cmd: Add a 'misc' command to access miscellaneous devices

Enable the command "misc" for accessing miscellaneous devices with
a MISC uclass driver. The command provides listing all MISC devices
as well as read and write functionalities via their drivers.

Signed-off-by: Bin Meng <bin.meng@windriver.com>

cmd/Kconfig

@@ -1025,6 +1025,14 @@ config CMD_LSBLK
 	  Print list of available block device drivers, and for each, the list
 	  of known block devices.
 
+config CMD_MISC
+	bool "misc"
+	depends on MISC
+	help
+	  Enable the command "misc" for accessing miscellaneous devices with
+	  a MISC uclass driver. The command provides listing all MISC devices
+	  as well as read and write functionalities via their drivers.
+
 config CMD_MMC
 	bool "mmc"
 	help

cmd/Makefile

@@ -94,6 +94,7 @@ obj-$(CONFIG_CMD_MEMORY) += mem.o
 obj-$(CONFIG_CMD_IO) += io.o
 obj-$(CONFIG_CMD_MFSL) += mfsl.o
 obj-$(CONFIG_CMD_MII) += mii.o
+obj-$(CONFIG_CMD_MISC) += misc.o
 obj-$(CONFIG_CMD_MDIO) += mdio.o
 obj-$(CONFIG_CMD_SLEEP) += sleep.o
 obj-$(CONFIG_CMD_MMC) += mmc.o

cmd/misc.c

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020 Wind River Systems, Inc.
+ *
+ * Author:
+ *   Bin Meng <bin.meng@windriver.com>
+ *
+ * A command interface to access misc devices with MISC uclass driver APIs.
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <errno.h>
+#include <misc.h>
+
+enum misc_op {
+	MISC_OP_READ,
+	MISC_OP_WRITE
+};
+
+static char *misc_op_str[] = {
+	"read",
+	"write"
+};
+
+static int do_misc_list(struct cmd_tbl *cmdtp, int flag,
+			int argc, char *const argv[])
+{
+	struct udevice *dev;
+
+	printf("Device               Index     Driver\n");
+	printf("-------------------------------------\n");
+	for (uclass_first_device(UCLASS_MISC, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		printf("%-20s %5d %10s\n", dev->name, dev->seq,
+		       dev->driver->name);
+	}
+
+	return 0;
+}
+
+static int do_misc_op(struct cmd_tbl *cmdtp, int flag,
+		      int argc, char *const argv[], enum misc_op op)
+{
+	int (*misc_op)(struct udevice *, int, void *, int);
+	struct udevice *dev;
+	int offset;
+	void *buf;
+	int size;
+	int ret;
+
+	ret = uclass_get_device_by_name(UCLASS_MISC, argv[0], &dev);
+	if (ret) {
+		printf("Unable to find device %s\n", argv[0]);
+		return ret;
+	}
+
+	offset = simple_strtoul(argv[1], NULL, 16);
+	buf = (void *)simple_strtoul(argv[2], NULL, 16);
+	size = simple_strtoul(argv[3], NULL, 16);
+
+	if (op == MISC_OP_READ)
+		misc_op = misc_read;
+	else
+		misc_op = misc_write;
+
+	ret = misc_op(dev, offset, buf, size);
+	if (ret < 0) {
+		if (ret == -ENOSYS) {
+			printf("The device does not support %s\n",
+			       misc_op_str[op]);
+			ret = 0;
+		}
+	} else {
+		if (ret == size)
+			ret = 0;
+		else
+			printf("Partially %s %d bytes\n", misc_op_str[op], ret);
+	}
+
+	return ret;
+}
+
+static int do_misc_read(struct cmd_tbl *cmdtp, int flag,
+			int argc, char *const argv[])
+{
+	return do_misc_op(cmdtp, flag, argc, argv, MISC_OP_READ);
+}
+
+static int do_misc_write(struct cmd_tbl *cmdtp, int flag,
+			 int argc, char *const argv[])
+{
+	return do_misc_op(cmdtp, flag, argc, argv, MISC_OP_WRITE);
+}
+
+static struct cmd_tbl misc_commands[] = {
+	U_BOOT_CMD_MKENT(list, 0, 1, do_misc_list, "", ""),
+	U_BOOT_CMD_MKENT(read, 4, 1, do_misc_read, "", ""),
+	U_BOOT_CMD_MKENT(write, 4, 1, do_misc_write, "", ""),
+};
+
+static int do_misc(struct cmd_tbl *cmdtp, int flag,
+		   int argc, char *const argv[])
+{
+	struct cmd_tbl *misc_cmd;
+	int ret;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+	misc_cmd = find_cmd_tbl(argv[1], misc_commands,
+				ARRAY_SIZE(misc_commands));
+	argc -= 2;
+	argv += 2;
+	if (!misc_cmd || argc != misc_cmd->maxargs)
+		return CMD_RET_USAGE;
+
+	ret = misc_cmd->cmd(misc_cmd, flag, argc, argv);
+
+	return cmd_process_error(misc_cmd, ret);
+}
+
+U_BOOT_CMD(
+	misc,	6,	1,	do_misc,
+	"Access miscellaneous devices with MISC uclass driver APIs",
+	"list                       - list all miscellaneous devices\n"
+	"misc read  name offset addr len - read `len' bytes starting at\n"
+	"				  `offset' of device `name'\n"
+	"				  to memory at `addr'\n"
+	"misc write name offset addr len - write `len' bytes starting at\n"
+	"				  `offset' of device `name'\n"
+	"				  from memory at `addr'"
+);