[PATCH v3 3/4] of: overlay: add per overlay sysfs attributes

From: Pantelis Antoniou
Date: Fri Apr 24 2015 - 05:46:53 EST


The two default overlay attributes are:

* A targets sysfs attribute listing the targets of the installed
overlay. The targets list the path on the kernel's device tree
where each overlay fragment is applied to

* A per overlay can_remove sysfs attribute that reports whether
the overlay can be removed or not due to another overlapping overlay.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
---
drivers/of/overlay.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index c335809..9af4d8d 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -375,8 +375,61 @@ static const struct attribute *overlay_global_attrs[] = {
NULL
};

+static ssize_t can_remove_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct of_overlay *ov = kobj_to_overlay(kobj);
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", overlay_removal_is_ok(ov));
+}
+
+static ssize_t targets_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct of_overlay *ov = kobj_to_overlay(kobj);
+ struct of_overlay_info *ovinfo;
+ char *s, *e;
+ ssize_t ret;
+ int i, len;
+
+ s = buf;
+ e = buf + PAGE_SIZE;
+
+ mutex_lock(&of_mutex);
+
+ /* targets */
+ for (i = 0; i < ov->count; i++) {
+ ovinfo = &ov->ovinfo_tab[i];
+
+ len = snprintf(s, e - s, "%s\n",
+ of_node_full_name(ovinfo->target));
+ if (len == 0) {
+ ret = -ENOSPC;
+ goto err;
+ }
+ s += len;
+ }
+
+ /* the buffer is zero terminated */
+ ret = s - buf;
+err:
+ mutex_unlock(&of_mutex);
+ return ret;
+}
+
+static struct kobj_attribute can_remove_attr = __ATTR_RO(can_remove);
+static struct kobj_attribute targets_attr = __ATTR_RO(targets);
+
+static struct attribute *overlay_attrs[] = {
+ &can_remove_attr.attr,
+ &targets_attr.attr,
+ NULL
+};
+
static struct kobj_type of_overlay_ktype = {
.release = of_overlay_release,
+ .sysfs_ops = &kobj_sysfs_ops, /* default kobj sysfs ops */
+ .default_attrs = overlay_attrs,
};

static struct kset *ov_kset;
--
1.7.12

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