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>

All conflicts seemed rather trivial, with some guidance from
Saeed Mameed on the tc_ct.c one.

Signed-off-by: David S. Miller <davem@davemloft.net>

For IPA v4.2, the exact interpretation of the register that defines
the timeout for avoiding head-of-line blocking was a little unclear.
We're only assigning a 0 timeout to it right now, so that wasn't
very important.  But now that I know how it's supposed to work, I'm
fixing it.

The register represents a tick counter, where each tick is equal to
128 IPA core clock cycles.  For IPA v3.5.1, the register contains
a simple counter value.  But for IPA v4.2, the register contains two
fields, base and scale, which approximate the tick counter as:
    ticks = base << scale
The base and scale values to use for a given tick count are computed
using clever bit operations, and measures are taken to make the
resulting time period as close as possible to that requested.

There's no need for ipa_endpoint_init_hol_block_timer() to return
an error, so change its return type to void.

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

Have functions that write endpoint configuration registers return
immediately if they are not valid for the direction of transfer for
the endpoint.  This allows most of the calls in ipa_endpoint_program()
to be made unconditionally.  Reorder the register writes to match
the order of their definition (based on offset).

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

IPA version 4.0+ does not support endpoint suspend.  Put a test at
the top of ipa_endpoint_program_suspend() that returns immediately
if suspend is not supported rather than making that check in the caller.

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

IPA version 3.5.1 has a hardware quirk that requires special
handling if an RX endpoint is suspended while aggregation is active.
This handling is implemented by ipa_endpoint_suspend_aggr().

Have ipa_endpoint_program_suspend() be responsible for calling
ipa_endpoint_suspend_aggr() if suspend mode is being enabled on
an endpoint.  If the endpoint does not support aggregation, or if
aggregation isn't active, this call will continue to have no effect.

Move the definition of ipa_endpoint_suspend_aggr() up in the file so
its definition precedes the new earlier reference to it.  This
requires ipa_endpoint_aggr_active() and ipa_endpoint_force_close()
to be moved as well.

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

IPA version 4.2 has a hardware quirk that affects endpoint delay
mode, so it isn't used there.  Isolate the test that avoids using
delay mode for that version inside ipa_endpoint_program_delay(),
rather than making that check in the caller.

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

The convention throughout the IPA driver is to directly use
single-bit field mask values, rather than using (for example)
u32_encode_bits() to set or clear them.

Fix the one place that doesn't follow that convention, which sets
HOL_BLOCK_EN_FMASK in ipa_endpoint_init_hol_block_enable().

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

The INIT_MODE endpoint configuration register is only valid for TX
endpoints.  Rather than writing a zero to that register for RX
endpoints, avoid writing the register at all.

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

The INIT_HDR_METADATA_MASK endpoint configuration register is only
valid for RX endpoints.  Rather than writing a zero to that register
for TX endpoints, avoid writing the register at all.

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