net/mlx5e: Consider internal buffers size in port buffer calculations

Currently, when a user triggers a change in port buffer headroom
(buffers 0-7), the driver checks that the requested headroom does
not exceed the total port buffer size. However, this check does not
take into account the internal buffers (buffers 8-9), which are also
part of the total port buffer. This can result in treating invalid port
buffer change requests as valid, causing unintended changes to the shared
buffer.

To address this, include the internal buffers size in the calculation of
available port buffer space which ensures that port buffer requests do not
exceed the correct limit.

Furthermore, remove internal buffers (8-9) size from the total_size
calculation as these buffers are reserved for internal use and are not
exposed to the user.

While at it, add verbosity to the debug prints in
mlx5e_port_query_buffer() function to ease future debugging.

Fixes: ecdf2dadee8e ("net/mlx5e: Receive buffer support for DCBX")
Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

net/mlx5e: Update shared buffer along with device buffer changes

Currently, the user can modify device's receive buffer size, modify the
mapping between QoS priority groups to buffers and change the buffer
state to become lossy/lossless via pfc command.

However, the shared receive buffer pool alignments, as a result of
such commands, is performed only when the shared buffer is in FW ownership.
When a user changes the mapping of priority groups or buffer size,
the shared buffer is moved to SW ownership.

Therefore, for devices that support shared buffer, handle the shared buffer
alignments in accordance to user's desired configurations.

Meaning, the following will be performed:
1. For every change of buffer's headroom, recalculate the size of shared
buffer to be equal to "total_buffer_size" - "new_headroom_size".
The new shared buffer size will be split in ratio of 3:1 between
lossy and lossless pools, respectively.

2. For each port buffer change, count the number of lossless buffers.
If there is only one lossless buffer, then set its lossless pool
usage threshold to be infinite. Otherwise, if there is more than
one lossless buffer, set a usage threshold for each lossless buffer.

While at it, add more verbosity to debug prints when handling user
commands, to assist in future debug.

Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

net/mlx5e: Fix port buffers cell size value

Device unit for port buffers size, xoff_threshold and xon_threshold is
cells. Fix a bug in driver where cell unit size was hard-coded to
128 bytes. This hard-coded value is buggy, as it is wrong for some hardware
versions.

Driver to read cell size from SBCAM register and translate bytes to cell
units accordingly.

In order to fix the bug, this patch exposes SBCAM (Shared buffer
capabilities mask) layout and defines.

If SBCAM.cap_cell_size is valid, use it for all bytes to cells
calculations. If not valid, fallback to 128.

Cell size do not change on the fly per device. Instead of issuing SBCAM
access reg command every time such translation is needed, cache it in
mlx5e_dcbx as part of mlx5e_dcbnl_initialize(). Pass dcbx.port_buff_cell_sz
as a param to every function that needs bytes to cells translation.

While fixing the bug, move MLX5E_BUFFER_CELL_SHIFT macro to
en_dcbnl.c, as it is only used by that file.

Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

net/mlx5e: Receive buffer configuration

Add APIs for buffer configuration based on the changes in
pfc configuration, cable len, buffer size configuration,
and priority to buffer mapping.

Note that the xoff fomula is as below
xoff = ((301+2.16 * len [m]) * speed [Gbps] + 2.72 MTU [B]
xoff_threshold = buffer_size - xoff
xon_threshold = xoff_threshold - MTU

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>