annotate doc/Flash-boot-wa @ 505:7bf0d909c87e

fc-loadtool flash ID check: change of reset after the check logic This change only affects those flash configurations that have ID checks enabled. The logic for resetting the flash after the ID check has been changed as follows: 1) If the check fails, we return without attempting to reset the flash. 2) If the check is successful, we reset the flash using the configured method (could be AMD or Intel or Intel W30) instead of always doing an AMD flash reset as the original code did.
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 27 May 2019 19:58:01 +0000
parents efb93f3e4ac7
children
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Mychaela Falconia <falcon@freecalypso.org>
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1 There is a tiny (120 bytes SREC file) program called flash-boot-wa that was
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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2 written in the spring of 2017 for the purpose of working around a problem that
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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3 happened on only one first-batch FCDEV3B board and never happened on any other
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Mychaela Falconia <falcon@freecalypso.org>
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4 board - but Murphy's law had it that this one troubled board just had to be the
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Mychaela Falconia <falcon@freecalypso.org>
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5 one on which my (Mother Mychaela's) very initial development and bring-up work
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Mychaela Falconia <falcon@freecalypso.org>
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6 was done.
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Mychaela Falconia <falcon@freecalypso.org>
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7
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Mychaela Falconia <falcon@freecalypso.org>
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8 The defect exhibited on that one board was as follows: it had no problem booting
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Mychaela Falconia <falcon@freecalypso.org>
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9 serially (fc-iram, fc-loadtool, fc-xram) and it had no problem booting from
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Mychaela Falconia <falcon@freecalypso.org>
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10 flash in mode 0 (see the Flash-boot-modes article in the freecalypso-docs
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Mychaela Falconia <falcon@freecalypso.org>
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11 repository), but booting from flash in mode 1 (the flash boot mode used by
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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12 FC Magnetite, which is our primary firmware) was troubled. The exact failure
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Mychaela Falconia <falcon@freecalypso.org>
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13 mode and the root cause were never solved, but the issue most likely involved
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Mychaela Falconia <falcon@freecalypso.org>
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14 the watchdog reset in some way (it occurs as part of flash boot mode 1 but not
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Mychaela Falconia <falcon@freecalypso.org>
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15 in mode 0 and not in serial downloading), and because Calypso's FDP output goes
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Mychaela Falconia <falcon@freecalypso.org>
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16 low during watchdog reset (or at least TI's CAL000 document says so), it is
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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17 plausible that the root cause involved the Spansion flash chip getting unhappy
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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18 as a result of being jerked with extra resets which don't meet its reset timing
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Mychaela Falconia <falcon@freecalypso.org>
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19 requirements.
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Mychaela Falconia <falcon@freecalypso.org>
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20
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Mychaela Falconia <falcon@freecalypso.org>
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21 Our new FCDEV3B V2 boards no longer use Calypso's FDP output (it is left
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Mychaela Falconia <falcon@freecalypso.org>
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22 unconnected) and feature a new flash reset circuit of our own design that meets
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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23 the reset timing requirements of our Spansion flash chip, hence the flash boot
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Mychaela Falconia <falcon@freecalypso.org>
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24 problem seen on that one FCDEV3B S/N 001 board is not expected to recur on any
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Mychaela Falconia <falcon@freecalypso.org>
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25 of our current or future boards. However, our little flash-boot-wa program is
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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26 kept around: removing a previously-released 120-byte program for no good reason
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Mychaela Falconia <falcon@freecalypso.org>
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27 is not the way of FOSS.
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28
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Mychaela Falconia <falcon@freecalypso.org>
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29 This flash-boot-wa program is loaded serially via fc-iram; it disables the boot
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Mychaela Falconia <falcon@freecalypso.org>
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30 ROM and jumps to address 0 (the opposite of what we do in compalstage for Mot
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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31 C1xx phones), thereby indirectly booting the made-for-boot-mode-1 firmware image
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Mychaela Falconia <falcon@freecalypso.org>
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32 in the flash. The intended usage was as follows:
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Mychaela Falconia <falcon@freecalypso.org>
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33
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34 fc-iram -h fcfam /dev/ttyXXX /opt/freecalypso/target-bin/flash-boot-wa.srec rvinterf
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Mychaela Falconia <falcon@freecalypso.org>
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35
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Mychaela Falconia <falcon@freecalypso.org>
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36 It is also worth noting that fc-iram has been extended to support second program
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Mychaela Falconia <falcon@freecalypso.org>
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37 invokation just like fc-xram (used in the invokation line above) just for this
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Mychaela Falconia <falcon@freecalypso.org>
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38 peculiar use case. The flash-boot-wa.srec helper can also be booted via
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
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39 fc-xram.