FreeCalypso > hg > freecalypso-tools

annotate doc/TIFFS-Overview @ 407:19e5a3e2f9c0

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fcup-settime: moved time() retrieval a little closer to the output A fundamental problem with all simple time transfer tools is that there is always some delay between the time retrieval on the source system and that transmitted time being set on the destination, and the resulting time on the destination system is off by that delay amount. This delay cannot be fully eliminated when working in a simple environment like ours, but we should make our best effort to minimize it. In the present case, moving the atinterf_init() call before the time() retrieval should make a teensy-tiny improvement.
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 11 Aug 2018 21:52:17 +0000
parents e7502631a0f9
children 579441d7dcd8
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Mychaela Falconia <falcon@freecalypso.org>
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1 All TI GSM firmwares known to this author (FreeCalypso developer Space Falcon)
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2 implement some kind of flash file system, or FFS. Several different FFS code
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3 implementations, and correspondingly several different on-flash data formats,
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Mychaela Falconia <falcon@freecalypso.org>
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4 have been used throughout the history of TI's involvement in the wireless
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Mychaela Falconia <falcon@freecalypso.org>
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5 terminal business. The FFS incarnation of primary interest to the FreeCalypso
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Mychaela Falconia <falcon@freecalypso.org>
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6 project is the one invented by Mads Meisner-Jensen at TI in the early 2000s
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7 (at least according to the comments in the sources available to us), and it is
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8 relevant to us in the following ways:
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9
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10 * When targeting the GSM modem in Openmoko's GTA01/02 smartphones, we need to
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Mychaela Falconia <falcon@freecalypso.org>
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11 work with the original FFS from the factory (call it MokoFFS), the same FFS
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Mychaela Falconia <falcon@freecalypso.org>
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12 as used by the mokoN firmwares: this FFS contains the IMEI and the RF
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13 calibration values from the factory, which we most certainly don't want to go
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14 without.
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15
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16 * The Leonardo firmware semi-src which we are using as the reference for
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Mychaela Falconia <falcon@freecalypso.org>
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17 building our own full source, multi-target GSM fw contains a turnkey-working
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Mychaela Falconia <falcon@freecalypso.org>
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18 implementation of this very FFS, using the on-flash format in question and
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19 providing run-time APIs expected by the rest of the GSM fw suite. Following
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20 the principle of ``if it ain't broke, don't fix it'', we can use this FFS not
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21 only on the gtamodem target, but also on other targets, including those where
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22 we would be starting from a blank state and thus have the freedom to use
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Mychaela Falconia <falcon@freecalypso.org>
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23 whatever FFS we like.
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24
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25 * The original proprietary fw on the Pirelli DP-L10 phone also happens to use
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Mychaela Falconia <falcon@freecalypso.org>
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26 an FFS in the same format. Pirelli's FFS does *not* contain the IMEI or any
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27 of the RF calibration values though, and trying to reuse it directly for our
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Mychaela Falconia <falcon@freecalypso.org>
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28 own FC GSM fw seems to be more trouble than benefit - so we'll probably have
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Mychaela Falconia <falcon@freecalypso.org>
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29 our fw start with a blank TIFFS instead - but there is still insight to be
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Mychaela Falconia <falcon@freecalypso.org>
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30 gained from in-vitro examination of captured Pirelli FFS images.
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31
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32 Naming
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33 ======
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34
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35 I have previously referred to the FFS format in question as Mokopir-FFS or
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Mychaela Falconia <falcon@freecalypso.org>
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36 MPFFS, from "Moko" and "Pirelli". I was originally hesitant to call it TIFFS,
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37 as lacking the source code, I had no way of knowing whether the FFS format and
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Mychaela Falconia <falcon@freecalypso.org>
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38 implementation were of TI's own invention, or something that TI licensed as a
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Mychaela Falconia <falcon@freecalypso.org>
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39 black box from one of their many proprietary software partners. (I was unable
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Mychaela Falconia <falcon@freecalypso.org>
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40 to identify it as any well-known, industry-standard FFS format, but absence of
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Mychaela Falconia <falcon@freecalypso.org>
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41 evidence is not evidence of absence.) But now that we have TI's original source
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42 code which implements this FFS (first the MV100-0.1.rar source, then the full
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43 Leonardo one), complete with comments and a HISTORY file, we know that our FFS
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Mychaela Falconia <falcon@freecalypso.org>
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44 was invented and implemented by someone named Mads Meisner-Jensen at TI - I'm
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Mychaela Falconia <falcon@freecalypso.org>
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45 guessing in the SSA group in Nice, France.
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46
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47 I am now making a naming transition from MPFFS to TIFFS: there is really no
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48 link between this FFS format and the Openmoko+Pirelli duo, other than the
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49 happenstance of me having first encountered this FFS on these two GSM device
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Mychaela Falconia <falcon@freecalypso.org>
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50 brands, and the name TIFFS is more neutrally-descriptive.
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51
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52 What it is
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53 ==========
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54
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55 In a rare departure from TI's norm (most of TI's GSM firmware and associated
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Mychaela Falconia <falcon@freecalypso.org>
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56 development tools suffer from heavy Windows poisoning), what I call TIFFS is
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Mychaela Falconia <falcon@freecalypso.org>
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57 very Unixy. It is a file system with a hierarchical directory tree structure
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58 and with Unixy forward-slash-separated, case-sensitive pathnames; the semantics
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59 of "what is a file" and "what is a directory" are exactly the same as in UNIX;
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60 and TIFFS even supports symlinks, although that support is a little under-
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61 developed, and apparently no FFS symlinks were ever used in any production GSM
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62 device. Thus the FFS implemented in TI-based GSM devices (modems and
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Mychaela Falconia <falcon@freecalypso.org>
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63 "dumbphones") is really no different from, for example, JFFS2 in embedded Linux
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64 systems.
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65
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66 (The only traditional UNIX file system features which are missing in TIFFS are
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67 the creation/modification/access timestamps and the ownership/permission
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68 fields.)
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69
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70 The FFS in a GSM device typically stores two kinds of content:
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71
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72 * Factory data: IMEI, RF calibration values, device make/model/revision
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73 ID strings etc. These files are expected to be programmed on the factory
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74 production line and not changed afterward.
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75
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76 * Dynamic data written into the FFS in normal device operation: when you use a
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Mychaela Falconia <falcon@freecalypso.org>
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77 "dumbphone" running TI-based firmware, every time you store something "on the
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Mychaela Falconia <falcon@freecalypso.org>
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78 phone" or in "non-volatile memory", that item is actually stored in the FFS.
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79 (Where else, if you think of it?) That includes contacts and received SMS
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80 stored "on the phone" instead of the SIM, any selections you make in the
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81 settings/preferences menus which persist across reboots (power cycles), call
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82 history etc.
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83
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84 It needs to be noted that the "dynamic data" aspect of FFS usage applies not
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85 only to complete phones, but also to modems like the one used in the GTA01/02.
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86 One would naively think that non-volatile storage of data in flash outside of
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87 factory programming would be needed only in a device with its own UI, and that
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88 a modem subservient to external AT commands would be completely stateless
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89 across reboot/power cycles; but that is not the case in actuality. TI's GSM
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90 firmwares, including the Openmoko ones (the "standard" mokoN), are designed to
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91 always "mount" their FFS with read/write access; TI's FFS implementation in the
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92 firmware has no concept of a "read-only mount".
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93
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94 I am still investigating just what kinds of data are routinely written into the
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95 non-volatile FFS by the firmware in normal operation on devices like the GTA0x
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96 modem, but there most definitely are some.
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97
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98 There is no hard separation between "static" and "dynamic" data in the file
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99 system structure; TIFFS is thus akin to an embedded Linux system with just a
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100 single root file system containing both "static" files like userland binaries
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101 and "dynamic" ones like configuration files under /etc which the user is
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102 expected to edit with vi after logging into the box, or log and similar files
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103 created by the system itself under /var, for example.
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104
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105 Where it lives
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106 ==============
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
107
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
108 The type of flash memory used in Calypso GSM modems and "dumbphones" is called
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
109 NOR flash. This NOR flash memory is physically divided (by the design of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
110 flash chip itself) into units called "sectors" or more descriptively, erase
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
111 blocks. The typical NOR flash sector size (in Calypso GSM devices) ranges from
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
112 64 KiB in the GTA02 modem's NOR flash (4 MiB total) to 256 KiB in the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
113 S71PL129NC0 flash+RAM chip used in the Pirelli DP-L10 (16 MiB of flash total).
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
114 The key physical property is that any bit may be changed from a '1' to a '0' at
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
115 any time, in any combination, but resetting of '0' bits back to ones can be
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
116 done only on the granularity of these largish sectors, in an operation called
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
117 "sector erase".
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
118
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
119 The location of TIFFS within the flash memory of a given GSM device is defined
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
120 by the firmware design of that device, but is always some integral number of
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
121 contiguous flash sectors. Some examples:
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
122
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
123 * On the GTA01/02 GSM modem, FFS occupies 7 sectors of 64 KiB each, starting at
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
124 flash offset 0x380000.
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
125
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
126 * On the Pirelli DP-L10, the FFS used by the original proprietary fw occupies
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
127 18 sectors of 256 KiB each (for 4.5 MiB in total), starting at the beginning
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
128 of the 2nd flash chip select (0x02000000 in the ARM7 address space).
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
129
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
130 * On Motorola/Compal C139/140 phones, the FFS used by the original proprietary
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
131 fw occupies 5 sectors of 64 KiB each (320 KiB in total), starting at 0x370000.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
132 C11x/123 use smaller FFS configurations, whereas C155/156 seem to have
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
133 switched to some other FFS format, different from our familiar TIFFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
134
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
135 * The smallest real FFS configuration called for by the table in dev.c in TI's
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
136 original Leonardo fw source is 3 sectors of 64 KiB each; the same table also
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
137 sports a 4 KiB x 4 configuration for RAM-based testing (emulation of FFS in
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
138 RAM without real flash).
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
139
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
140 * The largest FFS configuration that has been envisioned by the original
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
141 designers seems to be somewhere around 128 sectors.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
142
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
143 Each flash sector used for TIFFS begins with this 6-byte signature:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
144
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
145 46 66 73 23 10 02
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
146
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
147 The first 4 bytes are 'Ffs#' in ASCII, and the following two bytes are the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
148 format version number of 0x0210 in little-endian byte order. The following two
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
149 bytes give a count of how many times that sector has been erased and rewritten
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
150 (FF FF in "fresh" or "virgin" FFS images), and the following byte indicates
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
151 that block's role and status in the FFS life cycle.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
152
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
153 How it works
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
154 ============
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
155
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
156 Just like JFFS2 and other high-quality flash file systems, TIFFS is designed to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
157 recover gracefully from any possible power failure or crash: one can yank the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
158 battery from the GSM device (or induce a firmware crash) at the most mis-
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
159 opportune moment in the middle of an FFS write operation, and the FFS is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
160 expected to recover on the next boot cycle. I won't be able to document here
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
161 all gory details of exactly how this goal is achieved, partly because I haven't
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
162 studied the code to the requisite level of depth myself yet, but all of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
163 responsible code lives under gsm-fw/services/ffs in this freecalypso-sw source
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
164 tree; feel free to study it.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
165
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
166 In its "normal" or "clean" state (i.e., when not in the middle of a write
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
167 operation or recovery from an ungracefully interrupted one), a TIFFS instance
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
168 consists of the following 3 types of blocks:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
169
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
170 * One block containing inode records, indicated by AB in its type/flags/status
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
171 byte in the block header;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
172 * N-2 blocks (where N is the total number of flash sectors allocated for the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
173 FFS) containing (or waiting to be filled with) data chunks - indicated by BD
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
174 in the type/flags/status byte;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
175 * One "free" block, indicated by BF - destined to become a new AB or a new BD
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
176 at some point.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
177
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
178 Each object written into the FFS (file, directory or symlink) consists of a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
179 16-byte inode record written into the AB block and a data chunk written into
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
180 one of the BD blocks. The data chunk includes the name of the object, hence
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
181 one is required even for directories. Data chunks are contiguous, uncompressed,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
182 and subject to an upper size limit of 2048 or 8192 bytes, depending on the FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
183 configuration. Files larger than this limit are stored in a "segmented" form,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
184 giving rise to a 4th inode or object type (after file, directory and symlink):
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
185 segment. Each segment of a segmented file consists of not only a data chunk,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
186 but also an inode record for the segment, which gives the location of the data
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
187 chunk and ties the segment object into the overall FFS structure, making it
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
188 accessible.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
189
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
190 Because aside from complete sector erasure, flash memory bits can only
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
191 transition from '1' to '0' but not the other way around, overwriting an existing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
192 file with some new content (an operation which any reasonable file system must
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
193 implement in some way) cannot be done in place. Instead like most flash file
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
194 systems, TIFFS implements this common operation by writing the new version of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
195 the file to a new location (previously blank flash) and then invalidating the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
196 old version - and doing all that while keeping in mind the possibility of an
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
197 ungraceful crash or powerdown at any moment, and the requirement of recovering
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
198 gracefully from any such event.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
199
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
200 Of course as an FFS receives more write activity, even if one keeps overwriting
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
201 some existing files with new content of the same size, without adding to the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
202 visible total content size (think du(1) command), eventually all remaining blank
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
203 flash space will fill up. At that point (or at some earlier point, depending
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
204 on the FFS design and/or configuration) the FFS has to invoke a compaction or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
205 reclamation or garbage collection procedure: any "mixed" blocks containing both
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
206 valid and stale data are transitioned into a "stale-only" state by having the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
207 active data moved to a new block, and then the "all stale" blocks are subjected
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
208 to sector erasure, becoming new blank sectors. The logic responsible for these
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
209 operations once again needs to be resilient to the possibility of a crash or
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
210 powerdown occurring at the most mis-opportune moment, and it also needs to
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
211 implement flash wear leveling: there is a physical limit to how many times a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
212 given flash sector can be erased and rewritten before it goes bad.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
213
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
214 All of the above are common and well-known principles, successfully implemented
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
215 in well-known flash file systems such as JFFS2 in Linux. TIFFS is absolutely
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
216 no different in this regard; for the implementation details, read the source
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
217 code.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
218
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
219 How this FFS comes into being
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
220 =============================
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
221
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
222 (This section is only relevant to you if you plan on physically producing your
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
223 own GSM phones or modems on your own factory production line, like this author
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
224 fancies doing in the not-too-distant future, or if you simply enjoy knowing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
225 how it is done.)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
226
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
227 To my knowledge, TI never used or produced a tool akin to mkfs.jffs2 in the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
228 embedded Linux world, which would produce a TIFFS image complete with some
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
229 initial directory and file content "in vitro". Instead it appears that the FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
230 instances found in shipped products such as Openmoko phones have been created
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
231 "in vivo" by TI's firmware running on the device itself during the "production
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
232 test" phase.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
233
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
234 The process seems to go like this:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
235
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
236 * When the printed circuit board is physically populated with components such
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
237 as the Calypso chip and the flash chip, the latter can be blank - if the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
238 board design has the nIBOOT pin pulled low, enabling the Calypso boot ROM
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
239 (Openmoko and Pirelli both good on this one, but shame on Compal!), there is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
240 no need to preprogram the flash chip with anything prior to populating it on
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
241 the board, and the device remains fully unbrickable at all times afterward.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
242
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
243 * When the assembled board is powered up for the first time, with completely
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
244 blank flash, the Calypso boot ROM will sit there and patiently wait for a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
245 code download on either of its two UARTs.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
246
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
247 * Using TI's FLUID (Flash Loader Utility Independent of Device) or FreeCalypso's
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
248 fc-loadtool free replacement, the factory production station loads the main
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
249 firmware image into the flash. Note, it is just the firmware image at this
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
250 step, and the FFS sectors remain blank.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
251
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
252 * The board is commanded to reboot (or power-cycled), and the firmware image
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
253 boots for the first time.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
254
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
255 * TI's FFS implementation code in their standard firmware reacts to all blank
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
256 flash in the FFS sectors as follows: it performs what they call the preformat
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
257 operation, writing the TIFFS signature and a BF state byte into every FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
258 sector, but the main "format" operation, which sets up the AB/BD block roles,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
259 creates the root inode and makes the FFS ready to accept the creation of its
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
260 first directories and files, is not done automatically.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
261
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
262 In order to perform the FFS format operation and then fill the new FFS with
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
263 whatever directories and files are deemed needed to be present in "fresh"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
264 shipping products, the factory production station connects to the just-booted
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
265 firmware running on the target via the RVT/ETM protocol (see the RVTMUX
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
266 write-up), and sends "test mode" commands to this running firmware. These
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
267 "FFS test mode" (or TMFFS) commands include the format operation, an mkdir
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
268 operation to create directories, and a "file write" operation akin to doing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
269 'cat > /dir/whatever/file', creating files in FFS and storing any desired data
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
270 in them.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
271
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
272 The IMEI is assigned and written into FFS in this process, but it is not the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
273 only data item that will be unique for each individual device made. Much more
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
274 important are the RF calibration values: I have yet to learn exactly what is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
275 being (or needs to be) measured, how these measurements are performed (under
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
276 what conditions; what external test equipment is needed), and how these measured
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
277 and recorded RF calibration values affect GSM device operation, but this TI
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
278 presentation gives some clues:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
279
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
280 ftp://ftp.ifctf.org/pub/GSM/Calypso/rf_calibration.pdf
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
281
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
282 All of these calibration values are stored in a bunch of files under the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
283 /gsm/rf subtree, and these files seem to be "owned" by the L1 code. The latter
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
284 has RAM data structures which correspond to these files; upon normal boot the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
285 initialization code looks in FFS, and if it finds any of the RF calibration
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
286 files, it reads each present file into the corresponding RAM data structure,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
287 overwriting the compiled-in defaults. It appears (slightly uncertain because I
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
288 have not yet reintegrated the code in question into our own gsm-fw) that the RF
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
289 calibration files in FFS come into being as follows:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
290
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
291 * The RF calibration code in L1 (i.e., part of the main GSM fw) performs the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
292 measurements and stores results in its RAM data structures as commanded by
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
293 the production test station through the "test mode" interface;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
294
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
295 * A final test mode command directs the above L1 code to write its RAM data
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
296 structures into FFS.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
297
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
298 Once I actually learn this RF calibration process properly in connection with
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
299 building my own Calypso-based GSM "dumbphone", I'll be able to say exactly what
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
300 it would take to recreate these RF calibration values if they are lost. But
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
301 until then the only advice I can give is to make a backup copy of your modem
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
302 FFS with fc-loadtool, and to save it securely.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
303
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
304 Compal and Pirelli differences
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
305 ==============================
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
306
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
307 The above description refers to TI's vanilla reference version, and it seems
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
308 like Openmoko (FIC) was the only phone/modem manufacturer who followed it
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
309 without major deviations. In contrast, both Compal (Mot C1xx) and Foxconn
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
310 (Pirelli DP-L10) moved the vital per-unit factory data (IMEI and RF calibration)
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
311 out of the FFS into their own ad hoc flash data structures (which are very
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
312 difficult to reverse-engineer and make use of, unfortunately), leaving their FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
313 only for less critical data.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
314
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
315 In Compal's case (at least on the C139 model with which I have extensive
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
316 personal experience) the FFS stores only users' personal information and nothing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
317 more. One can turn the phone off, use fc-loadtool to erase the FFS sectors, and
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
318 boot the regular fw back up; the fw will automatically do a new FFS format (it
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
319 even displays a message on the LCD as it does so) and carry on happily as a
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
320 "fresh" or "blank", perfectly functional and usable phone.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
321
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
322 In Pirelli's case, booting their official fw with blank FFS sectors will also
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
323 result in the FFS being automatically formatted, but their fw expects some
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
324 static "asset" files to be present in this FFS: UI graphics and language
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
325 strings, ringtones, firmware images for the WiFi and VoIP processors and some
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
326 static configuration files, about 3 MiB in total. Thus although the firmware
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
327 will auto-format the blank FFS sectors, it won't function normally with all of
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
328 these "asset" files missing. Foxconn's original factory production line station
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
329 must have uploaded these files to each phone via the TMFFS2 protocol, and our
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
330 FreeCalypso suite now features a tool that can replicate this feat: fc-fsio.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
331
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
332 FreeCalypso support for TIFFS
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
333 =============================
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
334
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
335 Aside from implementing and using it in our own gsm-fw, FreeCalypso offers
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
336 the following support for TIFFS:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
337
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Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
338 1. We have a utility for "in vitro" examination of FFS images read out of GSM
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
339 devices with fc-loadtool. This tiffs utility (along with mokoffs and pirffs
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
340 wrappers) lives in the ffstools top-level directory of the freecalypso-sw
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
341 source tree. This TIFFS "in vitro analyzer" utility supplants the earlier
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
342 mpffs-* tools, and adds some additional examination functionality. It is
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
343 strictly a "read only" tool, however - it is not designed for "in vitro"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
344 editing of TIFFS images.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
345
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
346 2. A number of FC tools may be strung together into a kit for editing the FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
347 content of a GSM device, e.g., for changing the IMEI. The following pieces
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
348 will be involved:
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
349
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
350 * What is destined to eventually become our totally free GSM fw (the gsm-fw
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
351 source subtree at the top of freecalypso-sw) does not contain any of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
352 actual GSM protocol stack (or even L1) functionality yet, but it already
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
353 contains both the FFS code and those components (ETM and TMFFS[12]) which
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
354 are needed for interfacing an external "test mode shell" to this FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
355 implementation through the RVTMUX interface. And when our gsm-fw does gain
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
356 the actual GSM functionality, the ability to build a minimal FFS+ETM-only
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
357 configuration will still be retained.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
358
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
359 * The minimal FFS+ETM subset of gsm-fw can be built into a ramImage (runs
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
360 entirely from RAM via fc-xram, no flashing), and run on a physical device
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
361 such as the GTA0x GSM modem via the fc-xram host utility;
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
362
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
363 * After loading the ramImage, fc-xram will immediately exec our rvinterf host
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
364 utility (see rvinterf/README);
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
365
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
366 * Once the GSM device is running what is effectively an FFS editing agent out
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
367 of RAM, accessed via rvinterf over the serial channel, the user can run
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
368 fc-tmsh or fc-fsio, and this "test mode shell" provides commands for writing
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
369 things to FFS exactly like one would do in the factory production line
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
370 environment for which TI taylored their tools.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
371
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
372 The "in vivo" method of editing the FFS content of a GSM device described above
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
373 will probably sound very convoluted, and you may find yourself asking for a way
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
374 to do it "in vitro" instead: read the FFS out of flash with fc-loadtool, edit
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
375 that image "in vitro" with some utility on your PC, and then use fc-loadtool
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
376 again to program it back into your device. But consider that an "in vitro" FFS
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
377 modification would involve erasing and rewriting all sectors of your FFS,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
378 whereas an "in vivo" modification of some small file like the IMEI would be
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
379 just a short flash write operation without any erasures at all, i.e., kinder
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
380 on the flash.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
381
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
382 In any case, the "in vivo" method is already available now because all of the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
383 components involved therein are also needed for other development uses in the
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
384 FreeCalypso project, whereas developing a fully-functional "in vitro"
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
385 alternative (one that can create an FFS image "de novo" from a tree of files
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
386 and directories a la mkfs.jffs2, or add new files to an existing TIFFS image
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
387 etc) would be a good amount of extra work which we otherwise don't need - hence
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
388 the latter is not very likely to be written any time soon.
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
389
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
390 However, if the "in vitro" modification you seek is something trivial like
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
391 changing the byte content of a file such as /pcm/IMEI or /gsm/com/rfcap without
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
392 changing its length, you can use the existing "in vitro, read-only" tiffs host
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
393 utility to find the exact byte location of the file data within the TIFFS image,
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
394 and then use your favourite hex editor to whack whatever new byte content you
e7502631a0f9 initial import from freecalypso-sw rev 1033:5ab737ac3ad7
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
395 like at that offset.