[U-Boot] [PATCH 2/3] dm: add a command to list devices in a tree-like format

[Masahiro Yamada]

We are adding more and more drivers to driver model these days.
Compared with the ad-hoc driver system, it seems pretty difficult to
understand how drivers are working on driver model.  For ex.
  - Which devices have been bound?
  - Which devices have been probed?
  - Which is the parent of this device?
etc.

I hope this tool will help us test/review driver model patches.

Just hit "showdev" on the command line and it will list all the bound
devices in a tree-like format with Class and Probed flag.

  => showdev
   Class       Probed   Name
  ----------------------------------------
   root        [ + ]    root_driver
   demo        [   ]    |-- demo_shape_drv
   demo        [   ]    |-- demo_simple_drv
   demo        [   ]    |-- demo_shape_drv
   demo        [   ]    |-- demo_simple_drv
   demo        [   ]    |-- demo_shape_drv
   test        [   ]    |-- test_drv
   test        [   ]    |-- test_drv
   test        [   ]    |-- test_drv
   gpio        [   ]    |-- gpio_sandbox
   serial      [   ]    |-- serial_sandbox
   serial      [ + ]    |-- serial
   demo        [   ]    |-- triangle
   demo        [   ]    |-- square
   demo        [   ]    |-- hexagon
   gpio        [   ]    |-- gpios
   i2c         [ + ]    |-- i2c at 0
   i2c_eeprom  [ + ]    |   |-- eeprom at 2c
   i2c_emul    [ + ]    |   |   \-- emul
   i2c_generic [ + ]    |   \-- generic_59
   spi         [   ]    |-- spi at 0
   spi_emul    [   ]    |   \-- flash at 0
   cros_ec     [ + ]    \-- cros-ec at 0

Signed-off-by: Masahiro Yamada <yamada.m at jp.panasonic.com>
---

 common/Makefile      |  1 +
 common/cmd_showdev.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+)
 create mode 100644 common/cmd_showdev.c

diff --git a/common/Makefile b/common/Makefile
index 6cc4de8..c26c764 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_CMD_CPLBINFO) += cmd_cplbinfo.o
 obj-$(CONFIG_DATAFLASH_MMC_SELECT) += cmd_dataflash_mmc_mux.o
 obj-$(CONFIG_CMD_DATE) += cmd_date.o
 obj-$(CONFIG_CMD_DEMO) += cmd_demo.o
+obj-$(CONFIG_CMD_SHOWDEV) += cmd_showdev.o
 obj-$(CONFIG_CMD_SOUND) += cmd_sound.o
 ifdef CONFIG_4xx
 obj-$(CONFIG_CMD_SETGETDCR) += cmd_dcr.o
diff --git a/common/cmd_showdev.c b/common/cmd_showdev.c
new file mode 100644
index 0000000..6761865
--- /dev/null
+++ b/common/cmd_showdev.c
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2014 Panasonic Corporation
+ *   Author: Masahiro Yamada <yamada.m at jp.panasonic.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <dm/device.h>
+#include <dm/uclass.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define INDENT1 "    "
+#define INDENT2 "|   "
+#define INDENT3 "\\-- "
+#define INDENT4 "|-- "
+
+static void show_devices(struct udevice *dev, int depth, int last_flag)
+{
+	int i, is_last;
+	struct udevice *child;
+	char class_name[12];
+
+	/* print the first 11 characters to not break the tree-format. */
+	strlcpy(class_name, dev->uclass->uc_drv->name, sizeof(class_name));
+	printf(" %-11s ", class_name);
+
+	printf("[ %c ]    ", dev->flags & DM_FLAG_ACTIVATED ? '+' : ' ');
+
+	for (i = depth; i >= 0; i--) {
+		is_last = (last_flag >> i) & 1;
+		if (i) {
+			if (is_last)
+				printf(INDENT1);
+			else
+				printf(INDENT2);
+		} else {
+			if (is_last)
+				printf(INDENT3);
+			else
+				printf(INDENT4);
+		}
+	}
+
+	printf("%s\n", dev->name);
+
+	list_for_each_entry(child, &dev->child_head, sibling_node) {
+		last_flag <<= 1;
+		last_flag |= list_is_last(&child->sibling_node,
+					  &dev->child_head);
+		show_devices(child, depth + 1, last_flag);
+	}
+}
+
+static int do_showdev(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	printf(" Class       Probed   Name\n");
+	printf("----------------------------------------\n");
+
+	show_devices(gd->dm_root, -1, 0);
+
+	return 0;
+}
+
+U_BOOT_CMD(
+	showdev, 1, 1, do_showdev,
+	"show devices in a tree-like format.",
+	""
+);
-- 
1.9.1