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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>
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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>
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The only remaining user of the ipa_clock_{get,put}() interface is
ipa_isr_thread(). Replace calls to ipa_clock_get() there calling
pm_runtime_get_sync() instead. And call pm_runtime_put() there
rather than ipa_clock_put(). Warn if we ever get an error.
With that, we can get rid of ipa_clock_get() and ipa_clock_put().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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>
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Move the call to enable the IPA interrupt as a wakeup interrupt into
ipa_power_setup(), disable it in ipa_power_teardown().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now that ipa_clock_get_additional() is a trivial wrapper around
pm_runtime_get_if_active(), just open-code it in its only caller
and delete the function.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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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>
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Move ipa_suspend_handler() into "ipa_clock.c" from "ipa_main.c", to
group with the reset of the suspend/resume code. This IPA interrupt
is triggered if an IPA RX endpoint is suspended but has a packet to
be delivered.
Introduce ipa_power_setup() and ipa_power_teardown() to add and
remove the handler for the IPA SUSPEND interrupt at the same place
as before, while allowing the handler to remain private.
The "power" naming convention will be adopted elsewhere in this
file as well (soon).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Move ipa_suspend() and ipa_resume(), as well as the definition of
the ipa_pm_ops structure into "ipa_clock.c". Make ipa_pm_ops public
and declare it as extern in "ipa_clock.h".
This is part of centralizing IPA power management functionality into
"ipa_clock.c" (the file will eventually get a name change).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Define a new type of configuration data, used to initialize the
IPA core clock and interconnects. This is the first of three
patches, and defines the data types and interface but doesn't
yet use them.
Switch the return value if there is no matching configuration data
to ENODEV instead of ENOTSUPP (to avoid using the nonstandard errno).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This commit affects comments (and in one case, whitespace) only.
Throughout the IPA code, return statements are documented using
"@Return:", whereas they should use "Return:" instead. Fix these
mistakes.
In function definitions, some parameters are missing their comment
to describe them. And in structure definitions, some fields are
missing their comment to describe them. Add these missing
descriptions.
Some arguments changed name and type along the way, but their
descriptions were not updated (an endpoint pointer is now used in
many places that previously used an endpoint ID). Fix these
incorrect parameter descriptions.
In the description for the ipa_clock structure, one field had a
semicolon instead of a colon in its description. Fix this.
Add a missing function description for ipa_gsi_endpoint_data_empty().
All of these issues were identified when building with "W=1".
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Create a new function that returns the current rate of the IPA core
clock.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch incorporates three source files (and their headers). They're
grouped into one patch mainly for the purpose of making the number and
size of patches in this series somewhat reasonable.
- "ipa_clock.c" and "ipa_clock.h" implement clocking for the IPA device.
The IPA has a single core clock managed by the common clock framework.
In addition, the IPA has three buses whose bandwidth is managed by the
Linux interconnect framework. At this time the core clock and all
three buses are either on or off; we don't yet do any more fine-grained
management than that. The core clock and interconnects are enabled
and disabled as a unit, using a unified clock-like abstraction,
ipa_clock_get()/ipa_clock_put().
- "ipa_interrupt.c" and "ipa_interrupt.h" implement IPA interrupts.
There are two hardware IRQs used by the IPA driver (the other is
the GSI interrupt, described in a separate patch). Several types
of interrupt are handled by the IPA IRQ handler; these are not part
of data/fast path.
- The IPA has a region of local memory that is accessible by the AP
(and modem). Within that region are areas with certain defined
purposes. "ipa_mem.c" and "ipa_mem.h" define those regions, and
implement their initialization.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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