[PATCH v2 0/4] Introduce class devices

[PATCH v2 0/4] Introduce class devices

[Sascha Hauer]

Several subsystems already have a struct device embedded in their
subsystems specific structs. Allow to register these as class devices.
This way we collect devices of the same type on a list and can show
informations about these in a generic way.

Sascha Hauer (4):
  net: use for_each_netdev()
  base: add class device support
  net: register eth class
  watchdog: register watchdog class

Changes since v1:
- s/DECLARE_CLASS/DEFINE_DEV_CLASS
- explain why linker lists are used in commit message
- better Kconfig help test for class command

 commands/Kconfig                  |  6 +++++
 commands/Makefile                 |  1 +
 commands/class.c                  | 30 ++++++++++++++++++++++
 drivers/base/Makefile             |  1 +
 drivers/base/class.c              | 41 +++++++++++++++++++++++++++++++
 drivers/watchdog/wd_core.c        | 14 ++++++-----
 include/asm-generic/barebox.lds.h |  7 ++++++
 include/device.h                  | 21 ++++++++++++++++
 include/net.h                     |  4 +--
 net/eth.c                         | 12 +++++----
 net/ifup.c                        |  2 +-
 11 files changed, 125 insertions(+), 14 deletions(-)
 create mode 100644 commands/class.c
 create mode 100644 drivers/base/class.c

-- 
2.39.2

[PATCH v2 1/4] net: use for_each_netdev()

[Sascha Hauer]

We have a define to iterate over all network interfaces, use it on the
remaining places which still iterate over the list manually.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 net/eth.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/eth.c b/net/eth.c
index 98567d8d3f..26a36474f8 100644
--- a/net/eth.c
+++ b/net/eth.c
@@ -535,7 +535,7 @@ struct eth_device *of_find_eth_device_by_node(struct device_node *np)
 	 */
 	(void)of_device_ensure_probed(np);
 
-	list_for_each_entry(edev, &netdev_list, list)
+	for_each_netdev(edev)
 		if (edev->parent->of_node == np)
 			return edev;
 	return NULL;
@@ -546,7 +546,7 @@ void eth_open_all(void)
 {
 	struct eth_device *edev;
 
-	list_for_each_entry(edev, &netdev_list, list) {
+	for_each_netdev(edev) {
 		if (edev->global_mode == ETH_MODE_DISABLED)
 			continue;
 		eth_open(edev);
@@ -559,7 +559,7 @@ static int populate_ethaddr(void)
 	bool generated = false;
 	int ret;
 
-	list_for_each_entry(edev, &netdev_list, list) {
+	for_each_netdev(edev) {
 		if (!edev->parent || is_valid_ether_addr(edev->ethaddr))
 			continue;
 
-- 
2.39.2

[PATCH v2 2/4] base: add class device support

[Sascha Hauer]

This introduces the concept of class devices in barebox. Class devices
group together devices of the same type. Several subsystems like
watchdog and network devices have a struct device embedded in their
subsystem specific struct anyway, so we can use this as a class device.
As these class devices are collected on a list we can use this list to
iterate over all network/watchdog devices and thus free the subsystems
from the burden of keeping a list themselves.

There is a 'class' command added in this patch which can be used to show
all registered classes along with the devices registered for each class.

The classes known at compile time can be collected on a linker list
using the macro DEFINE_DEV_CLASS(). That way registering classes does
not need an additional initcall and also no care has to be taken that
this initcalls runs before the first user adds devices to a new class.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 commands/Kconfig                  |  6 +++++
 commands/Makefile                 |  1 +
 commands/class.c                  | 30 ++++++++++++++++++++++
 drivers/base/Makefile             |  1 +
 drivers/base/class.c              | 41 +++++++++++++++++++++++++++++++
 include/asm-generic/barebox.lds.h |  7 ++++++
 include/device.h                  | 21 ++++++++++++++++
 7 files changed, 107 insertions(+)
 create mode 100644 commands/class.c
 create mode 100644 drivers/base/class.c

diff --git a/commands/Kconfig b/commands/Kconfig
index 899673bfee..c9c4be67e0 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -68,6 +68,12 @@ config CMD_BOOTROM
 
 	  bootrom [-la]
 
+config CMD_CLASS
+	tristate
+	prompt "class"
+	help
+	  Show information about registered device classes
+
 config CMD_DEVINFO
 	tristate
 	default y
diff --git a/commands/Makefile b/commands/Makefile
index 30e1f8403e..f65187703f 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -115,6 +115,7 @@ obj-$(CONFIG_CMD_BAREBOX_UPDATE)+= barebox-update.o
 obj-$(CONFIG_CMD_MIITOOL)	+= miitool.o
 obj-$(CONFIG_CMD_DETECT)	+= detect.o
 obj-$(CONFIG_CMD_BOOT)		+= boot.o
+obj-$(CONFIG_CMD_CLASS)		+= class.o
 obj-$(CONFIG_CMD_DEVINFO)	+= devinfo.o
 obj-$(CONFIG_CMD_DEVUNBIND)	+= devunbind.o
 obj-$(CONFIG_CMD_DEVLOOKUP)	+= devlookup.o
diff --git a/commands/class.c b/commands/class.c
new file mode 100644
index 0000000000..f5d67b012f
--- /dev/null
+++ b/commands/class.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <common.h>
+#include <command.h>
+#include <complete.h>
+
+static int do_class(int argc, char *argv[])
+{
+	struct class *class;
+	struct device *dev;
+
+	class_for_each(class) {
+		printf("%s:\n", class->name);
+		class_for_each_device(class, dev) {
+			printf("    %s\n", dev_name(dev));
+		}
+	}
+
+	return 0;
+}
+
+BAREBOX_CMD_HELP_START(class)
+BAREBOX_CMD_HELP_TEXT("Show information about registered classes and their devices")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(class)
+	.cmd = do_class,
+	BAREBOX_CMD_DESC("show information about classes")
+	BAREBOX_CMD_GROUP(CMD_GRP_INFO)
+	BAREBOX_CMD_COMPLETE(empty_complete)
+BAREBOX_CMD_END
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index acc53763da..94b677eea0 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -3,6 +3,7 @@ obj-y	+= bus.o
 obj-y	+= driver.o
 obj-y	+= platform.o
 obj-y	+= resource.o
+obj-y	+= class.o
 obj-y	+= regmap/
 
 obj-$(CONFIG_PM_GENERIC_DOMAINS) += power.o
diff --git a/drivers/base/class.c b/drivers/base/class.c
new file mode 100644
index 0000000000..6757d34140
--- /dev/null
+++ b/drivers/base/class.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <device.h>
+#include <driver.h>
+#include <linux/list.h>
+
+LIST_HEAD(class_list);
+
+static int class_register(struct class *class)
+{
+	list_add_tail(&class->list, &class_list);
+
+	return 0;
+}
+
+int class_add_device(struct class *class, struct device *dev)
+{
+	list_add_tail(&dev->class_list, &class->devices);
+
+	return 0;
+}
+
+void class_remove_device(struct class *class, struct device *dev)
+{
+	list_del(&class->devices);
+}
+
+extern struct class __barebox_class_start;
+extern struct class __barebox_class_end;
+
+static int register_classes(void)
+{
+	struct class *c;
+
+	for (c = &__barebox_class_start;
+	     c != &__barebox_class_end;
+	     c++)
+		class_register(c);
+
+	return 0;
+}
+device_initcall(register_classes);
diff --git a/include/asm-generic/barebox.lds.h b/include/asm-generic/barebox.lds.h
index d3736ebaed..8bbf5907cd 100644
--- a/include/asm-generic/barebox.lds.h
+++ b/include/asm-generic/barebox.lds.h
@@ -70,6 +70,12 @@
 	KEEP(*(SORT_BY_NAME(.barebox_magicvar*)))	\
 	__barebox_magicvar_end = .;
 
+#define BAREBOX_CLASSES				\
+	STRUCT_ALIGN();				\
+	__barebox_class_start = .;		\
+	KEEP(*(SORT_BY_NAME(.barebox_class*)))	\
+	__barebox_class_end = .;
+
 #define BAREBOX_CLK_TABLE			\
 	STRUCT_ALIGN();				\
 	__clk_of_table_start = .;		\
@@ -138,6 +144,7 @@
 	BAREBOX_SYMS				\
 	KERNEL_CTORS()				\
 	BAREBOX_MAGICVARS			\
+	BAREBOX_CLASSES				\
 	BAREBOX_CLK_TABLE			\
 	BAREBOX_DTB				\
 	BAREBOX_RSA_KEYS			\
diff --git a/include/device.h b/include/device.h
index ad1bc7ca1e..992ac7aa7b 100644
--- a/include/device.h
+++ b/include/device.h
@@ -76,6 +76,8 @@ struct device {
 
 	struct list_head cdevs;
 
+	struct list_head class_list;
+
 	const struct platform_device_id *id_entry;
 	union {
 		struct device_node *device_node;
@@ -102,6 +104,25 @@ struct device {
 	char *deferred_probe_reason;
 };
 
+struct class {
+	const char *name;
+	struct list_head devices;
+	struct list_head list;
+};
+
+#define DEFINE_DEV_CLASS(_name, _classname)					\
+	struct class _name __ll_elem(.barebox_class_##_name) = {		\
+		.name = _classname,						\
+		.devices = LIST_HEAD_INIT(_name.devices),			\
+	}
+
+int class_add_device(struct class *class, struct device *dev);
+void class_remove_device(struct class *class, struct device *dev);
+
+extern struct list_head class_list;
+#define class_for_each_device(class, dev) list_for_each_entry(dev, &class->devices, class_list)
+#define class_for_each(class) list_for_each_entry(class, &class_list, list)
+
 struct device_alias {
 	struct device *dev;
 	struct list_head list;
-- 
2.39.2

[PATCH v2 3/4] net: register eth class

[Sascha Hauer]

Register network devices as class devices. This allows us to implement
for_each_netdev() by iterating over the network class devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 include/net.h | 4 ++--
 net/eth.c     | 6 ++++--
 net/ifup.c    | 2 +-
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/include/net.h b/include/net.h
index 5a6dd9ca7b..edfea0d105 100644
--- a/include/net.h
+++ b/include/net.h
@@ -599,8 +599,8 @@ void ifdown_edev(struct eth_device *edev);
 int ifdown(const char *name);
 void ifdown_all(void);
 
-extern struct list_head netdev_list;
+#define for_each_netdev(netdev) list_for_each_entry(netdev, &eth_class.devices, dev.class_list)
 
-#define for_each_netdev(netdev) list_for_each_entry(netdev, &netdev_list, list)
+extern struct class eth_class;
 
 #endif /* __NET_H__ */
diff --git a/net/eth.c b/net/eth.c
index 26a36474f8..9d7b5994a2 100644
--- a/net/eth.c
+++ b/net/eth.c
@@ -21,7 +21,7 @@
 #include <linux/ctype.h>
 #include <linux/stat.h>
 
-LIST_HEAD(netdev_list);
+DEFINE_DEV_CLASS(eth_class, "eth");
 
 struct eth_ethaddr {
 	struct list_head list;
@@ -445,7 +445,7 @@ int eth_register(struct eth_device *edev)
 	if (edev->init)
 		edev->init(edev);
 
-	list_add_tail(&edev->list, &netdev_list);
+	class_add_device(&eth_class, &edev->dev);
 
 	ret = eth_get_registered_ethaddr(edev, ethaddr);
 	if (!ret)
@@ -512,6 +512,8 @@ void eth_unregister(struct eth_device *edev)
 	if (IS_ENABLED(CONFIG_OFDEVICE))
 		free(edev->nodepath);
 
+	class_remove_device(&eth_class, &edev->dev);
+
 	free(edev->devname);
 
 	unregister_device(&edev->dev);
diff --git a/net/ifup.c b/net/ifup.c
index 5b92ee794d..41c1942670 100644
--- a/net/ifup.c
+++ b/net/ifup.c
@@ -358,7 +358,7 @@ int ifup_all(unsigned flags)
 	closedir(dir);
 
 	if ((flags & IFUP_FLAG_FORCE) || net_ifup_force_detect ||
-	    list_empty(&netdev_list))
+	    list_empty(&eth_class.devices))
 		device_detect_all();
 
 	/*
-- 
2.39.2

[PATCH v2 4/4] watchdog: register watchdog class

[Sascha Hauer]

Register watchdog devices as class devices. This allows us to implement
for_each_watchdog() by iterating over the network class devices.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/watchdog/wd_core.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/watchdog/wd_core.c b/drivers/watchdog/wd_core.c
index 42cbd7b72c..90ae233b0f 100644
--- a/drivers/watchdog/wd_core.c
+++ b/drivers/watchdog/wd_core.c
@@ -11,7 +11,9 @@
 #include <watchdog.h>
 #include <restart.h>
 
-static LIST_HEAD(watchdog_list);
+#define for_each_watchdog(wd) list_for_each_entry(wd, &watchdog_class.devices, dev.class_list)
+
+DEFINE_DEV_CLASS(watchdog_class, "watchdog");
 
 static const char *watchdog_name(struct watchdog *wd)
 {
@@ -267,7 +269,7 @@ int watchdog_register(struct watchdog *wd)
 			dev_warn(&wd->dev, "failed to register restart handler\n");
 	}
 
-	list_add_tail(&wd->list, &watchdog_list);
+	class_add_device(&watchdog_class, &wd->dev);
 
 	pr_debug("registering watchdog %s with priority %d\n", watchdog_name(wd),
 			wd->priority);
@@ -287,7 +289,7 @@ int watchdog_deregister(struct watchdog *wd)
 		poller_async_unregister(&wd->poller);
 	}
 
-	unregister_device(&wd->dev);
+	class_remove_device(&watchdog_class, &wd->dev);
 	list_del(&wd->list);
 
 	return 0;
@@ -299,7 +301,7 @@ struct watchdog *watchdog_get_default(void)
 	struct watchdog *tmp, *wd = NULL;
 	int priority = 0;
 
-	list_for_each_entry(tmp, &watchdog_list, list) {
+	for_each_watchdog(tmp) {
 		if (tmp->priority > priority) {
 			priority = tmp->priority;
 			wd = tmp;
@@ -336,7 +338,7 @@ struct watchdog *watchdog_get_by_name(const char *name)
 	if (!dev)
 		return NULL;
 
-	list_for_each_entry(tmp, &watchdog_list, list) {
+	for_each_watchdog(tmp) {
 		if (dev == tmp->hwdev || dev == &tmp->dev)
 			return tmp;
 	}
@@ -350,7 +352,7 @@ int watchdog_inhibit_all(void)
 	struct watchdog *wd;
 	int ret = 0;
 
-	list_for_each_entry(wd, &watchdog_list, list) {
+	for_each_watchdog(wd) {
 		int err;
 		if (!wd->priority || watchdog_hw_running(wd) == false)
 			continue;
-- 
2.39.2

Re: [PATCH v2 0/4] Introduce class devices

[Sascha Hauer]

On Tue, 11 Jun 2024 07:12:33 +0200, Sascha Hauer wrote:
> Several subsystems already have a struct device embedded in their
> subsystems specific structs. Allow to register these as class devices.
> This way we collect devices of the same type on a list and can show
> informations about these in a generic way.
> 
> Sascha Hauer (4):
>   net: use for_each_netdev()
>   base: add class device support
>   net: register eth class
>   watchdog: register watchdog class
> 
> [...]

Applied, thanks!

[1/4] net: use for_each_netdev()
      https://git.pengutronix.de/cgit/barebox/commit/?id=063f92edfa7a (link may not be stable)
[2/4] base: add class device support
      https://git.pengutronix.de/cgit/barebox/commit/?id=5d1215ff694a (link may not be stable)
[3/4] net: register eth class
      https://git.pengutronix.de/cgit/barebox/commit/?id=045fd2a498cc (link may not be stable)
[4/4] watchdog: register watchdog class
      https://git.pengutronix.de/cgit/barebox/commit/?id=aa90aa4a0588 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>