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env_dataflash.c

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  • Forked from Reform / reform-boundary-uboot
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    • Wolfgang Denk's avatar
      ea882baf
      New implementation for internal handling of environment variables. · ea882baf
      Wolfgang Denk authored
      
      Motivation:
      
      * Old environment code used a pessimizing implementation:
        - variable lookup used linear search => slow
        - changed/added variables were added at the end, i. e. most
          frequently used variables had the slowest access times => slow
        - each setenv() would calculate the CRC32 checksum over the whole
          environment block => slow
      * "redundant" envrionment was locked down to two copies
      * No easy way to implement features like "reset to factory defaults",
        or to select one out of several pre-defined (previously saved) sets
        of environment settings ("profiles")
      * No easy way to import or export environment settings
      
      ======================================================================
      
      API Changes:
      
      - Variable names starting with '#' are no longer allowed
      
        I didn't find any such variable names being used; it is highly
        recommended to follow standard conventions and start variable names
        with an alphanumeric character
      
      - "printenv" will now print a backslash at the end of all but the last
        lines of a multi-line variable value.
      
        Multi-line variables have never been formally defined, allthough
        there is no reason not to use them. Now we define rules how to deal
        with them, allowing for import and export.
      
      - Function forceenv() and the related code in saveenv() was removed.
        At the moment this is causing build problems for the only user of
        this code (schmoogie - which has no entry in MAINTAINERS); may be
        fixed later by implementing the "env set -f" feature.
      
      Inconsistencies:
      
      - "printenv" will '\\'-escape the '\n' in multi-line variables, while
        "printenv var" will not do that.
      
      ======================================================================
      
      Advantages:
      
      - "printenv" output much better readable (sorted)
      - faster!
      - extendable (additional variable properties can be added)
      - new, powerful features like "factory reset" or easy switching
        between several different environment settings ("profiles")
      
      Disadvantages:
      
      - Image size grows by typically 5...7 KiB (might shrink a bit again on
        systems with redundant environment with a following patch series)
      
      ======================================================================
      
      Implemented:
      
      - env command with subcommands:
      
        - env print [arg ...]
      
          same as "printenv": print environment
      
        - env set [-f] name [arg ...]
      
          same as "setenv": set (and delete) environment variables
      
          ["-f" - force setting even for read-only variables - not
          implemented yet.]
      
        - end delete [-f] name
      
          not implemented yet
      
          ["-f" - force delete even for read-only variables]
      
        - env save
      
          same as "saveenv": save environment
      
        - env export [-t | -b | -c] addr [size]
      
          export internal representation (hash table) in formats usable for
          persistent storage or processing:
      
      	-t:	export as text format; if size is given, data will be
      		padded with '\0' bytes; if not, one terminating '\0'
      		will be added (which is included in the "filesize"
      		setting so you can for exmple copy this to flash and
      		keep the termination).
      	-b:	export as binary format (name=value pairs separated by
      		'\0', list end marked by double "\0\0")
      	-c:	export as checksum protected environment format as
      		used for example by "saveenv" command
      	addr:	memory address where environment gets stored
      	size:	size of output buffer
      
      	With "-c" and size is NOT given, then the export command will
      	format the data as currently used for the persistent storage,
      	i. e. it will use CONFIG_ENV_SECT_SIZE as output block size and
      	prepend a valid CRC32 checksum and, in case of resundant
      	environment, a "current" redundancy flag. If size is given, this
      	value will be used instead of CONFIG_ENV_SECT_SIZE; again, CRC32
      	checksum and redundancy flag will be inserted.
      
      	With "-b" and "-t", always only the real data (including a
      	terminating '\0' byte) will be written; here the optional size
      	argument will be used to make sure not to overflow the user
      	provided buffer; the command will abort if the size is not
      	sufficient. Any remainign space will be '\0' padded.
      
              On successful return, the variable "filesize" will be set.
              Note that filesize includes the trailing/terminating '\0'
              byte(s).
      
              Usage szenario: create a text snapshot/backup of the current
      	settings:
      
      		=> env export -t 100000
      		=> era ${backup_addr} +${filesize}
      		=> cp.b 100000 ${backup_addr} ${filesize}
      
      	Re-import this snapshot, deleting all other settings:
      
      		=> env import -d -t ${backup_addr}
      
        - env import [-d] [-t | -b | -c] addr [size]
      
          import external format (text or binary) into hash table,
          optionally deleting existing values:
      
      	-d:	delete existing environment before importing;
      		otherwise overwrite / append to existion definitions
      	-t:	assume text format; either "size" must be given or the
      		text data must be '\0' terminated
      	-b:	assume binary format ('\0' separated, "\0\0" terminated)
      	-c:	assume checksum protected environment format
      	addr:	memory address to read from
      	size:	length of input data; if missing, proper '\0'
      		termination is mandatory
      
        - env default -f
      
          reset default environment: drop all environment settings and load
          default environment
      
        - env ask name [message] [size]
      
          same as "askenv": ask for environment variable
      
        - env edit name
      
          same as "editenv": edit environment variable
      
        - env run
      
          same as "run": run commands in an environment variable
      
      ======================================================================
      
      TODO:
      
      - drop default env as implemented now; provide a text file based
        initialization instead (eventually using several text files to
        incrementally build it from common blocks) and a tool to convert it
        into a binary blob / object file.
      
      - It would be nice if we could add wildcard support for environment
        variables; this is needed for variable name auto-completion,
        but it would also be nice to be able to say "printenv ip*" or
        "printenv *addr*"
      
      - Some boards don't link any more due to the grown code size:
        DU405, canyonlands, sequoia, socrates.
      
      	=> cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
      	       Stefan Roese <sr@denx.de>,
      	       Heiko Schocher <hs@denx.de>
      
      - Dropping forceenv() causes build problems on schmoogie
      
      	=> cc: Sergey Kubushyn <ksi@koi8.net>
      
      - Build tested on PPC and ARM only; runtime tested with NOR and NAND
        flash only => needs testing!!
      
      Signed-off-by: default avatarWolfgang Denk <wd@denx.de>
      Cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
      Cc: Stefan Roese <sr@denx.de>,
      Cc: Heiko Schocher <hs@denx.de>
      Cc: Sergey Kubushyn <ksi@koi8.net>
      ea882baf
      History
      New implementation for internal handling of environment variables.
      Wolfgang Denk authored
      
      Motivation:
      
      * Old environment code used a pessimizing implementation:
        - variable lookup used linear search => slow
        - changed/added variables were added at the end, i. e. most
          frequently used variables had the slowest access times => slow
        - each setenv() would calculate the CRC32 checksum over the whole
          environment block => slow
      * "redundant" envrionment was locked down to two copies
      * No easy way to implement features like "reset to factory defaults",
        or to select one out of several pre-defined (previously saved) sets
        of environment settings ("profiles")
      * No easy way to import or export environment settings
      
      ======================================================================
      
      API Changes:
      
      - Variable names starting with '#' are no longer allowed
      
        I didn't find any such variable names being used; it is highly
        recommended to follow standard conventions and start variable names
        with an alphanumeric character
      
      - "printenv" will now print a backslash at the end of all but the last
        lines of a multi-line variable value.
      
        Multi-line variables have never been formally defined, allthough
        there is no reason not to use them. Now we define rules how to deal
        with them, allowing for import and export.
      
      - Function forceenv() and the related code in saveenv() was removed.
        At the moment this is causing build problems for the only user of
        this code (schmoogie - which has no entry in MAINTAINERS); may be
        fixed later by implementing the "env set -f" feature.
      
      Inconsistencies:
      
      - "printenv" will '\\'-escape the '\n' in multi-line variables, while
        "printenv var" will not do that.
      
      ======================================================================
      
      Advantages:
      
      - "printenv" output much better readable (sorted)
      - faster!
      - extendable (additional variable properties can be added)
      - new, powerful features like "factory reset" or easy switching
        between several different environment settings ("profiles")
      
      Disadvantages:
      
      - Image size grows by typically 5...7 KiB (might shrink a bit again on
        systems with redundant environment with a following patch series)
      
      ======================================================================
      
      Implemented:
      
      - env command with subcommands:
      
        - env print [arg ...]
      
          same as "printenv": print environment
      
        - env set [-f] name [arg ...]
      
          same as "setenv": set (and delete) environment variables
      
          ["-f" - force setting even for read-only variables - not
          implemented yet.]
      
        - end delete [-f] name
      
          not implemented yet
      
          ["-f" - force delete even for read-only variables]
      
        - env save
      
          same as "saveenv": save environment
      
        - env export [-t | -b | -c] addr [size]
      
          export internal representation (hash table) in formats usable for
          persistent storage or processing:
      
      	-t:	export as text format; if size is given, data will be
      		padded with '\0' bytes; if not, one terminating '\0'
      		will be added (which is included in the "filesize"
      		setting so you can for exmple copy this to flash and
      		keep the termination).
      	-b:	export as binary format (name=value pairs separated by
      		'\0', list end marked by double "\0\0")
      	-c:	export as checksum protected environment format as
      		used for example by "saveenv" command
      	addr:	memory address where environment gets stored
      	size:	size of output buffer
      
      	With "-c" and size is NOT given, then the export command will
      	format the data as currently used for the persistent storage,
      	i. e. it will use CONFIG_ENV_SECT_SIZE as output block size and
      	prepend a valid CRC32 checksum and, in case of resundant
      	environment, a "current" redundancy flag. If size is given, this
      	value will be used instead of CONFIG_ENV_SECT_SIZE; again, CRC32
      	checksum and redundancy flag will be inserted.
      
      	With "-b" and "-t", always only the real data (including a
      	terminating '\0' byte) will be written; here the optional size
      	argument will be used to make sure not to overflow the user
      	provided buffer; the command will abort if the size is not
      	sufficient. Any remainign space will be '\0' padded.
      
              On successful return, the variable "filesize" will be set.
              Note that filesize includes the trailing/terminating '\0'
              byte(s).
      
              Usage szenario: create a text snapshot/backup of the current
      	settings:
      
      		=> env export -t 100000
      		=> era ${backup_addr} +${filesize}
      		=> cp.b 100000 ${backup_addr} ${filesize}
      
      	Re-import this snapshot, deleting all other settings:
      
      		=> env import -d -t ${backup_addr}
      
        - env import [-d] [-t | -b | -c] addr [size]
      
          import external format (text or binary) into hash table,
          optionally deleting existing values:
      
      	-d:	delete existing environment before importing;
      		otherwise overwrite / append to existion definitions
      	-t:	assume text format; either "size" must be given or the
      		text data must be '\0' terminated
      	-b:	assume binary format ('\0' separated, "\0\0" terminated)
      	-c:	assume checksum protected environment format
      	addr:	memory address to read from
      	size:	length of input data; if missing, proper '\0'
      		termination is mandatory
      
        - env default -f
      
          reset default environment: drop all environment settings and load
          default environment
      
        - env ask name [message] [size]
      
          same as "askenv": ask for environment variable
      
        - env edit name
      
          same as "editenv": edit environment variable
      
        - env run
      
          same as "run": run commands in an environment variable
      
      ======================================================================
      
      TODO:
      
      - drop default env as implemented now; provide a text file based
        initialization instead (eventually using several text files to
        incrementally build it from common blocks) and a tool to convert it
        into a binary blob / object file.
      
      - It would be nice if we could add wildcard support for environment
        variables; this is needed for variable name auto-completion,
        but it would also be nice to be able to say "printenv ip*" or
        "printenv *addr*"
      
      - Some boards don't link any more due to the grown code size:
        DU405, canyonlands, sequoia, socrates.
      
      	=> cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
      	       Stefan Roese <sr@denx.de>,
      	       Heiko Schocher <hs@denx.de>
      
      - Dropping forceenv() causes build problems on schmoogie
      
      	=> cc: Sergey Kubushyn <ksi@koi8.net>
      
      - Build tested on PPC and ARM only; runtime tested with NOR and NAND
        flash only => needs testing!!
      
      Signed-off-by: default avatarWolfgang Denk <wd@denx.de>
      Cc: Matthias Fuchs <matthias.fuchs@esd-electronics.com>,
      Cc: Stefan Roese <sr@denx.de>,
      Cc: Heiko Schocher <hs@denx.de>
      Cc: Sergey Kubushyn <ksi@koi8.net>
    compiler-gcc.h NaN GiB