cmd: Add bind/unbind commands to bind a device to a driver from the command line

In some cases it can be useful to be able to bind a device to a driver from
the command line.
The obvious example is for versatile devices such as USB gadget.
Another use case is when the devices are not yet ready at startup and
require some setup before the drivers are bound (ex: FPGA which bitsream is
fetched from a mass storage or ethernet)

usage example:

bind usb_dev_generic 0 usb_ether
unbind usb_dev_generic 0 usb_ether
or
unbind eth 1

bind /ocp/omap_dwc3@48380000/usb@48390000 usb_ether
unbind /ocp/omap_dwc3@48380000/usb@48390000

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

arch/sandbox/dts/test.dts

@@ -61,6 +61,17 @@
 		reg = <2 1>;
 	};
 
+	bind-test {
+		bind-test-child1 {
+			compatible = "sandbox,phy";
+			#phy-cells = <1>;
+		};
+
+		bind-test-child2 {
+			compatible = "simple-bus";
+		};
+	};
+
 	b-test {
 		reg = <3 1>;
 		compatible = "denx,u-boot-fdt-test";

cmd/Kconfig

@@ -607,6 +607,15 @@ config CMD_ADC
 	  Shows ADC device info and permit printing one-shot analog converted
 	  data from a named Analog to Digital Converter.
 
+config CMD_BIND
+	bool "bind/unbind - Bind or unbind a device to/from a driver"
+	depends on DM
+	help
+	  Bind or unbind a device to/from a driver from the command line.
+	  This is useful in situations where a device may be handled by several
+	  drivers. For example, this can be used to bind a UDC to the usb ether
+	  gadget driver from the command line.
+
 config CMD_CLK
 	bool "clk - Show clock frequencies"
 	help

cmd/Makefile

@@ -19,6 +19,7 @@ obj-$(CONFIG_SOURCE) += source.o
 obj-$(CONFIG_CMD_SOURCE) += source.o
 obj-$(CONFIG_CMD_BDI) += bdinfo.o
 obj-$(CONFIG_CMD_BEDBUG) += bedbug.o
+obj-$(CONFIG_CMD_BIND) += bind.o
 obj-$(CONFIG_CMD_BINOP) += binop.o
 obj-$(CONFIG_CMD_BLOCK_CACHE) += blkcache.o
 obj-$(CONFIG_CMD_BMP) += bmp.o

cmd/bind.c

@@ -0,0 +1,255 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2018 JJ Hiblot <jjhiblot@ti.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/uclass-internal.h>
+
+static int bind_by_class_index(const char *uclass, int index,
+			       const char *drv_name)
+{
+	static enum uclass_id uclass_id;
+	struct udevice *dev;
+	struct udevice *parent;
+	int ret;
+	struct driver *drv;
+
+	drv = lists_driver_lookup_name(drv_name);
+	if (!drv) {
+		printf("Cannot find driver '%s'\n", drv_name);
+		return -ENOENT;
+	}
+
+	uclass_id = uclass_get_by_name(uclass);
+	if (uclass_id == UCLASS_INVALID) {
+		printf("%s is not a valid uclass\n", uclass);
+		return -EINVAL;
+	}
+
+	ret = uclass_find_device(uclass_id, index, &parent);
+	if (!parent || ret) {
+		printf("Cannot find device %d of class %s\n", index, uclass);
+		return ret;
+	}
+
+	ret = device_bind_with_driver_data(parent, drv, drv->name, 0,
+					   ofnode_null(), &dev);
+	if (!dev || ret) {
+		printf("Unable to bind. err:%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int find_dev(const char *uclass, int index, struct udevice **devp)
+{
+	static enum uclass_id uclass_id;
+	int rc;
+
+	uclass_id = uclass_get_by_name(uclass);
+	if (uclass_id == UCLASS_INVALID) {
+		printf("%s is not a valid uclass\n", uclass);
+		return -EINVAL;
+	}
+
+	rc = uclass_find_device(uclass_id, index, devp);
+	if (!*devp || rc) {
+		printf("Cannot find device %d of class %s\n", index, uclass);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int unbind_by_class_index(const char *uclass, int index)
+{
+	int ret;
+	struct udevice *dev;
+
+	ret = find_dev(uclass, index, &dev);
+	if (ret)
+		return ret;
+
+	ret = device_remove(dev, DM_REMOVE_NORMAL);
+	if (ret) {
+		printf("Unable to remove. err:%d\n", ret);
+		return ret;
+	}
+
+	ret = device_unbind(dev);
+	if (ret) {
+		printf("Unable to unbind. err:%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int unbind_child_by_class_index(const char *uclass, int index,
+				       const char *drv_name)
+{
+	struct udevice *parent;
+	int ret;
+	struct driver *drv;
+
+	drv = lists_driver_lookup_name(drv_name);
+	if (!drv) {
+		printf("Cannot find driver '%s'\n", drv_name);
+		return -ENOENT;
+	}
+
+	ret = find_dev(uclass, index, &parent);
+	if (ret)
+		return ret;
+
+	ret = device_chld_remove(parent, drv, DM_REMOVE_NORMAL);
+	if (ret)
+		printf("Unable to remove all. err:%d\n", ret);
+
+	ret = device_chld_unbind(parent, drv);
+	if (ret)
+		printf("Unable to unbind all. err:%d\n", ret);
+
+	return ret;
+}
+
+static int bind_by_node_path(const char *path, const char *drv_name)
+{
+	struct udevice *dev;
+	struct udevice *parent = NULL;
+	int ret;
+	ofnode ofnode;
+	struct driver *drv;
+
+	drv = lists_driver_lookup_name(drv_name);
+	if (!drv) {
+		printf("%s is not a valid driver name\n", drv_name);
+		return -ENOENT;
+	}
+
+	ofnode = ofnode_path(path);
+	if (!ofnode_valid(ofnode)) {
+		printf("%s is not a valid node path\n", path);
+		return -EINVAL;
+	}
+
+	while (ofnode_valid(ofnode)) {
+		if (!device_find_global_by_ofnode(ofnode, &parent))
+			break;
+		ofnode = ofnode_get_parent(ofnode);
+	}
+
+	if (!parent) {
+		printf("Cannot find a parent device for node path %s\n", path);
+		return -ENODEV;
+	}
+
+	ofnode = ofnode_path(path);
+	ret = device_bind_with_driver_data(parent, drv, ofnode_get_name(ofnode),
+					   0, ofnode, &dev);
+	if (!dev || ret) {
+		printf("Unable to bind. err:%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int unbind_by_node_path(const char *path)
+{
+	struct udevice *dev;
+	int ret;
+	ofnode ofnode;
+
+	ofnode = ofnode_path(path);
+	if (!ofnode_valid(ofnode)) {
+		printf("%s is not a valid node path\n", path);
+		return -EINVAL;
+	}
+
+	ret = device_find_global_by_ofnode(ofnode, &dev);
+
+	if (!dev || ret) {
+		printf("Cannot find a device with path %s\n", path);
+		return -ENODEV;
+	}
+
+	ret = device_remove(dev, DM_REMOVE_NORMAL);
+	if (ret) {
+		printf("Unable to remove. err:%d\n", ret);
+		return ret;
+	}
+
+	ret = device_unbind(dev);
+	if (ret) {
+		printf("Unable to unbind. err:%d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int do_bind_unbind(cmd_tbl_t *cmdtp, int flag, int argc,
+			  char * const argv[])
+{
+	int ret = 0;
+	bool bind;
+	bool by_node;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	bind = (argv[0][0] == 'b');
+	by_node = (argv[1][0] == '/');
+
+	if (by_node && bind) {
+		if (argc != 3)
+			return CMD_RET_USAGE;
+		ret = bind_by_node_path(argv[1], argv[2]);
+	} else if (by_node && !bind) {
+		if (argc != 2)
+			return CMD_RET_USAGE;
+		ret = unbind_by_node_path(argv[1]);
+	} else if (!by_node && bind) {
+		int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
+
+		if (argc != 4)
+			return CMD_RET_USAGE;
+		ret = bind_by_class_index(argv[1], index, argv[3]);
+	} else if (!by_node && !bind) {
+		int index = (argc > 2) ? simple_strtoul(argv[2], NULL, 10) : 0;
+
+		if (argc == 3)
+			ret = unbind_by_class_index(argv[1], index);
+		else if (argc == 4)
+			ret = unbind_child_by_class_index(argv[1], index,
+							  argv[3]);
+		else
+			return CMD_RET_USAGE;
+	}
+
+	if (ret)
+		return CMD_RET_FAILURE;
+	else
+		return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(
+	bind,	4,	0,	do_bind_unbind,
+	"Bind a device to a driver",
+	"<node path> <driver>\n"
+	"bind <class> <index> <driver>\n"
+);
+
+U_BOOT_CMD(
+	unbind,	4,	0,	do_bind_unbind,
+	"Unbind a device from a driver",
+	"<node path>\n"
+	"unbind <class> <index>\n"
+	"unbind <class> <index> <driver>\n"
+);

configs/sandbox_defconfig

@@ -34,6 +34,7 @@ CONFIG_CMD_MD5SUM=y
 CONFIG_CMD_MEMINFO=y
 CONFIG_CMD_MEMTEST=y
 CONFIG_CMD_MX_CYCLIC=y
+CONFIG_CMD_BIND=y
 CONFIG_CMD_DEMO=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_GPT=y

test/py/tests/test_bind.py

@@ -0,0 +1,178 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
+
+import os.path
+import pytest
+import re
+
+def in_tree(response, name, uclass, drv, depth, last_child):
+	lines = [x.strip() for x in response.splitlines()]
+	leaf = ' ' * 4 * depth;
+	if not last_child:
+		leaf = leaf + '\|'
+	else:
+		leaf = leaf + '`'
+	leaf = leaf + '-- ' + name
+	line = ' *{:10.10}  [0-9]*  \[ [ +] \]   {:10.10}  {}$'.format(uclass, drv,leaf)
+	prog = re.compile(line)
+	for l in lines:
+		if prog.match(l):
+			return True
+	return False
+
+
+@pytest.mark.buildconfigspec('cmd_bind')
+def test_bind_unbind_with_node(u_boot_console):
+
+	#bind /bind-test. Device should come up as well as its children
+	response = u_boot_console.run_command("bind  /bind-test generic_simple_bus")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert in_tree(tree, "bind-test-child1", "phy", "phy_sandbox", 1, False)
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+
+	#Unbind child #1. No error expected and all devices should be there except for bind-test-child1
+	response = u_boot_console.run_command("unbind  /bind-test/bind-test-child1")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert "bind-test-child1" not in tree
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+
+	#bind child #1. No error expected and all devices should be there
+	response = u_boot_console.run_command("bind  /bind-test/bind-test-child1 phy_sandbox")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert in_tree(tree, "bind-test-child1", "phy", "phy_sandbox", 1, True)
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, False)
+
+	#Unbind child #2. No error expected and all devices should be there except for bind-test-child2
+	response = u_boot_console.run_command("unbind  /bind-test/bind-test-child2")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert in_tree(tree, "bind-test-child1", "phy", "phy_sandbox", 1, True)
+	assert "bind-test-child2" not in tree
+
+
+	#Bind child #2. No error expected and all devices should be there
+	response = u_boot_console.run_command("bind /bind-test/bind-test-child2 generic_simple_bus")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert in_tree(tree, "bind-test-child1", "phy", "phy_sandbox", 1, False)
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+
+	#Unbind parent. No error expected. All devices should be removed and unbound
+	response = u_boot_console.run_command("unbind  /bind-test")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert "bind-test" not in tree
+	assert "bind-test-child1" not in tree
+	assert "bind-test-child2" not in tree
+
+	#try binding invalid node with valid driver
+	response = u_boot_console.run_command("bind  /not-a-valid-node generic_simple_bus")
+	assert response != ''
+	tree = u_boot_console.run_command("dm tree")
+	assert "not-a-valid-node" not in tree
+
+	#try binding valid node with invalid driver
+	response = u_boot_console.run_command("bind  /bind-test not_a_driver")
+	assert response != ''
+	tree = u_boot_console.run_command("dm tree")
+	assert "bind-test" not in tree
+
+	#bind /bind-test. Device should come up as well as its children
+	response = u_boot_console.run_command("bind  /bind-test generic_simple_bus")
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test", "simple_bus", "generic_simple", 0, True)
+	assert in_tree(tree, "bind-test-child1", "phy", "phy_sandbox", 1, False)
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+
+	response = u_boot_console.run_command("unbind  /bind-test")
+	assert response == ''
+
+def get_next_line(tree, name):
+	treelines = [x.strip() for x in tree.splitlines() if x.strip()]
+	child_line = ""
+	for idx, line in enumerate(treelines):
+		if ("-- " + name) in line:
+			try:
+				child_line = treelines[idx+1]
+			except:
+				pass
+			break
+	return child_line
+
+@pytest.mark.buildconfigspec('cmd_bind')
+def test_bind_unbind_with_uclass(u_boot_console):
+	#bind /bind-test
+	response = u_boot_console.run_command("bind  /bind-test generic_simple_bus")
+	assert response == ''
+
+	#make sure bind-test-child2 is there and get its uclass/index pair
+	tree = u_boot_console.run_command("dm tree")
+	child2_line = [x.strip() for x in tree.splitlines() if "-- bind-test-child2" in x]
+	assert len(child2_line) == 1
+
+	child2_uclass = child2_line[0].split()[0]
+	child2_index = int(child2_line[0].split()[1])
+
+	#bind generic_simple_bus as a child of bind-test-child2
+	response = u_boot_console.run_command("bind  {} {} generic_simple_bus".format(child2_uclass, child2_index, "generic_simple_bus"))
+
+	#check that the child is there and its uclass/index pair is right
+	tree = u_boot_console.run_command("dm tree")
+
+	child_of_child2_line = get_next_line(tree, "bind-test-child2")
+	assert child_of_child2_line
+	child_of_child2_index = int(child_of_child2_line.split()[1])
+	assert in_tree(tree, "generic_simple_bus", "simple_bus", "generic_simple_bus", 2, True)
+	assert child_of_child2_index == child2_index + 1
+
+	#unbind the child and check it has been removed
+	response = u_boot_console.run_command("unbind  simple_bus {}".format(child_of_child2_index))
+	assert response == ''
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+	assert not in_tree(tree, "generic_simple_bus", "simple_bus", "generic_simple_bus", 2, True)
+	child_of_child2_line = get_next_line(tree, "bind-test-child2")
+	assert child_of_child2_line == ""
+
+	#bind generic_simple_bus as a child of bind-test-child2
+	response = u_boot_console.run_command("bind  {} {} generic_simple_bus".format(child2_uclass, child2_index, "generic_simple_bus"))
+
+	#check that the child is there and its uclass/index pair is right
+	tree = u_boot_console.run_command("dm tree")
+	treelines = [x.strip() for x in tree.splitlines() if x.strip()]
+
+	child_of_child2_line = get_next_line(tree, "bind-test-child2")
+	assert child_of_child2_line
+	child_of_child2_index = int(child_of_child2_line.split()[1])
+	assert in_tree(tree, "generic_simple_bus", "simple_bus", "generic_simple_bus", 2, True)
+	assert child_of_child2_index == child2_index + 1
+
+	#unbind the child and check it has been removed
+	response = u_boot_console.run_command("unbind  {} {} generic_simple_bus".format(child2_uclass, child2_index, "generic_simple_bus"))
+	assert response == ''
+
+	tree = u_boot_console.run_command("dm tree")
+	assert in_tree(tree, "bind-test-child2", "simple_bus", "generic_simple", 1, True)
+
+	child_of_child2_line = get_next_line(tree, "bind-test-child2")
+	assert child_of_child2_line == ""
+
+	#unbind the child again and check it doesn't change the tree
+	tree_old = u_boot_console.run_command("dm tree")
+	response = u_boot_console.run_command("unbind  {} {} generic_simple_bus".format(child2_uclass, child2_index, "generic_simple_bus"))
+	tree_new = u_boot_console.run_command("dm tree")
+
+	assert response == ''
+	assert tree_old == tree_new
+
+	response = u_boot_console.run_command("unbind  /bind-test")
+	assert response == ''