--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Virtual concat MTD device driver
+ *
+ * Copyright (C) 2018 Bernhard Frauendienst
+ * Author: Bernhard Frauendienst <kernel@nospam.obeliks.de>
+ */
+
+#include <linux/device.h>
+#include <linux/mtd/mtd.h>
+#include "mtdcore.h"
+#include <linux/mtd/partitions.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/mtd/concat.h>
+
+#define CONCAT_PROP "part-concat-next"
+#define CONCAT_POSTFIX "concat"
+#define MIN_DEV_PER_CONCAT 1
+
+static LIST_HEAD(concat_node_list);
+
+/**
+ * struct mtd_virt_concat_node - components of a concatenation
+ * @head: List handle
+ * @count: Number of nodes
+ * @nodes: Pointer to the nodes (partitions) to concatenate
+ * @concat: Concatenation container
+ */
+struct mtd_virt_concat_node {
+ struct list_head head;
+ unsigned int count;
+ struct device_node **nodes;
+ struct mtd_concat *concat;
+};
+
+/**
+ * mtd_is_part_concat - Check if the device is already part
+ * of a concatenated device
+ * @dev: pointer to 'device_node'
+ *
+ * Return: true if the device is already part of a concatenation,
+ * false otherwise.
+ */
+static bool mtd_is_part_concat(struct device_node *dev)
+{
+ struct mtd_virt_concat_node *item;
+ int idx;
+
+ list_for_each_entry(item, &concat_node_list, head) {
+ for (idx = 0; idx < item->count; idx++) {
+ if (item->nodes[idx] == dev)
+ return true;
+ }
+ }
+ return false;
+}
+
+static void mtd_virt_concat_put_mtd_devices(struct mtd_concat *concat)
+{
+ int i;
+
+ for (i = 0; i < concat->num_subdev; i++)
+ put_mtd_device(concat->subdev[i]);
+}
+
+void mtd_virt_concat_destroy_joins(void)
+{
+ struct mtd_virt_concat_node *item, *tmp;
+ struct mtd_info *mtd;
+
+ list_for_each_entry_safe(item, tmp, &concat_node_list, head) {
+ mtd = &item->concat->mtd;
+ if (item->concat) {
+ mtd_device_unregister(mtd);
+ kfree(mtd->name);
+ mtd_concat_destroy(mtd);
+ mtd_virt_concat_put_mtd_devices(item->concat);
+ }
+ }
+}
+
+/**
+ * mtd_virt_concat_destroy - Destroy the concat that includes the mtd object
+ * @mtd: pointer to 'mtd_info'
+ *
+ * Return: 0 on success, -error otherwise.
+ */
+int mtd_virt_concat_destroy(struct mtd_info *mtd)
+{
+ struct mtd_info *child, *master = mtd_get_master(mtd);
+ struct mtd_virt_concat_node *item, *tmp;
+ struct mtd_concat *concat;
+ int idx, ret = 0;
+ bool is_mtd_found;
+
+ list_for_each_entry_safe(item, tmp, &concat_node_list, head) {
+ is_mtd_found = false;
+
+ /* Find the concat item that hold the mtd device */
+ for (idx = 0; idx < item->count; idx++) {
+ if (item->nodes[idx] == mtd->dev.of_node) {
+ is_mtd_found = true;
+ break;
+ }
+ }
+ if (!is_mtd_found)
+ continue;
+ concat = item->concat;
+
+ /*
+ * Since this concatenated device is being removed, retrieve
+ * all MTD devices that are part of it and register them
+ * individually.
+ */
+ for (idx = 0; idx < concat->num_subdev; idx++) {
+ child = concat->subdev[idx];
+ if (child->dev.of_node != mtd->dev.of_node) {
+ ret = add_mtd_device(child);
+ if (ret)
+ goto out;
+ }
+ }
+ /* Destroy the concat */
+ if (concat->mtd.name) {
+ del_mtd_device(&concat->mtd);
+ kfree(concat->mtd.name);
+ mtd_concat_destroy(&concat->mtd);
+ mtd_virt_concat_put_mtd_devices(item->concat);
+ }
+
+ for (idx = 0; idx < item->count; idx++)
+ of_node_put(item->nodes[idx]);
+
+ kfree(item->nodes);
+ kfree(item);
+ }
+ return 0;
+out:
+ mutex_lock(&master->master.partitions_lock);
+ list_del(&child->part.node);
+ mutex_unlock(&master->master.partitions_lock);
+ kfree(mtd->name);
+ kfree(mtd);
+
+ return ret;
+}
+
+/**
+ * mtd_virt_concat_create_item - Create a concat item
+ * @parts: pointer to 'device_node'
+ * @count: number of mtd devices that make up
+ * the concatenated device.
+ *
+ * Return: 0 on success, -error otherwise.
+ */
+static int mtd_virt_concat_create_item(struct device_node *parts,
+ unsigned int count)
+{
+ struct mtd_virt_concat_node *item;
+ struct mtd_concat *concat;
+ int i;
+
+ for (i = 0; i < (count - 1); i++) {
+ if (mtd_is_part_concat(of_parse_phandle(parts, CONCAT_PROP, i)))
+ return 0;
+ }
+
+ item = kzalloc(sizeof(*item), GFP_KERNEL);
+ if (!item)
+ return -ENOMEM;
+
+ item->count = count;
+ item->nodes = kcalloc(count, sizeof(*item->nodes), GFP_KERNEL);
+ if (!item->nodes) {
+ kfree(item);
+ return -ENOMEM;
+ }
+
+ /*
+ * The partition in which "part-concat-next" property
+ * is defined is the first device in the list of concat
+ * devices.
+ */
+ item->nodes[0] = parts;
+
+ for (i = 1; i < count; i++)
+ item->nodes[i] = of_parse_phandle(parts, CONCAT_PROP, (i - 1));
+
+ concat = kzalloc(sizeof(*concat), GFP_KERNEL);
+ if (!concat) {
+ kfree(item);
+ return -ENOMEM;
+ }
+
+ concat->subdev = kcalloc(count, sizeof(*concat->subdev), GFP_KERNEL);
+ if (!concat->subdev) {
+ kfree(item);
+ kfree(concat);
+ return -ENOMEM;
+ }
+ item->concat = concat;
+
+ list_add_tail(&item->head, &concat_node_list);
+
+ return 0;
+}
+
+void mtd_virt_concat_destroy_items(void)
+{
+ struct mtd_virt_concat_node *item, *temp;
+ int i;
+
+ list_for_each_entry_safe(item, temp, &concat_node_list, head) {
+ for (i = 0; i < item->count; i++)
+ of_node_put(item->nodes[i]);
+
+ kfree(item->nodes);
+ kfree(item);
+ }
+}
+
+/**
+ * mtd_virt_concat_create_add - Add a mtd device to the concat list
+ * @mtd: pointer to 'mtd_info'
+ *
+ * Return: true on success, false otherwise.
+ */
+bool mtd_virt_concat_add(struct mtd_info *mtd)
+{
+ struct mtd_virt_concat_node *item;
+ struct mtd_concat *concat;
+ int idx;
+
+ list_for_each_entry(item, &concat_node_list, head) {
+ concat = item->concat;
+ for (idx = 0; idx < item->count; idx++) {
+ if (item->nodes[idx] == mtd->dev.of_node) {
+ concat->subdev[concat->num_subdev++] = mtd;
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+/**
+ * mtd_virt_concat_node_create - List all the concatenations found in DT
+ *
+ * Return: 0 on success, -error otherwise.
+ */
+int mtd_virt_concat_node_create(void)
+{
+ struct device_node *parts = NULL;
+ int ret = 0, count = 0;
+
+ /* List all the concatenations found in DT */
+ do {
+ parts = of_find_node_with_property(parts, CONCAT_PROP);
+ if (!of_device_is_available(parts))
+ continue;
+
+ if (mtd_is_part_concat(parts))
+ continue;
+
+ count = of_count_phandle_with_args(parts, CONCAT_PROP, NULL);
+ if (count < MIN_DEV_PER_CONCAT)
+ continue;
+
+ /*
+ * The partition in which "part-concat-next" property is defined
+ * is also part of the concat device, so increament count by 1.
+ */
+ count++;
+
+ ret = mtd_virt_concat_create_item(parts, count);
+ if (ret) {
+ of_node_put(parts);
+ goto destroy_items;
+ }
+ } while (parts);
+
+ return ret;
+
+destroy_items:
+ mtd_virt_concat_destroy_items();
+
+ return ret;
+}
+
+/**
+ * mtd_virt_concat_create_join - Create and register the concatenated
+ * MTD device.
+ *
+ * Return: 0 on success, -error otherwise.
+ */
+int mtd_virt_concat_create_join(void)
+{
+ struct mtd_virt_concat_node *item;
+ struct mtd_concat *concat;
+ struct mtd_info *mtd;
+ ssize_t name_sz;
+ int ret, idx;
+ char *name;
+
+ list_for_each_entry(item, &concat_node_list, head) {
+ concat = item->concat;
+ /*
+ * Check if item->count != concat->num_subdev, it indicates
+ * that the MTD information for all devices included in the
+ * concatenation are not handy, concat MTD device can't be
+ * created hence switch to next concat device.
+ */
+ if (item->count != concat->num_subdev) {
+ continue;
+ } else {
+ /* Calculate the legth of the name of the virtual device */
+ for (idx = 0, name_sz = 0; idx < concat->num_subdev; idx++)
+ name_sz += (strlen(concat->subdev[idx]->name) + 1);
+ name_sz += strlen(CONCAT_POSTFIX);
+ name = kmalloc(name_sz + 1, GFP_KERNEL);
+ if (!name) {
+ mtd_virt_concat_put_mtd_devices(concat);
+ return -ENOMEM;
+ }
+
+ ret = 0;
+ for (idx = 0; idx < concat->num_subdev; idx++) {
+ ret += sprintf((name + ret), "%s-",
+ concat->subdev[idx]->name);
+ }
+ sprintf((name + ret), CONCAT_POSTFIX);
+
+ if (concat->mtd.name) {
+ ret = memcmp(concat->mtd.name, name, name_sz);
+ if (ret == 0)
+ continue;
+ }
+ mtd = mtd_concat_create(concat->subdev, concat->num_subdev, name);
+ if (!mtd) {
+ kfree(name);
+ return -ENXIO;
+ }
+ concat->mtd = *mtd;
+ /* Arbitrary set the first device as parent */
+ concat->mtd.dev.parent = concat->subdev[0]->dev.parent;
+ concat->mtd.dev = concat->subdev[0]->dev;
+
+ /* Add the mtd device */
+ ret = add_mtd_device(&concat->mtd);
+ if (ret)
+ goto destroy_concat;
+ }
+ }
+
+ return 0;
+
+destroy_concat:
+ mtd_concat_destroy(mtd);
+
+ return ret;
+}
projects / thirdparty / kernel / linux.git / commitdiff
