[coreboot] x60 : adding WWAN support

Charles Devereaux coreboot at guylhem.net
Mon Sep 1 22:19:26 CEST 2014


I'm interested in WWAN support, mostly for the GPS features and the cool
things you can do with them (like a stratum ntp server).

I was told a EM770W doesn't even need a network registration to output NMEA
coordinates (http://forum.thinkpads.com/viewtopic.php?f=30&t=114426#p735612)
so I got one.

I looked at patch #4056 which enable WWAN for the EC, but it seems to only
part of the job: the ACPI table should also contain a GWAN key for

In drivers/platform/x86/thinkpad_acpi.c, you can see different references
to WAN:
        /* ACPI GWAN/SWAN bits */
        TP_ACPI_WANCARD_HWPRESENT       = 0x01, /* Wan hw available */
        TP_ACPI_WANCARD_RADIOSSW        = 0x02, /* Wan radio enabled */
        TP_ACPI_WANCARD_RESUMECTRL      = 0x04, /* Wan state at resume:
                                                   0 = disable, 1 = enable

In wan_get_status :
        if (!acpi_evalf(hkey_handle, &status, "GWAN", "d"))
                return -EIO;

Apparently, this last part cause the WWAN card not to be handled by
thinkpad-acpi, which would otherwise provide rfkill support (usefull to
save power, something I'd like to improve)

In acpi-3.dsl Scope (\_SB.PCI0.LPC.EC.HKEY, I see entries for both GWAN and
SWAN, and other things (WGPS, but what does it means???)

I believe similar entries should be added to coreboot asl, but I'm not sure
of how integrated they should be. If I understand correctly, following the
logic of patch #5242, there should be a conditional statement then some

If anyone is willing to submit a patch, I would be happy to test it.

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