crypto: qat - add sysfs_added flag for rate limiting

The qat_rl sysfs attribute group is registered within the adf_dev_start()
function, alongside other driver components.
If any of the functions preceding the group registration fails,
the adf_dev_start() function returns, and the caller, to undo the
operation, invokes adf_dev_stop() followed by adf_dev_shutdown().
However, the current flow lacks information about whether the
registration of the qat_rl attribute group was successful or not.

In cases where this condition is encountered, an error similar to
the following might be reported:

4xxx 0000:6b:00.0: Starting device qat_dev0
4xxx 0000:6b:00.0: qat_dev0 started 9 acceleration engines
4xxx 0000:6b:00.0: Failed to send init message
4xxx 0000:6b:00.0: Failed to start device qat_dev0
sysfs group 'qat_rl' not found for kobject '0000:6b:00.0'
...
sysfs_remove_groups+0x2d/0x50
adf_sysfs_rl_rm+0x44/0x70 [intel_qat]
adf_rl_stop+0x2d/0xb0 [intel_qat]
adf_dev_stop+0x33/0x1d0 [intel_qat]
adf_dev_down+0xf1/0x150 [intel_qat]
...
4xxx 0000:6b:00.0: qat_dev0 stopped 9 acceleration engines
4xxx 0000:6b:00.0: Resetting device qat_dev0

To prevent attempting to remove attributes from a group that has not
been added yet, a flag named 'sysfs_added' is introduced. This flag
is set to true upon the successful registration of the attribute group.

Fixes: d9fb8408376e ("crypto: qat - add rate limiting feature to qat_4xxx")
Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Ahsan Atta <ahsan.atta@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - add rate limiting sysfs interface

Add an interface for the rate limiting feature which allows to add,
remove and modify a QAT SLA (Service Level Agreement).

This adds a new sysfs attribute group, `qat_rl`, which can be accessed
from /sys/bus/pci/devices/<BUS:DEV:FUNCTION> with the following
hierarchy:
|-+ qat_rl
|---- id (RW) # SLA identifier
|---- cir (RW) # Committed Information Rate
|---- pir (RW) # Peak Information Rate
|---- srv (RW) # Service to be rate limited
|---- rp (RW) (HEX) # Ring pairs to be rate limited
|---- cap_rem (RW) # Remaining capability for a service
|---- sla_op (WO) # Allows to perform an operation on an SLA

The API works by setting the appropriate RW attributes and then
issuing a command through the `sla_op`. For example, to create an SLA, a
user needs to input the necessary data into the attributes cir, pir, srv
and rp and then write into `sla_op` the command `add` to execute the
operation.
The API also provides `cap_rem` attribute to get information about
the remaining device capability within a certain service which is
required when setting an SLA.

Signed-off-by: Ciunas Bennett <ciunas.bennett@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: qat - add rate limiting feature to qat_4xxx

The Rate Limiting (RL) feature allows to control the rate of requests
that can be submitted on a ring pair (RP). This allows sharing a QAT
device among multiple users while ensuring a guaranteed throughput.

The driver provides a mechanism that allows users to set policies, that
are programmed to the device. The device is then enforcing those policies.

Configuration of RL is accomplished through entities called SLAs
(Service Level Agreement). Each SLA object gets a unique identifier
and defines the limitations for a single service across up to four
ring pairs (RPs count allocated to a single VF).

The rate is determined using two fields:
* CIR (Committed Information Rate), i.e., the guaranteed rate.
* PIR (Peak Information Rate), i.e., the maximum rate achievable
when the device has available resources.
The rate values are expressed in permille scale i.e. 0-1000.
Ring pair selection is achieved by providing a 64-bit mask, where
each bit corresponds to one of the ring pairs.

This adds an interface and logic that allow to add, update, retrieve
and remove an SLA.

Signed-off-by: Damian Muszynski <damian.muszynski@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Tero Kristo <tero.kristo@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>