[U-Boot] any ongoing value to "CONFIG_SYS_FLASH_CHECKSUM" config variable?

[Robert P. J. Day]

 still going through common/board_r.c, and ran across the above CONFIG
variable, but it seems to have very little use these days. as you can
see from a recursive grep:

$ grep -r SYS_FLASH_CHECKSUM *

it shows up in board_r.c:

common/board_r.c:#ifdef CONFIG_SYS_FLASH_CHECKSUM
common/board_r.c:#endif /* CONFIG_SYS_FLASH_CHECKSUM */

then some under include/configs wherein only a small number of config
header files #define it (all the rest #undef it):

include/configs/P1010RDB.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/M5249EVB.h:#	define CONFIG_SYS_FLASH_CHECKSUM   <--
include/configs/MPC8315ERDB.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/socrates.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/yucca.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/mpc5121ads.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8323ERDB.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/M52277EVB.h:#	define CONFIG_SYS_FLASH_CHECKSUM   <--
include/configs/MPC8544DS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/bamboo.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8536DS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/vme8349.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/ac14xx.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8641HPCN.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/katmai.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/M54418TWR.h:#define CONFIG_SYS_FLASH_CHECKSUM      <--
include/configs/MPC837XEMDS.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/p1_twr.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/p1_p2_rdb_pc.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC832XEMDS.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/UCP1020.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8610HPCD.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8548CDS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/M5282EVB.h:#	define CONFIG_SYS_FLASH_CHECKSUM   <--
include/configs/M54455EVB.h:#	define CONFIG_SYS_FLASH_CHECKSUM   <--
include/configs/redwood.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC837XERDB.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8568MDS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8540ADS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/sbc8548.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8349EMDS.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/M54451EVB.h:#	define CONFIG_SYS_FLASH_CHECKSUM   <--
include/configs/MPC8541CDS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/TQM834x.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/sbc8641d.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8572DS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/BSC9132QDS.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8569MDS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/sbc8349.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/mecp5123.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8560ADS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
include/configs/aria.h:#undef CONFIG_SYS_FLASH_CHECKSUM
include/configs/MPC8555CDS.h:#undef	CONFIG_SYS_FLASH_CHECKSUM
scripts/config_whitelist.txt:CONFIG_SYS_FLASH_CHECKSUM

and in:

scripts/config_whitelist.txt:CONFIG_SYS_FLASH_CHECKSUM

and that's it. the code in board_r.c is:

  #ifdef CONFIG_SYS_FLASH_CHECKSUM
        /*
        * Compute and print flash CRC if flashchecksum is set to 'y'
        *
        * NOTE: Maybe we should add some WATCHDOG_RESET()? XXX
        */
        if (getenv_yesno("flashchecksum") == 1) {
                printf("  CRC: %08X", crc32(0,
                        (const unsigned char *) CONFIG_SYS_FLASH_BASE,
                        flash_size));
        }
  #endif /* CONFIG_SYS_FLASH_CHECKSUM */

wherein, even if that variable is set, a further test is made of the
environment variable "flashchecksum."

  is there still value to this CONFIG variable given that only a
half-dozen boards define it? am i overlooking something obvious?

rday

-- 

========================================================================
Robert P. J. Day                                 Ottawa, Ontario, CANADA
                        http://crashcourse.ca

Twitter:                                       http://twitter.com/rpjday
LinkedIn:                               http://ca.linkedin.com/in/rpjday
========================================================================