[PATCH v24 04/11] cxl: Prepare memdev creation for type2

[<alejandro.lucero-palau@amd.com>]

From: Alejandro Lucero <alucerop@amd.com>

Current cxl core is relying on a CXL_DEVTYPE_CLASSMEM type device when
creating a memdev leading to problems when obtaining cxl_memdev_state
references from a CXL_DEVTYPE_DEVMEM type.

Modify check for obtaining cxl_memdev_state adding CXL_DEVTYPE_DEVMEM
support.

Make devm_cxl_add_memdev accessible from an accel driver.

Signed-off-by: Alejandro Lucero <alucerop@amd.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/memdev.c | 15 +++++++++++--
 drivers/cxl/cxlmem.h      |  6 ------
 drivers/cxl/mem.c         | 45 +++++++++++++++++++++++++++++----------
 include/cxl/cxl.h         |  6 ++++++
 4 files changed, 53 insertions(+), 19 deletions(-)

diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
index 166ec6b7d041..759b43364ed7 100644
--- a/drivers/cxl/core/memdev.c
+++ b/drivers/cxl/core/memdev.c
@@ -7,6 +7,7 @@
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/pci.h>
+#include <cxl/cxl.h>
 #include <cxlmem.h>
 #include "trace.h"
 #include "core.h"
@@ -576,9 +577,16 @@ static const struct device_type cxl_memdev_type = {
 	.groups = cxl_memdev_attribute_groups,
 };
 
+static const struct device_type cxl_accel_memdev_type = {
+	.name = "cxl_accel_memdev",
+	.release = cxl_memdev_release,
+	.devnode = cxl_memdev_devnode,
+};
+
 bool is_cxl_memdev(const struct device *dev)
 {
-	return dev->type == &cxl_memdev_type;
+	return (dev->type == &cxl_memdev_type ||
+		dev->type == &cxl_accel_memdev_type);
 }
 EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, "CXL");
 
@@ -773,7 +781,10 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
 	dev->parent = cxlds->dev;
 	dev->bus = &cxl_bus_type;
 	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
-	dev->type = &cxl_memdev_type;
+	if (cxlds->type == CXL_DEVTYPE_DEVMEM)
+		dev->type = &cxl_accel_memdev_type;
+	else
+		dev->type = &cxl_memdev_type;
 	device_set_pm_not_required(dev);
 	INIT_WORK(&cxlmd->detach_work, detach_memdev);
 
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 281546de426e..c98db6f18aa2 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -34,10 +34,6 @@
 	(FIELD_GET(CXLMDEV_RESET_NEEDED_MASK, status) !=                       \
 	 CXLMDEV_RESET_NEEDED_NOT)
 
-struct cxl_memdev_attach {
-	int (*probe)(struct cxl_memdev *cxlmd);
-};
-
 /**
  * struct cxl_memdev - CXL bus object representing a Type-3 Memory Device
  * @dev: driver core device object
@@ -103,8 +99,6 @@ static inline bool is_cxl_endpoint(struct cxl_port *port)
 
 struct cxl_memdev *__devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
 					 const struct cxl_memdev_attach *attach);
-struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
-				       const struct cxl_memdev_attach *attach);
 int devm_cxl_sanitize_setup_notifier(struct device *host,
 				     struct cxl_memdev *cxlmd);
 struct cxl_memdev_state;
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index fcffe24dcb42..ff858318091f 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -65,6 +65,26 @@ static int cxl_debugfs_poison_clear(void *data, u64 dpa)
 DEFINE_DEBUGFS_ATTRIBUTE(cxl_poison_clear_fops, NULL,
 			 cxl_debugfs_poison_clear, "%llx\n");
 
+static void cxl_memdev_poison_enable(struct cxl_memdev_state *mds,
+				     struct cxl_memdev *cxlmd,
+				     struct dentry *dentry)
+{
+	/*
+	 * Avoid poison debugfs for DEVMEM aka accelerators as they rely on
+	 * cxl_memdev_state.
+	 */
+	if (!mds)
+		return;
+
+	if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
+		debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
+				    &cxl_poison_inject_fops);
+
+	if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
+		debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
+				    &cxl_poison_clear_fops);
+}
+
 static int cxl_mem_probe(struct device *dev)
 {
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
@@ -92,12 +112,7 @@ static int cxl_mem_probe(struct device *dev)
 	dentry = cxl_debugfs_create_dir(dev_name(dev));
 	debugfs_create_devm_seqfile(dev, "dpamem", dentry, cxl_mem_dpa_show);
 
-	if (test_bit(CXL_POISON_ENABLED_INJECT, mds->poison.enabled_cmds))
-		debugfs_create_file("inject_poison", 0200, dentry, cxlmd,
-				    &cxl_poison_inject_fops);
-	if (test_bit(CXL_POISON_ENABLED_CLEAR, mds->poison.enabled_cmds))
-		debugfs_create_file("clear_poison", 0200, dentry, cxlmd,
-				    &cxl_poison_clear_fops);
+	cxl_memdev_poison_enable(mds, cxlmd, dentry);
 
 	rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
 	if (rc)
@@ -206,16 +221,24 @@ static ssize_t trigger_poison_list_store(struct device *dev,
 }
 static DEVICE_ATTR_WO(trigger_poison_list);
 
-static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
+static bool cxl_poison_attr_visible(struct kobject *kobj, struct attribute *a)
 {
 	struct device *dev = kobj_to_dev(kobj);
 	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
 	struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
 
-	if (a == &dev_attr_trigger_poison_list.attr)
-		if (!test_bit(CXL_POISON_ENABLED_LIST,
-			      mds->poison.enabled_cmds))
-			return 0;
+	if (!mds ||
+	    !test_bit(CXL_POISON_ENABLED_LIST, mds->poison.enabled_cmds))
+		return false;
+
+	return true;
+}
+
+static umode_t cxl_mem_visible(struct kobject *kobj, struct attribute *a, int n)
+{
+	if (a == &dev_attr_trigger_poison_list.attr &&
+	    !cxl_poison_attr_visible(kobj, a))
+		return 0;
 
 	return a->mode;
 }
diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
index 1346771edc4e..10a9b8fa2f6b 100644
--- a/include/cxl/cxl.h
+++ b/include/cxl/cxl.h
@@ -149,6 +149,10 @@ struct cxl_dpa_partition {
 
 #define CXL_NR_PARTITIONS_MAX 2
 
+struct cxl_memdev_attach {
+	int (*probe)(struct cxl_memdev *cxlmd);
+};
+
 /**
  * struct cxl_dev_state - The driver device state
  *
@@ -225,4 +229,6 @@ struct cxl_dev_state *_devm_cxl_dev_state_create(struct device *dev,
 	})
 
 int cxl_set_capacity(struct cxl_dev_state *cxlds, u64 capacity);
+struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds,
+				       const struct cxl_memdev_attach *attach);
 #endif /* __CXL_CXL_H__ */
-- 
2.34.1