Merge tag 'cxl-fixes-6.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl

Pull cxl fixes from Dave Jiang:

 - Fix no cxl_nvd during pmem region auto-assemble

 - Avoid NULLL pointer dereference in region lookup

 - Add missing checks to interleave capability

 - Add cxl kdoc fix to address document compilation error

* tag 'cxl-fixes-6.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/cxl/cxl:
  cxl: documentation: add missing files to cxl driver-api
  cxl/region: check interleave capability
  cxl/region: Avoid null pointer dereference in region lookup
  cxl/mem: Fix no cxl_nvd during pmem region auto-assembling

6 files changed, 151 insertions, 25 deletions

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 784843fa2a22..3df10517a327 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -52,6 +52,14 @@ int devm_cxl_add_passthrough_decoder(struct cxl_port *port)
 	struct cxl_dport *dport = NULL;
 	int single_port_map[1];
 	unsigned long index;
+	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
+
+	/*
+	 * Capability checks are moot for passthrough decoders, support
+	 * any and all possibilities.
+	 */
+	cxlhdm->interleave_mask = ~0U;
+	cxlhdm->iw_cap_mask = ~0UL;
 
 	cxlsd = cxl_switch_decoder_alloc(port, 1);
 	if (IS_ERR(cxlsd))
@@ -79,6 +87,11 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
 		cxlhdm->interleave_mask |= GENMASK(11, 8);
 	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
 		cxlhdm->interleave_mask |= GENMASK(14, 12);
+	cxlhdm->iw_cap_mask = BIT(1) | BIT(2) | BIT(4) | BIT(8);
+	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY, hdm_cap))
+		cxlhdm->iw_cap_mask |= BIT(3) | BIT(6) | BIT(12);
+	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
+		cxlhdm->iw_cap_mask |= BIT(16);
 }
 
 static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
diff --git a/drivers/cxl/core/pmem.c b/drivers/cxl/core/pmem.c
index e69625a8d6a1..c00f3a933164 100644
--- a/drivers/cxl/core/pmem.c
+++ b/drivers/cxl/core/pmem.c
@@ -62,10 +62,14 @@ static int match_nvdimm_bridge(struct device *dev, void *data)
 	return is_cxl_nvdimm_bridge(dev);
 }
 
-struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd)
+/**
+ * cxl_find_nvdimm_bridge() - find a bridge device relative to a port
+ * @port: any descendant port of an nvdimm-bridge associated
+ *        root-cxl-port
+ */
+struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port)
 {
-	struct cxl_root *cxl_root __free(put_cxl_root) =
-		find_cxl_root(cxlmd->endpoint);
+	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
 	struct device *dev;
 
 	if (!cxl_root)
@@ -242,18 +246,20 @@ static void cxlmd_release_nvdimm(void *_cxlmd)
 
 /**
  * devm_cxl_add_nvdimm() - add a bridge between a cxl_memdev and an nvdimm
+ * @parent_port: parent port for the (to be added) @cxlmd endpoint port
  * @cxlmd: cxl_memdev instance that will perform LIBNVDIMM operations
  *
  * Return: 0 on success negative error code on failure.
  */
-int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd)
+int devm_cxl_add_nvdimm(struct cxl_port *parent_port,
+			struct cxl_memdev *cxlmd)
 {
 	struct cxl_nvdimm_bridge *cxl_nvb;
 	struct cxl_nvdimm *cxl_nvd;
 	struct device *dev;
 	int rc;
 
-	cxl_nvb = cxl_find_nvdimm_bridge(cxlmd);
+	cxl_nvb = cxl_find_nvdimm_bridge(parent_port);
 	if (!cxl_nvb)
 		return -ENODEV;
 
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 3c2b6144be23..538ebd5a64fd 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1101,6 +1101,26 @@ static int cxl_port_attach_region(struct cxl_port *port,
 	}
 	cxld = cxl_rr->decoder;
 
+	/*
+	 * the number of targets should not exceed the target_count
+	 * of the decoder
+	 */
+	if (is_switch_decoder(&cxld->dev)) {
+		struct cxl_switch_decoder *cxlsd;
+
+		cxlsd = to_cxl_switch_decoder(&cxld->dev);
+		if (cxl_rr->nr_targets > cxlsd->nr_targets) {
+			dev_dbg(&cxlr->dev,
+				"%s:%s %s add: %s:%s @ %d overflows targets: %d\n",
+				dev_name(port->uport_dev), dev_name(&port->dev),
+				dev_name(&cxld->dev), dev_name(&cxlmd->dev),
+				dev_name(&cxled->cxld.dev), pos,
+				cxlsd->nr_targets);
+			rc = -ENXIO;
+			goto out_erase;
+		}
+	}
+
 	rc = cxl_rr_ep_add(cxl_rr, cxled);
 	if (rc) {
 		dev_dbg(&cxlr->dev,
@@ -1210,6 +1230,50 @@ static int check_last_peer(struct cxl_endpoint_decoder *cxled,
 	return 0;
 }
 
+static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
+{
+	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
+	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
+	unsigned int interleave_mask;
+	u8 eiw;
+	u16 eig;
+	int high_pos, low_pos;
+
+	if (!test_bit(iw, &cxlhdm->iw_cap_mask))
+		return -ENXIO;
+	/*
+	 * Per CXL specification r3.1(8.2.4.20.13 Decoder Protection),
+	 * if eiw < 8:
+	 *   DPAOFFSET[51: eig + 8] = HPAOFFSET[51: eig + 8 + eiw]
+	 *   DPAOFFSET[eig + 7: 0]  = HPAOFFSET[eig + 7: 0]
+	 *
+	 *   when the eiw is 0, all the bits of HPAOFFSET[51: 0] are used, the
+	 *   interleave bits are none.
+	 *
+	 * if eiw >= 8:
+	 *   DPAOFFSET[51: eig + 8] = HPAOFFSET[51: eig + eiw] / 3
+	 *   DPAOFFSET[eig + 7: 0]  = HPAOFFSET[eig + 7: 0]
+	 *
+	 *   when the eiw is 8, all the bits of HPAOFFSET[51: 0] are used, the
+	 *   interleave bits are none.
+	 */
+	ways_to_eiw(iw, &eiw);
+	if (eiw == 0 || eiw == 8)
+		return 0;
+
+	granularity_to_eig(ig, &eig);
+	if (eiw > 8)
+		high_pos = eiw + eig - 1;
+	else
+		high_pos = eiw + eig + 7;
+	low_pos = eig + 8;
+	interleave_mask = GENMASK(high_pos, low_pos);
+	if (interleave_mask & ~cxlhdm->interleave_mask)
+		return -ENXIO;
+
+	return 0;
+}
+
 static int cxl_port_setup_targets(struct cxl_port *port,
 				  struct cxl_region *cxlr,
 				  struct cxl_endpoint_decoder *cxled)
@@ -1360,6 +1424,15 @@ static int cxl_port_setup_targets(struct cxl_port *port,
 			return -ENXIO;
 		}
 	} else {
+		rc = check_interleave_cap(cxld, iw, 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);
+			return rc;
+		}
+
 		cxld->interleave_ways = iw;
 		cxld->interleave_granularity = ig;
 		cxld->hpa_range = (struct range) {
@@ -1796,6 +1869,15 @@ static int cxl_region_attach(struct cxl_region *cxlr,
 	struct cxl_dport *dport;
 	int rc = -ENXIO;
 
+	rc = check_interleave_cap(&cxled->cxld, p->interleave_ways,
+				  p->interleave_granularity);
+	if (rc) {
+		dev_dbg(&cxlr->dev, "%s iw: %d ig: %d is not supported\n",
+			dev_name(&cxled->cxld.dev), p->interleave_ways,
+			p->interleave_granularity);
+		return rc;
+	}
+
 	if (cxled->mode != cxlr->mode) {
 		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
 			dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
@@ -2688,22 +2770,33 @@ static int __cxl_dpa_to_region(struct device *dev, void *arg)
 {
 	struct cxl_dpa_to_region_context *ctx = arg;
 	struct cxl_endpoint_decoder *cxled;
+	struct cxl_region *cxlr;
 	u64 dpa = ctx->dpa;
 
 	if (!is_endpoint_decoder(dev))
 		return 0;
 
 	cxled = to_cxl_endpoint_decoder(dev);
-	if (!cxled->dpa_res || !resource_size(cxled->dpa_res))
+	if (!cxled || !cxled->dpa_res || !resource_size(cxled->dpa_res))
 		return 0;
 
 	if (dpa > cxled->dpa_res->end || dpa < cxled->dpa_res->start)
 		return 0;
 
-	dev_dbg(dev, "dpa:0x%llx mapped in region:%s\n", dpa,
-		dev_name(&cxled->cxld.region->dev));
+	/*
+	 * Stop the region search (return 1) when an endpoint mapping is
+	 * found. The region may not be fully constructed so offering
+	 * the cxlr in the context structure is not guaranteed.
+	 */
+	cxlr = cxled->cxld.region;
+	if (cxlr)
+		dev_dbg(dev, "dpa:0x%llx mapped in region:%s\n", dpa,
+			dev_name(&cxlr->dev));
+	else
+		dev_dbg(dev, "dpa:0x%llx mapped in endpoint:%s\n", dpa,
+			dev_name(dev));
 
-	ctx->cxlr = cxled->cxld.region;
+	ctx->cxlr = cxlr;
 
 	return 1;
 }
@@ -2847,7 +2940,7 @@ static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
 		 * bridge for one device is the same for all.
 		 */
 		if (i == 0) {
-			cxl_nvb = cxl_find_nvdimm_bridge(cxlmd);
+			cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
 			if (!cxl_nvb)
 				return -ENODEV;
 			cxlr->cxl_nvb = cxl_nvb;
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 603c0120cff8..a6613a6f8923 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -47,6 +47,8 @@ extern const struct nvdimm_security_ops *cxl_security_ops;
 #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
 #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
 #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
+#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
+#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
 #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
 #define   CXL_HDM_DECODER_ENABLE BIT(1)
 #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
@@ -855,8 +857,8 @@ struct cxl_nvdimm_bridge *devm_cxl_add_nvdimm_bridge(struct device *host,
 struct cxl_nvdimm *to_cxl_nvdimm(struct device *dev);
 bool is_cxl_nvdimm(struct device *dev);
 bool is_cxl_nvdimm_bridge(struct device *dev);
-int devm_cxl_add_nvdimm(struct cxl_memdev *cxlmd);
-struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_memdev *cxlmd);
+int devm_cxl_add_nvdimm(struct cxl_port *parent_port, struct cxl_memdev *cxlmd);
+struct cxl_nvdimm_bridge *cxl_find_nvdimm_bridge(struct cxl_port *port);
 
 #ifdef CONFIG_CXL_REGION
 bool is_cxl_pmem_region(struct device *dev);
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 19aba81cdf13..af8169ccdbc0 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -395,9 +395,9 @@ enum cxl_devtype {
 
 /**
  * struct cxl_dpa_perf - DPA performance property entry
- * @dpa_range - range for DPA address
- * @coord - QoS performance data (i.e. latency, bandwidth)
- * @qos_class - QoS Class cookies
+ * @dpa_range: range for DPA address
+ * @coord: QoS performance data (i.e. latency, bandwidth)
+ * @qos_class: QoS Class cookies
  */
 struct cxl_dpa_perf {
 	struct range dpa_range;
@@ -464,13 +464,14 @@ struct cxl_dev_state {
  * @active_persistent_bytes: sum of hard + soft persistent
  * @next_volatile_bytes: volatile capacity change pending device reset
  * @next_persistent_bytes: persistent capacity change pending device reset
+ * @ram_perf: performance data entry matched to RAM partition
+ * @pmem_perf: performance data entry matched to PMEM partition
  * @event: event log driver state
  * @poison: poison driver state info
  * @security: security driver state info
  * @fw: firmware upload / activation state
+ * @mbox_wait: RCU wait for mbox send completely
  * @mbox_send: @dev specific transport for transmitting mailbox commands
- * @ram_perf: performance data entry matched to RAM partition
- * @pmem_perf: performance data entry matched to PMEM partition
  *
  * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
  * details on capacity parameters.
@@ -851,11 +852,21 @@ static inline void cxl_mem_active_dec(void)
 
 int cxl_mem_sanitize(struct cxl_memdev *cxlmd, u16 cmd);
 
+/**
+ * struct cxl_hdm - HDM Decoder registers and cached / decoded capabilities
+ * @regs: mapped registers, see devm_cxl_setup_hdm()
+ * @decoder_count: number of decoders for this port
+ * @target_count: for switch decoders, max downstream port targets
+ * @interleave_mask: interleave granularity capability, see check_interleave_cap()
+ * @iw_cap_mask: bitmask of supported interleave ways, see check_interleave_cap()
+ * @port: mapped cxl_port, see devm_cxl_setup_hdm()
+ */
 struct cxl_hdm {
 	struct cxl_component_regs regs;
 	unsigned int decoder_count;
 	unsigned int target_count;
 	unsigned int interleave_mask;
+	unsigned long iw_cap_mask;
 	struct cxl_port *port;
 };
 
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 0c79d9ce877c..2f1b49bfe162 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -152,6 +152,15 @@ static int cxl_mem_probe(struct device *dev)
 		return -ENXIO;
 	}
 
+	if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM)) {
+		rc = devm_cxl_add_nvdimm(parent_port, cxlmd);
+		if (rc) {
+			if (rc == -ENODEV)
+				dev_info(dev, "PMEM disabled by platform\n");
+			return rc;
+		}
+	}
+
 	if (dport->rch)
 		endpoint_parent = parent_port->uport_dev;
 	else
@@ -174,14 +183,6 @@ unlock:
 	if (rc)
 		return rc;
 
-	if (resource_size(&cxlds->pmem_res) && IS_ENABLED(CONFIG_CXL_PMEM)) {
-		rc = devm_cxl_add_nvdimm(cxlmd);
-		if (rc == -ENODEV)
-			dev_info(dev, "PMEM disabled by platform\n");
-		else
-			return rc;
-	}
-
 	/*
 	 * The kernel may be operating out of CXL memory on this device,
 	 * there is no spec defined way to determine whether this device