[PATCH v5 3/3] fpga: region: Use standard dev_release for class driver

[Russ Weight <russell.h.weight@intel.com>]

The FPGA region class driver data structure is being treated as a
managed resource instead of using standard dev_release call-back
to release the class data structure. This change removes the
managed resource code and combines the create() and register()
functions into a single register() function.

Signed-off-by: Russ Weight <russell.h.weight@intel.com>
---
v5:
  - Rebased on top of recently accepted patches.
  - Created the fpga_region_ops data structure which is optionally passed
    to fpga_region_register(). compat_id, the get_bridges() pointer, and
    the priv pointer are included in the fpga_region_ops structure.
v4:
  - Added the compat_id parameter to fpga_region_register() to ensure
    that the compat_id is set before the device_register() call.
  - Modified the dfl_fpga_feature_devs_enumerate() function to restore
    the fpga_region_register() call to the correct location.
v3:
  - Cleaned up comment header for fpga_region_register()
  - Fix fpga_region_register() error return on ida_simple_get() failure
v2:
  - No changes
---
 drivers/fpga/dfl-fme-pr.c        |   2 +-
 drivers/fpga/dfl-fme-region.c    |  32 ++++++---
 drivers/fpga/dfl.c               |  12 ++--
 drivers/fpga/fpga-bridge.c       |   2 +-
 drivers/fpga/fpga-region.c       | 119 ++++++++-----------------------
 drivers/fpga/of-fpga-region.c    |  14 ++--
 include/linux/fpga/fpga-region.h |  38 ++++++----
 7 files changed, 86 insertions(+), 133 deletions(-)

diff --git a/drivers/fpga/dfl-fme-pr.c b/drivers/fpga/dfl-fme-pr.c
index d61ce9a18879..4805d8c533d4 100644
--- a/drivers/fpga/dfl-fme-pr.c
+++ b/drivers/fpga/dfl-fme-pr.c
@@ -151,7 +151,7 @@ static int fme_pr(struct platform_device *pdev, unsigned long arg)
 	 * reenabling the bridge to clear things out between acceleration runs.
 	 * so no need to hold the bridges after partial reconfiguration.
 	 */
-	if (region->get_bridges)
+	if (region->rops && region->rops->get_bridges)
 		fpga_bridges_put(&region->bridge_list);
 
 	put_device(&region->dev);
diff --git a/drivers/fpga/dfl-fme-region.c b/drivers/fpga/dfl-fme-region.c
index a64c13e198a0..16d8b3f6f07a 100644
--- a/drivers/fpga/dfl-fme-region.c
+++ b/drivers/fpga/dfl-fme-region.c
@@ -21,12 +21,29 @@
 
 static int fme_region_get_bridges(struct fpga_region *region)
 {
-	struct dfl_fme_region_pdata *pdata = region->priv;
+	struct dfl_fme_region_pdata *pdata = region->rops->priv;
 	struct device *dev = &pdata->br->dev;
 
 	return fpga_bridge_get_to_list(dev, region->info, &region->bridge_list);
 }
 
+static struct fpga_region_ops *
+fme_region_get_ops(struct device *dev, struct fpga_manager *mgr,
+		   struct dfl_fme_region_pdata *pdata)
+{
+	struct fpga_region_ops *ops;
+
+	ops = devm_kzalloc(dev, sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return NULL;
+
+	ops->get_bridges = fme_region_get_bridges;
+	ops->compat_id = mgr->mops->compat_id;
+	ops->priv = pdata;
+
+	return ops;
+}
+
 static int fme_region_probe(struct platform_device *pdev)
 {
 	struct dfl_fme_region_pdata *pdata = dev_get_platdata(&pdev->dev);
@@ -39,20 +56,15 @@ static int fme_region_probe(struct platform_device *pdev)
 	if (IS_ERR(mgr))
 		return -EPROBE_DEFER;
 
-	region = devm_fpga_region_create(dev, mgr, fme_region_get_bridges);
-	if (!region) {
-		ret = -ENOMEM;
+	region = fpga_region_register(dev, mgr,
+				      fme_region_get_ops(dev, mgr, pdata));
+	if (IS_ERR(region)) {
+		ret = PTR_ERR(region);
 		goto eprobe_mgr_put;
 	}
 
-	region->priv = pdata;
-	region->compat_id = mgr->mops->compat_id;
 	platform_set_drvdata(pdev, region);
 
-	ret = fpga_region_register(region);
-	if (ret)
-		goto eprobe_mgr_put;
-
 	dev_dbg(dev, "DFL FME FPGA Region probed\n");
 
 	return 0;
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 511b20ff35a3..3905995ef6d5 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -1400,19 +1400,15 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
 	if (!cdev)
 		return ERR_PTR(-ENOMEM);
 
-	cdev->region = devm_fpga_region_create(info->dev, NULL, NULL);
-	if (!cdev->region) {
-		ret = -ENOMEM;
-		goto free_cdev_exit;
-	}
-
 	cdev->parent = info->dev;
 	mutex_init(&cdev->lock);
 	INIT_LIST_HEAD(&cdev->port_dev_list);
 
-	ret = fpga_region_register(cdev->region);
-	if (ret)
+	cdev->region = fpga_region_register(info->dev, NULL, NULL);
+	if (IS_ERR(cdev->region)) {
+		ret = PTR_ERR(cdev->region);
 		goto free_cdev_exit;
+	}
 
 	/* create and init build info for enumeration */
 	binfo = devm_kzalloc(info->dev, sizeof(*binfo), GFP_KERNEL);
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index 15be378b64ab..f7e8500561f4 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -312,7 +312,7 @@ static struct attribute *fpga_bridge_attrs[] = {
 ATTRIBUTE_GROUPS(fpga_bridge);
 
 /**
- * fpga_bridge_register - create and register a FPGA Bridge device
+ * fpga_bridge_register - create and register an FPGA Bridge device
  * @parent:	FPGA bridge device from pdev
  * @name:	FPGA bridge name
  * @br_ops:	pointer to structure of fpga bridge ops
diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index a4838715221f..7199ad93814f 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -115,8 +115,8 @@ int fpga_region_program_fpga(struct fpga_region *region)
 	 * In some cases, we already have a list of bridges in the
 	 * fpga region struct.  Or we don't have any bridges.
 	 */
-	if (region->get_bridges) {
-		ret = region->get_bridges(region);
+	if (region->rops && region->rops->get_bridges) {
+		ret = region->rops->get_bridges(region);
 		if (ret) {
 			dev_err(dev, "failed to get fpga region bridges\n");
 			goto err_unlock_mgr;
@@ -147,7 +147,7 @@ int fpga_region_program_fpga(struct fpga_region *region)
 	return 0;
 
 err_put_br:
-	if (region->get_bridges)
+	if (region->rops && region->rops->get_bridges)
 		fpga_bridges_put(&region->bridge_list);
 err_unlock_mgr:
 	fpga_mgr_unlock(region->mgr);
@@ -163,12 +163,12 @@ static ssize_t compat_id_show(struct device *dev,
 {
 	struct fpga_region *region = to_fpga_region(dev);
 
-	if (!region->compat_id)
+	if (!region->rops || !region->rops->compat_id)
 		return -ENOENT;
 
 	return sprintf(buf, "%016llx%016llx\n",
-		       (unsigned long long)region->compat_id->id_h,
-		       (unsigned long long)region->compat_id->id_l);
+		       (unsigned long long)region->rops->compat_id->id_h,
+		       (unsigned long long)region->rops->compat_id->id_l);
 }
 
 static DEVICE_ATTR_RO(compat_id);
@@ -180,39 +180,35 @@ static struct attribute *fpga_region_attrs[] = {
 ATTRIBUTE_GROUPS(fpga_region);
 
 /**
- * fpga_region_create - alloc and init a struct fpga_region
+ * fpga_region_register - create and register an FPGA Region device
  * @parent: device parent
  * @mgr: manager that programs this region
- * @get_bridges: optional function to get bridges to a list
+ * @rops: optional: FPGA Region ops for low level FPGA Region drivers
  *
- * The caller of this function is responsible for freeing the resulting region
- * struct with fpga_region_free().  Using devm_fpga_region_create() instead is
- * recommended.
- *
- * Return: struct fpga_region or NULL
+ * Return: struct fpga_region or ERR_PTR()
  */
-struct fpga_region
-*fpga_region_create(struct device *parent,
-		    struct fpga_manager *mgr,
-		    int (*get_bridges)(struct fpga_region *))
+struct fpga_region *
+fpga_region_register(struct device *parent, struct fpga_manager *mgr,
+		     struct fpga_region_ops *rops)
 {
 	struct fpga_region *region;
 	int id, ret = 0;
 
 	region = kzalloc(sizeof(*region), GFP_KERNEL);
 	if (!region)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
-	if (id < 0)
+	if (id < 0) {
+		ret = id;
 		goto err_free;
+	}
 
 	region->mgr = mgr;
-	region->get_bridges = get_bridges;
+	region->rops = rops;
 	mutex_init(&region->mutex);
 	INIT_LIST_HEAD(&region->bridge_list);
 
-	device_initialize(&region->dev);
 	region->dev.class = fpga_region_class;
 	region->dev.parent = parent;
 	region->dev.of_node = parent->of_node;
@@ -222,6 +218,12 @@ struct fpga_region
 	if (ret)
 		goto err_remove;
 
+	ret = device_register(&region->dev);
+	if (ret) {
+		put_device(&region->dev);
+		return ERR_PTR(ret);
+	}
+
 	return region;
 
 err_remove:
@@ -229,76 +231,7 @@ struct fpga_region
 err_free:
 	kfree(region);
 
-	return NULL;
-}
-EXPORT_SYMBOL_GPL(fpga_region_create);
-
-/**
- * fpga_region_free - free an FPGA region created by fpga_region_create()
- * @region: FPGA region
- */
-void fpga_region_free(struct fpga_region *region)
-{
-	ida_simple_remove(&fpga_region_ida, region->dev.id);
-	kfree(region);
-}
-EXPORT_SYMBOL_GPL(fpga_region_free);
-
-static void devm_fpga_region_release(struct device *dev, void *res)
-{
-	struct fpga_region *region = *(struct fpga_region **)res;
-
-	fpga_region_free(region);
-}
-
-/**
- * devm_fpga_region_create - create and initialize a managed FPGA region struct
- * @parent: device parent
- * @mgr: manager that programs this region
- * @get_bridges: optional function to get bridges to a list
- *
- * This function is intended for use in an FPGA region driver's probe function.
- * After the region driver creates the region struct with
- * devm_fpga_region_create(), it should register it with fpga_region_register().
- * The region driver's remove function should call fpga_region_unregister().
- * The region struct allocated with this function will be freed automatically on
- * driver detach.  This includes the case of a probe function returning error
- * before calling fpga_region_register(), the struct will still get cleaned up.
- *
- * Return: struct fpga_region or NULL
- */
-struct fpga_region
-*devm_fpga_region_create(struct device *parent,
-			 struct fpga_manager *mgr,
-			 int (*get_bridges)(struct fpga_region *))
-{
-	struct fpga_region **ptr, *region;
-
-	ptr = devres_alloc(devm_fpga_region_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return NULL;
-
-	region = fpga_region_create(parent, mgr, get_bridges);
-	if (!region) {
-		devres_free(ptr);
-	} else {
-		*ptr = region;
-		devres_add(parent, ptr);
-	}
-
-	return region;
-}
-EXPORT_SYMBOL_GPL(devm_fpga_region_create);
-
-/**
- * fpga_region_register - register an FPGA region
- * @region: FPGA region
- *
- * Return: 0 or -errno
- */
-int fpga_region_register(struct fpga_region *region)
-{
-	return device_add(&region->dev);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(fpga_region_register);
 
@@ -316,6 +249,10 @@ EXPORT_SYMBOL_GPL(fpga_region_unregister);
 
 static void fpga_region_dev_release(struct device *dev)
 {
+	struct fpga_region *region = to_fpga_region(dev);
+
+	ida_simple_remove(&fpga_region_ida, region->dev.id);
+	kfree(region);
 }
 
 /**
diff --git a/drivers/fpga/of-fpga-region.c b/drivers/fpga/of-fpga-region.c
index e3c25576b6b9..55b7c4ec8f6d 100644
--- a/drivers/fpga/of-fpga-region.c
+++ b/drivers/fpga/of-fpga-region.c
@@ -392,6 +392,10 @@ static struct notifier_block fpga_region_of_nb = {
 	.notifier_call = of_fpga_region_notify,
 };
 
+static struct fpga_region_ops of_fpga_region_ops = {
+	.get_bridges = of_fpga_region_get_bridges;
+};
+
 static int of_fpga_region_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -405,16 +409,12 @@ static int of_fpga_region_probe(struct platform_device *pdev)
 	if (IS_ERR(mgr))
 		return -EPROBE_DEFER;
 
-	region = devm_fpga_region_create(dev, mgr, of_fpga_region_get_bridges);
-	if (!region) {
-		ret = -ENOMEM;
+	region = fpga_region_register(dev, mgr, &of_fpga_region_ops);
+	if (IS_ERR(region)) {
+		ret = PTR_ERR(region);
 		goto eprobe_mgr_put;
 	}
 
-	ret = fpga_region_register(region);
-	if (ret)
-		goto eprobe_mgr_put;
-
 	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
 	platform_set_drvdata(pdev, region);
 
diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
index 27cb706275db..02626dfd41ed 100644
--- a/include/linux/fpga/fpga-region.h
+++ b/include/linux/fpga/fpga-region.h
@@ -7,6 +7,24 @@
 #include <linux/fpga/fpga-mgr.h>
 #include <linux/fpga/fpga-bridge.h>
 
+struct fpga_region;
+
+/**
+ * struct fpga_region_ops - ops for low level fpga region drivers
+ * @get_bridges: optional function to get bridges to a list
+ * @compat_id: optional: FPGA manager id for compatibility check.
+ * @priv: optional: private data
+ *
+ * fpga_region_ops are the low level functions implemented by a specific
+ * fpga region driver.  The optional ones are tested for NULL before being
+ * referenced, so leaving them out is fine.
+ */
+struct fpga_region_ops {
+	int (*get_bridges)(struct fpga_region *region);
+	struct fpga_compat_id *compat_id;
+	void *priv;
+};
+
 /**
  * struct fpga_region - FPGA Region structure
  * @dev: FPGA Region device
@@ -14,9 +32,7 @@
  * @bridge_list: list of FPGA bridges specified in region
  * @mgr: FPGA manager
  * @info: FPGA image info
- * @compat_id: FPGA region id for compatibility check.
- * @priv: private data
- * @get_bridges: optional function to get bridges to a list
+ * @rops: optional: FPGA Region ops for low level FPGA region drivers
  */
 struct fpga_region {
 	struct device dev;
@@ -24,9 +40,7 @@ struct fpga_region {
 	struct list_head bridge_list;
 	struct fpga_manager *mgr;
 	struct fpga_image_info *info;
-	struct fpga_compat_id *compat_id;
-	void *priv;
-	int (*get_bridges)(struct fpga_region *region);
+	struct fpga_region_ops *rops;
 };
 
 #define to_fpga_region(d) container_of(d, struct fpga_region, dev)
@@ -37,15 +51,9 @@ struct fpga_region *fpga_region_class_find(
 
 int fpga_region_program_fpga(struct fpga_region *region);
 
-struct fpga_region
-*fpga_region_create(struct device *dev, struct fpga_manager *mgr,
-		    int (*get_bridges)(struct fpga_region *));
-void fpga_region_free(struct fpga_region *region);
-int fpga_region_register(struct fpga_region *region);
+struct fpga_region *
+fpga_region_register(struct device *dev, struct fpga_manager *mgr,
+		     struct fpga_region_ops *rops);
 void fpga_region_unregister(struct fpga_region *region);
 
-struct fpga_region
-*devm_fpga_region_create(struct device *dev, struct fpga_manager *mgr,
-			int (*get_bridges)(struct fpga_region *));
-
 #endif /* _FPGA_REGION_H */
-- 
2.25.1