Merge branch 'for-next/state'

Documentation/devicetree/bindings/barebox/barebox,state.rst

@@ -0,0 +1,107 @@
+barebox,state
+=============
+
+Overview
+--------
+
+
+Boards often have the need to store variables in persistent memory.
+The constraints are often different from what the regular environment
+can do:
+
+* compact binary format to make it suitable for small EEPROMs/MRAMs
+* atomic save/restore of the whole variable set
+* redundancy
+
+``barebox,state`` is a framework to describe, access, store and
+restore a set of variables. A state variable set can be fully
+described in a devicetree node. This node could be part of the regular
+devicetree blob or it could be an extra devicetree solely for the
+state. The state variable set contains variables of different types
+and a place to store the variable set.
+
+A state node contains a description of a set of variables along with a
+place where the variables are stored.
+
+Required properties:
+
+* ``compatible``: should be ``barebox,state``;
+* ``magic``: A 32bit number used as a magic to identify the state
+
+Optional properties:
+
+* ``backend``: describes where the data for this state is stored
+* ``backend-type``: should be ``raw`` or ``dtb``.
+
+Variable nodes
+--------------
+
+These are subnodes of a state node each describing a single
+variable. The node name may end with ``@<ADDRESS>``, but the suffix is
+sripped from the variable name.
+
+State variables have a type. Currenty supported types are: ``uint32``,
+``enum32`` and ``mac`` address. Fixed length strings are planned but
+not implemented. Variable length strings are not planned.
+
+Required properties:
+
+* ``reg``: Standard ``reg`` property with ``#address-cells = <1>`` and
+  ``#size-cells = <1>``. Defines the ``offset`` and ``size`` of the
+  variable in the ``raw`` backend. ``size`` must fit the node
+  ``type``. Variables are not allowed to overlap.
+* ``type``: Should be ``uint32``, ``enum32`` or ``mac`` for the type
+  of the variable
+* ``names``: For ``enum32`` values only, this specifies the values
+  possible for ``enum32``.
+
+Optional properties:
+
+* ``default``: The default value if the variable cannot be read from
+  storage. For ``enum32`` values it is an integer representing an
+  offset into the names array.
+
+Example::
+
+  state: state@0 {
+  	magic = <0x27031977>;
+  	compatible = "barebox,state";
+  	backend-type = "raw";
+  	backend = &eeprom, "partname:state";
+
+  	foo {
+		reg = <0x00 0x4>;
+  		type = "u32";
+  		default = <0x0>;
+  	};
+
+  	bar {
+		reg = <0x10 0x4>;
+  		type = "enum32";
+  		names = "baz", "qux";
+  		default ="qux";
+  	};
+  };
+
+Backends
+--------
+
+Currently two backends exist. The raw backend is a very compact format
+consisting of a magic value for identification, the raw values and a
+CRC. Two copies are maintained for making sure that during update the
+storage device still contains a valid state. The dtb backend stores
+the state as a devicetree binary blob. This is exactly the original
+devicetree description of the state itself, but additionally contains
+the actual values of the variables. Unlike the raw state backend the
+dtb state backend can describe itself.
+
+Frontend
+--------
+
+As frontend a state instance is a regular barebox device which has
+device parameters for the state variables. With this the variables can
+be accessed like normal shell variables. The ``state`` command is used
+to save/restore a state to the backend device.
+
+After initializing the variable can be accessed with ``$state.foo``.
+``state -s`` stores the state to eeprom.

commands/Kconfig

@@ -2096,6 +2096,11 @@ config CMD_TIME
 	  Note: This command depends on COMMAND being interruptible,
 	  otherwise the timer may overrun resulting in incorrect results
 
+config CMD_STATE
+	tristate
+	depends on STATE
+	prompt "state"
+
 # end Miscellaneous commands
 endmenu
 

commands/Makefile

@@ -110,3 +110,4 @@ obj-$(CONFIG_CMD_FIRMWARELOAD)	+= firmwareload.o
 obj-$(CONFIG_CMD_CMP)		+= cmp.o
 obj-$(CONFIG_CMD_NV)		+= nv.o
 obj-$(CONFIG_CMD_DEFAULTENV)	+= defaultenv.o
+obj-$(CONFIG_CMD_STATE)		+= state.o

commands/state.c

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2012 Jan Luebbe <j.luebbe@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <getopt.h>
+#include <command.h>
+#include <state.h>
+
+static int do_state(int argc, char *argv[])
+{
+	int opt, ret = 0;
+	struct state *state = NULL;
+	int do_save = 0, do_load = 0;
+	const char *statename = "state";
+
+	while ((opt = getopt(argc, argv, "sl")) > 0) {
+		switch (opt) {
+		case 's':
+			do_save = 1;
+			break;
+		case 'l':
+			do_load = 1;
+			break;
+		default:
+			return COMMAND_ERROR_USAGE;
+		}
+	}
+
+	if (do_save && do_load)
+		return COMMAND_ERROR_USAGE;
+
+	if (!do_save && !do_load) {
+		state_info();
+		return 0;
+	}
+
+	if (optind < argc)
+		statename = argv[optind];
+
+	state = state_by_name(statename);
+	if (!state) {
+		printf("cannot find state %s\n", statename);
+		return -ENOENT;
+	}
+
+	if (do_save)
+		ret = state_save(state);
+	else if (do_load)
+		ret = state_load(state);
+
+	return ret;
+}
+
+static const __maybe_unused char cmd_state_help[] =
+"Usage: state [OPTIONS] [STATENAME]\n"
+"\n"
+"options:\n"
+"-s        save state\n"
+"-l        load state\n";
+
+BAREBOX_CMD_START(state)
+	.cmd		= do_state,
+	BAREBOX_CMD_DESC("handle state information")
+	BAREBOX_CMD_GROUP(CMD_GRP_MISC)
+	BAREBOX_CMD_HELP(cmd_state_help)
+BAREBOX_CMD_END

common/Kconfig

@@ -706,6 +706,13 @@ config BAREBOXCRC32_TARGET
 config POLLER
 	bool "generic polling infrastructure"
 
+config STATE
+	bool "generic state infrastructure"
+	depends on OF_BAREBOX_DRIVERS
+	select ENVIRONMENT_VARIABLES
+	select OFTREE
+	select PARAMETER
+
 config RESET_SOURCE
 	bool "detect Reset cause"
 	depends on GLOBALVAR

common/Makefile

@@ -42,6 +42,7 @@ obj-$(CONFIG_POLLER)		+= poller.o
 obj-$(CONFIG_RESET_SOURCE)	+= reset_source.o
 obj-$(CONFIG_SHELL_HUSH)	+= hush.o
 obj-$(CONFIG_SHELL_SIMPLE)	+= parser.o
+obj-$(CONFIG_STATE)		+= state.o
 obj-$(CONFIG_UIMAGE)		+= image.o uimage.o
 obj-$(CONFIG_MENUTREE)		+= menutree.o
 obj-$(CONFIG_EFI_GUID)		+= efi-guid.o

drivers/misc/Kconfig

@@ -15,4 +15,8 @@ config SRAM
 	help
 	  This driver adds support for memory mapped SRAM.
 
+config STATE_DRV
+	tristate "state driver"
+	depends on STATE
+
 endmenu

drivers/misc/Makefile

@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_JTAG)		+= jtag.o
 obj-$(CONFIG_SRAM)		+= sram.o
+obj-$(CONFIG_STATE_DRV)		+= state.o

drivers/misc/state.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2013 Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <malloc.h>
+#include <of.h>
+#include <state.h>
+
+#include <linux/err.h>
+
+static int state_probe(struct device_d *dev)
+{
+	struct device_node *np = dev->device_node;
+	struct state *state;
+	const char *alias;
+	const char *backend_type = NULL;
+	int ret;
+	char *path;
+
+	if (!np)
+		return -EINVAL;
+
+	alias = of_alias_get(np);
+	if (!alias)
+		alias = "state";
+
+	state = state_new_from_node(alias, np);
+	if (IS_ERR(state))
+		return PTR_ERR(state);
+
+	ret = of_find_path(np, "backend", &path);
+	if (ret)
+		return ret;
+
+	dev_info(dev, "outpath: %s\n", path);
+
+	ret = of_property_read_string(np, "backend-type", &backend_type);
+	if (ret)
+		return ret;
+	else if (!strcmp(backend_type, "raw"))
+		ret = state_backend_raw_file(state, path, 0, 0);
+	else if (!strcmp(backend_type, "dtb"))
+		ret = state_backend_dtb_file(state, path);
+	else
+		dev_warn(dev, "invalid backend type: %s\n", backend_type);
+
+	if (ret)
+		return ret;
+
+	state_load(state);
+
+	return 0;
+}
+
+static __maybe_unused struct of_device_id state_ids[] = {
+	{
+		.compatible = "barebox,state",
+	}, {
+		/* sentinel */
+	}
+};
+
+static struct driver_d state_driver = {
+	.name = "state",
+	.probe = state_probe,
+	.of_compatible = DRV_OF_COMPAT(state_ids),
+};
+device_platform_driver(state_driver);

include/state.h

@@ -0,0 +1,21 @@
+#ifndef __STATE_H
+#define __STATE_H
+
+struct state;
+
+int state_backend_dtb_file(struct state *state, const char *path);
+int state_backend_raw_file(struct state *state, const char *path,
+		off_t offset, size_t size);
+
+struct state *state_new_from_fdt(const char *name, void *fdt);
+struct state *state_new_from_node(const char *name, struct device_node *node);
+
+struct state *state_by_name(const char *name);
+struct state *state_by_node(const struct device_node *node);
+int state_get_name(const struct state *state, char const **name);
+
+int state_load(struct state *state);
+int state_save(struct state *state);
+void state_info(void);
+
+#endif /* __STATE_H */