netdev - Re: [PATCH v11 net-next 00/15] net: mvpp2: Add TX Flow Control support

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Date:   Tue, 9 Feb 2021 12:40:41 +0100
From:   Marcin Wojtas <mw@...ihalf.com>
To:     Stefan Chulski <stefanc@...vell.com>
Cc:     netdev <netdev@...r.kernel.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        "David S. Miller" <davem@...emloft.net>, nadavh@...vell.com,
        Yan Markman <ymarkman@...vell.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Jakub Kicinski <kuba@...nel.org>,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        Andrew Lunn <andrew@...n.ch>,
        Russell King <rmk+kernel@...linux.org.uk>, atenart@...nel.org,
        devicetree@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
        Grégory Clement <gregory.clement@...tlin.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v11 net-next 00/15] net: mvpp2: Add TX Flow Control support

Hi Stefan,

wt., 9 lut 2021 o 09:43 <stefanc@...vell.com> napisał(a):
>
> From: Stefan Chulski <stefanc@...vell.com>
>
> Armada hardware has a pause generation mechanism in GOP (MAC).
> The GOP generate flow control frames based on an indication programmed in Ports Control 0 Register. There is a bit per port.
> However assertion of the PortX Pause bits in the ports control 0 register only sends a one time pause.
> To complement the function the GOP has a mechanism to periodically send pause control messages based on periodic counters.
> This mechanism ensures that the pause is effective as long as the Appropriate PortX Pause is asserted.
>
> Problem is that Packet Processor that actually can drop packets due to lack of resources not connected to the GOP flow control generation mechanism.
> To solve this issue Armada has firmware running on CM3 CPU dedicated for Flow Control support.
> Firmware monitors Packet Processor resources and asserts XON/XOFF by writing to Ports Control 0 Register.
>
> MSS shared SRAM memory used to communicate between CM3 firmware and PP2 driver.
> During init PP2 driver informs firmware about used BM pools, RXQs, congestion and depletion thresholds.
>
> The pause frames are generated whenever congestion or depletion in resources is detected.
> The back pressure is stopped when the resource reaches a sufficient level.
> So the congestion/depletion and sufficient level implement a hysteresis that reduces the XON/XOFF toggle frequency.
>
> Packet Processor v23 hardware introduces support for RX FIFO fill level monitor.
> Patch "add PPv23 version definition" to differ between v23 and v22 hardware.
> Patch "add TX FC firmware check" verifies that CM3 firmware supports Flow Control monitoring.
>
> v10 --> v11
> - Improve "net: mvpp2: add CM3 SRAM memory map" comment
> - Move condition check to 'net: mvpp2: always compare hw-version vs MVPP21' patch
>
> v9 --> v10
> - Add CM3 SRAM description to PPv2 documentation
>
> v8 --> v9
> - Replace generic pool allocation with devm_ioremap_resource
>
> v7 --> v8
> - Reorder "always compare hw-version vs MVPP21" and "add PPv23 version definition" commits
> - Typo fixes
> - Remove condition fix from "add RXQ flow control configurations"
>
> v6 --> v7
> - Reduce patch set from 18 to 15 patches
>  - Documentation change combined into a single patch
>  - RXQ and BM size change combined into a single patch
>  - Ring size change check moved into "add RXQ flow control configurations" commit
>
> v5 --> v6
> - No change
>
> v4 --> v5
> - Add missed Signed-off
> - Fix warnings in patches 3 and 12
> - Add revision requirement to warning message
> - Move mss_spinlock into RXQ flow control configurations patch
> - Improve FCA RXQ non occupied descriptor threshold commit message
>
> v3 --> v4
> - Remove RFC tag
>
> v2 --> v3
> - Remove inline functions
> - Add PPv2.3 description into marvell-pp2.txt
> - Improve mvpp2_interrupts_mask/unmask procedure
> - Improve FC enable/disable procedure
> - Add priv->sram_pool check
> - Remove gen_pool_destroy call
> - Reduce Flow Control timer to x100 faster
>
> v1 --> v2
> - Add memory requirements information
> - Add EPROBE_DEFER if of_gen_pool_get return NULL
> - Move Flow control configuration to mvpp2_mac_link_up callback
> - Add firmware version info with Flow control support
>
> Konstantin Porotchkin (1):
>   dts: marvell: add CM3 SRAM memory to cp11x ethernet device tree
>
> Stefan Chulski (14):
>   doc: marvell: add CM3 address space and PPv2.3 description
>   net: mvpp2: add CM3 SRAM memory map
>   net: mvpp2: always compare hw-version vs MVPP21
>   net: mvpp2: add PPv23 version definition
>   net: mvpp2: increase BM pool and RXQ size
>   net: mvpp2: add FCA periodic timer configurations
>   net: mvpp2: add FCA RXQ non occupied descriptor threshold
>   net: mvpp2: enable global flow control
>   net: mvpp2: add RXQ flow control configurations
>   net: mvpp2: add ethtool flow control configuration support
>   net: mvpp2: add BM protection underrun feature support
>   net: mvpp2: add PPv23 RX FIFO flow control
>   net: mvpp2: set 802.3x GoP Flow Control mode
>   net: mvpp2: add TX FC firmware check
>
>  Documentation/devicetree/bindings/net/marvell-pp2.txt |   6 +-
>  arch/arm64/boot/dts/marvell/armada-cp11x.dtsi         |   2 +-
>  drivers/net/ethernet/marvell/mvpp2/mvpp2.h            | 124 ++++-
>  drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c       | 526 ++++++++++++++++++--
>  4 files changed, 609 insertions(+), 49 deletions(-)
>

For the series:
Acked-by: Marcin Wojtas <mw@...ihalf.com>

Thanks,
Marcin