From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/drivers/base/component.c | 224 +++++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 198 insertions(+), 26 deletions(-)
diff --git a/kernel/drivers/base/component.c b/kernel/drivers/base/component.c
index ee4d3b3..dcfbe72 100644
--- a/kernel/drivers/base/component.c
+++ b/kernel/drivers/base/component.c
@@ -11,16 +11,42 @@
#include <linux/device.h>
#include <linux/kref.h>
#include <linux/list.h>
-#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
+
+/**
+ * DOC: overview
+ *
+ * The component helper allows drivers to collect a pile of sub-devices,
+ * including their bound drivers, into an aggregate driver. Various subsystems
+ * already provide functions to get hold of such components, e.g.
+ * of_clk_get_by_name(). The component helper can be used when such a
+ * subsystem-specific way to find a device is not available: The component
+ * helper fills the niche of aggregate drivers for specific hardware, where
+ * further standardization into a subsystem would not be practical. The common
+ * example is when a logical device (e.g. a DRM display driver) is spread around
+ * the SoC on various components (scanout engines, blending blocks, transcoders
+ * for various outputs and so on).
+ *
+ * The component helper also doesn't solve runtime dependencies, e.g. for system
+ * suspend and resume operations. See also :ref:`device links<device_link>`.
+ *
+ * Components are registered using component_add() and unregistered with
+ * component_del(), usually from the driver's probe and disconnect functions.
+ *
+ * Aggregate drivers first assemble a component match list of what they need
+ * using component_match_add(). This is then registered as an aggregate driver
+ * using component_master_add_with_match(), and unregistered using
+ * component_master_del().
+ */
struct component;
struct component_match_array {
void *data;
int (*compare)(struct device *, void *);
+ int (*compare_typed)(struct device *, int, void *);
void (*release)(struct device *, void *);
struct component *component;
bool duplicate;
@@ -48,6 +74,7 @@
bool bound;
const struct component_ops *ops;
+ int subcomponent;
struct device *dev;
};
@@ -85,17 +112,7 @@
return 0;
}
-static int component_devices_open(struct inode *inode, struct file *file)
-{
- return single_open(file, component_devices_show, inode->i_private);
-}
-
-static const struct file_operations component_devices_fops = {
- .open = component_devices_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
+DEFINE_SHOW_ATTRIBUTE(component_devices);
static int __init component_debug_init(void)
{
@@ -142,7 +159,7 @@
}
static struct component *find_component(struct master *master,
- int (*compare)(struct device *, void *), void *compare_data)
+ struct component_match_array *mc)
{
struct component *c;
@@ -150,7 +167,11 @@
if (c->master && c->master != master)
continue;
- if (compare(c->dev, compare_data))
+ if (mc->compare && mc->compare(c->dev, mc->data))
+ return c;
+
+ if (mc->compare_typed &&
+ mc->compare_typed(c->dev, c->subcomponent, mc->data))
return c;
}
@@ -176,7 +197,7 @@
if (match->compare[i].component)
continue;
- c = find_component(master, mc->compare, mc->data);
+ c = find_component(master, mc);
if (!c) {
ret = -ENXIO;
break;
@@ -312,15 +333,12 @@
return 0;
}
-/*
- * Add a component to be matched, with a release function.
- *
- * The match array is first created or extended if necessary.
- */
-void component_match_add_release(struct device *master,
+static void __component_match_add(struct device *master,
struct component_match **matchptr,
void (*release)(struct device *, void *),
- int (*compare)(struct device *, void *), void *compare_data)
+ int (*compare)(struct device *, void *),
+ int (*compare_typed)(struct device *, int, void *),
+ void *compare_data)
{
struct component_match *match = *matchptr;
@@ -352,12 +370,68 @@
}
match->compare[match->num].compare = compare;
+ match->compare[match->num].compare_typed = compare_typed;
match->compare[match->num].release = release;
match->compare[match->num].data = compare_data;
match->compare[match->num].component = NULL;
match->num++;
}
+
+/**
+ * component_match_add_release - add a component match entry with release callback
+ * @master: device with the aggregate driver
+ * @matchptr: pointer to the list of component matches
+ * @release: release function for @compare_data
+ * @compare: compare function to match against all components
+ * @compare_data: opaque pointer passed to the @compare function
+ *
+ * Adds a new component match to the list stored in @matchptr, which the @master
+ * aggregate driver needs to function. The list of component matches pointed to
+ * by @matchptr must be initialized to NULL before adding the first match. This
+ * only matches against components added with component_add().
+ *
+ * The allocated match list in @matchptr is automatically released using devm
+ * actions, where upon @release will be called to free any references held by
+ * @compare_data, e.g. when @compare_data is a &device_node that must be
+ * released with of_node_put().
+ *
+ * See also component_match_add() and component_match_add_typed().
+ */
+void component_match_add_release(struct device *master,
+ struct component_match **matchptr,
+ void (*release)(struct device *, void *),
+ int (*compare)(struct device *, void *), void *compare_data)
+{
+ __component_match_add(master, matchptr, release, compare, NULL,
+ compare_data);
+}
EXPORT_SYMBOL(component_match_add_release);
+
+/**
+ * component_match_add_typed - add a component match entry for a typed component
+ * @master: device with the aggregate driver
+ * @matchptr: pointer to the list of component matches
+ * @compare_typed: compare function to match against all typed components
+ * @compare_data: opaque pointer passed to the @compare function
+ *
+ * Adds a new component match to the list stored in @matchptr, which the @master
+ * aggregate driver needs to function. The list of component matches pointed to
+ * by @matchptr must be initialized to NULL before adding the first match. This
+ * only matches against components added with component_add_typed().
+ *
+ * The allocated match list in @matchptr is automatically released using devm
+ * actions.
+ *
+ * See also component_match_add_release() and component_match_add_typed().
+ */
+void component_match_add_typed(struct device *master,
+ struct component_match **matchptr,
+ int (*compare_typed)(struct device *, int, void *), void *compare_data)
+{
+ __component_match_add(master, matchptr, NULL, NULL, compare_typed,
+ compare_data);
+}
+EXPORT_SYMBOL(component_match_add_typed);
static void free_master(struct master *master)
{
@@ -378,6 +452,18 @@
kfree(master);
}
+/**
+ * component_master_add_with_match - register an aggregate driver
+ * @dev: device with the aggregate driver
+ * @ops: callbacks for the aggregate driver
+ * @match: component match list for the aggregate driver
+ *
+ * Registers a new aggregate driver consisting of the components added to @match
+ * by calling one of the component_match_add() functions. Once all components in
+ * @match are available, it will be assembled by calling
+ * &component_master_ops.bind from @ops. Must be unregistered by calling
+ * component_master_del().
+ */
int component_master_add_with_match(struct device *dev,
const struct component_master_ops *ops,
struct component_match *match)
@@ -414,6 +500,15 @@
}
EXPORT_SYMBOL_GPL(component_master_add_with_match);
+/**
+ * component_master_del - unregister an aggregate driver
+ * @dev: device with the aggregate driver
+ * @ops: callbacks for the aggregate driver
+ *
+ * Unregisters an aggregate driver registered with
+ * component_master_add_with_match(). If necessary the aggregate driver is first
+ * disassembled by calling &component_master_ops.unbind from @ops.
+ */
void component_master_del(struct device *dev,
const struct component_master_ops *ops)
{
@@ -434,13 +529,23 @@
{
WARN_ON(!component->bound);
- component->ops->unbind(component->dev, master->dev, data);
+ if (component->ops && component->ops->unbind)
+ component->ops->unbind(component->dev, master->dev, data);
component->bound = false;
/* Release all resources claimed in the binding of this component */
devres_release_group(component->dev, component);
}
+/**
+ * component_unbind_all - unbind all components of an aggregate driver
+ * @master_dev: device with the aggregate driver
+ * @data: opaque pointer, passed to all components
+ *
+ * Unbinds all components of the aggregate @dev by passing @data to their
+ * &component_ops.unbind functions. Should be called from
+ * &component_master_ops.unbind.
+ */
void component_unbind_all(struct device *master_dev, void *data)
{
struct master *master;
@@ -515,6 +620,15 @@
return ret;
}
+/**
+ * component_bind_all - bind all components of an aggregate driver
+ * @master_dev: device with the aggregate driver
+ * @data: opaque pointer, passed to all components
+ *
+ * Binds all components of the aggregate @dev by passing @data to their
+ * &component_ops.bind functions. Should be called from
+ * &component_master_ops.bind.
+ */
int component_bind_all(struct device *master_dev, void *data)
{
struct master *master;
@@ -549,7 +663,8 @@
}
EXPORT_SYMBOL_GPL(component_bind_all);
-int component_add(struct device *dev, const struct component_ops *ops)
+static int __component_add(struct device *dev, const struct component_ops *ops,
+ int subcomponent)
{
struct component *component;
int ret;
@@ -560,6 +675,7 @@
component->ops = ops;
component->dev = dev;
+ component->subcomponent = subcomponent;
dev_dbg(dev, "adding component (ops %ps)\n", ops);
@@ -578,8 +694,66 @@
return ret < 0 ? ret : 0;
}
+
+/**
+ * component_add_typed - register a component
+ * @dev: component device
+ * @ops: component callbacks
+ * @subcomponent: nonzero identifier for subcomponents
+ *
+ * Register a new component for @dev. Functions in @ops will be call when the
+ * aggregate driver is ready to bind the overall driver by calling
+ * component_bind_all(). See also &struct component_ops.
+ *
+ * @subcomponent must be nonzero and is used to differentiate between multiple
+ * components registerd on the same device @dev. These components are match
+ * using component_match_add_typed().
+ *
+ * The component needs to be unregistered at driver unload/disconnect by
+ * calling component_del().
+ *
+ * See also component_add().
+ */
+int component_add_typed(struct device *dev, const struct component_ops *ops,
+ int subcomponent)
+{
+ if (WARN_ON(subcomponent == 0))
+ return -EINVAL;
+
+ return __component_add(dev, ops, subcomponent);
+}
+EXPORT_SYMBOL_GPL(component_add_typed);
+
+/**
+ * component_add - register a component
+ * @dev: component device
+ * @ops: component callbacks
+ *
+ * Register a new component for @dev. Functions in @ops will be called when the
+ * aggregate driver is ready to bind the overall driver by calling
+ * component_bind_all(). See also &struct component_ops.
+ *
+ * The component needs to be unregistered at driver unload/disconnect by
+ * calling component_del().
+ *
+ * See also component_add_typed() for a variant that allows multipled different
+ * components on the same device.
+ */
+int component_add(struct device *dev, const struct component_ops *ops)
+{
+ return __component_add(dev, ops, 0);
+}
EXPORT_SYMBOL_GPL(component_add);
+/**
+ * component_del - unregister a component
+ * @dev: component device
+ * @ops: component callbacks
+ *
+ * Unregister a component added with component_add(). If the component is bound
+ * into an aggregate driver, this will force the entire aggregate driver, including
+ * all its components, to be unbound.
+ */
void component_del(struct device *dev, const struct component_ops *ops)
{
struct component *c, *component = NULL;
@@ -603,5 +777,3 @@
kfree(component);
}
EXPORT_SYMBOL_GPL(component_del);
-
-MODULE_LICENSE("GPL v2");
--
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