CellularDevice::get_default_instance() is a weak method and is overriden
by either a default construction provided in the code or by application
at some stage. This method needs to be flagged otherwise using another
driver will be hindered by the default overriding of this driver.
Using malloc will require us to add stdlib.h somewhere in the path for
the application. Maybe the CI apps are adding stdlib.h and that's why
the code would have worked. In a custom app, it can happen that the
header is not included. Using new avoids the need to add stdlib.h
anywhere and it is more in line with C++.
For default construction of the driver, it would be necessary to define
the pins. However as we don't know the correct pins, until/unless user
sets them up for us. So it makes sense to mark the pins as NC. It would
be easier to debug if the pins are set to NC if user forgot to set them
up.
To make this driver more useful, we needed to do some changes. The
wirings for the modem can differ on the board so we also need to be
flexible in our approach.
It is now mandatory to provide the power pin and pin polarity in the
constructor alongwith the file handle. Reset pin is optional.
Standard 3GPP TS27.007 states that the AT+CGSN command can optionally
have type parameter that determines the output. However Quiectel EC2X
series doesn't accept parameters. We need to reflect that in the
cellular properties setup.
Provides basic power up / power down sequences for Quectel EC2X series
modems. Can be used in PPP mode. For using the on-board IP stack, we
will need to add and implement classes that provide context.
Driver constructor takes power and reset control pins along with the
FileHandle. A default construction is provided which can be chosen by
the application in its mbed_app.json. Otherwise the user is free to
construct as per demand.
Since commit 12c6b1bd8, the i.MX RT1050 has effectively had its data
cache disabled, as the SDRAM was marked Shareable; for the Cortex-M7,
shareable memory is not cached.
This was done to make the Ethernet driver work without any cache
maintenance code. This commit adds cache maintenance and memory barriers
to the Ethernet driver, and removes the Shareable attribute from the
SDRAM, so the data cache is used again.
Cache code in the base fsl_enet.c driver has not been activated - the
bulk of it is in higher-level Read and Write calls that we're not using,
and there is one flawed invalidate in its initialisation. Instead
imx_emac.cpp takes full cache responsibility.
This commit also marks the SDRAM as read/write-allocate. As the
Cortex-M7 has its "Dynamic read allocate mode" to automatically switch
back to read-allocate in cases where write allocate is working poorly
(eg large memset), this should result in a performance boost with no
downside.
Activating write-allocate is also an attempt to provoke any flaws in
cache maintenance - the Ethernet transmit buffers for example will be
more likely to have a little data in the cache that needs cleaning.
Mirela Chirica
Martin Kojtal
Kevin Bracey
Marc Emmers
paul-szczepanek-arm
Martin Kojtal
Cruz Monrreal
Tymoteusz Bloch
Ari Parkkila
Oren Cohen
Hasnain Virk
Teppo Järvelin
Mahesh Mahadevan