linux-toradex.git/drivers/net/ipa, branch v5.16

net: ipa: kill ipa_cmd_pipeline_clear()

2021-11-23T12:26:40+00:00

Calling ipa_cmd_pipeline_clear() after stopping the channel
underlying the AP<-modem RX endpoint can lead to a deadlock.

This occurs in the ->runtime_suspend device power operation for the
IPA driver.  While this callback is in progress, any other requests
for power will block until the callback returns.

Stopping the AP<-modem RX channel does not prevent the modem from
sending another packet to this endpoint.  If a packet arrives for an
RX channel when the channel is stopped, an SUSPEND IPA interrupt
condition will be pending.  Handling an IPA interrupt requires
power, so ipa_isr_thread() calls pm_runtime_get_sync() first thing.

The problem occurs because a "pipeline clear" command will not
complete while such a SUSPEND interrupt condition exists.  So the
SUSPEND IPA interrupt handler won't proceed until it gets power;
that won't happen until the ->runtime_suspend callback (and its
"pipeline clear" command) completes; and that can't happen while
the SUSPEND interrupt condition exists.

It turns out that in this case there is no need to use the "pipeline
clear" command.  There are scenarios in which clearing the pipeline
is required while suspending, but those are not (yet) supported
upstream.  So a simple fix, avoiding the potential deadlock, is to
stop calling ipa_cmd_pipeline_clear() in ipa_endpoint_suspend().
This removes the only user of ipa_cmd_pipeline_clear(), so get rid
of that function.  It can be restored again whenever it's needed.

This is basically a manual revert along with an explanation for
commit 6cb63ea6a39ea ("net: ipa: introduce ipa_cmd_tag_process()").

Fixes: 6cb63ea6a39ea ("net: ipa: introduce ipa_cmd_tag_process()")
Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller

net: ipa: separate disabling setup from modem stop

2021-11-23T12:06:40+00:00

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 
Signed-off-by: David S. Miller

net: ipa: directly disable ipa-setup-ready interrupt

2021-11-23T12:06:40+00:00

We currently maintain a "disabled" Boolean flag to determine whether
the "ipa-setup-ready" SMP2P IRQ handler does anything.  That flag
must be accessed under protection of a mutex.

Instead, disable the SMP2P interrupt when requested, which prevents
the interrupt handler from ever being called.  More importantly, it
synchronizes a thread disabling the interrupt with the completion of
the interrupt handler in case they run concurrently.

Use the IPA setup_complete flag rather than the disabled flag in the
handler to determine whether to ignore any interrupts arriving after
the first.

Rename the "disabled" flag to be "setup_disabled", to be specific
about its purpose.

Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications")
Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller

net: ipa: disable HOLB drop when updating timer

2021-11-15T13:25:45+00:00

The head-of-line blocking timer should only be modified when
head-of-line drop is disabled.

One of the steps in recovering from a modem crash is to enable
dropping of packets with timeout of 0 (immediate).  We don't know
how the modem configured its endpoints, so before we program the
timer, we need to ensure HOL_BLOCK is disabled.

Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller

net: ipa: HOLB register sometimes must be written twice

2021-11-15T13:25:45+00:00

Starting with IPA v4.5, the HOL_BLOCK_EN register must be written
twice when enabling head-of-line blocking avoidance.

Fixes: 84f9bd12d46db ("soc: qcom: ipa: IPA endpoints")
Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller

net/ipa: ipa_resource: Fix wrong for loop range

2021-11-13T03:59:45+00:00

The source group count was mistakenly assigned to both dst and src loops.
Fix it to make IPA probe and work again.

Fixes: 4fd704b3608a ("net: ipa: record number of groups in data")
Acked-by: AngeloGioacchino Del Regno 
Reviewed-by: Marijn Suijten 
Signed-off-by: Konrad Dybcio 
Reviewed-by: Alex Elder 
Link: https://lore.kernel.org/r/20211111183724.593478-1-konrad.dybcio@somainline.org
Signed-off-by: Jakub Kicinski

Merge tag 'asm-generic-fixes-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2021-10-08T18:57:54+00:00

Pull asm-generic fixes from Arnd Bergmann:
 "There is one build fix for Arm platforms that ended up impacting most
  architectures because of the way the drivers/firmware Kconfig file is
  wired up:

  The CONFIG_QCOM_SCM dependency have caused a number of randconfig
  regressions over time, and some still remain in v5.15-rc4. The fix we
  agreed on in the end is to make this symbol selected by any driver
  using it, and then building it even for non-Arm platforms with
  CONFIG_COMPILE_TEST.

  To make this work on all architectures, the drivers/firmware/Kconfig
  file needs to be included for all architectures to make the symbol
  itself visible.

  In a separate discussion, we found that a sound driver patch that is
  pending for v5.16 needs the same change to include this Kconfig file,
  so the easiest solution seems to have my Kconfig rework included in
  v5.15.

  Finally, the branch also includes a small unrelated build fix for
  NOMMU architectures"

Link: https://lore.kernel.org/all/20210928153508.101208f8@canb.auug.org.au/
Link: https://lore.kernel.org/all/20210928075216.4193128-1-arnd@kernel.org/
Link: https://lore.kernel.org/all/20211007151010.333516-1-arnd@kernel.org/

* tag 'asm-generic-fixes-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic/io.h: give stub iounmap() on !MMU same prototype as elsewhere
  qcom_scm: hide Kconfig symbol
  firmware: include drivers/firmware/Kconfig unconditionally

qcom_scm: hide Kconfig symbol

2021-10-07T14:51:57+00:00

Now that SCM can be a loadable module, we have to add another
dependency to avoid link failures when ipa or adreno-gpu are
built-in:

aarch64-linux-ld: drivers/net/ipa/ipa_main.o: in function `ipa_probe':
ipa_main.c:(.text+0xfc4): undefined reference to `qcom_scm_is_available'

ld.lld: error: undefined symbol: qcom_scm_is_available
>>> referenced by adreno_gpu.c
>>>               gpu/drm/msm/adreno/adreno_gpu.o:(adreno_zap_shader_load) in archive drivers/built-in.a

This can happen when CONFIG_ARCH_QCOM is disabled and we don't select
QCOM_MDT_LOADER, but some other module selects QCOM_SCM. Ideally we'd
use a similar dependency here to what we have for QCOM_RPROC_COMMON,
but that causes dependency loops from other things selecting QCOM_SCM.

This appears to be an endless problem, so try something different this
time:

 - CONFIG_QCOM_SCM becomes a hidden symbol that nothing 'depends on'
   but that is simply selected by all of its users

 - All the stubs in include/linux/qcom_scm.h can go away

 - arm-smccc.h needs to provide a stub for __arm_smccc_smc() to
   allow compile-testing QCOM_SCM on all architectures.

 - To avoid a circular dependency chain involving RESET_CONTROLLER
   and PINCTRL_SUNXI, drop the 'select RESET_CONTROLLER' statement.
   According to my testing this still builds fine, and the QCOM
   platform selects this symbol already.

Acked-by: Kalle Valo 
Acked-by: Alex Elder 
Signed-off-by: Arnd Bergmann

net: ipa: initialize all filter table slots

2021-09-08T11:10:33+00:00

There is an off-by-one problem in ipa_table_init_add(), when
initializing filter tables.

In that function, the number of filter table entries is determined
based on the number of set bits in the filter map.  However that
count does *not* include the extra "slot" in the filter table that
holds the filter map itself.  Meanwhile, ipa_table_addr() *does*
include the filter map in the memory it returns, but because the
count it's provided doesn't include it, it includes one too few
table entries.

Fix this by including the extra slot for the filter map in the count
computed in ipa_table_init_add().

Note: ipa_filter_reset_table() does not have this problem; it resets
filter table entries one by one, but does not overwrite the filter
bitmap.

Fixes: 2b9feef2b6c2 ("soc: qcom: ipa: filter and routing tables")
Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller

net: ipa: rename "ipa_clock.c"

2021-08-22T08:44:17+00:00

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

Signed-off-by: Alex Elder 
Signed-off-by: David S. Miller