1 files changed, 119 insertions, 0 deletions

diff --git a/drivers/mtd/nand/ecc.c b/drivers/mtd/nand/ecc.c
index 6c43dfda01d4..5250764cedee 100644
--- a/drivers/mtd/nand/ecc.c
+++ b/drivers/mtd/nand/ecc.c
@@ -96,6 +96,12 @@
 #include <linux/module.h>
 #include <linux/mtd/nand.h>
 #include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+
+static LIST_HEAD(on_host_hw_engines);
+static DEFINE_MUTEX(on_host_hw_engines_mutex);
 
 /**
  * nand_ecc_init_ctx - Init the ECC engine context
@@ -611,6 +617,119 @@ struct nand_ecc_engine *nand_ecc_get_on_die_hw_engine(struct nand_device *nand)
 }
 EXPORT_SYMBOL(nand_ecc_get_on_die_hw_engine);
 
+int nand_ecc_register_on_host_hw_engine(struct nand_ecc_engine *engine)
+{
+	struct nand_ecc_engine *item;
+
+	if (!engine)
+		return -EINVAL;
+
+	/* Prevent multiple registrations of one engine */
+	list_for_each_entry(item, &on_host_hw_engines, node)
+		if (item == engine)
+			return 0;
+
+	mutex_lock(&on_host_hw_engines_mutex);
+	list_add_tail(&engine->node, &on_host_hw_engines);
+	mutex_unlock(&on_host_hw_engines_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL(nand_ecc_register_on_host_hw_engine);
+
+int nand_ecc_unregister_on_host_hw_engine(struct nand_ecc_engine *engine)
+{
+	if (!engine)
+		return -EINVAL;
+
+	mutex_lock(&on_host_hw_engines_mutex);
+	list_del(&engine->node);
+	mutex_unlock(&on_host_hw_engines_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL(nand_ecc_unregister_on_host_hw_engine);
+
+static struct nand_ecc_engine *nand_ecc_match_on_host_hw_engine(struct device *dev)
+{
+	struct nand_ecc_engine *item;
+
+	list_for_each_entry(item, &on_host_hw_engines, node)
+		if (item->dev == dev)
+			return item;
+
+	return NULL;
+}
+
+struct nand_ecc_engine *nand_ecc_get_on_host_hw_engine(struct nand_device *nand)
+{
+	struct nand_ecc_engine *engine = NULL;
+	struct device *dev = &nand->mtd.dev;
+	struct platform_device *pdev;
+	struct device_node *np;
+
+	if (list_empty(&on_host_hw_engines))
+		return NULL;
+
+	/* Check for an explicit nand-ecc-engine property */
+	np = of_parse_phandle(dev->of_node, "nand-ecc-engine", 0);
+	if (np) {
+		pdev = of_find_device_by_node(np);
+		if (!pdev)
+			return ERR_PTR(-EPROBE_DEFER);
+
+		engine = nand_ecc_match_on_host_hw_engine(&pdev->dev);
+		platform_device_put(pdev);
+		of_node_put(np);
+
+		if (!engine)
+			return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	if (engine)
+		get_device(engine->dev);
+
+	return engine;
+}
+EXPORT_SYMBOL(nand_ecc_get_on_host_hw_engine);
+
+void nand_ecc_put_on_host_hw_engine(struct nand_device *nand)
+{
+	put_device(nand->ecc.engine->dev);
+}
+EXPORT_SYMBOL(nand_ecc_put_on_host_hw_engine);
+
+/*
+ * In the case of a pipelined engine, the device registering the ECC
+ * engine is not necessarily the ECC engine itself but may be a host controller.
+ * It is then useful to provide a helper to retrieve the right device object
+ * which actually represents the ECC engine.
+ */
+struct device *nand_ecc_get_engine_dev(struct device *host)
+{
+	struct platform_device *ecc_pdev;
+	struct device_node *np;
+
+	/*
+	 * If the device node contains this property, it means we need to follow
+	 * it in order to get the right ECC engine device we are looking for.
+	 */
+	np = of_parse_phandle(host->of_node, "nand-ecc-engine", 0);
+	if (!np)
+		return host;
+
+	ecc_pdev = of_find_device_by_node(np);
+	if (!ecc_pdev) {
+		of_node_put(np);
+		return NULL;
+	}
+
+	platform_device_put(ecc_pdev);
+	of_node_put(np);
+
+	return &ecc_pdev->dev;
+}
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Miquel Raynal <miquel.raynal@bootlin.com>");
 MODULE_DESCRIPTION("Generic ECC engine");