net: ipa: don't save the platform device

The IPA platform device is now only used as the structure containing
the IPA device structure. Replace the platform device pointer with
a pointer to the device structure.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: kill ipa_power_modem_queue_wake()

All ipa_power_modem_queue_wake() does is call netif_wake_queue()
on the modem netdev. There is no need to wrap that call in a
trivial function (and certainly not one defined in "ipa_power.c").

So get rid of ipa_power_modem_queue_wake(), and replace its one
caller with a direct call to netif_wake_queue(). Determine the
netdev pointer to use from the private TX endpoint's netdev pointer.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240130192305.250915-8-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: kill ipa_power_modem_queue_active()

All ipa_power_modem_queue_active() does now is call netif_wake_queue().
Just call netif_wake_queue() in the two places it's needed, and get
rid of ipa_power_modem_queue_active().

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240130192305.250915-7-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: kill ipa_power_modem_queue_stop()

All ipa_power_modem_queue_stop() does now is call netif_stop_queue().
Just call netif_stop_queue() in the one place it's needed, and get
rid of ipa_power_modem_queue_stop().

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240130192305.250915-6-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: begin simplifying TX queue stop

There are a number of flags used in the IPA driver to attempt to
manage race conditions that can occur between runtime resume and
netdev transmit. If we disable TX before requesting power, we can
avoid these races entirely, simplifying things considerably.

This patch implements the main change, disabling transmit always in
the net_device->ndo_start_xmit() callback, then re-enabling it again
whenever we find power is active (or when we drop the skb).

The patches that follow will refactor the "old" code to the point
that most of it can be eliminated.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240130192305.250915-3-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: stash modem TX and RX endpoints

Rather than repeatedly looking up the endpoints in the name map,
save the modem TX and RX endpoint pointers in the netdev private
area.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20240130192305.250915-2-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: update copyrights

Some source files state copyright dates that are earlier than the
last modification of the file. Change the copyright year to 2022 in
all such cases.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20220930224549.3503434-1-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: save a copy of endpoint default config

All elements of the default endpoint configuration are used in the
code when programming an endpoint for use. But none of the other
configuration data is ever needed once things are initialized.

So rather than saving a pointer to *all* of the configuration data,
save a copy of only the endpoint configuration portion.

This will eventually allow endpoint configuration to be modifiable
at runtime. But even before that it means we won't keep a pointer
to configuration data after when no longer needed.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: rename a few endpoint config data types

Rename the just-moved data structure types to drop the "_data"
suffix, to make it more obvious they are no longer meant to be used
just as read-only initialization data. Rename the fields and
variables of these types to use "config" instead of "data" in the
name. This is another small step meant to facilitate review.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: open-code ether_setup()

About half of the fields set by the call in ipa_modem_netdev_setup()
are overwritten after the call. Instead, just skip the call, and
open-code the (other) assignments it makes to the net_device
structure fields.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: kill ipa_modem_init()

A recent commit made disabling the SMP2P "setup ready" interrupt
unrelated to ipa_modem_stop(). Given that, it seems fitting to get
rid of ipa_modem_init() and ipa_modem_exit() (which are trivial
wrapper functions), and call ipa_smp2p_init() and ipa_smp2p_exit()
directly instead.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: separate disabling setup from modem stop

The IPA setup_complete flag is set at the end of ipa_setup(), when
the setup phase of initialization has completed successfully. This
occurs as part of driver probe processing, or (if "modem-init" is
specified in the DTS file) it is triggered by the "ipa-setup-ready"
SMP2P interrupt generated by the modem.

In the latter case, it's possible for driver shutdown (or remove) to
begin while setup processing is underway, and this can't be allowed.
The problem is that the setup_complete flag is not adequate to signal
that setup is underway.

If setup_complete is set, it will never be un-set, so that case is
not a problem. But if setup_complete is false, there's a chance
setup is underway.

Because setup is triggered by an interrupt on a "modem-init" system,
there is a simple way to ensure the value of setup_complete is safe
to read. The threaded handler--if it is executing--will complete as
part of a request to disable the "ipa-modem-ready" interrupt. This
means that ipa_setup() (which is called from the handler) will run
to completion if it was underway, or will never be called otherwise.

The request to disable the "ipa-setup-ready" interrupt is currently
made within ipa_modem_stop(). Instead, disable the interrupt
outside that function in the two places it's called. In the case of
ipa_remove(), this ensures the setup_complete flag is safe to read
before we read it.

Rename ipa_smp2p_disable() to be ipa_smp2p_irq_disable_setup(), to be
more specific about its effect.

Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: rename "ipa_clock.c"

Finally, rename "ipa_clock.c" to be "ipa_power.c" and "ipa_clock.h"
to be "ipa_power.h".

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: rename ipa_clock_* symbols

Rename a number of functions to clarify that there is no longer a
notion of an "IPA clock," but rather that the functions are more
generally related to IPA power management.

ipa_clock_enable() -> ipa_power_enable()
ipa_clock_disable() -> ipa_power_disable()
ipa_clock_rate() -> ipa_core_clock_rate()
ipa_clock_init() -> ipa_power_init()
ipa_clock_exit() -> ipa_power_exit()

Rename the ipa_clock structure to be ipa_power. Rename all
variables and fields using that structure type "power" rather
than "clock".

Rename the ipa_clock_data structure to be ipa_power_data, and more
broadly, just substitute "power" for "clock" in places that
previously represented things related to the "IPA clock".

Update comments throughout.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: use autosuspend

Use runtime power management autosuspend.

Up until this point, we only suspended the IPA hardware for system
suspend; now we'll suspend it aggressively using runtime power
management, setting the initial autosuspend delay to half a second
of inactivity.

Replace pm_runtime_put() calls with pm_runtime_put_autosuspend(),
call pm_runtime_mark_last_busy() before each of those. In places
where we're shutting things down, or decrementing power references
for errors, use pm_runtime_put_noidle() instead.

Finally, remove ipa_runtime_idle(), so the ->runtime_suspend
callback will occur if idle.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: don't use ipa_clock_get() in "ipa_modem.c"

When we open or close the modem network device we need to ensure the
hardware is powered. Replace the callers of ipa_clock_get() found
in ipa_open() and ipa_stop() with calls to pm_runtime_get_sync().
If an error is returned, simply return that error to the caller
(without any error or warning message). This could conceivably
occur if the function was called while the system was suspended,
but that really shouldn't happen. Replace corresponding calls to
ipa_clock_put() with pm_runtime_put() also.

If the modem crashes we also need to ensure the hardware is powered
to recover. If getting power returns an error there's not much we
can do, but at least report the error. (Ideally the remoteproc SSR
code would ensure the AP was not suspended when it sends the
notification, but that is not (yet) the case.)

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: fix TX queue race

Jakub Kicinski pointed out a race condition in ipa_start_xmit() in a
recently-accepted series of patches:
https://lore.kernel.org/netdev/20210812195035.2816276-1-elder@linaro.org/
We are stopping the modem TX queue in that function if the power
state is not active. We restart the TX queue again once hardware
resume is complete.

TX path Power Management
------- ----------------
pm_runtime_get(); no power Start resume
Stop TX queue ...
pm_runtime_put() Resume complete
return NETDEV_TX_BUSY Start TX queue

pm_runtime_get()
Power present, transmit
pm_runtime_put() (auto-suspend)

The issue is that the power management (resume) activity and the
network transmit activity can occur concurrently, and there's a
chance the queue will be stopped *after* it has been started again.

TX path Power Management
------- ----------------
Resume underway
pm_runtime_get(); no power ...
Resume complete
Start TX queue
Stop TX queue <-- No more transmits after this
pm_runtime_put()
return NETDEV_TX_BUSY

We address this using a STARTED flag to indicate when the TX queue
has been started from the resume path, and a spinlock to make the
flag and queue updates happen atomically.

TX path Power Management
------- ----------------
Resume underway
pm_runtime_get(); no power Resume complete
start TX queue \
If STARTED flag is *not* set: > atomic
Stop TX queue set STARTED flag /
pm_runtime_put()
return NETDEV_TX_BUSY

A second flag is used to address a different race that involves
another path requesting power.

TX path Other path Power Management
------- ---------- ----------------
pm_runtime_get_sync() Resume
Start TX queue \ atomic
Set STARTED flag /
(do its thing)
pm_runtime_put()
(auto-suspend)
pm_runtime_get() Mark delayed resume
STARTED *is* set, so
do *not* stop TX queue <-- Queue should be stopped here
pm_runtime_put()
return NETDEV_TX_BUSY Suspend done, resume
Resume complete
pm_runtime_get()
Stop TX queue
(STARTED is *not* set) Start TX queue \ atomic
pm_runtime_put() Set STARTED flag /
return NETDEV_TX_BUSY

So a STOPPED flag is set in the transmit path when it has stopped
the TX queue, and this pair of operations is also protected by the
spinlock. The resume path only restarts the TX queue if the STOPPED
flag is set. This case isn't a major problem, but it avoids the
"non-trivial amount of useless work" done by the networking stack
when NETDEV_TX_BUSY is returned.

Fixes: 6b51f802d652b ("net: ipa: ensure hardware has power in ipa_start_xmit()")
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: don't hold clock reference while netdev open

Currently a clock reference is taken whenever the ->ndo_open
callback for the modem netdev is called. That reference is dropped
when the device is closed, in ipa_stop().

We no longer need this, because ipa_start_xmit() now handles the
situation where the hardware power state is not active.

Drop the clock reference in ipa_open() when we're done, and take a
new reference in ipa_stop() before we begin closing the interface.

Finally (and unrelated, but trivial), change the return type of
ipa_start_xmit() to be netdev_tx_t instead of int.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: don't stop TX on suspend

Currently we stop the modem netdev transmit queue when suspending
the hardware. For system suspend this ensured we'd never attempt
to transmit while attempting to suspend the modem endpoints.

For runtime suspend, the IPA hardware might get suspended while the
system is operating. In that case we want an attempt to transmit a
packet to cause the hardware to resume if necessary. But if we
disable the queue this cannot happen.

So stop disabling the queue on suspend. In case we end up disabling
it in ipa_start_xmit() (see the previous commit), we still arrange
to start the TX queue on resume.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: ensure hardware has power in ipa_start_xmit()

We need to ensure the hardware is powered when we transmit a packet.
But if it's not, we can't block to wait for it. So asynchronously
request power in ipa_start_xmit(), and only proceed if the return
value indicates the power state is active.

If the hardware is not active, a runtime resume request will have
been initiated. In that case, stop the network stack from further
transmit attempts until the resume completes. Return NETDEV_TX_BUSY,
to retry sending the packet once the queue is restarted.

If the power request returns an error (other than -EINPROGRESS,
which just means a resume requested elsewhere isn't complete), just
drop the packet.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: re-enable transmit in PM WQ context

Create a new work structure in the modem private data, and use it to
re-enable the modem network device transmit queue when resuming.

This is needed by the next patch, which stops the TX queue if IPA
power isn't active when a transmit request arrives. Packets will
start arriving the instant the TX queue is enabled, but resuming
isn't complete until ipa_modem_resume() returns. This way we're
sure to be resumed before transmits are allowed again.

Cancel it before calling ipa_stop() in ipa_modem_stop() to ensure
the transmit queue restart completes before it gets stopped there.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: have ipa_clock_get() return a value

We currently assume no errors occur when enabling or disabling the
IPA core clock and interconnects. And although this commit exposes
errors that could occur, we generally assume this won't happen in
practice.

This commit changes ipa_clock_get() and ipa_clock_put() so each
returns a value. The values returned are meant to mimic what the
runtime power management functions return, so we can set up error
handling here before we make the switch. Have ipa_clock_get()
increment the reference count even if it returns an error, to match
the behavior of pm_runtime_get().

More details follow.

When taking a reference in ipa_clock_get(), return 0 for the first
reference, 1 for subsequent references, or a negative error code if
an error occurs. Note that if ipa_clock_get() returns an error, we
must not touch hardware; in some cases such errors now cause entire
blocks of code to be skipped.

When dropping a reference in ipa_clock_put(), we return 0 or an
error code. The error would come from ipa_clock_disable(), which
now returns what ipa_interconnect_disable() returns (either 0 or a
negative error code). For now, callers ignore the return value;
if an error occurs, a message will have already been logged, and
little more can actually be done to improve the situation.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: reorder netdev pointer assignments

Assign the ipa->modem_netdev and endpoint->netdev pointers *before*
registering the network device. As soon as the device is
registered it can be opened, and by that time we'll want those
pointers valid.

Similarly, don't make those pointers NULL until *after* the modem
network device is unregistered in ipa_modem_stop().

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: don't suspend/resume modem if not up

The modem network device is set up by ipa_modem_start(). But its
TX queue is not actually started and endpoints enabled until it is
opened.

So avoid stopping the modem network device TX queue and disabling
endpoints on suspend or stop unless the netdev is marked UP. And
skip attempting to resume unless it is UP.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: add a clock reference for netdev operations

The IPA network device can be opened at any time, and an opened
network device can be stopped any time. Both of these callback
functions require access to the hardware, and therefore they need
the IPA clock to be operational. Take an IPA clock reference in
both the ->open and ->stop callback functions, dropping the
reference when they are done accessing hardware.

The ->start_xmit callback requires a little different handling,
and that will be added separately.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: add clock reference for remoteproc SSR

The remoteproc SSR callback function for the modem requires hardware
access when handling a modem crash or shutdown. Take and later
release an IPA clock reference in ipa_modem_crashed(), to ensure the
hardware is operational.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: introduce ipa_uc_clock()

The first time it's booted, the modem loads and starts the
IPA-resident microcontroller. Once the microcontroller has
completed its initialization, it notifies the AP it's "ready"
by sending an INIT_COMPLETED response message.

Until it receives that microcontroller message, the AP must ensure
the IPA core clock remains operational. Currently, a "proxy" clock
reference is taken in ipa_uc_config(), dropping it again once the
message is received.

However there could be a long delay between when ipa_config()
completes and when modem actually starts. And because the
microcontroller gets loaded by the modem, there's no need to
get the modem "proxy clock" until the first time it starts.

Create a new function ipa_uc_clock() which takes the "proxy" clock
reference for the microcontroller. Call it when we get remoteproc
SSR notification that the modem is about to start. Keep an
additional flag to record whether this proxy clock reference needs
to be dropped at shutdown time, and issue a warning if we get the
microcontroller message either before the clock reference is taken,
or after it has already been dropped.

Drop the nearby use of "hh" length modifiers, which are no longer
encouraged in the kernel.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: kill ipa_modem_setup()

The functions ipa_modem_setup() and ipa_modem_teardown() are trivial
wrappers that call ipa_qmi_setup() and ipa_qmi_teardown(). Just
call the QMI functions directly, and get rid of the wrappers.

Improve the documentation of what setting up QMI does.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: ipa: ipa_stop() does not return an error

In ipa_modem_stop(), if the modem netdev pointer is non-null we call
ipa_stop(). We check for an error and if one is returned we handle
it. But ipa_stop() never returns an error, so this extra handling
is unnecessary. Simplify the code in ipa_modem_stop() based on the
knowledge no error handling is needed at this spot.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: only set endpoint netdev pointer when in use

In ipa_modem_start(), we set endpoint netdev pointers before the
network device is registered. If registration fails, we don't undo
those assignments. Instead, wait to assign the netdev pointer until
after registration succeeds.

Set these endpoint netdev pointers to NULL in ipa_modem_stop()
before unregistering the network device.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: modem: add missing SET_NETDEV_DEV() for proper sysfs links

At the moment it is quite hard to identify the network interface
provided by IPA in userspace components: The network interface is
created as virtual device, without any link to the IPA device.
The interface name ("rmnet_ipa%d") is the only indication that the
network interface belongs to IPA, but this is not very reliable.

Add SET_NETDEV_DEV() to associate the network interface with the
IPA parent device. This allows userspace services like ModemManager
to properly identify that this network interface is provided by IPA
and belongs to the modem.

Cc: Alex Elder <elder@kernel.org>
Fixes: a646d6ec9098 ("soc: qcom: ipa: modem and microcontroller")
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20210106100755.56800-1-stephan@gerhold.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: new notification infrastructure

Use the new SSR notifier infrastructure to request notifications of
modem events, rather than the remoteproc IPA notification system.
The latter was put in place temporarily with the knowledge that the
new mechanism would become available.

Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20200724181142.13581-2-elder@linaro.org
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

soc: qcom: ipa: Add a missing '\n' in a log message

Message logged by 'dev_xxx()' or 'pr_xxx()' should end with a '\n'.

Fixes: a646d6ec9098 ("soc: qcom: ipa: modem and microcontroller")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

soc: qcom: ipa: fix spelling mistake "cahces" -> "caches"

There is a spelling mistake in a dev_err message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

soc: qcom: ipa: modem and microcontroller

This patch includes code implementing the modem functionality.
There are several communication paths between the AP and modem,
separate from the main data path provided by IPA. SMP2P provides
primitive messaging and interrupt capability, and QMI allows more
complex out-of-band messaging to occur between entities on the AP
and modem. (SMP2P and QMI support are added by the next patch.)
Management of these (plus the network device implementing the data
path) is done by code within "ipa_modem.c".

Sort of unrelated, this patch also includes the code supporting the
microcontroller CPU present on the IPA. The microcontroller can be
used to implement special handling of packets, but at this time we
don't support that. Still, it is a component that needs to be
initialized, and in the event of a crash we need to do some
synchronization between the AP and the microcontroller.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>