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etmsync Pirelli IMEI retrieval: fix poor use of printf() Bug reported by Vadim Yanitskiy <fixeria@osmocom.org>: the construct where a static-allocated string was passed to printf() without any format arguments causes newer compilers to report a security problem. Given that formatted output is not needed here, just fixed string output, change printf() to fputs(), and direct the error message to stderr while at it.
author Mychaela Falconia <falcon@freecalypso.org>
date Thu, 23 May 2024 17:29:57 +0000
parents 0f138858ff39
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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461
10e168596dfd doc/SIM-hardware-debugging: article written
Mychaela Falconia <falcon@freecalypso.org>
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1 This article is only going to be of interest to those who are physically
10e168596dfd doc/SIM-hardware-debugging: article written
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2 producing Calypso-based hardware and therefore get to deal with the joys of
10e168596dfd doc/SIM-hardware-debugging: article written
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3 yield troubleshooting and failure analysis. If you are a mere user or software
10e168596dfd doc/SIM-hardware-debugging: article written
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4 developer working on known-good hardware made by someone other than you, then
10e168596dfd doc/SIM-hardware-debugging: article written
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5 none of the following applies to you.
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6
10e168596dfd doc/SIM-hardware-debugging: article written
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7 Testing the SIM interface on a Calypso device
10e168596dfd doc/SIM-hardware-debugging: article written
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8 =============================================
10e168596dfd doc/SIM-hardware-debugging: article written
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9
10e168596dfd doc/SIM-hardware-debugging: article written
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10 A basic pass/fail test of the SIM interface is quite straightforward: simply
10e168596dfd doc/SIM-hardware-debugging: article written
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11 insert a test SIM into the socket (at FreeCalypso hw manufacturing we currently
10e168596dfd doc/SIM-hardware-debugging: article written
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12 use Sysmocom SIMs for this purpose) and issue an AT+CFUN=1 command to the
10e168596dfd doc/SIM-hardware-debugging: article written
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13 standard firmware; if the SIM interface hardware is good, the command will
10e168596dfd doc/SIM-hardware-debugging: article written
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14 complete successfully with an OK response, otherwise it will throw up an error.
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15
10e168596dfd doc/SIM-hardware-debugging: article written
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16 But what do you do when this basic test fails? If you get a "SIM not inserted"
10e168596dfd doc/SIM-hardware-debugging: article written
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17 error even though the SIM *is* in fact inserted, how do you debug it further?
10e168596dfd doc/SIM-hardware-debugging: article written
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18 In order to facilitate lower-level debugging of SIM interface woes, we have
10e168596dfd doc/SIM-hardware-debugging: article written
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19 implemented a standalone simtest program described in this article. To run
10e168596dfd doc/SIM-hardware-debugging: article written
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20 this simtest program on your Calypso device, run an fc-iram command like this:
10e168596dfd doc/SIM-hardware-debugging: article written
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21
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22 fc-iram -h fcfam /dev/ttyXXX /opt/freecalypso/target-bin/simtest.srec
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23
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24 Like other interactive programs in our target-utils suite, this simtest program
10e168596dfd doc/SIM-hardware-debugging: article written
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25 will present a '=' prompt for you to type further commands. The following
10e168596dfd doc/SIM-hardware-debugging: article written
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26 sequence of commands should bring up the SIM interface if the hardware is good:
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27
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28 abbinit
10e168596dfd doc/SIM-hardware-debugging: article written
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29 volt 1.8
10e168596dfd doc/SIM-hardware-debugging: article written
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30 setup
10e168596dfd doc/SIM-hardware-debugging: article written
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31 poll on
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32 reset 1
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33
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34 (Update for fc-host-tools-r11: the explicit abbinit command is no longer needed,
0f138858ff39 doc/SIM-hardware-debugging: note that abbinit is no longer needed
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35 but it is harmless to issue this extra command like before.)
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36
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37 You can change volt 1.8 to volt 3 if needed, but all recently made SIMs prefer
10e168596dfd doc/SIM-hardware-debugging: article written
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38 1.8 V and merely tolerate higher voltages. TI's Iota ABB chip, which is what
10e168596dfd doc/SIM-hardware-debugging: article written
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39 we target in FreeCalypso, does not support 5V SIMs - it doesn't have a charge
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40 pump or any other boost converter to produce 5 V from lower battery voltages.
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41 (It is not just TI but all mobile chipset vendors; it has been a very long time
10e168596dfd doc/SIM-hardware-debugging: article written
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42 since anyone made a phone that can power 5V SIMs, and any old 5V-only SIMs have
10e168596dfd doc/SIM-hardware-debugging: article written
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43 thus stopped being usable just as long ago.)
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44
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45 If the hardware is good and you have a working SIM inserted in the socket as
10e168596dfd doc/SIM-hardware-debugging: article written
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46 you execute the above commands, you should see ATR bytes from your SIM appear
10e168596dfd doc/SIM-hardware-debugging: article written
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47 in your terminal window the moment you issue the last reset 1 command: that
10e168596dfd doc/SIM-hardware-debugging: article written
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48 final command transitions the SIM reset line from low to high, if the SIM has
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49 been given good power and clock prior to this event, this transition causes it
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50 to initialize and emit its Answer To Reset, and once you issue the poll on
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51 command, our simtest program listens for incoming bytes from the SIM at the
461
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52 same time while it listens for you to type further commands.
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53
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54 If you execute the above command sequence with a known-good SIM inserted in the
10e168596dfd doc/SIM-hardware-debugging: article written
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55 socket and you don't see any ATR bytes on the final reset 1 command, then you
10e168596dfd doc/SIM-hardware-debugging: article written
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56 have confirmed with a lower-level tool that your SIM interface hardware is
10e168596dfd doc/SIM-hardware-debugging: article written
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57 having some issues. Give it a poweroff command, rerun the fc-iram command to
10e168596dfd doc/SIM-hardware-debugging: article written
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58 get a fresh session, and get your oscilloscope ready. Now execute the commands
10e168596dfd doc/SIM-hardware-debugging: article written
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59 slowly, probing with your o'scope at each step:
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60
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61 abbinit
10e168596dfd doc/SIM-hardware-debugging: article written
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62 volt 1.8
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63
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64 The volt command enables the VRSIM regulator in the Iota ABB chip and causes it
10e168596dfd doc/SIM-hardware-debugging: article written
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65 to put out the selected voltage. You should see this voltage appear on SIM
10e168596dfd doc/SIM-hardware-debugging: article written
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66 socket contact C1 (VCC); if it fails to appear there, then trace out the circuit
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67 coming from VRSIM, and the VRSIM regulator itself (inside the chip) may also be
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68 suspect.
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69
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70 setup
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71
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72 This command puts the SIM interface block inside the Calypso into a sensible
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73 state and enables the SIM interface level shifters in the Iota ABB. After this
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74 command you should see a good 3.25 MHz clock (13 MHz divided by 4) with selected
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75 SIM voltage levels on the SIM CLK line (socket contact C3), the RST line (socket
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76 contact C2) should be low, and the I/O line (socket contact C7) should be high.
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77 The SIM clock is produced in the Calypso and then voltage-translated by a
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78 unidirectional buffer in the Iota ABB, thus if the clock fails to appear at the
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79 SIM socket, look for issues in that signal path. For the I/O line to be high
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80 at this point in the bring-up sequence, the resistor pull-ups on both DBB-to-ABB
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81 and ABB-to-socket sides need to be working; if the I/O line is high on the
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82 DBB-to-ABB side and the pull-up on the ABB-to-socket side is good, but the I/O
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83 line on the ABB-to-socket side is still low, then there may be something wrong
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84 with the level shifter in the ABB holding it low.
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85
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86 poll on
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87 reset 1
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88
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89 (The poll on command can be omitted if you are doing o'scope probing on an empty
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90 socket and thus not expecting any ATR.) As you issue that reset 1 command, hold
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91 your oscilloscope probe on SIM socket contact C2, which is the RST line - it
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92 should go from low to high. Our simtest utility's reset command (reset 0 or
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93 reset 1) manipulates one bit in one Calypso register that controls the Calypso
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94 chip's SIM_RST output, which then passes through a unidirectional level shifter
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95 in the Iota ABB on its way to SIM socket contact C2.
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96
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97 On those two FCDEV3B V2 boards that have been rejected as defective because of a
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98 non-working SIM interface and which are now being revisited for a more thorough
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99 investigation, we have not yet seen any problems with the SIM power supply
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100 voltage, with the SIM CLK line or with the I/O line pull-up, but on both boards
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101 the SIM RST line is not working: we see a constant low at socket contact C2
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102 (the only probe-able point in the entire SIM reset signal path), and reset 1
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103 produces no effect. Unfortunately there is no way to probe the DBBSRST signal
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104 going from Calypso to Iota (it goes from one BGA to the other on an inner layer
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105 without coming up to the surface except right under the two ball pads), thus it
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106 is too difficult to tell where the breakage occurs: is it the Calypso failing
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107 to put out a high on its SIM_RST output when commanded to do so by the register
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108 setting, is it some fault in the PCB shorting this signal to GND before it
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109 reaches Iota's DBBSRST input, is it some fault inside the Iota chip itself that
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110 causes it to put out a low on its SIMRST output even though the DBBSRST input
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111 is high, or is it some fault in the PCB shorting the ABB-to-socket SIM RST
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112 output to GND?
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113
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114 Given that FCDEV3B is not intended to be a high-volume product (we only need to
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115 make enough good boards to provide one to every interested developer or
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116 tinkerer), it will probably make more economic sense to simply reject SIM-
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117 defective boards and write them off as a loss than to spend astronomical amounts
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118 on PCB microsurgery to expose the DBBSRST signal for probing or other in-depth
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119 troubleshooting measures along those lines. For future board designs that may
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120 need to be produced in higher volumes, the Mother's current plan is to add
10e168596dfd doc/SIM-hardware-debugging: article written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
121 probe-able test points on DBBSCK and DBBSRST lines, so that if similar problems
10e168596dfd doc/SIM-hardware-debugging: article written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
122 recur, we'll be able to quickly isolate them to the Calypso side or the Iota
10e168596dfd doc/SIM-hardware-debugging: article written
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff changeset
123 side.