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>

3 files changed, 265 insertions, 0 deletions

diff --git a/cmd/Kconfig b/cmd/Kconfig
index d5abcfd42a..b667df8985 100644
--- a/cmd/Kconfig
+++ b/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
diff --git a/cmd/Makefile b/cmd/Makefile
index 12d2118f1d..ef0213580d 100644
--- a/cmd/Makefile
+++ b/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
diff --git a/cmd/bind.c b/cmd/bind.c
new file mode 100644
index 0000000000..44a5f17f0d
--- /dev/null
+++ b/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"
+);