i2c: octeon: check correct size of maximum RECV_LEN packet

I2C_SMBUS_BLOCK_MAX defines already the maximum number as defined in the
SMBus 2.0 specs. No reason to add one to it.

Fixes: 886f6f8337dd ("i2c: octeon: Support I2C_M_RECV_LEN")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Robert Richter <rric@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

i2c: octeon: Prevent error message on bus error

The error message:

[Fri Feb 16 13:42:13 2018] i2c-thunderx 0000:01:09.4: unhandled state: 0

is mis-leading as state 0 (bus error) is not an unknown state.

Return -EIO as before but avoid printing the message. Also rename
STAT_ERROR to STATE_BUS_ERROR.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: thunderx: Limit register access retries

Do not infinitely retry register readq and writeq operations
in order to not lock up the CPU in case the TWSI gets stuck.

Return -EIO in case of a failed data read. For all other
cases just return so subsequent operations will fail
and trigger the recovery.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: thunderx: Remove double-check after interrupt

Commit 1bb1ff3e7c74 ("i2c: octeon: Improve performance if interrupt is
early") added a double-check around the wait_event_timeout() condition.
The performance problem that this commit tried to work-around
could not be reproduced. It also makes the wait condition more
complicated then it should be. Therefore remove the double-check.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: thunderx: TWSI software reset in recovery

I've seen i2c recovery reporting long loops of:

[ 1035.887818] i2c i2c-4: SCL is stuck low, exit recovery
[ 1037.999748] i2c i2c-4: SCL is stuck low, exit recovery
[ 1040.111694] i2c i2c-4: SCL is stuck low, exit recovery
...

Add a TWSI software reset which clears the status and
STA,STP,IFLG in SW_TWSI_EOP_TWSI_CTL.

With this the recovery works fine and above message is not seen.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Revert "i2c: octeon: thunderx: Limit register access retries"

This reverts commit 70121f7f3725 ("i2c: octeon: thunderx: Limit register access retries").
Using readq_poll_timeout instead of __raw_readq triggers the following
debug warning:

[ 78.871568] ipmi_ssif: Trying hotmod-specified SSIF interface at i2c address 0x12, adapter Cavium ThunderX i2c adapter at 0000:01:09.4, slave address 0x0
[ 78.886107] do not call blocking ops when !TASK_RUNNING; state=2 set at [<fffffc00080e0088>] prepare_to_wait_event+0x58/0x10c
[ 78.897436] ------------[ cut here ]------------
[ 78.902050] WARNING: CPU: 6 PID: 2235 at kernel/sched/core.c:7718 __might_sleep+0x80/0x88

[...]

[ 79.133553] [<fffffc00080c3aac>] __might_sleep+0x80/0x88
[ 79.138862] [<fffffc0000e30138>] octeon_i2c_test_iflg+0x4c/0xbc [i2c_thunderx]
[ 79.146077] [<fffffc0000e30958>] octeon_i2c_test_ready+0x18/0x70 [i2c_thunderx]
[ 79.153379] [<fffffc0000e30b04>] octeon_i2c_wait+0x154/0x1a4 [i2c_thunderx]
[ 79.160334] [<fffffc0000e310bc>] octeon_i2c_xfer+0xf4/0xf60 [i2c_thunderx]

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Acked-by: Steven J. Hill <steven.hill@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: thunderx: Limit register access retries

Do not infinitely retry register readq and writeq operations
in order to not lock up the CPU in case the TWSI gets stuck.

Return -ETIMEDOUT in case of a failed data read. For all other
cases just return so subsequent operations will fail.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: Fix high-level controller status check

In case the high-level controller (HLC) is used the status code is
reported at a different location. Check that location after HLC
write operations if the ready bit is not set and return an appropriate
error code instead of always returning -EAGAIN.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: Avoid sending STOP during recovery

Due to a bug in the ThunderX I2C hardware sending STOP during
a recovery attempt could lock up the hardware. To work around
this problem do not send STOP at the beginning of the recovery
but use the override registers to bring the TWSI including
the high-level controller out of the bad state.

Signed-off-by: Dmitry Bazhenov <dmitry.bazhenov@auriga.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[Changed commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: Fix set SCL recovery function

The set SCL recovery function unconditionally pulls the SCL line low.
Only pull SCL line low according to val parameter.

Signed-off-by: Dmitry Bazhenov <dmitry.bazhenov@auriga.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
[Changed commit message]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: Use booleon values for booleon variables

Initialize booleon values with true instead of 1.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon,thunderx: Move register offsets to struct

The register offsets are different between Octeon and ThunderX so move
them into the algorithm struct and get rid of the define.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

i2c: octeon: Split the driver into two parts

Move common functionality into a separate file in preparation of the
re-use from the ThunderX i2c driver.

Functions are slightly re-ordered but no other changes are included.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>