MC7455 location support

Mon Apr 17 19:03:14 UTC 2017

On Sat, 2017-04-15 at 11:27 +0000, Karoly Pados wrote:
> Hi!
> 
> Sorry for the late reply, we have a 4-day holiday here and I spend
> less time at the computer.
> 
> > > But it does appear to support the LOC service (location) which is
> > > a
> > > newer service that ModemManager (and libqmi) doesn't yet support.
> > > So I
> > > think that's the current problem.
> > 
> > Ouch :/ Patches welcome!! :)
> 
> I can look into it, given there is some description or specification
> of the loc service protocol I can use. Do you have any pointers?
> Unfortunately I don't think I can allow myself the time to do full
> reverse engineering of the modem communication, so some doc about the
> QMI messages for the loc service would be nice (I'm not even familiar
> with QMI itself). 

It's pretty well described in the GobiAPI headers in libqmi git.

I started describing the boilerplate, but that took too long so I just
went ahead and did it:

https://cgit.freedesktop.org/libqmi/commit/?id=4da476f676678d83a5c73b94c4337c9a437fb6a1

Three parts are left for filling in the messages and TLVs; what I've
done is incomplete:

1) Messages: look in GobiConnectionMgmtAPIEnums.h for the message
numbers, eg:

   eQMI_LOC_START,                  // 034 Start GPS session

which you can then translate into the first part of the JSON for a new
message in qmi-service-loc.json:

  {  "name"    : "Start",
     "type"    : "Message",
     "service" : "LOC",
     "id"      : "0x0022",
     "version" : "1.0",
     "since"   : "1.19",

"version" is the QMI service version that this command first appeared
in, and I'd guess Start appeared in v1.0 of QMI_SVC_LOC.  "since" is
the libqmi version that this message was first defined in, so we'll use
"1.19" since libqmi is 1.18 and this would be in the next release
(1.19).

2) TLVs: these are found in GobiConnectionMgmtAPIStructs.h with a bit
of searching.  Look for "LOCStart" and you'll find the applicable TLVs
for eQMI_LOC_START.  For example:

// Structure to describe request TLV 0x01 for LOCStart()
struct sLOCStartRequest_SessionID
{
   UINT8 mSessionID;
};

That means TLV ID 0x01 for the Start message of the LOC service, and it
has a single member: a uint8 session id.  That becomes this JSON:

     { "name"          : "Session ID",
       "id"            : "0x01",
       "mandatory"     : "no",
       "type"          : "TLV",
       "since"         : "1.19",
       "format"        : "guint8" },

Repeat for each of the TLVs you want to add; if it's unclear how to add
the JSON for one (and it will be, like for
sLOCStartRequest_ApplicationID) feel free to ask!

3) Enums: when you come across a TLV that includes an enum, like:

// Structure to describe request TLV 0x12 for LOCStart()
struct sLOCStartRequest_EnableIntermediateReports
{
   eQMILOCIntermediateReportState mEnableIntermediateReports;
};

we usually create a mirror libqmi enum.  So you go look up
eQMILOCIntermediateReportState GobiConnectionMgmtAPIEnums.h and find:

// Enum to describe QMI LOC Intermediate Report State
enum eQMILOCIntermediateReportState:UINT32
{
   eQMILOCIntermediateReportState_Enable         = 1,
   eQMILOCIntermediateReportState_Disable        = 2,
};

note the UINT32 there; we'll remember that for later in the JSON.  This
enum becomes the libqmi-glib enum in src/libmm-glib/qmi-enums-loc.h:

/**
 * QmiLocIntermediateReportState:
 * @QMI_LOC_INTERMEDIATE_REPORT_STATE_UNKNOWN: Unknown.
 * @QMI_LOC_INTERMEDIATE_REPORT_STATE_ENABLE: Enable intermediate state reporting.
 * @QMI_LOC_INTERMEDIATE_REPORT_STATE_DISABLE: Disable intermediate state reporting.
 *
 * Whether to enable or disable intermediate state reporting.
 *
 * Since: 1.19
 */
typedef enum {
    QMI_LOC_INTERMEDIATE_REPORT_STATE_UNKNOWN = 0,
    QMI_LOC_INTERMEDIATE_REPORT_STATE_ENABLE = 1,
    QMI_LOC_INTERMEDIATE_REPORT_STATE_DISABLE = 2,
} QmiLocIntermediateReportState;

and then back in the JSON...  the TLV above becomes:

  { "name"          : "Intermediate Report State",
    "id"            : "0x12",
    "mandatory"     : "no",
    "type"          : "TLV",
    "since"         : "1.0",
    "format"        : "guint32",
    "public-format" : "QmiLocIntermediateReportState" } ] },

"format" is the QMI API size of the variable that libqmi uses when
converting the enum to the QMI protocol, while "public-format" is the
fancy enum that we've defined that will be used in the libqmi API.

Let us know if you have more questions...

Thanks!
Dan

> LG,
> Károly Pados
> 
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> ___________________________________________________________________
> 
> April 15, 2017 12:11 AM, "Aleksander Morgado" <aleksander at aleksander.
> es> wrote:
> 
> > On Thu, Apr 13, 2017 at 8:30 PM, Dan Williams <dcbw at redhat.com>
> > wrote:
> > 
> > > > > also, if you have ModemManager debug logs, that would be
> > > > > great to
> > > > > see
> > > > > too so we can make sure things are being set up correctly.
> > > > 
> > > > Attached. Also output of mmcli -m 0 in separate file.
> > > 
> > > Thanks. This shows your device is in fact in QMI mode, and that
> > > the
> > > firmware doesn't implement the "PDS" (Position Determination
> > > Service)
> > > that is normally used for this.
> > > 
> > > But it does appear to support the LOC service (location) which is
> > > a
> > > newer service that ModemManager (and libqmi) doesn't yet support.
> > > So I
> > > think that's the current problem.
> > 
> > Ouch :/ Patches welcome!! :)
> > 
> > --
> > Aleksander
> > https://aleksander.es
> > _______________________________________________
> > ModemManager-devel mailing list
> > ModemManager-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/modemmanager-devel
> 
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