cxl/region: Refactor cxl_port_setup_targets()

---
 drivers/cxl/core/region.c | 49 +++++++++++++--------------------------
 drivers/cxl/cxl.h         | 21 +++++++++++++++++
 2 files changed, 37 insertions(+), 33 deletions(-)

drivers/cxl/core/region.c +16 ~~-33~~

index a048bd5c06cb..bc087ca63946 100644
@@ -493,11 +493,9 @@ static int set_interleave_ways(struct cxl_region *cxlr, int val)
 	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
 	struct cxl_region_params *p = &cxlr->params;
 	int save, rc;
-	u8 iw;
 
-	rc = ways_to_eiw(val, &iw);
-	if (rc)
-		return rc;
+	if (!ways_valid(val))
+		return -EINVAL;
 
 	/*
 	 * Even for x3, x6, and x12 interleaves the region interleave must be a

@@ -566,12 +564,9 @@ static int set_interleave_granularity(struct cxl_region *cxlr, int val)
 	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
 	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
 	struct cxl_region_params *p = &cxlr->params;
-	int rc;
-	u16 ig;
 
-	rc = granularity_to_eig(val, &ig);
-	if (rc)
-		return rc;
+	if (!granularity_valid(val))
+		return -EINVAL;
 
 	/*
 	 * When the host-bridge is interleaved, disallow region granularity !=

@@ -1451,8 +1446,6 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 	struct cxl_decoder *cxld = cxl_rr->decoder;
 	struct cxl_switch_decoder *cxlsd;
 	struct cxl_port *iter = port;
-	u16 eig, peig;
-	u8 eiw, peiw;
 
 	/*
 	 * While root level decoders support x3, x6, x12, switch level

@@ -1524,48 +1517,38 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 		parent_iw = parent_cxld->interleave_ways;
 	}
 
-	rc = granularity_to_eig(parent_ig, &peig);
-	if (rc) {
+	if (!granularity_valid(parent_ig)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid parent granularity: %d\n",
 			dev_name(parent_port->uport_dev),
 			dev_name(&parent_port->dev), parent_ig);
-		return rc;
+		return -EINVAL;
 	}
 
-	rc = ways_to_eiw(parent_iw, &peiw);
-	if (rc) {
+	if (!ways_valid(parent_iw)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid parent interleave: %d\n",
 			dev_name(parent_port->uport_dev),
 			dev_name(&parent_port->dev), parent_iw);
-		return rc;
+		return -EINVAL;
 	}
 
 	iw = cxl_rr->nr_targets;
-	rc = ways_to_eiw(iw, &eiw);
-	if (rc) {
+	if (!ways_valid(iw)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",
 			dev_name(port->uport_dev), dev_name(&port->dev), iw);
-		return rc;
+		return -EINVAL;
 	}
 
 	/*
 	 * Interleave granularity is a multiple of @parent_port granularity.
 	 * Multiplier is the parent port interleave ways.
 	 */
-	rc = granularity_to_eig(parent_ig * parent_iw, &eig);
-	if (rc) {
+	ig = parent_ig * parent_iw;
+
+	if (!granularity_valid(ig)) {
 		dev_dbg(&cxlr->dev,
 			"%s: invalid granularity calculation (%d * %d)\n",
 			dev_name(&parent_port->dev), parent_ig, parent_iw);
-		return rc;
-	}
-
-	rc = eig_to_granularity(eig, &ig);
-	if (rc) {
-		dev_dbg(&cxlr->dev, "%s:%s: invalid interleave: %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev),
-			256 << eig);
-		return rc;
+		return -EINVAL;
 	}
 
 	if (iw > 8 || iw > cxlsd->nr_targets) {

@@ -3131,13 +3114,13 @@ static bool cxl_is_hpa_in_chunk(u64 hpa, struct cxl_region *cxlr, int pos)
  */
 int cxl_validate_translation_params(u8 eiw, u16 eig, int pos)
 {
-	int ways, gran;
+	int ways;
 
 	if (eiw_to_ways(eiw, &ways)) {
 		pr_debug("%s: invalid eiw=%u\n", __func__, eiw);
 		return -EINVAL;
 	}
-	if (eig_to_granularity(eig, &gran)) {
+	if (!eig_valid(eig)) {
 		pr_debug("%s: invalid eig=%u\n", __func__, eig);
 		return -EINVAL;
 	}

drivers/cxl/cxl.h +21 -0

index f03ee0addc45..4c9173e07f1f 100644
@@ -146,6 +146,27 @@ static inline int ways_to_eiw(unsigned int ways, u8 *eiw)
 	return 0;
 }
 
+static inline bool eig_valid(u16 eig)
+{
+	int granularity;
+
+	return eig_to_granularity(eig, &granularity) == 0;
+}
+
+static inline bool granularity_valid(int granularity)
+{
+	u16 eig;
+
+	return granularity_to_eig(granularity, &eig) == 0;
+}
+
+static inline bool ways_valid(unsigned int ways)
+{
+	u8 eiw;
+
+	return ways_to_eiw(ways, &eiw) == 0;
+}
+
 /* RAS Registers CXL 2.0 8.2.5.9 CXL RAS Capability Structure */
 #define CXL_RAS_UNCORRECTABLE_STATUS_OFFSET 0x0
 #define   CXL_RAS_UNCORRECTABLE_STATUS_MASK (GENMASK(16, 14) | GENMASK(11, 0))

Signature · 1 line

2.37.3

Jonathan Cameron

maintainer Reviewed-by on v2 1/8

2026-10-12 15:07 UTC #2 lore raw

Re: [PATCH v2 1/8] cxl: Add interleave encoding validity helpers

Quoted 6 lines · On Sat, 10 Oct 2026 17:20:16 -0700 Alison Schofield…

Some callers of ways_to_eiw(), granularity_to_eig(), and eig_to_granularity() only need to determine whether an input is valid, but must provide storage for a converted value that is then discarded. This obscures the purpose of the call and requires unnecessary temporary variables.

Quoted 7 lines

Define and use new helpers that provide a validation-only interface for those callers.
cxl_port_setup_targets() also encodes and then decodes its calculated granularity solely to validate it. Calculate the granularity directly and validate it instead, making the calculation explicit and removing the encode/decode round trip.

Nice. I'd missed that one completely!

Quoted 6 lines

No functional change.
Suggested-by Jonathan Cameron <[email protected]>
Signed-off-by Alison Schofield <[email protected]>
Reviewed-by Dave Jiang <[email protected]>

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #3 lore raw

PATCH v2 2/8 cxl/region: Name the interleave locals in cxl_port_setup_targets()

cxl_port_setup_targets() derives the interleave granularity of one decoder from the granularity and ways of the decoder above it, and takes that decoder's own ways from the topology below it. The values from the level above are named parent_iw and parent_ig, but the values being derived are the bare iw and ig, so the reader has to work out which level each one describes.

Rename iw and ig to child_iw and child_ig to match the parent_ prefix used for the level above.

No functional change.

[1] https://lore.kernel.org/linux-cxl/[email protected]/#r

---
 drivers/cxl/core/region.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

drivers/cxl/core/region.c +16 ~~-16~~

index bc087ca63946..1a42753fda48 100644
@@ -1437,7 +1437,7 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 				  struct cxl_endpoint_decoder *cxled)
 {
 	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
-	int parent_iw, parent_ig, ig, iw, rc, pos = cxled->pos;
+	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;
 	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
 	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);

@@ -1531,10 +1531,10 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 		return -EINVAL;
 	}
 
-	iw = cxl_rr->nr_targets;
-	if (!ways_valid(iw)) {
+	child_iw = cxl_rr->nr_targets;
+	if (!ways_valid(child_iw)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev), iw);
+			dev_name(port->uport_dev), dev_name(&port->dev), child_iw);
 		return -EINVAL;
 	}

@@ -1542,32 +1542,32 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 	 * Interleave granularity is a multiple of @parent_port granularity.
 	 * Multiplier is the parent port interleave ways.
 	 */
-	ig = parent_ig * parent_iw;
+	child_ig = parent_ig * parent_iw;
 
-	if (!granularity_valid(ig)) {
+	if (!granularity_valid(child_ig)) {
 		dev_dbg(&cxlr->dev,
 			"%s: invalid granularity calculation (%d * %d)\n",
 			dev_name(&parent_port->dev), parent_ig, parent_iw);
 		return -EINVAL;
 	}
 
-	if (iw > 8 || iw > cxlsd->nr_targets) {
+	if (child_iw > 8 || child_iw > cxlsd->nr_targets) {
 		dev_dbg(&cxlr->dev,
 			"%s:%s:%s: ways: %d overflows targets: %d\n",
 			dev_name(port->uport_dev), dev_name(&port->dev),
-			dev_name(&cxld->dev), iw, cxlsd->nr_targets);
+			dev_name(&cxld->dev), child_iw, cxlsd->nr_targets);
 		return -ENXIO;
 	}
 
 	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
-		if (cxld->interleave_ways != iw ||
-		    (iw > 1 && cxld->interleave_granularity != ig) ||
+		if (cxld->interleave_ways != child_iw ||
+		    (child_iw > 1 && cxld->interleave_granularity != child_ig) ||
 		    !spa_maps_hpa(p, &cxld->hpa_range) ||
 		    ((cxld->flags & CXL_DECODER_F_ENABLE) == 0)) {
 			dev_err(&cxlr->dev,
 				"%s:%s %s expected iw: %d ig: %d %pr\n",
 				dev_name(port->uport_dev), dev_name(&port->dev),
-				__func__, iw, ig, p->res);
+				__func__, child_iw, child_ig, p->res);
 			dev_err(&cxlr->dev,
 				"%s:%s %s got iw: %d ig: %d state: %s %#llx:%#llx\n",
 				dev_name(port->uport_dev), dev_name(&port->dev),

@@ -1578,24 +1578,24 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 			return -ENXIO;
 		}
 	} else {
-		rc = check_interleave_cap(cxld, iw, ig);
+		rc = check_interleave_cap(cxld, child_iw, child_ig);
 		if (rc) {
 			dev_dbg(&cxlr->dev,
 				"%s:%s iw: %d ig: %d is not supported\n",
 				dev_name(port->uport_dev),
-				dev_name(&port->dev), iw, ig);
+				dev_name(&port->dev), child_iw, child_ig);
 			return rc;
 		}
 
-		cxld->interleave_ways = iw;
-		cxld->interleave_granularity = ig;
+		cxld->interleave_ways = child_iw;
+		cxld->interleave_granularity = child_ig;
 		cxld->hpa_range = (struct range) {
 			.start = p->res->start,
 			.end = p->res->end,
 		};
 	}
 	dev_dbg(&cxlr->dev, "%s:%s iw: %d ig: %d\n", dev_name(port->uport_dev),
-		dev_name(&port->dev), iw, ig);
+		dev_name(&port->dev), child_iw, child_ig);
 add_target:
 	if (cxl_rr->nr_targets_set == cxl_rr->nr_targets) {
 		dev_dbg(&cxlr->dev,

Signature · 1 line

2.37.3

Alison Schofield

author maintainer

2026-10-12 03:02 UTC #4 lore raw

Re: [PATCH v2 2/8] cxl/region: Name the interleave locals in cxl_port_setup_targets()

Quoted 11 lines · Alison Schofield

cxl_port_setup_targets() derives the interleave granularity of one decoder from the granularity and ways of the decoder above it, and takes that decoder's own ways from the topology below it. The values from the level above are named parent_iw and parent_ig, but the values being derived are the bare iw and ig, so the reader has to work out which level each one describes.
Rename iw and ig to child_iw and child_ig to match the parent_ prefix used for the level above.
No functional change.

Oopsy daisy, I was suppose to drop this patch based on our discussion in v5 of the mixed gran set[1], rather than carry it forward here. Sorry RobertR!

It'll be gone in a v3 of this set.

Quoted 109 lines

---
 drivers/cxl/core/region.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

drivers/cxl/core/region.c +16 ~~-16~~

index bc087ca63946..1a42753fda48 100644
@@ -1437,7 +1437,7 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 				  struct cxl_endpoint_decoder *cxled)
 {
 	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
-	int parent_iw, parent_ig, ig, iw, rc, pos = cxled->pos;
+	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;
 	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
 	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);

@@ -1531,10 +1531,10 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 		return -EINVAL;
 	}
 
-	iw = cxl_rr->nr_targets;
-	if (!ways_valid(iw)) {
+	child_iw = cxl_rr->nr_targets;
+	if (!ways_valid(child_iw)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev), iw);
+			dev_name(port->uport_dev), dev_name(&port->dev), child_iw);
 		return -EINVAL;
 	}

@@ -1542,32 +1542,32 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 	 * Interleave granularity is a multiple of @parent_port granularity.
 	 * Multiplier is the parent port interleave ways.
 	 */
-	ig = parent_ig * parent_iw;
+	child_ig = parent_ig * parent_iw;
 
-	if (!granularity_valid(ig)) {
+	if (!granularity_valid(child_ig)) {
 		dev_dbg(&cxlr->dev,
 			"%s: invalid granularity calculation (%d * %d)\n",
 			dev_name(&parent_port->dev), parent_ig, parent_iw);
 		return -EINVAL;
 	}
 
-	if (iw > 8 || iw > cxlsd->nr_targets) {
+	if (child_iw > 8 || child_iw > cxlsd->nr_targets) {
 		dev_dbg(&cxlr->dev,
 			"%s:%s:%s: ways: %d overflows targets: %d\n",
 			dev_name(port->uport_dev), dev_name(&port->dev),
-			dev_name(&cxld->dev), iw, cxlsd->nr_targets);
+			dev_name(&cxld->dev), child_iw, cxlsd->nr_targets);
 		return -ENXIO;
 	}
 
 	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
-		if (cxld->interleave_ways != iw ||
-		    (iw > 1 && cxld->interleave_granularity != ig) ||
+		if (cxld->interleave_ways != child_iw ||
+		    (child_iw > 1 && cxld->interleave_granularity != child_ig) ||
 		    !spa_maps_hpa(p, &cxld->hpa_range) ||
 		    ((cxld->flags & CXL_DECODER_F_ENABLE) == 0)) {
 			dev_err(&cxlr->dev,
 				"%s:%s %s expected iw: %d ig: %d %pr\n",
 				dev_name(port->uport_dev), dev_name(&port->dev),
-				__func__, iw, ig, p->res);
+				__func__, child_iw, child_ig, p->res);
 			dev_err(&cxlr->dev,
 				"%s:%s %s got iw: %d ig: %d state: %s %#llx:%#llx\n",
 				dev_name(port->uport_dev), dev_name(&port->dev),

@@ -1578,24 +1578,24 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 			return -ENXIO;
 		}
 	} else {
-		rc = check_interleave_cap(cxld, iw, ig);
+		rc = check_interleave_cap(cxld, child_iw, child_ig);
 		if (rc) {
 			dev_dbg(&cxlr->dev,
 				"%s:%s iw: %d ig: %d is not supported\n",
 				dev_name(port->uport_dev),
-				dev_name(&port->dev), iw, ig);
+				dev_name(&port->dev), child_iw, child_ig);
 			return rc;
 		}
 
-		cxld->interleave_ways = iw;
-		cxld->interleave_granularity = ig;
+		cxld->interleave_ways = child_iw;
+		cxld->interleave_granularity = child_ig;
 		cxld->hpa_range = (struct range) {
 			.start = p->res->start,
 			.end = p->res->end,
 		};
 	}
 	dev_dbg(&cxlr->dev, "%s:%s iw: %d ig: %d\n", dev_name(port->uport_dev),
-		dev_name(&port->dev), iw, ig);
+		dev_name(&port->dev), child_iw, child_ig);
 add_target:
 	if (cxl_rr->nr_targets_set == cxl_rr->nr_targets) {
 		dev_dbg(&cxlr->dev,

Signature · 1 line

2.37.3

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #5 lore raw

PATCH v2 3/8 cxl/region: Rename cxl_port_setup_targets() to cxl_switch_port_setup_targets()

cxl_port_setup_targets() configures the switch decoder targets for a region. It runs for each switch port, including host bridges, between the root and an endpoint.

Rename the function to cxl_switch_port_setup_targets() to make its scope explicit.

No functional change.

Assisted-by LLM

---
 drivers/cxl/core/region.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

drivers/cxl/core/region.c +4 -4

index 1a42753fda48..d564443a1d39 100644
@@ -1432,9 +1432,9 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 
-static int cxl_port_setup_targets(struct cxl_port *port,
-				  struct cxl_region *cxlr,
-				  struct cxl_endpoint_decoder *cxled)
+static int cxl_switch_port_setup_targets(struct cxl_port *port,
+					 struct cxl_region *cxlr,
+					 struct cxl_endpoint_decoder *cxled)
 {
 	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
 	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;

@@ -1716,7 +1716,7 @@ static int cxl_region_setup_targets(struct cxl_region *cxlr)
 		 */
 		for (ep = cxl_ep_load(iter, cxlmd); iter;
 		     iter = ep->next, ep = cxl_ep_load(iter, cxlmd)) {
-			rc = cxl_port_setup_targets(iter, cxlr, cxled);
+			rc = cxl_switch_port_setup_targets(iter, cxlr, cxled);
 			if (rc) {
 				cxl_region_teardown_targets(cxlr);
 				return rc;

Signature · 1 line

2.37.3

Jonathan Cameron

maintainer Reviewed-by on v2 3/8

2026-10-12 15:12 UTC #6 lore raw

Re: [PATCH v2 3/8] cxl/region: Rename cxl_port_setup_targets() to cxl_switch_port_setup_targets()

Quoted 4 lines · On Sat, 10 Oct 2026 17:20:18 -0700 Alison Schofield…

cxl_port_setup_targets() configures the switch decoder targets for a region. It runs for each switch port, including host bridges, between the root and an endpoint.

Quoted 8 lines

Rename the function to cxl_switch_port_setup_targets() to make its scope explicit.
No functional change.
Suggested-by Dave Jiang <[email protected]>
Assisted-by LLM
Signed-off-by Alison Schofield <[email protected]>

Dave Jiang

maintainer

2026-10-13 16:46 UTC #7 lore raw

Re: [PATCH v2 3/8] cxl/region: Rename cxl_port_setup_targets() to cxl_switch_port_setup_targets()

Quoted 21 lines · Alison Schofield

cxl_port_setup_targets() configures the switch decoder targets for a region. It runs for each switch port, including host bridges, between the root and an endpoint.
Rename the function to cxl_switch_port_setup_targets() to make its scope explicit.
No functional change.
Suggested-by Dave Jiang <[email protected]>
Assisted-by LLM
Signed-off-by Alison Schofield <[email protected]>
---
 drivers/cxl/core/region.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
drivers/cxl/core/region.c +0 -0
index 1a42753fda48..d564443a1d39 100644

drivers/cxl/core/region.c static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig) · line 1435

Quoted 7 lines

drivers/cxl/core/region.c +1 -3

@@ -1432,9 +1432,9 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 
-static int cxl_port_setup_targets(struct cxl_port *port,
-				  struct cxl_region *cxlr,
-				  struct cxl_endpoint_decoder *cxled)
+static int cxl_switch_port_setup_targets(struct cxl_port *port,

Pass in cxlsd since it's a switch port function? That would enforce the type.

Quoted 14 lines

drivers/cxl/core/region.c +3 -1

+					 struct cxl_region *cxlr,
+					 struct cxl_endpoint_decoder *cxled)
 {
 	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
 	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;

@@ -1716,7 +1716,7 @@ static int cxl_region_setup_targets(struct cxl_region *cxlr)
 		 */
 		for (ep = cxl_ep_load(iter, cxlmd); iter;
 		     iter = ep->next, ep = cxl_ep_load(iter, cxlmd)) {
-			rc = cxl_port_setup_targets(iter, cxlr, cxled);
+			rc = cxl_switch_port_setup_targets(iter, cxlr, cxled);
 			if (rc) {
 				cxl_region_teardown_targets(cxlr);
 				return rc;

Alison Schofield

author maintainer

2026-10-17 00:08 UTC #8 lore raw

Re: [PATCH v2 3/8] cxl/region: Rename cxl_port_setup_targets() to cxl_switch_port_setup_targets()

Quoted 27 lines · Dave Jiang

Quoted 24 lines · Alison Schofield
cxl_port_setup_targets() configures the switch decoder targets for a region. It runs for each switch port, including host bridges, between the root and an endpoint.
Rename the function to cxl_switch_port_setup_targets() to make its scope explicit.
No functional change.
Suggested-by Dave Jiang <[email protected]>
Assisted-by LLM
Signed-off-by Alison Schofield <[email protected]>
---
 drivers/cxl/core/region.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
drivers/cxl/core/region.c +0 -0
index 1a42753fda48..d564443a1d39 100644
@@ -1432,9 +1432,9 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 

Quoted 8 lines

drivers/cxl/core/region.c static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig) · line 1435
Quoted 4 lines
drivers/cxl/core/region.c +1 -3
-static int cxl_port_setup_targets(struct cxl_port *port,
-				  struct cxl_region *cxlr,
-				  struct cxl_endpoint_decoder *cxled)
+static int cxl_switch_port_setup_targets(struct cxl_port *port,
Pass in cxlsd since it's a switch port function? That would enforce the type.
DJ

oops...overlooked in v3 but picked up for v4.

Thanks!

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #9 lore raw

PATCH v2 4/8 cxl/region: Factor out cxl_port_peer_distance()

cxl_switch_port_setup_targets() is nearly 200 lines long and open codes each step of adding an endpoint to a port's decoder. One of those steps calculates the distance between region positions that share a downstream port.

Move that calculation to a new helper, cxl_port_peer_distance().

No functional change.

Assisted-by LLM

---
 drivers/cxl/core/region.c | 50 +++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 21 deletions(-)

drivers/cxl/core/region.c +29 ~~-21~~

index d564443a1d39..b288421203a9 100644
@@ -1432,6 +1432,33 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 
+static int cxl_port_peer_distance(struct cxl_port *port, struct cxl_region *cxlr)
+{
+	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
+	struct cxl_region_ref *cxl_rr_iter;
+	struct cxl_port *iter = port;
+	int distance = 1;
+
+	/*
+	 * The "distance" between peer downstream ports represents which
+	 * endpoint positions in the region interleave a given port can
+	 * host.
+	 *
+	 * For example, at the root of a hierarchy the distance is
+	 * always 1 as every index targets a different host-bridge. At
+	 * each subsequent switch level those ports map every Nth region
+	 * position where N is the width of the switch == distance.
+	 */
+	do {
+		cxl_rr_iter = cxl_rr_load(iter, cxlr);
+		distance *= cxl_rr_iter->nr_targets;
+		iter = to_cxl_port(iter->dev.parent);
+	} while (!is_cxl_root(iter));
+	distance *= cxlrd->cxlsd.cxld.interleave_ways;
+
+	return distance;
+}
+
 static int cxl_switch_port_setup_targets(struct cxl_port *port,
 					 struct cxl_region *cxlr,
 					 struct cxl_endpoint_decoder *cxled)

@@ -1445,7 +1472,6 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 	struct cxl_region_params *p = &cxlr->params;
 	struct cxl_decoder *cxld = cxl_rr->decoder;
 	struct cxl_switch_decoder *cxlsd;
-	struct cxl_port *iter = port;
 
 	/*
 	 * While root level decoders support x3, x6, x12, switch level

@@ -1460,27 +1486,9 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 
 	cxlsd = to_cxl_switch_decoder(&cxld->dev);
 	if (cxl_rr->nr_targets_set) {
-		int i, distance = 1;
-		struct cxl_region_ref *cxl_rr_iter;
+		int distance = cxl_port_peer_distance(port, cxlr);
 
-		/*
-		 * The "distance" between peer downstream ports represents which
-		 * endpoint positions in the region interleave a given port can
-		 * host.
-		 *
-		 * For example, at the root of a hierarchy the distance is
-		 * always 1 as every index targets a different host-bridge. At
-		 * each subsequent switch level those ports map every Nth region
-		 * position where N is the width of the switch == distance.
-		 */
-		do {
-			cxl_rr_iter = cxl_rr_load(iter, cxlr);
-			distance *= cxl_rr_iter->nr_targets;
-			iter = to_cxl_port(iter->dev.parent);
-		} while (!is_cxl_root(iter));
-		distance *= cxlrd->cxlsd.cxld.interleave_ways;
-
-		for (i = 0; i < cxl_rr->nr_targets_set; i++)
+		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
 			if (ep->dport == cxlsd->target[i]) {
 				rc = check_last_peer(cxled, ep, cxl_rr,
 						     distance);

Signature · 1 line

2.37.3

Jonathan Cameron

maintainer Reviewed-by on v2 4/8

2026-10-12 15:16 UTC #10 lore raw

Re: [PATCH v2 4/8] cxl/region: Factor out cxl_port_peer_distance()

Quoted 5 lines · On Sat, 10 Oct 2026 17:20:19 -0700 Alison Schofield…

cxl_switch_port_setup_targets() is nearly 200 lines long and open codes each step of adding an endpoint to a port's decoder. One of those steps calculates the distance between region positions that share a downstream port.

Quoted 7 lines

Move that calculation to a new helper, cxl_port_peer_distance().
No functional change.
Assisted-by LLM
Signed-off-by Alison Schofield <[email protected]>
Reviewed-by Dave Jiang <[email protected]>

I wonder if the docs make more sense made function documentation rather than inline. Either way lgtm

Quoted 18 lines

---
 drivers/cxl/core/region.c | 50 +++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 21 deletions(-)

drivers/cxl/core/region.c +6 -0

index d564443a1d39..b288421203a9 100644
@@ -1432,6 +1432,33 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 
+static int cxl_port_peer_distance(struct cxl_port *port, struct cxl_region *cxlr)
+{
+	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
+	struct cxl_region_ref *cxl_rr_iter;
+	struct cxl_port *iter = port;
+	int distance = 1;

drivers/cxl/core/region.c static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig) · line 1450

Quoted 10 lines

drivers/cxl/core/region.c +10 -0

+
+	/*
+	 * The "distance" between peer downstream ports represents which
+	 * endpoint positions in the region interleave a given port can
+	 * host.
+	 *
+	 * For example, at the root of a hierarchy the distance is
+	 * always 1 as every index targets a different host-bridge. At
+	 * each subsequent switch level those ports map every Nth region
+	 * position where N is the width of the switch == distance.

Maybe promote this to be function documentation now this function is only concerned with finding that distance!

Quoted 52 lines

drivers/cxl/core/region.c +13 ~~-21~~

+	 */
+	do {
+		cxl_rr_iter = cxl_rr_load(iter, cxlr);
+		distance *= cxl_rr_iter->nr_targets;
+		iter = to_cxl_port(iter->dev.parent);
+	} while (!is_cxl_root(iter));
+	distance *= cxlrd->cxlsd.cxld.interleave_ways;
+
+	return distance;
+}
+
 static int cxl_switch_port_setup_targets(struct cxl_port *port,
 					 struct cxl_region *cxlr,
 					 struct cxl_endpoint_decoder *cxled)

@@ -1445,7 +1472,6 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 	struct cxl_region_params *p = &cxlr->params;
 	struct cxl_decoder *cxld = cxl_rr->decoder;
 	struct cxl_switch_decoder *cxlsd;
-	struct cxl_port *iter = port;
 
 	/*
 	 * While root level decoders support x3, x6, x12, switch level

@@ -1460,27 +1486,9 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 
 	cxlsd = to_cxl_switch_decoder(&cxld->dev);
 	if (cxl_rr->nr_targets_set) {
-		int i, distance = 1;
-		struct cxl_region_ref *cxl_rr_iter;
+		int distance = cxl_port_peer_distance(port, cxlr);
 
-		/*
-		 * The "distance" between peer downstream ports represents which
-		 * endpoint positions in the region interleave a given port can
-		 * host.
-		 *
-		 * For example, at the root of a hierarchy the distance is
-		 * always 1 as every index targets a different host-bridge. At
-		 * each subsequent switch level those ports map every Nth region
-		 * position where N is the width of the switch == distance.
-		 */
-		do {
-			cxl_rr_iter = cxl_rr_load(iter, cxlr);
-			distance *= cxl_rr_iter->nr_targets;
-			iter = to_cxl_port(iter->dev.parent);
-		} while (!is_cxl_root(iter));
-		distance *= cxlrd->cxlsd.cxld.interleave_ways;
-
-		for (i = 0; i < cxl_rr->nr_targets_set; i++)
+		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
 			if (ep->dport == cxlsd->target[i]) {
 				rc = check_last_peer(cxled, ep, cxl_rr,
 						     distance);

Alison Schofield

author maintainer

2026-10-13 04:23 UTC #11 lore raw

Re: [PATCH v2 4/8] cxl/region: Factor out cxl_port_peer_distance()

Quoted 10 lines · Jonathan Cameron

Quoted 7 lines · On Sat, 10 Oct 2026 17:20:19 -0700 Alison Schofield…
cxl_switch_port_setup_targets() is nearly 200 lines long and open codes each step of adding an endpoint to a port's decoder. One of those steps calculates the distance between region positions that share a downstream port.
Move that calculation to a new helper, cxl_port_peer_distance().

Quoted 8 lines

Quoted 5 lines
No functional change.
Assisted-by LLM
Signed-off-by Alison Schofield <[email protected]>
Reviewed-by Dave Jiang <[email protected]>
I wonder if the docs make more sense made function documentation rather than inline. Either way lgtm

Thanks for the review, and yes that docs make more sense moved, now that it's the only thing the helper does.

I think you are partway thru reviewing (me being hopeful you'll review more ;)) and I've posted a v3. So hoping you continue your review in v3!

Quoted 87 lines

Quoted 18 lines

---
 drivers/cxl/core/region.c | 50 +++++++++++++++++++++++----------------
 1 file changed, 29 insertions(+), 21 deletions(-)

drivers/cxl/core/region.c +6 -0

index d564443a1d39..b288421203a9 100644
@@ -1432,6 +1432,33 @@ static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
 	return 0;
 }
 
+static int cxl_port_peer_distance(struct cxl_port *port, struct cxl_region *cxlr)
+{
+	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
+	struct cxl_region_ref *cxl_rr_iter;
+	struct cxl_port *iter = port;
+	int distance = 1;

drivers/cxl/core/region.c static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig) · line 1450

Quoted 10 lines

drivers/cxl/core/region.c +10 -0

+
+	/*
+	 * The "distance" between peer downstream ports represents which
+	 * endpoint positions in the region interleave a given port can
+	 * host.
+	 *
+	 * For example, at the root of a hierarchy the distance is
+	 * always 1 as every index targets a different host-bridge. At
+	 * each subsequent switch level those ports map every Nth region
+	 * position where N is the width of the switch == distance.

Maybe promote this to be function documentation now this function is only concerned with finding that distance!

Quoted 52 lines

drivers/cxl/core/region.c +13 ~~-21~~

+	 */
+	do {
+		cxl_rr_iter = cxl_rr_load(iter, cxlr);
+		distance *= cxl_rr_iter->nr_targets;
+		iter = to_cxl_port(iter->dev.parent);
+	} while (!is_cxl_root(iter));
+	distance *= cxlrd->cxlsd.cxld.interleave_ways;
+
+	return distance;
+}
+
 static int cxl_switch_port_setup_targets(struct cxl_port *port,
 					 struct cxl_region *cxlr,
 					 struct cxl_endpoint_decoder *cxled)

@@ -1445,7 +1472,6 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 	struct cxl_region_params *p = &cxlr->params;
 	struct cxl_decoder *cxld = cxl_rr->decoder;
 	struct cxl_switch_decoder *cxlsd;
-	struct cxl_port *iter = port;
 
 	/*
 	 * While root level decoders support x3, x6, x12, switch level

@@ -1460,27 +1486,9 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 
 	cxlsd = to_cxl_switch_decoder(&cxld->dev);
 	if (cxl_rr->nr_targets_set) {
-		int i, distance = 1;
-		struct cxl_region_ref *cxl_rr_iter;
+		int distance = cxl_port_peer_distance(port, cxlr);
 
-		/*
-		 * The "distance" between peer downstream ports represents which
-		 * endpoint positions in the region interleave a given port can
-		 * host.
-		 *
-		 * For example, at the root of a hierarchy the distance is
-		 * always 1 as every index targets a different host-bridge. At
-		 * each subsequent switch level those ports map every Nth region
-		 * position where N is the width of the switch == distance.
-		 */
-		do {
-			cxl_rr_iter = cxl_rr_load(iter, cxlr);
-			distance *= cxl_rr_iter->nr_targets;
-			iter = to_cxl_port(iter->dev.parent);
-		} while (!is_cxl_root(iter));
-		distance *= cxlrd->cxlsd.cxld.interleave_ways;
-
-		for (i = 0; i < cxl_rr->nr_targets_set; i++)
+		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
 			if (ep->dport == cxlsd->target[i]) {
 				rc = check_last_peer(cxled, ep, cxl_rr,
 						     distance);

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #12 lore raw

PATCH v2 5/8 cxl/region: Factor out cxl_port_parent_interleave()

cxl_switch_port_setup_targets() derives a decoder's interleave from the interleave of the decoder above it. That parent interleave comes from either the root decoder or a switch decoder, and each case is open coded along with the parent validity checks.

Move the parent interleave lookup and validation to a new helper, cxl_port_parent_interleave().

No functional change.

Assisted-by LLM

---
 drivers/cxl/core/region.c | 88 +++++++++++++++++++++++----------------
 1 file changed, 52 insertions(+), 36 deletions(-)

drivers/cxl/core/region.c +52 ~~-36~~

index b288421203a9..a4688c6b54cb 100644
@@ -1459,45 +1459,13 @@ static int cxl_port_peer_distance(struct cxl_port *port, struct cxl_region *cxlr
 	return distance;
 }
 
-static int cxl_switch_port_setup_targets(struct cxl_port *port,
-					 struct cxl_region *cxlr,
-					 struct cxl_endpoint_decoder *cxled)
+static int cxl_port_parent_interleave(struct cxl_port *port, struct cxl_region *cxlr,
+				      int *iw, int *ig)
 {
-	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
-	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;
 	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
-	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
-	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
-	struct cxl_ep *ep = cxl_ep_load(port, cxlmd);
+	struct cxl_root_decoder *cxlrd = cxlr->cxlrd;
 	struct cxl_region_params *p = &cxlr->params;
-	struct cxl_decoder *cxld = cxl_rr->decoder;
-	struct cxl_switch_decoder *cxlsd;
-
-	/*
-	 * While root level decoders support x3, x6, x12, switch level
-	 * decoders only support powers of 2 up to x16.
-	 */
-	if (!is_power_of_2(cxl_rr->nr_targets)) {
-		dev_dbg(&cxlr->dev, "%s:%s: invalid target count %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev),
-			cxl_rr->nr_targets);
-		return -EINVAL;
-	}
-
-	cxlsd = to_cxl_switch_decoder(&cxld->dev);
-	if (cxl_rr->nr_targets_set) {
-		int distance = cxl_port_peer_distance(port, cxlr);
-
-		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
-			if (ep->dport == cxlsd->target[i]) {
-				rc = check_last_peer(cxled, ep, cxl_rr,
-						     distance);
-				if (rc)
-					return rc;
-				goto out_target_set;
-			}
-		goto add_target;
-	}
+	int parent_iw, parent_ig;
 
 	if (is_cxl_root(parent_port)) {
 		/*

@@ -1539,6 +1507,54 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port,
 		return -EINVAL;
 	}
 
+	*iw = parent_iw;
+	*ig = parent_ig;
+
+	return 0;
+}
+
+static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_region *cxlr,
+					 struct cxl_endpoint_decoder *cxled)
+{
+	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;
+	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
+	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
+	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+	struct cxl_ep *ep = cxl_ep_load(port, cxlmd);
+	struct cxl_region_params *p = &cxlr->params;
+	struct cxl_decoder *cxld = cxl_rr->decoder;
+	struct cxl_switch_decoder *cxlsd;
+
+	/*
+	 * While root level decoders support x3, x6, x12, switch level
+	 * decoders only support powers of 2 up to x16.
+	 */
+	if (!is_power_of_2(cxl_rr->nr_targets)) {
+		dev_dbg(&cxlr->dev, "%s:%s: invalid target count %d\n",
+			dev_name(port->uport_dev), dev_name(&port->dev),
+			cxl_rr->nr_targets);
+		return -EINVAL;
+	}
+
+	cxlsd = to_cxl_switch_decoder(&cxld->dev);
+	if (cxl_rr->nr_targets_set) {
+		int distance = cxl_port_peer_distance(port, cxlr);
+
+		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
+			if (ep->dport == cxlsd->target[i]) {
+				rc = check_last_peer(cxled, ep, cxl_rr,
+						     distance);
+				if (rc)
+					return rc;
+				goto out_target_set;
+			}
+		goto add_target;
+	}
+
+	rc = cxl_port_parent_interleave(port, cxlr, &parent_iw, &parent_ig);
+	if (rc)
+		return rc;
+
 	child_iw = cxl_rr->nr_targets;
 	if (!ways_valid(child_iw)) {
 		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",

Signature · 1 line

2.37.3

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #13 lore raw

PATCH v2 6/8 cxl/region: Factor out cxl_port_calc_interleave()

cxl_switch_port_setup_targets() calculates the interleave ways and granularity of a port's decoder from the parent interleave and the number of targets below the port, then validates the result. That calculation and its checks are open coded between the target search and the decoder setup.

Move the calculation and its checks to a new helper, cxl_port_calc_interleave(), so that the interleave for the port's decoder is calculated and validated in one place.

No functional change.

Assisted-by LLM

---
 drivers/cxl/core/region.c | 81 ++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 31 deletions(-)

drivers/cxl/core/region.c +50 ~~-31~~

index a4688c6b54cb..42daa69a40eb 100644
@@ -1513,11 +1513,58 @@ static int cxl_port_parent_interleave(struct cxl_port *port, struct cxl_region *
 	return 0;
 }
 
+static int cxl_port_calc_interleave(struct cxl_port *port, struct cxl_region *cxlr,
+				    struct cxl_region_ref *cxl_rr, int *iw, int *ig)
+{
+	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
+	int parent_iw, parent_ig, child_iw, child_ig, rc;
+	struct cxl_decoder *cxld = cxl_rr->decoder;
+	struct cxl_switch_decoder *cxlsd;
+
+	rc = cxl_port_parent_interleave(port, cxlr, &parent_iw, &parent_ig);
+	if (rc)
+		return rc;
+
+	child_iw = cxl_rr->nr_targets;
+	if (!ways_valid(child_iw)) {
+		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",
+			dev_name(port->uport_dev), dev_name(&port->dev),
+			child_iw);
+		return -EINVAL;
+	}
+
+	/*
+	 * Interleave granularity is a multiple of @parent_port granularity.
+	 * Multiplier is the parent port interleave ways.
+	 */
+	child_ig = parent_ig * parent_iw;
+
+	if (!granularity_valid(child_ig)) {
+		dev_dbg(&cxlr->dev,
+			"%s: invalid granularity calculation (%d * %d)\n",
+			dev_name(&parent_port->dev), parent_ig, parent_iw);
+		return -EINVAL;
+	}
+
+	cxlsd = to_cxl_switch_decoder(&cxld->dev);
+	if (child_iw > 8 || child_iw > cxlsd->nr_targets) {
+		dev_dbg(&cxlr->dev,
+			"%s:%s:%s: ways: %d overflows targets: %d\n",
+			dev_name(port->uport_dev), dev_name(&port->dev),
+			dev_name(&cxld->dev), child_iw, cxlsd->nr_targets);
+		return -ENXIO;
+	}
+
+	*iw = child_iw;
+	*ig = child_ig;
+
+	return 0;
+}
+
 static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_region *cxlr,
 					 struct cxl_endpoint_decoder *cxled)
 {
-	int parent_iw, parent_ig, child_iw, child_ig, rc, pos = cxled->pos;
-	struct cxl_port *parent_port = to_cxl_port(port->dev.parent);
+	int child_iw, child_ig, rc, pos = cxled->pos;
 	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
 	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
 	struct cxl_ep *ep = cxl_ep_load(port, cxlmd);

@@ -1551,38 +1598,10 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_regio
 		goto add_target;
 	}
 
-	rc = cxl_port_parent_interleave(port, cxlr, &parent_iw, &parent_ig);
+	rc = cxl_port_calc_interleave(port, cxlr, cxl_rr, &child_iw, &child_ig);
 	if (rc)
 		return rc;
 
-	child_iw = cxl_rr->nr_targets;
-	if (!ways_valid(child_iw)) {
-		dev_dbg(&cxlr->dev, "%s:%s: invalid port interleave: %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev), child_iw);
-		return -EINVAL;
-	}
-
-	/*
-	 * Interleave granularity is a multiple of @parent_port granularity.
-	 * Multiplier is the parent port interleave ways.
-	 */
-	child_ig = parent_ig * parent_iw;
-
-	if (!granularity_valid(child_ig)) {
-		dev_dbg(&cxlr->dev,
-			"%s: invalid granularity calculation (%d * %d)\n",
-			dev_name(&parent_port->dev), parent_ig, parent_iw);
-		return -EINVAL;
-	}
-
-	if (child_iw > 8 || child_iw > cxlsd->nr_targets) {
-		dev_dbg(&cxlr->dev,
-			"%s:%s:%s: ways: %d overflows targets: %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev),
-			dev_name(&cxld->dev), child_iw, cxlsd->nr_targets);
-		return -ENXIO;
-	}
-
 	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
 		if (cxld->interleave_ways != child_iw ||
 		    (child_iw > 1 && cxld->interleave_granularity != child_ig) ||

Signature · 1 line

2.37.3

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #14 lore raw

PATCH v2 7/8 cxl/region: Factor out cxl_port_setup_decoder()

Once cxl_switch_port_setup_targets() has calculated the interleave for a port's decoder, it either checks that interleave against the decoder settings found for an auto region, or checks the decoder's interleave capabilities and programs the decoder for a user created region. Both paths are open coded in cxl_switch_port_setup_targets().

Move both paths to a new helper, cxl_port_setup_decoder().

No functional change.

Assisted-by LLM

---
 drivers/cxl/core/region.c | 88 ++++++++++++++++++++++-----------------
 1 file changed, 50 insertions(+), 38 deletions(-)

drivers/cxl/core/region.c +50 ~~-38~~

index 42daa69a40eb..98aef1d5a4dd 100644
@@ -1561,46 +1561,11 @@ static int cxl_port_calc_interleave(struct cxl_port *port, struct cxl_region *cx
 	return 0;
 }
 
-static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_region *cxlr,
-					 struct cxl_endpoint_decoder *cxled)
+static int cxl_port_setup_decoder(struct cxl_port *port, struct cxl_region *cxlr,
+				  struct cxl_decoder *cxld, int child_iw, int child_ig)
 {
-	int child_iw, child_ig, rc, pos = cxled->pos;
-	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
-	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
-	struct cxl_ep *ep = cxl_ep_load(port, cxlmd);
 	struct cxl_region_params *p = &cxlr->params;
-	struct cxl_decoder *cxld = cxl_rr->decoder;
-	struct cxl_switch_decoder *cxlsd;
-
-	/*
-	 * While root level decoders support x3, x6, x12, switch level
-	 * decoders only support powers of 2 up to x16.
-	 */
-	if (!is_power_of_2(cxl_rr->nr_targets)) {
-		dev_dbg(&cxlr->dev, "%s:%s: invalid target count %d\n",
-			dev_name(port->uport_dev), dev_name(&port->dev),
-			cxl_rr->nr_targets);
-		return -EINVAL;
-	}
-
-	cxlsd = to_cxl_switch_decoder(&cxld->dev);
-	if (cxl_rr->nr_targets_set) {
-		int distance = cxl_port_peer_distance(port, cxlr);
-
-		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
-			if (ep->dport == cxlsd->target[i]) {
-				rc = check_last_peer(cxled, ep, cxl_rr,
-						     distance);
-				if (rc)
-					return rc;
-				goto out_target_set;
-			}
-		goto add_target;
-	}
-
-	rc = cxl_port_calc_interleave(port, cxlr, cxl_rr, &child_iw, &child_ig);
-	if (rc)
-		return rc;
+	int rc;
 
 	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
 		if (cxld->interleave_ways != child_iw ||

@@ -1639,6 +1604,53 @@ static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_regio
 	}
 	dev_dbg(&cxlr->dev, "%s:%s iw: %d ig: %d\n", dev_name(port->uport_dev),
 		dev_name(&port->dev), child_iw, child_ig);
+
+	return 0;
+}
+
+static int cxl_switch_port_setup_targets(struct cxl_port *port, struct cxl_region *cxlr,
+					 struct cxl_endpoint_decoder *cxled)
+{
+	int child_iw, child_ig, rc, pos = cxled->pos;
+	struct cxl_region_ref *cxl_rr = cxl_rr_load(port, cxlr);
+	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+	struct cxl_ep *ep = cxl_ep_load(port, cxlmd);
+	struct cxl_decoder *cxld = cxl_rr->decoder;
+	struct cxl_switch_decoder *cxlsd;
+
+	/*
+	 * While root level decoders support x3, x6, x12, switch level
+	 * decoders only support powers of 2 up to x16.
+	 */
+	if (!is_power_of_2(cxl_rr->nr_targets)) {
+		dev_dbg(&cxlr->dev, "%s:%s: invalid target count %d\n",
+			dev_name(port->uport_dev), dev_name(&port->dev),
+			cxl_rr->nr_targets);
+		return -EINVAL;
+	}
+
+	cxlsd = to_cxl_switch_decoder(&cxld->dev);
+	if (cxl_rr->nr_targets_set) {
+		int distance = cxl_port_peer_distance(port, cxlr);
+
+		for (int i = 0; i < cxl_rr->nr_targets_set; i++)
+			if (ep->dport == cxlsd->target[i]) {
+				rc = check_last_peer(cxled, ep, cxl_rr,
+						     distance);
+				if (rc)
+					return rc;
+				goto out_target_set;
+			}
+		goto add_target;
+	}
+
+	rc = cxl_port_calc_interleave(port, cxlr, cxl_rr, &child_iw, &child_ig);
+	if (rc)
+		return rc;
+
+	rc = cxl_port_setup_decoder(port, cxlr, cxld, child_iw, child_ig);
+	if (rc)
+		return rc;
 add_target:
 	if (cxl_rr->nr_targets_set == cxl_rr->nr_targets) {
 		dev_dbg(&cxlr->dev,

Signature · 1 line

2.37.3

Alison Schofield

author maintainer

2026-10-11 00:20 UTC #15 lore raw

PATCH v2 8/8 cxl/region: Factor out cxl_switch_port_add_target()

cxl_switch_port_setup_targets() adds an endpoint's downstream port to a port's decoder target list. For an auto region it checks that the decoder already targets that downstream port at the next position. For a user created region it programs the downstream port at that position. That step is open coded behind an add_target label that the target search jumps to.

Move that step to a new helper, cxl_switch_port_add_target(). The helper takes the switch decoder whose target list it updates, rather than the port, which makes its scope explicit. With the decoder setup and the target add now in helpers, the path for the first endpoint to reach a port becomes an else branch of the target search, so the add_target label is no longer needed.

No functional change.

Assisted-by LLM