0x4071,
0xA6, 0x6A, 0xB4, 0x0C, 0x0B, 0x4F, 0x8E, 0x52);

-
-static u64 cxl_xor_hpa_to_spa(struct cxl_root_decoder *cxlrd, u64 hpa)
+static u64 cxl_xor_hpa_to_spa(struct cxl_decoder *cxld, u64 hpa)
{
+ struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(&cxld->dev);
struct cxl_cxims_data *cximsd = cxlrd->platform_data;
int hbiw = cxlrd->cxlsd.nr_targets;
u64 val;
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index a56b84e7103a..c118bda93e86 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2936,9 +2936,12 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
/* Apply the hpa_offset to the region base address */
hpa = hpa_offset + p->res->start;

- /* Root decoder translation overrides typical modulo decode */
+ /*
+ * Root decoder translation overrides typical modulo decode.
+ * Note that a root decoder's HPA is equal to its SPA.
+ */
if (cxlrd->hpa_to_spa)
- hpa = cxlrd->hpa_to_spa(cxlrd, hpa);
+ hpa = cxlrd->hpa_to_spa(&cxlrd->cxlsd.cxld, hpa);

if (hpa < p->res->start || hpa > p->res->end) {
dev_dbg(&cxlr->dev,
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 50e7d878bb6f..b19ba47242c6 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -418,8 +418,7 @@ struct cxl_switch_decoder {
struct cxl_dport *target[];
};

-struct cxl_root_decoder;
-typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
+typedef u64 (*cxl_to_hpa_fn)(struct cxl_decoder *cxld, u64 hpa);

/**
* struct cxl_root_decoder - Static platform CXL address decoder
@@ -434,7 +433,7 @@ typedef u64 (*cxl_hpa_to_spa_fn)(struct cxl_root_decoder *cxlrd, u64 hpa);
struct cxl_root_decoder {
struct resource *res;
atomic_t region_id;
- cxl_hpa_to_spa_fn hpa_to_spa;
+ cxl_to_hpa_fn hpa_to_spa;
void *platform_data;
struct mutex range_lock;
int qos_class;
--
2.39.5