FreeCalypso > hg > freecalypso-tools

annotate doc/Flash-boot-wa @ 867:dfd98dd46068

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
ringtools: fc-pwt-comp utility written
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 28 Mar 2022 05:45:31 +0000
parents efb93f3e4ac7
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
462
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
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>
parents:
diff changeset
3 happened on only one first-batch FCDEV3B board and never happened on any other
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
4 board - but Murphy's law had it that this one troubled board just had to be the
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
5 one on which my (Mother Mychaela's) very initial development and bring-up work
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
6 was done.
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
7
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
8 The defect exhibited on that one board was as follows: it had no problem booting
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
9 serially (fc-iram, fc-loadtool, fc-xram) and it had no problem booting from
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
10 flash in mode 0 (see the Flash-boot-modes article in the freecalypso-docs
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
12 FC Magnetite, which is our primary firmware) was troubled. The exact failure
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
13 mode and the root cause were never solved, but the issue most likely involved
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
14 the watchdog reset in some way (it occurs as part of flash boot mode 1 but not
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
15 in mode 0 and not in serial downloading), and because Calypso's FDP output goes
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
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>
parents:
diff changeset
18 as a result of being jerked with extra resets which don't meet its reset timing
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
19 requirements.
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
20
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
21 Our new FCDEV3B V2 boards no longer use Calypso's FDP output (it is left
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
23 the reset timing requirements of our Spansion flash chip, hence the flash boot
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
24 problem seen on that one FCDEV3B S/N 001 board is not expected to recur on any
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
26 kept around: removing a previously-released 120-byte program for no good reason
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
27 is not the way of FOSS.
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
28
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
29 This flash-boot-wa program is loaded serially via fc-iram; it disables the boot
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
31 C1xx phones), thereby indirectly booting the made-for-boot-mode-1 firmware image
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
32 in the flash. The intended usage was as follows:
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
33
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
34 fc-iram -h fcfam /dev/ttyXXX /opt/freecalypso/target-bin/flash-boot-wa.srec rvinterf
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
35
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
36 It is also worth noting that fc-iram has been extended to support second program
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
37 invokation just like fc-xram (used in the invokation line above) just for this
efb93f3e4ac7 doc/Flash-boot-wa: explanatory article added
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
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>
parents:
diff changeset
39 fc-xram.