Create master device without partition when
CONFIG_MTD_PARTITIONED_MASTER flag is unset.

This streamlines device tree and allows to anchor
runtime power management on master device in all cases.

Signed-off-by: Alexander Usyskin <alexander.usys...@intel.com>
---
 drivers/mtd/mtdcore.c | 123 ++++++++++++++++++++++++++++++++----------
 drivers/mtd/mtdpart.c |   6 +--
 2 files changed, 95 insertions(+), 34 deletions(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 724f917f91ba..bbc502ef75de 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -68,7 +68,13 @@ static struct class mtd_class = {
        .pm = MTD_CLS_PM_OPS,
 };
 
+static struct class mtd_master_class = {
+       .name = "mtd_master",
+       .pm = MTD_CLS_PM_OPS,
+};
+
 static DEFINE_IDR(mtd_idr);
+static DEFINE_IDR(mtd_master_idr);
 
 /* These are exported solely for the purpose of mtd_blkdevs.c. You
    should not use them for _anything_ else */
@@ -83,8 +89,9 @@ EXPORT_SYMBOL_GPL(__mtd_next_device);
 
 static LIST_HEAD(mtd_notifiers);
 
-
+#define MTD_MASTER_DEVS 255
 #define MTD_DEVT(index) MKDEV(MTD_CHAR_MAJOR, (index)*2)
+static dev_t mtd_master_devt;
 
 /* REVISIT once MTD uses the driver model better, whoever allocates
  * the mtd_info will probably want to use the release() hook...
@@ -104,6 +111,17 @@ static void mtd_release(struct device *dev)
        device_destroy(&mtd_class, index + 1);
 }
 
+static void mtd_master_release(struct device *dev)
+{
+       struct mtd_info *mtd = dev_get_drvdata(dev);
+
+       idr_remove(&mtd_master_idr, mtd->index);
+       of_node_put(mtd_get_of_node(mtd));
+
+       if (mtd_is_partition(mtd))
+               release_mtd_partition(mtd);
+}
+
 static void mtd_device_release(struct kref *kref)
 {
        struct mtd_info *mtd = container_of(kref, struct mtd_info, refcnt);
@@ -367,6 +385,11 @@ static const struct device_type mtd_devtype = {
        .release        = mtd_release,
 };
 
+static const struct device_type mtd_master_devtype = {
+       .name           = "mtd_master",
+       .release        = mtd_master_release,
+};
+
 static bool mtd_expert_analysis_mode;
 
 #ifdef CONFIG_DEBUG_FS
@@ -639,12 +662,12 @@ static void mtd_check_of_node(struct mtd_info *mtd)
  *     notify each currently active MTD 'user' of its arrival. Returns
  *     zero on success or non-zero on failure.
  */
-
 int add_mtd_device(struct mtd_info *mtd)
 {
        struct device_node *np = mtd_get_of_node(mtd);
        struct mtd_info *master = mtd_get_master(mtd);
        struct mtd_notifier *not;
+       bool partitioned = true;
        int i, error, ofidx;
 
        /*
@@ -655,6 +678,11 @@ int add_mtd_device(struct mtd_info *mtd)
        if (WARN_ONCE(mtd->dev.type, "MTD already registered\n"))
                return -EEXIST;
 
+       if ((master == mtd) && !IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) {
+               partitioned = false;
+               pr_debug("mtd: unpartitioned master %s\n", mtd->name);
+       }
+
        BUG_ON(mtd->writesize == 0);
 
        /*
@@ -687,10 +715,17 @@ int add_mtd_device(struct mtd_info *mtd)
        ofidx = -1;
        if (np)
                ofidx = of_alias_get_id(np, "mtd");
-       if (ofidx >= 0)
-               i = idr_alloc(&mtd_idr, mtd, ofidx, ofidx + 1, GFP_KERNEL);
-       else
-               i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
+       if (partitioned) {
+               if (ofidx >= 0)
+                       i = idr_alloc(&mtd_idr, mtd, ofidx, ofidx + 1, 
GFP_KERNEL);
+               else
+                       i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
+       } else {
+               if (ofidx >= 0)
+                       i = idr_alloc(&mtd_master_idr, mtd, ofidx, ofidx + 1, 
GFP_KERNEL);
+               else
+                       i = idr_alloc(&mtd_master_idr, mtd, 0, 0, GFP_KERNEL);
+       }
        if (i < 0) {
                error = i;
                goto fail_locked;
@@ -738,15 +773,23 @@ int add_mtd_device(struct mtd_info *mtd)
        /* Caller should have set dev.parent to match the
         * physical device, if appropriate.
         */
-       mtd->dev.type = &mtd_devtype;
-       mtd->dev.class = &mtd_class;
-       mtd->dev.devt = MTD_DEVT(i);
-       dev_set_name(&mtd->dev, "mtd%d", i);
+       if (partitioned) {
+               mtd->dev.type = &mtd_devtype;
+               mtd->dev.class = &mtd_class;
+               mtd->dev.devt = MTD_DEVT(i);
+               dev_set_name(&mtd->dev, "mtd%d", i);
+       } else {
+               mtd->dev.type = &mtd_master_devtype;
+               mtd->dev.class = &mtd_master_class;
+               mtd->dev.devt = MKDEV(MAJOR(mtd_master_devt), i);
+               dev_set_name(&mtd->dev, "mtd_master%d", i);
+       }
        dev_set_drvdata(&mtd->dev, mtd);
        mtd_check_of_node(mtd);
        of_node_get(mtd_get_of_node(mtd));
        error = device_register(&mtd->dev);
        if (error) {
+               pr_err("mtd: %s device_register fail %d\n", mtd->name, error);
                put_device(&mtd->dev);
                goto fail_added;
        }
@@ -758,8 +801,10 @@ int add_mtd_device(struct mtd_info *mtd)
 
        mtd_debugfs_populate(mtd);
 
-       device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, NULL,
-                     "mtd%dro", i);
+       if (partitioned) {
+               device_create(&mtd_class, mtd->dev.parent, MTD_DEVT(i) + 1, 
NULL,
+                             "mtd%dro", i);
+       }
 
        pr_debug("mtd: Giving out device %d to %s\n", i, mtd->name);
        /* No need to get a refcount on the module containing
@@ -769,13 +814,16 @@ int add_mtd_device(struct mtd_info *mtd)
 
        mutex_unlock(&mtd_table_mutex);
 
-       if (of_property_read_bool(mtd_get_of_node(mtd), "linux,rootfs")) {
-               if (IS_BUILTIN(CONFIG_MTD)) {
-                       pr_info("mtd: setting mtd%d (%s) as root device\n", 
mtd->index, mtd->name);
-                       ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
-               } else {
-                       pr_warn("mtd: can't set mtd%d (%s) as root device - mtd 
must be builtin\n",
-                               mtd->index, mtd->name);
+       if (partitioned) {
+               if (of_property_read_bool(mtd_get_of_node(mtd), 
"linux,rootfs")) {
+                       if (IS_BUILTIN(CONFIG_MTD)) {
+                               pr_info("mtd: setting mtd%d (%s) as root 
device\n",
+                                       mtd->index, mtd->name);
+                               ROOT_DEV = MKDEV(MTD_BLOCK_MAJOR, mtd->index);
+                       } else {
+                               pr_warn("mtd: can't set mtd%d (%s) as root 
device - mtd must be builtin\n",
+                                       mtd->index, mtd->name);
+                       }
                }
        }
 
@@ -790,7 +838,10 @@ int add_mtd_device(struct mtd_info *mtd)
        device_unregister(&mtd->dev);
 fail_added:
        of_node_put(mtd_get_of_node(mtd));
-       idr_remove(&mtd_idr, i);
+       if (partitioned)
+               idr_remove(&mtd_idr, i);
+       else
+               idr_remove(&mtd_master_idr, i);
 fail_locked:
        mutex_unlock(&mtd_table_mutex);
        return error;
@@ -1061,11 +1112,10 @@ int mtd_device_parse_register(struct mtd_info *mtd, 
const char * const *types,
        if (ret)
                goto out;
 
-       if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER)) {
-               ret = add_mtd_device(mtd);
-               if (ret)
-                       goto out;
-       }
+       /* Master device */
+       ret = add_mtd_device(mtd);
+       if (ret)
+               goto out;
 
        /* Prefer parsed partitions over driver-provided fallback */
        ret = parse_mtd_partitions(mtd, types, parser_data);
@@ -1261,8 +1311,7 @@ int __get_mtd_device(struct mtd_info *mtd)
                mtd = mtd->parent;
        }
 
-       if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
-               kref_get(&master->refcnt);
+       kref_get(&master->refcnt);
 
        return 0;
 }
@@ -1356,8 +1405,7 @@ void __put_mtd_device(struct mtd_info *mtd)
                mtd = parent;
        }
 
-       if (IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER))
-               kref_put(&master->refcnt, mtd_device_release);
+       kref_put(&master->refcnt, mtd_device_release);
 
        module_put(master->owner);
 
@@ -2524,6 +2572,16 @@ static int __init init_mtd(void)
        if (ret)
                goto err_reg;
 
+       ret = class_register(&mtd_master_class);
+       if (ret)
+               goto err_reg2;
+
+       ret = alloc_chrdev_region(&mtd_master_devt, 0, MTD_MASTER_DEVS, 
"mtd_master");
+       if (ret < 0) {
+               pr_err("unable to allocate char dev region\n");
+               goto err_chrdev;
+       }
+
        mtd_bdi = mtd_bdi_init("mtd");
        if (IS_ERR(mtd_bdi)) {
                ret = PTR_ERR(mtd_bdi);
@@ -2548,6 +2606,10 @@ static int __init init_mtd(void)
        bdi_unregister(mtd_bdi);
        bdi_put(mtd_bdi);
 err_bdi:
+       unregister_chrdev_region(mtd_master_devt, MTD_MASTER_DEVS);
+err_chrdev:
+       class_unregister(&mtd_master_class);
+err_reg2:
        class_unregister(&mtd_class);
 err_reg:
        pr_err("Error registering mtd class or bdi: %d\n", ret);
@@ -2561,9 +2623,12 @@ static void __exit cleanup_mtd(void)
        if (proc_mtd)
                remove_proc_entry("mtd", NULL);
        class_unregister(&mtd_class);
+       class_unregister(&mtd_master_class);
+       unregister_chrdev_region(mtd_master_devt, MTD_MASTER_DEVS);
        bdi_unregister(mtd_bdi);
        bdi_put(mtd_bdi);
        idr_destroy(&mtd_idr);
+       idr_destroy(&mtd_master_idr);
 }
 
 module_init(init_mtd);
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 6811a714349d..268c3d5ccdea 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -86,8 +86,7 @@ static struct mtd_info *allocate_partition(struct mtd_info 
*parent,
         * parent conditional on that option. Note, this is a way to
         * distinguish between the parent and its partitions in sysfs.
         */
-       child->dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) || 
mtd_is_partition(parent) ?
-                           &parent->dev : parent->dev.parent;
+       child->dev.parent = &parent->dev;
        child->dev.of_node = part->of_node;
        child->parent = parent;
        child->part.offset = part->offset;
@@ -590,9 +589,6 @@ static int mtd_part_of_parse(struct mtd_info *master,
        int ret, err = 0;
 
        dev = &master->dev;
-       /* Use parent device (controller) if the top level MTD is not 
registered */
-       if (!IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) && 
!mtd_is_partition(master))
-               dev = master->dev.parent;
 
        np = mtd_get_of_node(master);
        if (mtd_is_partition(master))
-- 
2.43.0

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