In message: Re: [linux-yocto][v5.15/standard/preempt-rt/base][PATCH] OF:
DT-Overlay configfs interface (v8)
on 30/05/2023 Quanyang Wang wrote:
> Hi Bruce,
>
> I wrote the wrong branch information. It should be:
>
> v6.1/standard/preempt-rt/base
>
> v6.1/standard/base
>
> And this patch will conflict with another patch ("Revert "OF: DT-Overlay
> configfs interface (v8)" I just sent which is
>
> https://lists.yoctoproject.org/g/linux-yocto/topic/v6_1_standard_preempt_rt_sdkv6_1_xlnx_soc_patch/99215104?p=,,,20,0,0,0::recentpostdate/sticky,,,20,2,0,99215104,previd%3D1685429439939095335,nextid%3D1684520876284512837&previd=1685429439939095335&nextid=1684520876284512837
>
> So the patch in the above URL should be applied first and then this patch.
>
> Sorry for the inconvenience.
No problem!
I have it sorted out and the functionality should now be on all BSP branches.
The rpi branches carry a similar change, but I reverted the rpi version,
otherwise
the conflicts are a mess.
Bruce
>
> Thanks,
>
> Quanyang
>
> On 5/30/23 14:43, quanyang.wang via lists.yoctoproject.org wrote:
> > From: Pantelis Antoniou <pantelis.anton...@konsulko.com>
> >
> > commit 999eb1a8fdc4512412c7bc519c895bc2a6fabbe0 from
> > https://github.com/Xilinx/linux-xlnx.git
> >
> > Add a runtime interface to using configfs for generic device tree overlay
> > usage. With it its possible to use device tree overlays without having
> > to use a per-platform overlay manager.
> >
> > Please see Documentation/devicetree/configfs-overlays.txt for more info.
> >
> > Changes since v7:
> > - Xilinx alignment
> > - of: configfs: Fix error handling from of_overlay_create()
> > - of: configfs: lock while resolving and applying
> > - of: configfs: Fix memory leak in create overlay
> > - of: configfs: Fix compilation warning
> > - of: configfs: Use of_overlay_fdt_apply API call
> >
> > Changes since v6:
> > - Default groups properties API changed.
> >
> > Changes since v5:
> > - New style configfs.
> >
> > Changes since v4:
> > - Loading fix for multiple overlays as found out by
> > Geert Uytterhoeven <ge...@linux-m68k.org>
> >
> > Changes since v3:
> > - Fixed compilation on SPARC & Xtensa
> >
> > Changes since v2:
> > - Removed ifdef CONFIG_OF_OVERLAY (since for now it's required)
> > - Created a documentation entry
> > - Slight rewording in Kconfig
> >
> > Changes since v1:
> > - of_resolve() -> of_resolve_phandles().
> >
> > Signed-off-by: Pantelis Antoniou <pantelis.anton...@konsulko.com>
> > Signed-off-by: Nava kishore Manne <nava.ma...@xilinx.com>
> > Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pan...@xilinx.com>
> > State: not-upstreamable
> > Signed-off-by: Liwei Song <liwei.s...@windriver.com>
> > [Liwei: remove overlay_lock to fix "unused-variable" warning.]
> > Signed-off-by: Bruce Ashfield <bruce.ashfi...@gmail.com>
> > ---
> > Hi Bruce,
> > Would you please help merge this patch to the branches:
> > v5.15/standard/preempt-rt/base
> > v5.15/standard/base
> > Thanks,
> > Quanyang
> > ---
> > .../devicetree/configfs-overlays.txt | 31 ++
> > drivers/of/Kconfig | 11 +
> > drivers/of/Makefile | 1 +
> > drivers/of/configfs.c | 292 ++++++++++++++++++
> > 4 files changed, 335 insertions(+)
> > create mode 100644 Documentation/devicetree/configfs-overlays.txt
> > create mode 100644 drivers/of/configfs.c
> >
> > diff --git a/Documentation/devicetree/configfs-overlays.txt
> > b/Documentation/devicetree/configfs-overlays.txt
> > new file mode 100644
> > index 0000000000000..5fa43e0643072
> > --- /dev/null
> > +++ b/Documentation/devicetree/configfs-overlays.txt
> > @@ -0,0 +1,31 @@
> > +Howto use the configfs overlay interface.
> > +
> > +A device-tree configfs entry is created in /config/device-tree/overlays
> > +and and it is manipulated using standard file system I/O.
> > +Note that this is a debug level interface, for use by developers and
> > +not necessarily something accessed by normal users due to the
> > +security implications of having direct access to the kernel's device tree.
> > +
> > +* To create an overlay you mkdir the directory:
> > +
> > + # mkdir /config/device-tree/overlays/foo
> > +
> > +* Either you echo the overlay firmware file to the path property file.
> > +
> > + # echo foo.dtbo >/config/device-tree/overlays/foo/path
> > +
> > +* Or you cat the contents of the overlay to the dtbo file
> > +
> > + # cat foo.dtbo >/config/device-tree/overlays/foo/dtbo
> > +
> > +The overlay file will be applied, and devices will be created/destroyed
> > +as required.
> > +
> > +To remove it simply rmdir the directory.
> > +
> > + # rmdir /config/device-tree/overlays/foo
> > +
> > +The rationalle of the dual interface (firmware & direct copy) is that each
> > is
> > +better suited to different use patterns. The firmware interface is what's
> > +intended to be used by hardware managers in the kernel, while the copy
> > interface
> > +make sense for developers (since it avoids problems with namespaces).
> > diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
> > index 80b5fd44ab1c7..da62bc6766952 100644
> > --- a/drivers/of/Kconfig
> > +++ b/drivers/of/Kconfig
> > @@ -94,4 +94,15 @@ config OF_DMA_DEFAULT_COHERENT
> > # arches should select this if DMA is coherent by default for OF devices
> > bool
> > +config OF_CONFIGFS
> > + bool "Device Tree Overlay ConfigFS interface"
> > + select CONFIGFS_FS
> > + depends on OF_OVERLAY
> > + help
> > + Select this option to enable simple user-space driven DT overlay
> > + interface to support device tree manipulated at runtime.
> > + Say Y here to include this support.
> > +
> > + If unsure, say N.
> > +
> > endif # OF
> > diff --git a/drivers/of/Makefile b/drivers/of/Makefile
> > index e0360a44306e2..90c92ced24e62 100644
> > --- a/drivers/of/Makefile
> > +++ b/drivers/of/Makefile
> > @@ -1,6 +1,7 @@
> > # SPDX-License-Identifier: GPL-2.0
> > obj-y = base.o device.o platform.o property.o
> > obj-$(CONFIG_OF_KOBJ) += kobj.o
> > +obj-$(CONFIG_OF_CONFIGFS) += configfs.o
> > obj-$(CONFIG_OF_DYNAMIC) += dynamic.o
> > obj-$(CONFIG_OF_FLATTREE) += fdt.o
> > obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o
> > diff --git a/drivers/of/configfs.c b/drivers/of/configfs.c
> > new file mode 100644
> > index 0000000000000..64caba77a7193
> > --- /dev/null
> > +++ b/drivers/of/configfs.c
> > @@ -0,0 +1,292 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Configfs entries for device-tree
> > + *
> > + * Copyright (C) 2013 - Pantelis Antoniou <pa...@antoniou-consulting.com>
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License
> > + * as published by the Free Software Foundation; either version
> > + * 2 of the License, or (at your option) any later version.
> > + */
> > +#include <linux/ctype.h>
> > +#include <linux/cpu.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_fdt.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/sizes.h>
> > +#include <linux/slab.h>
> > +#include <linux/proc_fs.h>
> > +#include <linux/configfs.h>
> > +#include <linux/types.h>
> > +#include <linux/stat.h>
> > +#include <linux/limits.h>
> > +#include <linux/file.h>
> > +#include <linux/vmalloc.h>
> > +#include <linux/firmware.h>
> > +
> > +#include "of_private.h"
> > +
> > +struct cfs_overlay_item {
> > + struct config_item item;
> > +
> > + char path[PATH_MAX];
> > +
> > + const struct firmware *fw;
> > + struct device_node *overlay;
> > + int ov_id;
> > +
> > + void *dtbo;
> > + int dtbo_size;
> > +
> > + void *mem;
> > +};
> > +
> > +static int create_overlay(struct cfs_overlay_item *overlay, void *blob)
> > +{
> > + int err;
> > +
> > + /* FIXME */
> > + err = of_overlay_fdt_apply(blob, overlay->dtbo_size, &overlay->ov_id);
> > + if (err < 0) {
> > + pr_err("%s: Failed to create overlay (err=%d)\n",
> > + __func__, err);
> > + return err;
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static inline struct cfs_overlay_item
> > + *to_cfs_overlay_item(struct config_item *item)
> > +{
> > + return item ? container_of(item, struct cfs_overlay_item, item) : NULL;
> > +}
> > +
> > +static ssize_t cfs_overlay_item_path_show(struct config_item *item, char
> > *page)
> > +{
> > + return sprintf(page, "%s\n", to_cfs_overlay_item(item)->path);
> > +}
> > +
> > +static ssize_t cfs_overlay_item_path_store(struct config_item *item,
> > + const char *page, size_t count)
> > +{
> > + struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
> > + const char *p = page;
> > + char *s;
> > + int err;
> > +
> > + /* if it's set do not allow changes */
> > + if (overlay->path[0] != '\0' || overlay->dtbo_size > 0)
> > + return -EPERM;
> > +
> > + /* copy to path buffer (and make sure it's always zero terminated */
> > + count = snprintf(overlay->path, sizeof(overlay->path) - 1, "%s", p);
> > + overlay->path[sizeof(overlay->path) - 1] = '\0';
> > +
> > + /* strip trailing newlines */
> > + s = overlay->path + strlen(overlay->path);
> > + while (s > overlay->path && *--s == '\n')
> > + *s = '\0';
> > +
> > + pr_debug("%s: path is '%s'\n", __func__, overlay->path);
> > +
> > + err = request_firmware(&overlay->fw, overlay->path, NULL);
> > + if (err != 0)
> > + goto out_err;
> > +
> > + overlay->dtbo_size = overlay->fw->size;
> > + err = create_overlay(overlay, (void *)overlay->fw->data);
> > + if (err < 0)
> > + goto out_err;
> > +
> > + return count;
> > +
> > +out_err:
> > +
> > + release_firmware(overlay->fw);
> > + overlay->fw = NULL;
> > +
> > + overlay->path[0] = '\0';
> > +
> > + return count;
> > +}
> > +
> > +static ssize_t cfs_overlay_item_status_show(struct config_item *item,
> > + char *page)
> > +{
> > + return sprintf(page, "%s\n", to_cfs_overlay_item(item)->ov_id >= 0 ?
> > + "applied" : "unapplied");
> > +}
> > +
> > +CONFIGFS_ATTR(cfs_overlay_item_, path);
> > +CONFIGFS_ATTR_RO(cfs_overlay_item_, status);
> > +
> > +static struct configfs_attribute *cfs_overlay_attrs[] = {
> > + &cfs_overlay_item_attr_path,
> > + &cfs_overlay_item_attr_status,
> > + NULL,
> > +};
> > +
> > +ssize_t cfs_overlay_item_dtbo_read(struct config_item *item,
> > + void *buf, size_t max_count)
> > +{
> > + struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
> > +
> > + pr_debug("%s: buf=%p max_count=%zu\n", __func__, buf, max_count);
> > +
> > + if (!overlay->dtbo)
> > + return 0;
> > +
> > + /* copy if buffer provided */
> > + if (buf) {
> > + /* the buffer must be large enough */
> > + if (overlay->dtbo_size > max_count)
> > + return -ENOSPC;
> > +
> > + memcpy(buf, overlay->dtbo, overlay->dtbo_size);
> > + }
> > +
> > + return overlay->dtbo_size;
> > +}
> > +
> > +ssize_t cfs_overlay_item_dtbo_write(struct config_item *item,
> > + const void *buf, size_t count)
> > +{
> > + struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
> > + int err;
> > +
> > + /* if it's set do not allow changes */
> > + if (overlay->path[0] != '\0' || overlay->dtbo_size > 0)
> > + return -EPERM;
> > +
> > + /* copy the contents */
> > + overlay->dtbo = kmemdup(buf, count, GFP_KERNEL);
> > + if (!overlay->dtbo)
> > + return -ENOMEM;
> > +
> > + overlay->dtbo_size = count;
> > +
> > + err = create_overlay(overlay, overlay->dtbo);
> > + if (err < 0)
> > + goto out_err;
> > +
> > + return count;
> > +
> > +out_err:
> > + kfree(overlay->dtbo);
> > + overlay->dtbo = NULL;
> > + overlay->dtbo_size = 0;
> > +
> > + return err;
> > +}
> > +
> > +CONFIGFS_BIN_ATTR(cfs_overlay_item_, dtbo, NULL, SZ_1M);
> > +
> > +static struct configfs_bin_attribute *cfs_overlay_bin_attrs[] = {
> > + &cfs_overlay_item_attr_dtbo,
> > + NULL,
> > +};
> > +
> > +static void cfs_overlay_release(struct config_item *item)
> > +{
> > + struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
> > +
> > + if (overlay->ov_id >= 0)
> > + of_overlay_remove(&overlay->ov_id);
> > + if (overlay->fw)
> > + release_firmware(overlay->fw);
> > + /* kfree with NULL is safe */
> > + kfree(overlay->dtbo);
> > + kfree(overlay->mem);
> > + kfree(overlay);
> > +}
> > +
> > +static struct configfs_item_operations cfs_overlay_item_ops = {
> > + .release = cfs_overlay_release,
> > +};
> > +
> > +static struct config_item_type cfs_overlay_type = {
> > + .ct_item_ops = &cfs_overlay_item_ops,
> > + .ct_attrs = cfs_overlay_attrs,
> > + .ct_bin_attrs = cfs_overlay_bin_attrs,
> > + .ct_owner = THIS_MODULE,
> > +};
> > +
> > +static struct config_item
> > + *cfs_overlay_group_make_item(struct config_group *group,
> > + const char *name)
> > +{
> > + struct cfs_overlay_item *overlay;
> > +
> > + overlay = kzalloc(sizeof(*overlay), GFP_KERNEL);
> > + if (!overlay)
> > + return ERR_PTR(-ENOMEM);
> > + overlay->ov_id = -1;
> > + config_item_init_type_name(&overlay->item, name, &cfs_overlay_type);
> > +
> > + return &overlay->item;
> > +}
> > +
> > +static void cfs_overlay_group_drop_item(struct config_group *group,
> > + struct config_item *item)
> > +{
> > + struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
> > +
> > + config_item_put(&overlay->item);
> > +}
> > +
> > +static struct configfs_group_operations overlays_ops = {
> > + .make_item = cfs_overlay_group_make_item,
> > + .drop_item = cfs_overlay_group_drop_item,
> > +};
> > +
> > +static struct config_item_type overlays_type = {
> > + .ct_group_ops = &overlays_ops,
> > + .ct_owner = THIS_MODULE,
> > +};
> > +
> > +static struct configfs_group_operations of_cfs_ops = {
> > + /* empty - we don't allow anything to be created */
> > +};
> > +
> > +static struct config_item_type of_cfs_type = {
> > + .ct_group_ops = &of_cfs_ops,
> > + .ct_owner = THIS_MODULE,
> > +};
> > +
> > +struct config_group of_cfs_overlay_group;
> > +
> > +static struct configfs_subsystem of_cfs_subsys = {
> > + .su_group = {
> > + .cg_item = {
> > + .ci_namebuf = "device-tree",
> > + .ci_type = &of_cfs_type,
> > + },
> > + },
> > + .su_mutex = __MUTEX_INITIALIZER(of_cfs_subsys.su_mutex),
> > +};
> > +
> > +static int __init of_cfs_init(void)
> > +{
> > + int ret;
> > +
> > + pr_info("%s\n", __func__);
> > +
> > + config_group_init(&of_cfs_subsys.su_group);
> > + config_group_init_type_name(&of_cfs_overlay_group, "overlays",
> > + &overlays_type);
> > + configfs_add_default_group(&of_cfs_overlay_group,
> > + &of_cfs_subsys.su_group);
> > +
> > + ret = configfs_register_subsystem(&of_cfs_subsys);
> > + if (ret != 0) {
> > + pr_err("%s: failed to register subsys\n", __func__);
> > + goto out;
> > + }
> > + pr_info("%s: OK\n", __func__);
> > +out:
> > + return ret;
> > +}
> > +late_initcall(of_cfs_init);
> >
> >
> >
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