[RFC PATCH 4/7] cxl/core/hdm: Allocate resources from the media

[Ben Widawsky <ben.widawsky@intel.com>]

Similar to how decoders consume address space for the root decoder, they
also consume space on the device's physical media. For future
allocations, it's important to mark those as used/busy.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
 drivers/cxl/core/core.h |  6 +++
 drivers/cxl/core/hdm.c  | 44 +++++++++++++++++-
 drivers/cxl/core/port.c | 99 +++++++++++++++++++++++++++++++++--------
 drivers/cxl/cxl.h       | 16 +++++--
 4 files changed, 142 insertions(+), 23 deletions(-)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 1a50c0fc399c..1dea4dbb4f33 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -9,6 +9,12 @@ extern const struct device_type cxl_nvdimm_type;
 
 extern struct attribute_group cxl_base_attribute_group;
 
+extern struct device_attribute dev_attr_create_pmem_region;
+extern struct device_attribute dev_attr_delete_region;
+
+extern int *gen_pool_vcookie;
+extern int *gen_pool_pcookie;
+
 struct cxl_send_command;
 struct cxl_mem_query_commands;
 int cxl_query_cmd(struct cxl_memdev *cxlmd,
diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 83404cdb846b..4a4e07a010ec 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright(c) 2022 Intel Corporation. All rights reserved. */
 #include <linux/io-64-nonatomic-hi-lo.h>
+#include <linux/genalloc.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 
@@ -188,8 +189,11 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
 	else
 		cxld->target_type = CXL_DECODER_ACCELERATOR;
 
-	if (is_endpoint_decoder(&cxld->dev))
+	if (is_endpoint_decoder(&cxld->dev)) {
+		to_cxl_endpoint_decoder(cxld)->skip =
+			ioread64_hi_lo(hdm + CXL_HDM_DECODER0_TL_LOW(which));
 		return 0;
+	}
 
 	target_list.value =
 		ioread64_hi_lo(hdm + CXL_HDM_DECODER0_TL_LOW(which));
@@ -199,6 +203,35 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,
 	return 0;
 }
 
+static void cxl_request_regions(struct cxl_endpoint_decoder *cxled,
+				resource_size_t base)
+{
+	struct cxl_port *port = to_cxl_port(cxled->base.dev.parent);
+	struct genpool_data_fixed gpdf;
+	struct range r = cxled->hrange;
+	unsigned long addr;
+	void *type;
+
+	if (!(cxled->base.flags & CXL_DECODER_F_ENABLE))
+		return;
+
+	gpdf.offset = base;
+	addr = gen_pool_alloc_algo_owner(port->media, range_len(&r),
+					 gen_pool_fixed_alloc, &gpdf, &type);
+	if (addr != base || (base == 0 && !type)) {
+		dev_warn(&port->dev, "Couldn't allocate media\n");
+		return;
+	} else if (type == &gen_pool_pcookie) {
+		dev_warn(&port->dev, "Enumerated a persistent capacity\n");
+		return;
+	}
+
+	cxled->drange = (struct range) {
+		.start = addr,
+		.end = addr + range_len(&r) - 1,
+	};
+}
+
 /**
  * devm_cxl_enumerate_decoders - add decoder objects per HDM register set
  * @cxlhdm: Structure to populate with HDM capabilities
@@ -208,6 +241,7 @@ int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm)
 	void __iomem *hdm = cxlhdm->regs.hdm_decoder;
 	struct cxl_port *port = cxlhdm->port;
 	int i, committed, failed;
+	u64 base = 0;
 	u32 ctrl;
 
 	/*
@@ -230,6 +264,7 @@ int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm)
 	for (i = 0, failed = 0; i < cxlhdm->decoder_count; i++) {
 		int target_map[CXL_DECODER_MAX_INTERLEAVE] = { 0 };
 		int rc, target_count = cxlhdm->target_count;
+		struct cxl_endpoint_decoder *cxled;
 		struct cxl_decoder *cxld;
 
 		if (is_cxl_endpoint(port))
@@ -255,6 +290,13 @@ int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm)
 				 "Failed to add decoder to port\n");
 			return rc;
 		}
+
+		if (!is_cxl_endpoint(port))
+			continue;
+
+		cxled = to_cxl_endpoint_decoder(cxld);
+		cxl_request_regions(cxled, base + cxled->skip);
+		base += cxled->skip + range_len(&cxled->hrange);
 	}
 
 	if (failed == cxlhdm->decoder_count) {
diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 6653de4dfb43..fe50a42bed7b 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -452,16 +452,44 @@ static struct cxl_port *cxl_port_alloc(struct device *uport,
 	return ERR_PTR(rc);
 }
 
-/**
- * devm_cxl_add_port - register a cxl_port in CXL memory decode hierarchy
- * @host: host device for devm operations
- * @uport: "physical" device implementing this upstream port
- * @component_reg_phys: (optional) for configurable cxl_port instances
- * @parent_port: next hop up in the CXL memory decode hierarchy
- */
-struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
-				   resource_size_t component_reg_phys,
-				   struct cxl_port *parent_port)
+int *gen_pool_vcookie;
+int *gen_pool_pcookie;
+
+static int create_gen_pools(struct cxl_port *ep, u64 capacity, u64 pmem_offset)
+{
+	int rc;
+
+	ep->media = gen_pool_create(ilog2(SZ_256M), NUMA_NO_NODE);
+	if (IS_ERR(ep->media))
+		return PTR_ERR(ep->media);
+
+	if (pmem_offset) {
+		rc = gen_pool_add_owner(ep->media, 0, -1, pmem_offset,
+					NUMA_NO_NODE, &gen_pool_vcookie);
+		if (rc) {
+			gen_pool_destroy(ep->media);
+			return rc;
+		}
+	}
+
+	if (pmem_offset < capacity) {
+		rc = gen_pool_add_owner(ep->media, pmem_offset, -1,
+					capacity - pmem_offset, NUMA_NO_NODE,
+					&gen_pool_pcookie);
+		if (rc) {
+			gen_pool_destroy(ep->media);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static struct cxl_port *__devm_cxl_add_port(struct device *host,
+					    struct device *uport,
+					    resource_size_t component_reg_phys,
+					    u64 capacity, u64 pmem_offset,
+					    struct cxl_port *parent_port)
 {
 	struct cxl_port *port;
 	struct device *dev;
@@ -474,12 +502,15 @@ struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
 	if (parent_port)
 		port->depth = parent_port->depth + 1;
 	dev = &port->dev;
-	if (is_cxl_memdev(uport))
+	if (is_cxl_memdev(uport)) {
 		rc = dev_set_name(dev, "endpoint%d", port->id);
-	else if (parent_port)
+		if (!rc)
+			rc = create_gen_pools(port, capacity, pmem_offset);
+	} else if (parent_port) {
 		rc = dev_set_name(dev, "port%d", port->id);
-	else
+	} else {
 		rc = dev_set_name(dev, "root%d", port->id);
+	}
 	if (rc)
 		goto err;
 
@@ -502,10 +533,22 @@ struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
 	put_device(dev);
 	return ERR_PTR(rc);
 }
-EXPORT_SYMBOL_NS_GPL(devm_cxl_add_port, CXL);
 
-static int *gen_pool_vcookie;
-static int *gen_pool_pcookie;
+/**
+ * devm_cxl_add_port - register a cxl_port in CXL memory decode hierarchy
+ * @host: host device for devm operations
+ * @uport: "physical" device implementing this upstream port
+ * @component_reg_phys: (optional) for configurable cxl_port instances
+ * @parent_port: next hop up in the CXL memory decode hierarchy
+ */
+struct cxl_port *devm_cxl_add_port(struct device *host, struct device *uport,
+				   resource_size_t component_reg_phys,
+				   struct cxl_port *parent_port)
+{
+	return __devm_cxl_add_port(host, uport, component_reg_phys, 0, 0,
+				   parent_port);
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_add_port, CXL);
 
 struct cxl_port *devm_cxl_add_endpoint_port(struct device *host,
 					    struct device *uport,
@@ -513,9 +556,9 @@ struct cxl_port *devm_cxl_add_endpoint_port(struct device *host,
 					    u64 capacity, u64 pmem_offset,
 					    struct cxl_port *parent_port)
 {
-	int rc;
 	struct cxl_port *ep =
-		devm_cxl_add_port(host, uport, component_reg_phys, parent_port);
+		__devm_cxl_add_port(host, uport, component_reg_phys, capacity,
+				    pmem_offset, parent_port);
 	if (IS_ERR(ep) || !capacity)
 		return ep;
 
@@ -526,6 +569,8 @@ struct cxl_port *devm_cxl_add_endpoint_port(struct device *host,
 	}
 
 	if (pmem_offset) {
+		int rc;
+
 		rc = gen_pool_add_owner(ep->media, 0, -1, pmem_offset,
 					NUMA_NO_NODE, &gen_pool_vcookie);
 		if (rc) {
@@ -537,6 +582,8 @@ struct cxl_port *devm_cxl_add_endpoint_port(struct device *host,
 	}
 
 	if (pmem_offset < capacity) {
+		int rc;
+
 		rc = gen_pool_add_owner(ep->media, pmem_offset, -1,
 					capacity - pmem_offset, NUMA_NO_NODE,
 					&gen_pool_pcookie);
@@ -1250,6 +1297,7 @@ static struct cxl_decoder *__cxl_decoder_alloc(struct cxl_port *port,
 		cxled = kzalloc(sizeof(*cxled), GFP_KERNEL);
 		if (!cxled)
 			return NULL;
+		cxled->drange = (struct range){ 0, -1 };
 		cxld = &cxled->base;
 	} else if (is_cxl_root(port)) {
 		struct cxl_root_decoder *cxlrd;
@@ -1504,6 +1552,21 @@ EXPORT_SYMBOL_NS_GPL(cxl_decoder_add, CXL);
 
 static void cxld_unregister(void *dev)
 {
+	struct cxl_decoder *cxld = to_cxl_decoder(dev);
+
+	if (is_endpoint_decoder(&cxld->dev)) {
+		struct cxl_endpoint_decoder *cxled =
+			to_cxl_endpoint_decoder(cxld);
+		struct cxl_port *ep = to_cxl_port(cxld->dev.parent);
+
+		if (!range_len(&cxled->drange))
+			goto out;
+
+		gen_pool_free(ep->media, cxled->drange.start,
+			      range_len(&cxled->drange));
+	}
+
+out:
 	device_unregister(dev);
 }
 
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index d18e93e77f7e..e88b1efe54d3 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -245,11 +245,15 @@ struct cxl_decoder {
 /**
  * struct cxl_endpoint_decoder - An decoder residing in a CXL endpoint.
  * @base: Base class decoder
- * @range: Host physical address space consumed by this decoder.
+ * @hrange: Host physical address space consumed by this decoder.
+ * @drange: device space consumed by this decoder.
+ * @skip: The skip count as specified in the CXL specification.
  */
 struct cxl_endpoint_decoder {
 	struct cxl_decoder base;
-	struct range range;
+	struct range hrange;
+	struct range drange;
+	u64 skip;
 };
 
 /**
@@ -269,11 +273,15 @@ struct cxl_switch_decoder {
  * @base: Base class decoder
  * @res: host address space owned by this decoder
  * @targets: Downstream targets (ie. hostbridges).
+ * @next_region_id: The pre-cached next region id.
+ * @id_lock: Protects next_region_id
  */
 struct cxl_root_decoder {
 	struct cxl_decoder base;
 	struct resource res;
 	struct cxl_decoder_targets *targets;
+	int next_region_id;
+	struct mutex id_lock; /* synchronizes access to next_region_id */
 };
 
 #define _to_cxl_decoder(x)                                                     \
@@ -441,7 +449,7 @@ static inline void cxl_set_decoder_extent(struct cxl_decoder *cxld,
 		to_cxl_root_decoder(cxld)->res =
 			(struct resource)DEFINE_RES_MEM(base, size);
 	else if (is_endpoint_decoder(&cxld->dev))
-		to_cxl_endpoint_decoder(cxld)->range = (struct range){
+		to_cxl_endpoint_decoder(cxld)->drange = (struct range){
 			.start = base,
 			.end = base + size - 1
 		};
@@ -464,7 +472,7 @@ static inline struct range cxl_get_decoder_extent(struct cxl_decoder *cxld)
 			.end = cxlrd->res.end
 		};
 	} else if (is_endpoint_decoder(&cxld->dev)) {
-		ret = to_cxl_endpoint_decoder(cxld)->range;
+		ret = to_cxl_endpoint_decoder(cxld)->drange;
 	} else {
 		ret = to_cxl_switch_decoder(cxld)->range;
 	}
-- 
2.35.1