shared-qmi: implement reworked mode and capabilities management

This commit introduces several improvements and changes in the way
modes and capabilities are managed in QMI capable devices. It is
organized into a single commit, as all changes in all 6 operations
(load current capabilities, load supported capabilities, set current
capabilities, load supported modes, load current modes, set current
modes) are related one to the other (given that the same QMI commands
are used for both capabilities and mode management).

The primary change is related to which capabilities are reported as
supported for a given device. In the previous implementation we
allowed switching between every combination possible for GSM/UMTS+LTE,
CDMA/EVDO+LTE or GSM/UMTS+CDMA/EVDO+LTE devices. E.g. we would allow
"LTE only" and "GSM/UMTS only" capabilities for GSM/UMTS+LTE devices,
even if they would both be managed in exactly the same way. That setup
wasn't ideal, because it meant that switching to a "LTE only"
configuration would require a power cycle, as capability switching
requires a power cycle, even if no change was expected in the exposed
DBus interfaces (which is why we require the power cycle). So, instead
of allowing every possible capability combination, we use capability
switching logic exclusively for configuring GSM/UMTS+CDMA/EVDO devices
(regardless of whether it has LTE or not) to add or remove the
GSM/UMTS and CDMA/EVDO capabilities. E.g. for a GSM/UMTS+CDMA/EVDO+LTE
device we would allow 3 combinatios: "GSM/UMTS+LTE", "CDMA/EVDO+LTE"
and "GSM/UMTS+CDMA/EVDO+LTE".

The "GSM/UMTS+CDMA/EVDO+LTE" is a special case because for this one we
allow switching to "LTE only" capabilities while we forbid switching
to "4G only" mode. As the same commands are used for mode and
capability switching, if we didn't have "LTE only" and we allowed "4G
only" mode instead and rebooted the device, we would end up not being
able to know which other capabilities (GSM/UMTS or CDMA/EVDO or both)
were also enabled.

Now that we have capability switching confined to a very subset of
combinations, we can use the mode switching logic to e.g. allow "4G
only" configurations in all non multimode devices, as well as masks of
allowed modes with one being preferred, which we didn't allow before.
In the previous implementation all mode switching logic was disabled
for LTE capable QMI devices. In the new implementation, we use the
"Acquisition Order Preference" TLV in NAS Set System Selection
Preference to define the full list of mode preferences for all
supported modes.

We also no longer just assume that NAS Technology Preference is always
available and NAS System Selection Preference only after NAS >= 1.1.
This logic is flawed, instead we're going to probe for those features
once when loading current capabilities, and we then just implement the
capabilities/mode switching logic based on that.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/mm-modem-helpers-qmi.h b/src/mm-modem-helpers-qmi.h
index 8f02b95b..1deea7c3 100644
--- a/src/mm-modem-helpers-qmi.h
+++ b/src/mm-modem-helpers-qmi.h
@@ -46,6 +46,8 @@ MMModemAccessTechnology mm_modem_access_technologies_from_qmi_radio_interface_ar
 MMModemAccessTechnology mm_modem_access_technology_from_qmi_data_capability (QmiNasDataCapability cap);
 MMModemAccessTechnology mm_modem_access_technologies_from_qmi_data_capability_array (GArray *data_capabilities);
 
+MMModemMode mm_modem_mode_from_qmi_nas_radio_interface (QmiNasRadioInterface iface);
+
 MMModemMode mm_modem_mode_from_qmi_radio_technology_preference (QmiNasRadioTechnologyPreference qmi);
 QmiNasRadioTechnologyPreference mm_modem_mode_to_qmi_radio_technology_preference (MMModemMode mode,
                                                                                   gboolean is_cdma);
@@ -58,6 +60,12 @@ QmiNasRatModePreference mm_modem_mode_to_qmi_rat_mode_preference (MMModemMode mo
 MMModemCapability mm_modem_capability_from_qmi_rat_mode_preference (QmiNasRatModePreference qmi);
 QmiNasRatModePreference mm_modem_capability_to_qmi_rat_mode_preference (MMModemCapability caps);
 
+GArray *mm_modem_capability_to_qmi_acquisition_order_preference (MMModemCapability caps);
+GArray *mm_modem_mode_to_qmi_acquisition_order_preference       (MMModemMode       allowed,
+                                                                 MMModemMode       preferred,
+                                                                 gboolean          is_cdma,
+                                                                 gboolean          is_3gpp);
+
 MMModemCapability mm_modem_capability_from_qmi_radio_technology_preference (QmiNasRadioTechnologyPreference qmi);
 QmiNasRadioTechnologyPreference mm_modem_capability_to_qmi_radio_technology_preference (MMModemCapability caps);