Grygorii Strashko e3a5e33fae drivers: net: cpsw: ale: add broadcast/multicast rate limit support
The CPSW ALE supports feature to rate limit number ingress
broadcast(BC)/multicast(MC) packets per/sec which main purpose is BC/MC
storm prevention.

The ALE BC/MC packet rate limit configuration consist of two parts:
- global
  ALE_CONTROL.ENABLE_RATE_LIMIT bit 0 which enables rate limiting globally
  ALE_PRESCALE.PRESCALE specifies rate limiting interval
- per-port
  ALE_PORTCTLx.BCASTMCAST/_LIMIT specifies number of BC/MC packets allowed
  per rate limiting interval.
  When port.BCASTMCAST/_LIMIT is 0 rate limiting is disabled for Port.

When BC/MC packet rate limiting is enabled the number of allowed packets
per/sec is defined as:
  number_of_packets/sec = (Fclk / ALE_PRESCALE) * port.BCASTMCAST/_LIMIT

Hence, the ALE_PRESCALE configuration is common for all ports the 1ms
interval is selected and configured during ALE initialization while
port.BCAST/MCAST_LIMIT are configured per-port.
This allows to achieve:
 - min number_of_packets = 1000 when port.BCAST/MCAST_LIMIT = 1
 - max number_of_packets = 1000 * 255 = 255000
   when port.BCAST/MCAST_LIMIT = 0xFF

The ALE_CONTROL.ENABLE_RATE_LIMIT can also be enabled once during ALE
initialization as rate limiting enabled by non zero port.BCASTMCAST/_LIMIT
values.

This patch implements above logic in ALE and adds new ALE APIs
 cpsw_ale_rx_ratelimit_bc();
 cpsw_ale_rx_ratelimit_mc();

Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-13 12:42:39 +01:00
2022-04-01 11:46:09 -07:00
2022-04-03 14:08:21 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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