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Message-ID: <20260112163514.2551809-4-gourry@gourry.net>
Date: Mon, 12 Jan 2026 11:35:11 -0500
From: Gregory Price <gourry@...rry.net>
To: linux-cxl@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
kernel-team@...a.com,
dave@...olabs.net,
jonathan.cameron@...wei.com,
dave.jiang@...el.com,
alison.schofield@...el.com,
vishal.l.verma@...el.com,
ira.weiny@...el.com,
dan.j.williams@...el.com
Subject: [PATCH 3/6] cxl/core/region: move pmem memctrl logic into memctrl/pmem_region
Move the pmem_region logic from region.c into memctrl/pmem_region.c.
Restrict the valid controllers for pmem to the pmem controller.
Simplify the controller selection logic in region probe.
Cc:
Signed-off-by: Gregory Price <gourry@...rry.net>
---
drivers/cxl/core/core.h | 1 +
drivers/cxl/core/memctrl/Makefile | 1 +
drivers/cxl/core/memctrl/memctrl.c | 2 +
drivers/cxl/core/memctrl/pmem_region.c | 191 +++++++++++++++++++++
drivers/cxl/core/region.c | 221 +++----------------------
drivers/cxl/cxl.h | 2 +
6 files changed, 217 insertions(+), 201 deletions(-)
create mode 100644 drivers/cxl/core/memctrl/pmem_region.c
diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 18cb84950500..59175890a6ac 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -46,6 +46,7 @@ u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
u64 dpa);
int cxl_enable_memctrl(struct cxl_region *cxlr);
int devm_cxl_add_dax_region(struct cxl_region *cxlr);
+int devm_cxl_add_pmem_region(struct cxl_region *cxlr);
#else
static inline u64 cxl_dpa_to_hpa(struct cxl_region *cxlr,
diff --git a/drivers/cxl/core/memctrl/Makefile b/drivers/cxl/core/memctrl/Makefile
index 1c52c7d75570..efffc8ba2c0b 100644
--- a/drivers/cxl/core/memctrl/Makefile
+++ b/drivers/cxl/core/memctrl/Makefile
@@ -3,3 +3,4 @@
cxl_core-$(CONFIG_CXL_REGION) += memctrl/memctrl.o
cxl_core-$(CONFIG_CXL_REGION) += memctrl/dax_region.o
cxl_core-$(CONFIG_CXL_REGION) += memctrl/sysram_region.o
+cxl_core-$(CONFIG_CXL_REGION) += memctrl/pmem_region.o
diff --git a/drivers/cxl/core/memctrl/memctrl.c b/drivers/cxl/core/memctrl/memctrl.c
index 40ffb59353bb..1b661465bdeb 100644
--- a/drivers/cxl/core/memctrl/memctrl.c
+++ b/drivers/cxl/core/memctrl/memctrl.c
@@ -36,6 +36,8 @@ int cxl_enable_memctrl(struct cxl_region *cxlr)
return devm_cxl_add_dax_region(cxlr);
case CXL_MEMCTRL_SYSRAM:
return devm_cxl_add_sysram_region(cxlr);
+ case CXL_MEMCTRL_PMEM:
+ return devm_cxl_add_pmem_region(cxlr);
default:
return -EINVAL;
}
diff --git a/drivers/cxl/core/memctrl/pmem_region.c b/drivers/cxl/core/memctrl/pmem_region.c
new file mode 100644
index 000000000000..57668dd82d71
--- /dev/null
+++ b/drivers/cxl/core/memctrl/pmem_region.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <cxlmem.h>
+#include <cxl.h>
+#include "../core.h"
+
+static void cxl_pmem_region_release(struct device *dev)
+{
+ struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
+ int i;
+
+ for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
+ struct cxl_memdev *cxlmd = cxlr_pmem->mapping[i].cxlmd;
+
+ put_device(&cxlmd->dev);
+ }
+
+ kfree(cxlr_pmem);
+}
+
+static const struct attribute_group *cxl_pmem_region_attribute_groups[] = {
+ &cxl_base_attribute_group,
+ NULL,
+};
+
+const struct device_type cxl_pmem_region_type = {
+ .name = "cxl_pmem_region",
+ .release = cxl_pmem_region_release,
+ .groups = cxl_pmem_region_attribute_groups,
+};
+bool is_cxl_pmem_region(struct device *dev)
+{
+ return dev->type == &cxl_pmem_region_type;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_pmem_region, "CXL");
+
+struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
+{
+ if (dev_WARN_ONCE(dev, !is_cxl_pmem_region(dev),
+ "not a cxl_pmem_region device\n"))
+ return NULL;
+ return container_of(dev, struct cxl_pmem_region, dev);
+}
+EXPORT_SYMBOL_NS_GPL(to_cxl_pmem_region, "CXL");
+static struct lock_class_key cxl_pmem_region_key;
+
+static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
+{
+ struct cxl_region_params *p = &cxlr->params;
+ struct cxl_nvdimm_bridge *cxl_nvb;
+ struct device *dev;
+ int i;
+
+ guard(rwsem_read)(&cxl_rwsem.region);
+ if (p->state != CXL_CONFIG_COMMIT)
+ return -ENXIO;
+
+ struct cxl_pmem_region *cxlr_pmem __free(kfree) =
+ kzalloc(struct_size(cxlr_pmem, mapping, p->nr_targets), GFP_KERNEL);
+ if (!cxlr_pmem)
+ return -ENOMEM;
+
+ cxlr_pmem->hpa_range.start = p->res->start;
+ cxlr_pmem->hpa_range.end = p->res->end;
+
+ /* Snapshot the region configuration underneath the cxl_rwsem.region */
+ cxlr_pmem->nr_mappings = p->nr_targets;
+ for (i = 0; i < p->nr_targets; i++) {
+ struct cxl_endpoint_decoder *cxled = p->targets[i];
+ struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
+ struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
+
+ /*
+ * Regions never span CXL root devices, so by definition the
+ * bridge for one device is the same for all.
+ */
+ if (i == 0) {
+ cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
+ if (!cxl_nvb)
+ return -ENODEV;
+ cxlr->cxl_nvb = cxl_nvb;
+ }
+ m->cxlmd = cxlmd;
+ get_device(&cxlmd->dev);
+ m->start = cxled->dpa_res->start;
+ m->size = resource_size(cxled->dpa_res);
+ m->position = i;
+ }
+
+ dev = &cxlr_pmem->dev;
+ device_initialize(dev);
+ lockdep_set_class(&dev->mutex, &cxl_pmem_region_key);
+ device_set_pm_not_required(dev);
+ dev->parent = &cxlr->dev;
+ dev->bus = &cxl_bus_type;
+ dev->type = &cxl_pmem_region_type;
+ cxlr_pmem->cxlr = cxlr;
+ cxlr->cxlr_pmem = no_free_ptr(cxlr_pmem);
+
+ return 0;
+}
+
+static void cxlr_pmem_unregister(void *_cxlr_pmem)
+{
+ struct cxl_pmem_region *cxlr_pmem = _cxlr_pmem;
+ struct cxl_region *cxlr = cxlr_pmem->cxlr;
+ struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
+
+ /*
+ * Either the bridge is in ->remove() context under the device_lock(),
+ * or cxlr_release_nvdimm() is cancelling the bridge's release action
+ * for @cxlr_pmem and doing it itself (while manually holding the bridge
+ * lock).
+ */
+ device_lock_assert(&cxl_nvb->dev);
+ cxlr->cxlr_pmem = NULL;
+ cxlr_pmem->cxlr = NULL;
+ device_unregister(&cxlr_pmem->dev);
+}
+
+static void cxlr_release_nvdimm(void *_cxlr)
+{
+ struct cxl_region *cxlr = _cxlr;
+ struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
+
+ scoped_guard(device, &cxl_nvb->dev) {
+ if (cxlr->cxlr_pmem)
+ devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
+ cxlr->cxlr_pmem);
+ }
+ cxlr->cxl_nvb = NULL;
+ put_device(&cxl_nvb->dev);
+}
+
+/**
+ * devm_cxl_add_pmem_region() - add a cxl_region-to-nd_region bridge
+ * @cxlr: parent CXL region for this pmem region bridge device
+ *
+ * Return: 0 on success negative error code on failure.
+ */
+int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
+{
+ struct cxl_pmem_region *cxlr_pmem;
+ struct cxl_nvdimm_bridge *cxl_nvb;
+ struct device *dev;
+ int rc;
+
+ rc = cxl_pmem_region_alloc(cxlr);
+ if (rc)
+ return rc;
+ cxlr_pmem = cxlr->cxlr_pmem;
+ cxl_nvb = cxlr->cxl_nvb;
+
+ dev = &cxlr_pmem->dev;
+ rc = dev_set_name(dev, "pmem_region%d", cxlr->id);
+ if (rc)
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
+ dev_name(dev));
+
+ scoped_guard(device, &cxl_nvb->dev) {
+ if (cxl_nvb->dev.driver)
+ rc = devm_add_action_or_reset(&cxl_nvb->dev,
+ cxlr_pmem_unregister,
+ cxlr_pmem);
+ else
+ rc = -ENXIO;
+ }
+
+ if (rc)
+ goto err_bridge;
+
+ /* @cxlr carries a reference on @cxl_nvb until cxlr_release_nvdimm */
+ return devm_add_action_or_reset(&cxlr->dev, cxlr_release_nvdimm, cxlr);
+
+err:
+ put_device(dev);
+err_bridge:
+ put_device(&cxl_nvb->dev);
+ cxlr->cxl_nvb = NULL;
+ return rc;
+}
+
+
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index eeab091f043a..85c20a09246d 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -642,6 +642,9 @@ static ssize_t ctrl_show(struct device *dev, struct device_attribute *attr,
case CXL_MEMCTRL_SYSRAM:
desc = "sysram";
break;
+ case CXL_MEMCTRL_PMEM:
+ desc = "pmem";
+ break;
default:
desc = "";
break;
@@ -661,6 +664,10 @@ static ssize_t ctrl_store(struct device *dev, struct device_attribute *attr,
if ((rc = ACQUIRE_ERR(rwsem_write_kill, &rwsem)))
return rc;
+ /* PMEM only has one controller - the pmem controller */
+ if (cxlr->mode == CXL_PARTMODE_PMEM)
+ return -EBUSY;
+
if (p->state >= CXL_CONFIG_COMMIT)
return -EBUSY;
@@ -2648,7 +2655,11 @@ static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
return cxlr;
cxlr->mode = mode;
cxlr->type = type;
- cxlr->memctrl = CXL_MEMCTRL_NONE;
+
+ if (mode == CXL_PARTMODE_PMEM)
+ cxlr->memctrl = CXL_MEMCTRL_PMEM;
+ else
+ cxlr->memctrl = CXL_MEMCTRL_NONE;
dev = &cxlr->dev;
rc = dev_set_name(dev, "region%d", id);
@@ -2797,46 +2808,6 @@ static ssize_t delete_region_store(struct device *dev,
}
DEVICE_ATTR_WO(delete_region);
-static void cxl_pmem_region_release(struct device *dev)
-{
- struct cxl_pmem_region *cxlr_pmem = to_cxl_pmem_region(dev);
- int i;
-
- for (i = 0; i < cxlr_pmem->nr_mappings; i++) {
- struct cxl_memdev *cxlmd = cxlr_pmem->mapping[i].cxlmd;
-
- put_device(&cxlmd->dev);
- }
-
- kfree(cxlr_pmem);
-}
-
-static const struct attribute_group *cxl_pmem_region_attribute_groups[] = {
- &cxl_base_attribute_group,
- NULL,
-};
-
-const struct device_type cxl_pmem_region_type = {
- .name = "cxl_pmem_region",
- .release = cxl_pmem_region_release,
- .groups = cxl_pmem_region_attribute_groups,
-};
-
-bool is_cxl_pmem_region(struct device *dev)
-{
- return dev->type == &cxl_pmem_region_type;
-}
-EXPORT_SYMBOL_NS_GPL(is_cxl_pmem_region, "CXL");
-
-struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev)
-{
- if (dev_WARN_ONCE(dev, !is_cxl_pmem_region(dev),
- "not a cxl_pmem_region device\n"))
- return NULL;
- return container_of(dev, struct cxl_pmem_region, dev);
-}
-EXPORT_SYMBOL_NS_GPL(to_cxl_pmem_region, "CXL");
-
struct cxl_poison_context {
struct cxl_port *port;
int part;
@@ -3268,64 +3239,6 @@ static int region_offset_to_dpa_result(struct cxl_region *cxlr, u64 offset,
return -ENXIO;
}
-static struct lock_class_key cxl_pmem_region_key;
-
-static int cxl_pmem_region_alloc(struct cxl_region *cxlr)
-{
- struct cxl_region_params *p = &cxlr->params;
- struct cxl_nvdimm_bridge *cxl_nvb;
- struct device *dev;
- int i;
-
- guard(rwsem_read)(&cxl_rwsem.region);
- if (p->state != CXL_CONFIG_COMMIT)
- return -ENXIO;
-
- struct cxl_pmem_region *cxlr_pmem __free(kfree) =
- kzalloc(struct_size(cxlr_pmem, mapping, p->nr_targets), GFP_KERNEL);
- if (!cxlr_pmem)
- return -ENOMEM;
-
- cxlr_pmem->hpa_range.start = p->res->start;
- cxlr_pmem->hpa_range.end = p->res->end;
-
- /* Snapshot the region configuration underneath the cxl_rwsem.region */
- cxlr_pmem->nr_mappings = p->nr_targets;
- for (i = 0; i < p->nr_targets; i++) {
- struct cxl_endpoint_decoder *cxled = p->targets[i];
- struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
- struct cxl_pmem_region_mapping *m = &cxlr_pmem->mapping[i];
-
- /*
- * Regions never span CXL root devices, so by definition the
- * bridge for one device is the same for all.
- */
- if (i == 0) {
- cxl_nvb = cxl_find_nvdimm_bridge(cxlmd->endpoint);
- if (!cxl_nvb)
- return -ENODEV;
- cxlr->cxl_nvb = cxl_nvb;
- }
- m->cxlmd = cxlmd;
- get_device(&cxlmd->dev);
- m->start = cxled->dpa_res->start;
- m->size = resource_size(cxled->dpa_res);
- m->position = i;
- }
-
- dev = &cxlr_pmem->dev;
- device_initialize(dev);
- lockdep_set_class(&dev->mutex, &cxl_pmem_region_key);
- device_set_pm_not_required(dev);
- dev->parent = &cxlr->dev;
- dev->bus = &cxl_bus_type;
- dev->type = &cxl_pmem_region_type;
- cxlr_pmem->cxlr = cxlr;
- cxlr->cxlr_pmem = no_free_ptr(cxlr_pmem);
-
- return 0;
-}
-
static void cxl_dax_region_release(struct device *dev)
{
struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
@@ -3358,92 +3271,6 @@ struct cxl_dax_region *to_cxl_dax_region(struct device *dev)
}
EXPORT_SYMBOL_NS_GPL(to_cxl_dax_region, "CXL");
-static void cxlr_pmem_unregister(void *_cxlr_pmem)
-{
- struct cxl_pmem_region *cxlr_pmem = _cxlr_pmem;
- struct cxl_region *cxlr = cxlr_pmem->cxlr;
- struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
-
- /*
- * Either the bridge is in ->remove() context under the device_lock(),
- * or cxlr_release_nvdimm() is cancelling the bridge's release action
- * for @cxlr_pmem and doing it itself (while manually holding the bridge
- * lock).
- */
- device_lock_assert(&cxl_nvb->dev);
- cxlr->cxlr_pmem = NULL;
- cxlr_pmem->cxlr = NULL;
- device_unregister(&cxlr_pmem->dev);
-}
-
-static void cxlr_release_nvdimm(void *_cxlr)
-{
- struct cxl_region *cxlr = _cxlr;
- struct cxl_nvdimm_bridge *cxl_nvb = cxlr->cxl_nvb;
-
- scoped_guard(device, &cxl_nvb->dev) {
- if (cxlr->cxlr_pmem)
- devm_release_action(&cxl_nvb->dev, cxlr_pmem_unregister,
- cxlr->cxlr_pmem);
- }
- cxlr->cxl_nvb = NULL;
- put_device(&cxl_nvb->dev);
-}
-
-/**
- * devm_cxl_add_pmem_region() - add a cxl_region-to-nd_region bridge
- * @cxlr: parent CXL region for this pmem region bridge device
- *
- * Return: 0 on success negative error code on failure.
- */
-static int devm_cxl_add_pmem_region(struct cxl_region *cxlr)
-{
- struct cxl_pmem_region *cxlr_pmem;
- struct cxl_nvdimm_bridge *cxl_nvb;
- struct device *dev;
- int rc;
-
- rc = cxl_pmem_region_alloc(cxlr);
- if (rc)
- return rc;
- cxlr_pmem = cxlr->cxlr_pmem;
- cxl_nvb = cxlr->cxl_nvb;
-
- dev = &cxlr_pmem->dev;
- rc = dev_set_name(dev, "pmem_region%d", cxlr->id);
- if (rc)
- goto err;
-
- rc = device_add(dev);
- if (rc)
- goto err;
-
- dev_dbg(&cxlr->dev, "%s: register %s\n", dev_name(dev->parent),
- dev_name(dev));
-
- scoped_guard(device, &cxl_nvb->dev) {
- if (cxl_nvb->dev.driver)
- rc = devm_add_action_or_reset(&cxl_nvb->dev,
- cxlr_pmem_unregister,
- cxlr_pmem);
- else
- rc = -ENXIO;
- }
-
- if (rc)
- goto err_bridge;
-
- /* @cxlr carries a reference on @cxl_nvb until cxlr_release_nvdimm */
- return devm_add_action_or_reset(&cxlr->dev, cxlr_release_nvdimm, cxlr);
-
-err:
- put_device(dev);
-err_bridge:
- put_device(&cxl_nvb->dev);
- cxlr->cxl_nvb = NULL;
- return rc;
-}
-
static int match_decoder_by_range(struct device *dev, const void *data)
{
const struct range *r1, *r2 = data;
@@ -3929,26 +3756,18 @@ static int cxl_region_probe(struct device *dev)
return rc;
}
- switch (cxlr->mode) {
- case CXL_PARTMODE_PMEM:
- rc = devm_cxl_region_edac_register(cxlr);
- if (rc)
- dev_dbg(&cxlr->dev, "CXL EDAC registration for region_id=%d failed\n",
- cxlr->id);
-
- return devm_cxl_add_pmem_region(cxlr);
- case CXL_PARTMODE_RAM:
- rc = devm_cxl_region_edac_register(cxlr);
- if (rc)
- dev_dbg(&cxlr->dev, "CXL EDAC registration for region_id=%d failed\n",
- cxlr->id);
-
- return cxl_enable_memctrl(cxlr);
- default:
+ if (cxlr->mode > CXL_PARTMODE_PMEM) {
dev_dbg(&cxlr->dev, "unsupported region mode: %d\n",
cxlr->mode);
return -ENXIO;
}
+
+ rc = devm_cxl_region_edac_register(cxlr);
+ if (rc)
+ dev_dbg(&cxlr->dev, "CXL EDAC registration for region_id=%d failed\n",
+ cxlr->id);
+
+ return cxl_enable_memctrl(cxlr);
}
static struct cxl_driver cxl_region_driver = {
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index bb4f877b4e8f..c69d27a2e97d 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -509,12 +509,14 @@ enum cxl_partition_mode {
* Auto - either BIOS-configured as SysRAM, or default to DAX
* DAX - creates a dax_region controller for the cxl_region
* SYSRAM - hotplugs the region directly as System RAM
+ * PMEM - persistent memory controller (nvdimm)
*/
enum cxl_memctrl_mode {
CXL_MEMCTRL_NONE,
CXL_MEMCTRL_AUTO,
CXL_MEMCTRL_DAX,
CXL_MEMCTRL_SYSRAM,
+ CXL_MEMCTRL_PMEM,
};
/*
--
2.52.0
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