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: update comments

This patch just updates comments throughout the IPA code.

Transaction state is now tracked using indexes into an array rather
than linked lists, and a few comments refer to the "old way" of
doing things. The description of how transactions are used was
changed to refer to "operations" rather than "commands", to
(hopefully) remove a possible ambiguity.

IPA register offsets and fields are now handled differently as well,
and the register documentation is updated to better describe the
code.

A few minor updates to comments were made (e.g., adding a missing
word, fixing a typo or punctuation, etc.).

Finally, the local macro atomic_dec_not_zero() is no longer used, so
it is deleted.

Signed-off-by: Alex Elder <elder@linaro.org>
Link: https://lore.kernel.org/r/20220930224527.3503404-1-elder@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: kill all other transaction lists

None of the transaction lists are actually needed any more, because
transaction IDs (which have been shown to be equivalent) are used
instead. So we can remove all of them, as well as the spinlock
that protects updates to them.

Not requiring a lock simplifies gsi_trans_free() as well; we only
need to check the reference count once to decide whether we've hit
the last reference.

This makes the links field in the gsi_trans structure unused, so get
rid of that as well.

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

net: ipa: introduce gsi_trans_tx_committed()

Create a new function that encapsulates recording information needed
for TX channel statistics when a transaction is committed.

Record the accumulated length in the transaction before the call
(for both RX and TX), so it can be used when updating TX statistics.

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

net: ipa: rename two transaction fields

There are two fields in a GSI transaction that keep track of TRE
counts. The first represents the number of TREs reserved for the
transaction in the TRE ring; that's currently named "tre_count".
The second is the number of TREs that are actually *used* by the
transaction at the time it is committed.

Rename the "tre_count" field to be "rsvd_count", to make its meaning
a little more specific. The "_count" is present in the name mainly
to avoid interpreting it as a reserved (not-to-be-used) field. This
name also distinguishes it from the "tre_count" field associated
with a channel.

Rename the "used" field to be "used_count", to match the convention
used for reserved TREs.

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

net: ipa: use data space for command opcodes

The 64-bit data field in a transaction is not used for commands.
And the opcode array is *only* used for commands. They're
(currently) the same size; save a little space in the transaction
structure by enclosing the two fields in a union.

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

net: ipa: remove command info pool

The ipa_cmd_info structure now contains only one field, and it's an
enumerated type whose values all fit in 8 bits. Currently we'll
never use more than 8 TREs in a command transaction, and we can
represent that number of command opcodes in the same space as a 64
bit pointer to an ipa_cmd_info structure.

Define IPA_COMMAND_TRANS_TRE_MAX as the maximum number of TREs that
can be in a command transaction. Replace the info pointer in a
transaction with a fixed-size array named cmd_opcode[] of that many
bytes. Store the opcode in this array when adding a command TRE to
a transaction, as was done previously for the info array. This
makes the ipa_cmd_info unused, so get rid of it.

When committing an immediate command transaction, use the channel's
Boolean command flag to determine whether to fill in the opcode,
which will be taken (as before) from the array in the transaction.

This makes the command info pool unnecessary, so get rid of it.

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

net: ipa: remove command direction argument

We no longer use the direction argument for gsi_trans_cmd_add(), so
get rid of it in its definition, and in its seven callers.

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

net: ipa: kill gsi_trans_commit_wait_timeout()

Since the beginning gsi_trans_commit_wait_timeout() has existed to
provide a way to allow waiting a limited time for a transaction
to complete. But that function has never been used.

In fact, there is no use for this function, because a transaction
committed to hardware should *always* complete. The only reason it
might not complete is if there were a hardware failure, or perhaps a
system configuration error.

Furthermore, if a timeout ever did occur, the IPA hardware would be
in an indeterminate state, from which there is no recovery. It
would require some sort of complete IPA reset, and would require the
participation of the modem, and at this time there is no such
sequence defined.

So get rid of the definition of gsi_trans_commit_wait_timeout(), and
update a few comments accordingly.

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

net: ipa: introduce gsi_channel_trans_idle()

Create a new function that returns true if all transactions for a
channel are available for use.

Use it in ipa_endpoint_replenish_enable() to see whether to start
replenishing, and in ipa_endpoint_replenish() to determine whether
it's necessary after a failure to schedule delayed work to ensure a
future replenish attempt occurs.

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

net: ipa: fix all kernel-doc warnings

Fix all warnings produced when running:
scripts/kernel-doc -none drivers/net/ipa/*.[ch]

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

net: ipa: declare the page pointer type in "gsi_trans.h"

The second argument to gsi_trans_page_add() is a page pointer.
That declaration is found in header files used by "gsi_trans.h" for
(at least) arm64 and x86 builds, but apparently not for alpha
builds.

Fix this by adding a declaration of struct page to the top of
"gsi_trans.h".

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: ipa: fix kerneldoc comments

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>

soc: qcom: ipa: GSI transactions

This patch implements GSI transactions. A GSI transaction is a
structure that represents a single request (consisting of one or
more TREs) sent to the GSI hardware. The last TRE in a transaction
includes a flag requesting that the GSI interrupt the AP to notify
that it has completed.

TREs are executed and completed strictly in order. For this reason,
the completion of a single TRE implies that all previous TREs (in
particular all of those "earlier" in a transaction) have completed.

Whenever there is a need to send a request (a set of TREs) to the
IPA, a GSI transaction is allocated, specifying the number of TREs
that will be required. Details of the request (e.g. transfer offsets
and length) are represented by in a Linux scatterlist array that is
incorporated in the transaction structure.

Once all commands (TREs) are added to a transaction it is committed.
When the hardware signals that the request has completed, a callback
function allows for cleanup or followup activity to be performed
before the transaction is freed.

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