431 lines
12 KiB
Diff
431 lines
12 KiB
Diff
Below patch is a squash of following 4 commits borrowed from ayufan's
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https://github.com/ayufan-rock64/linux-mainline-kernel repo:
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From cc22206776d61948f6984a4f03d8013eb4f92984 Mon Sep 17 00:00:00 2001
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From: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
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Date: Wed, 3 Dec 2014 13:23:28 +0200
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Subject: [PATCH] OF: DT-Overlay configfs interface
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This is a port of Pantelis Antoniou's v3 port that makes use of the
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new upstreamed configfs support for binary attributes.
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Original commit message:
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Add a runtime interface to using configfs for generic device tree overlay
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usage. With it its possible to use device tree overlays without having
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to use a per-platform overlay manager.
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Please see Documentation/devicetree/configfs-overlays.txt for more info.
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Changes since v2:
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- Removed ifdef CONFIG_OF_OVERLAY (since for now it's required)
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- Created a documentation entry
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- Slight rewording in Kconfig
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Changes since v1:
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- of_resolve() -> of_resolve_phandles().
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Originally-signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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DT configfs: Fix build errors on other platforms
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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DT configfs: fix build error
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There is an error when compiling rpi-4.6.y branch:
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CC drivers/of/configfs.o
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drivers/of/configfs.c:291:21: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
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.default_groups = of_cfs_def_groups,
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^
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drivers/of/configfs.c:291:21: note: (near initialization for 'of_cfs_subsys.su_group.default_groups.next')
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The .default_groups is linked list since commit
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1ae1602de028acaa42a0f6ff18d19756f8e825c6.
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This commit uses configfs_add_default_group to fix this problem.
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Change-Id: Id4903c9725ebc355aadd067bbc32047db622ce61
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Signed-off-by: Slawomir Stepien <sst@poczta.fm>
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From 7cfb967c52d374ddcb0fc9194f38d1d5f9d8cdd8 Mon Sep 17 00:00:00 2001
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From: popcornmix <popcornmix@gmail.com>
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Date: Sun, 3 Dec 2017 21:43:03 +0000
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Subject: [PATCH] configfs: New of_overlay API
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From 8637321fabb045fe8617360ef1b058978b0d8457 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Mon, 4 Dec 2017 14:07:40 +0000
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Subject: [PATCH] SQUASH: config_fs: of_overlay_apply takes a pointer
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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From 274dfabb947ca32116a429c582c74aaee6ff1b5b Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Kamil=20Trzci=C5=84ski?= <ayufan@ayufan.eu>
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Date: Mon, 14 May 2018 11:28:09 +0200
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Subject: [PATCH] ayufan: fix overlayfs to compile on 4.17 kernel
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Change-Id: I421887697d2ba6e52aba9100100b7664760e2001
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diff --git a/Documentation/devicetree/configfs-overlays.txt b/Documentation/devicetree/configfs-overlays.txt
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new file mode 100644
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index 0000000000000..5fa43e0643072
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--- /dev/null
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+++ b/Documentation/devicetree/configfs-overlays.txt
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@@ -0,0 +1,31 @@
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+Howto use the configfs overlay interface.
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+
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+A device-tree configfs entry is created in /config/device-tree/overlays
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+and and it is manipulated using standard file system I/O.
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+Note that this is a debug level interface, for use by developers and
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+not necessarily something accessed by normal users due to the
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+security implications of having direct access to the kernel's device tree.
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+
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+* To create an overlay you mkdir the directory:
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+
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+ # mkdir /config/device-tree/overlays/foo
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+
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+* Either you echo the overlay firmware file to the path property file.
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+
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+ # echo foo.dtbo >/config/device-tree/overlays/foo/path
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+
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+* Or you cat the contents of the overlay to the dtbo file
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+
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+ # cat foo.dtbo >/config/device-tree/overlays/foo/dtbo
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+
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+The overlay file will be applied, and devices will be created/destroyed
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+as required.
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+
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+To remove it simply rmdir the directory.
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+
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+ # rmdir /config/device-tree/overlays/foo
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+
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+The rationalle of the dual interface (firmware & direct copy) is that each is
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+better suited to different use patterns. The firmware interface is what's
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+intended to be used by hardware managers in the kernel, while the copy interface
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+make sense for developers (since it avoids problems with namespaces).
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diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
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index 37c2ccbefecdc..d3fc81a40c0e7 100644
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--- a/drivers/of/Kconfig
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+++ b/drivers/of/Kconfig
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@@ -103,4 +103,11 @@ config OF_OVERLAY
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config OF_NUMA
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bool
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+config OF_CONFIGFS
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+ bool "Device Tree Overlay ConfigFS interface"
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+ select CONFIGFS_FS
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+ select OF_OVERLAY
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+ help
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+ Enable a simple user-space driven DT overlay interface.
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+
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endif # OF
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diff --git a/drivers/of/Makefile b/drivers/of/Makefile
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index 663a4af0cccd5..b00a95adf5199 100644
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--- a/drivers/of/Makefile
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+++ b/drivers/of/Makefile
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@@ -1,6 +1,7 @@
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# SPDX-License-Identifier: GPL-2.0
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obj-y = base.o device.o platform.o property.o
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obj-$(CONFIG_OF_KOBJ) += kobj.o
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+obj-$(CONFIG_OF_CONFIGFS) += configfs.o
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obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
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obj-$(CONFIG_OF_FLATTREE) += fdt.o
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obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
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diff --git a/drivers/of/configfs.c b/drivers/of/configfs.c
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new file mode 100644
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index 000000000..5dd509e8f
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--- /dev/null
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+++ b/drivers/of/configfs.c
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@@ -0,0 +1,290 @@
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+/*
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+ * Configfs entries for device-tree
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+ *
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+ * Copyright (C) 2013 - Pantelis Antoniou <panto@antoniou-consulting.com>
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version
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+ * 2 of the License, or (at your option) any later version.
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+ */
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+#include <linux/ctype.h>
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+#include <linux/cpu.h>
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+#include <linux/module.h>
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+#include <linux/of.h>
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+#include <linux/of_fdt.h>
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+#include <linux/spinlock.h>
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+#include <linux/slab.h>
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+#include <linux/proc_fs.h>
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+#include <linux/configfs.h>
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+#include <linux/types.h>
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+#include <linux/stat.h>
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+#include <linux/limits.h>
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+#include <linux/file.h>
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+#include <linux/vmalloc.h>
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+#include <linux/firmware.h>
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+#include <linux/sizes.h>
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+
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+#include "of_private.h"
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+
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+struct cfs_overlay_item {
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+ struct config_item item;
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+
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+ char path[PATH_MAX];
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+
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+ const struct firmware *fw;
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+ struct device_node *overlay;
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+ int ov_id;
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+
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+ void *dtbo;
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+ int dtbo_size;
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+};
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+
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+static int create_overlay(struct cfs_overlay_item *overlay, void *blob, u32 blob_size)
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+{
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+ int err;
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+
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+ err = of_overlay_fdt_apply(blob, blob_size, &overlay->ov_id);
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+ if (err < 0) {
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+ pr_err("%s: Failed to create overlay (err=%d)\n",
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+ __func__, err);
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+ goto out_err;
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+ }
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+
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+out_err:
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+ return err;
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+}
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+
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+static inline struct cfs_overlay_item *to_cfs_overlay_item(
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+ struct config_item *item)
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+{
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+ return item ? container_of(item, struct cfs_overlay_item, item) : NULL;
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+}
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+
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+static ssize_t cfs_overlay_item_path_show(struct config_item *item,
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+ char *page)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+ return sprintf(page, "%s\n", overlay->path);
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+}
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+
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+static ssize_t cfs_overlay_item_path_store(struct config_item *item,
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+ const char *page, size_t count)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+ const char *p = page;
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+ char *s;
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+ int err;
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+
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+ /* if it's set do not allow changes */
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+ if (overlay->path[0] != '\0' || overlay->dtbo_size > 0)
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+ return -EPERM;
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+
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+ /* copy to path buffer (and make sure it's always zero terminated */
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+ count = snprintf(overlay->path, sizeof(overlay->path) - 1, "%s", p);
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+ overlay->path[sizeof(overlay->path) - 1] = '\0';
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+
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+ /* strip trailing newlines */
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+ s = overlay->path + strlen(overlay->path);
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+ while (s > overlay->path && *--s == '\n')
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+ *s = '\0';
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+
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+ pr_debug("%s: path is '%s'\n", __func__, overlay->path);
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+
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+ err = request_firmware(&overlay->fw, overlay->path, NULL);
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+ if (err != 0)
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+ goto out_err;
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+
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+ err = create_overlay(overlay, (void *)overlay->fw->data, overlay->fw->size);
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+ if (err != 0)
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+ goto out_err;
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+
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+ return count;
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+
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+out_err:
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+
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+ release_firmware(overlay->fw);
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+ overlay->fw = NULL;
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+
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+ overlay->path[0] = '\0';
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+ return err;
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+}
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+
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+static ssize_t cfs_overlay_item_status_show(struct config_item *item,
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+ char *page)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+
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+ return sprintf(page, "%s\n",
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+ overlay->ov_id >= 0 ? "applied" : "unapplied");
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+}
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+
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+CONFIGFS_ATTR(cfs_overlay_item_, path);
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+CONFIGFS_ATTR_RO(cfs_overlay_item_, status);
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+
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+static struct configfs_attribute *cfs_overlay_attrs[] = {
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+ &cfs_overlay_item_attr_path,
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+ &cfs_overlay_item_attr_status,
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+ NULL,
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+};
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+
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+ssize_t cfs_overlay_item_dtbo_read(struct config_item *item,
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+ void *buf, size_t max_count)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+
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+ pr_debug("%s: buf=%p max_count=%zu\n", __func__,
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+ buf, max_count);
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+
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+ if (overlay->dtbo == NULL)
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+ return 0;
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+
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+ /* copy if buffer provided */
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+ if (buf != NULL) {
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+ /* the buffer must be large enough */
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+ if (overlay->dtbo_size > max_count)
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+ return -ENOSPC;
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+
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+ memcpy(buf, overlay->dtbo, overlay->dtbo_size);
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+ }
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+
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+ return overlay->dtbo_size;
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+}
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+
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+ssize_t cfs_overlay_item_dtbo_write(struct config_item *item,
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+ const void *buf, size_t count)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+ int err;
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+
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+ /* if it's set do not allow changes */
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+ if (overlay->path[0] != '\0' || overlay->dtbo_size > 0)
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+ return -EPERM;
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+
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+ /* copy the contents */
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+ overlay->dtbo = kmemdup(buf, count, GFP_KERNEL);
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+ if (overlay->dtbo == NULL)
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+ return -ENOMEM;
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+
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+ overlay->dtbo_size = count;
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+
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+ err = create_overlay(overlay, overlay->dtbo, overlay->dtbo_size);
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+ if (err != 0)
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+ goto out_err;
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+
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+ return count;
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+
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+out_err:
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+ kfree(overlay->dtbo);
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+ overlay->dtbo = NULL;
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+ overlay->dtbo_size = 0;
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+
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+ return err;
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+}
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+
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+CONFIGFS_BIN_ATTR(cfs_overlay_item_, dtbo, NULL, SZ_1M);
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+
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+static struct configfs_bin_attribute *cfs_overlay_bin_attrs[] = {
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+ &cfs_overlay_item_attr_dtbo,
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+ NULL,
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+};
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+
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+static void cfs_overlay_release(struct config_item *item)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+
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+ if (overlay->ov_id >= 0)
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+ of_overlay_remove(&overlay->ov_id);
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+ if (overlay->fw)
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+ release_firmware(overlay->fw);
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+ /* kfree with NULL is safe */
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+ kfree(overlay->dtbo);
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+ kfree(overlay);
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+}
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+
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+static struct configfs_item_operations cfs_overlay_item_ops = {
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+ .release = cfs_overlay_release,
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+};
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+
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+static struct config_item_type cfs_overlay_type = {
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+ .ct_item_ops = &cfs_overlay_item_ops,
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+ .ct_attrs = cfs_overlay_attrs,
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+ .ct_bin_attrs = cfs_overlay_bin_attrs,
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+ .ct_owner = THIS_MODULE,
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+};
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+
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+static struct config_item *cfs_overlay_group_make_item(
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+ struct config_group *group, const char *name)
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+{
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+ struct cfs_overlay_item *overlay;
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+
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+ overlay = kzalloc(sizeof(*overlay), GFP_KERNEL);
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+ if (!overlay)
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+ return ERR_PTR(-ENOMEM);
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+ overlay->ov_id = -1;
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+
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+ config_item_init_type_name(&overlay->item, name, &cfs_overlay_type);
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+ return &overlay->item;
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+}
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+
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+static void cfs_overlay_group_drop_item(struct config_group *group,
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+ struct config_item *item)
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+{
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+ struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
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+
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+ config_item_put(&overlay->item);
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+}
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+
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+static struct configfs_group_operations overlays_ops = {
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+ .make_item = cfs_overlay_group_make_item,
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+ .drop_item = cfs_overlay_group_drop_item,
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+};
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+
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+static struct config_item_type overlays_type = {
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+ .ct_group_ops = &overlays_ops,
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+ .ct_owner = THIS_MODULE,
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+};
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+
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+static struct configfs_group_operations of_cfs_ops = {
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+ /* empty - we don't allow anything to be created */
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+};
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+
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+static struct config_item_type of_cfs_type = {
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+ .ct_group_ops = &of_cfs_ops,
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+ .ct_owner = THIS_MODULE,
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+};
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+
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+struct config_group of_cfs_overlay_group;
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+
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+static struct configfs_subsystem of_cfs_subsys = {
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+ .su_group = {
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+ .cg_item = {
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+ .ci_namebuf = "device-tree",
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+ .ci_type = &of_cfs_type,
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+ },
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+ },
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+ .su_mutex = __MUTEX_INITIALIZER(of_cfs_subsys.su_mutex),
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+};
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+
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+static int __init of_cfs_init(void)
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+{
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+ int ret;
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+
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+ pr_info("%s\n", __func__);
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+
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+ config_group_init(&of_cfs_subsys.su_group);
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+ config_group_init_type_name(&of_cfs_overlay_group, "overlays",
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+ &overlays_type);
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+ configfs_add_default_group(&of_cfs_overlay_group,
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+ &of_cfs_subsys.su_group);
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+
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+ ret = configfs_register_subsystem(&of_cfs_subsys);
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+ if (ret != 0) {
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+ pr_err("%s: failed to register subsys\n", __func__);
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+ goto out;
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+ }
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+ pr_info("%s: OK\n", __func__);
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+out:
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+ return ret;
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+}
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+late_initcall(of_cfs_init);
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