of: configfs: Add configfs function

Signed-off-by: Jianlong Huang <jianlong.huang@starfivetech.com>

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 3dfeae8..6e83e9c 100644 (file)
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -98,4 +98,11 @@ 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
+        select OF_OVERLAY
+        help
+          Enable a simple user-space driven DT overlay interface.
+
 endif # OF

diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index c13b982..76b665c 100644 (file)
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_OF_UNITTEST) += unittest.o
 obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
 obj-$(CONFIG_OF_RESOLVE)  += resolver.o
 obj-$(CONFIG_OF_OVERLAY) += overlay.o
+obj-$(CONFIG_OF_CONFIGFS) += configfs.o
 obj-$(CONFIG_OF_NUMA) += of_numa.o
 
 ifdef CONFIG_KEXEC_FILE

diff --git a/drivers/of/configfs.c b/drivers/of/configfs.c
new file mode 100644 (file)
index 0000000..8134ae3
--- /dev/null
+++ b/drivers/of/configfs.c
@@ -0,0 +1,277 @@
+/*
+ * Configfs entries for device-tree
+ *
+ * Copyright (C) 2013 - Pantelis Antoniou <panto@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/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 <linux/sizes.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;
+};
+
+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)
+{
+       struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
+       return sprintf(page, "%s\n", overlay->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)
+               return err;
+
+       err = of_overlay_fdt_apply((void *)overlay->fw->data,
+                                  (u32)overlay->fw->size, &overlay->ov_id);
+       if (err != 0)
+               goto out_err;
+
+       return count;
+
+out_err:
+
+       release_firmware(overlay->fw);
+       overlay->fw = NULL;
+
+       overlay->path[0] = '\0';
+       return err;
+}
+
+static ssize_t cfs_overlay_item_status_show(struct config_item *item,
+               char *page)
+{
+       struct cfs_overlay_item *overlay = to_cfs_overlay_item(item);
+
+       return sprintf(page, "%s\n",
+                       overlay->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 == NULL)
+               return 0;
+
+       /* copy if buffer provided */
+       if (buf != NULL) {
+               /* 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 == NULL)
+               return -ENOMEM;
+
+       overlay->dtbo_size = count;
+
+       err = of_overlay_fdt_apply(overlay->dtbo, overlay->dtbo_size,
+                                  &overlay->ov_id);
+       if (err != 0)
+               goto out_err;
+
+       return count;
+
+out_err:
+       kfree(overlay->dtbo);
+       overlay->dtbo = NULL;
+       overlay->dtbo_size = 0;
+       overlay->ov_id = 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);
+}
+
+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);
+
+       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);