RE: [PATCH net-next 3/3] net: stmmac: Introducing support for Page Pool

[Jose Abreu <Jose.Abreu@synopsys.com>]

From: Jon Hunter <jonathanh@nvidia.com>
Date: Jul/24/2019, 12:58:15 (UTC+00:00)

> 
> On 24/07/2019 12:34, Jose Abreu wrote:
> > From: Jon Hunter <jonathanh@nvidia.com>
> > Date: Jul/24/2019, 12:10:47 (UTC+00:00)
> > 
> >>
> >> On 24/07/2019 11:04, Jose Abreu wrote:
> >>
> >> ...
> >>
> >>> Jon, I was able to replicate (at some level) your setup:
> >>>
> >>> # dmesg | grep -i arm-smmu
> >>> [    1.337322] arm-smmu 70040000.iommu: probing hardware 
> >>> configuration...
> >>> [    1.337330] arm-smmu 70040000.iommu: SMMUv2 with:
> >>> [    1.337338] arm-smmu 70040000.iommu:         stage 1 translation
> >>> [    1.337346] arm-smmu 70040000.iommu:         stage 2 translation
> >>> [    1.337354] arm-smmu 70040000.iommu:         nested translation
> >>> [    1.337363] arm-smmu 70040000.iommu:         stream matching with 128 
> >>> register groups
> >>> [    1.337374] arm-smmu 70040000.iommu:         1 context banks (0 
> >>> stage-2 only)
> >>> [    1.337383] arm-smmu 70040000.iommu:         Supported page sizes: 
> >>> 0x61311000
> >>> [    1.337393] arm-smmu 70040000.iommu:         Stage-1: 48-bit VA -> 
> >>> 48-bit IPA
> >>> [    1.337402] arm-smmu 70040000.iommu:         Stage-2: 48-bit IPA -> 
> >>> 48-bit PA
> >>>
> >>> # dmesg | grep -i stmmac
> >>> [    1.344106] stmmaceth 70000000.ethernet: Adding to iommu group 0
> >>> [    1.344233] stmmaceth 70000000.ethernet: no reset control found
> >>> [    1.348276] stmmaceth 70000000.ethernet: User ID: 0x10, Synopsys ID: 
> >>> 0x51
> >>> [    1.348285] stmmaceth 70000000.ethernet:     DWMAC4/5
> >>> [    1.348293] stmmaceth 70000000.ethernet: DMA HW capability register 
> >>> supported
> >>> [    1.348302] stmmaceth 70000000.ethernet: RX Checksum Offload Engine 
> >>> supported
> >>> [    1.348311] stmmaceth 70000000.ethernet: TX Checksum insertion 
> >>> supported
> >>> [    1.348320] stmmaceth 70000000.ethernet: TSO supported
> >>> [    1.348328] stmmaceth 70000000.ethernet: Enable RX Mitigation via HW 
> >>> Watchdog Timer
> >>> [    1.348337] stmmaceth 70000000.ethernet: TSO feature enabled
> >>> [    1.348409] libphy: stmmac: probed
> >>> [ 4159.140990] stmmaceth 70000000.ethernet eth0: PHY [stmmac-0:01] 
> >>> driver [Generic PHY]
> >>> [ 4159.141005] stmmaceth 70000000.ethernet eth0: phy: setting supported 
> >>> 00,00000000,000062ff advertising 00,00000000,000062ff
> >>> [ 4159.142359] stmmaceth 70000000.ethernet eth0: No Safety Features 
> >>> support found
> >>> [ 4159.142369] stmmaceth 70000000.ethernet eth0: IEEE 1588-2008 Advanced 
> >>> Timestamp supported
> >>> [ 4159.142429] stmmaceth 70000000.ethernet eth0: registered PTP clock
> >>> [ 4159.142439] stmmaceth 70000000.ethernet eth0: configuring for 
> >>> phy/gmii link mode
> >>> [ 4159.142452] stmmaceth 70000000.ethernet eth0: phylink_mac_config: 
> >>> mode=phy/gmii/Unknown/Unknown adv=00,00000000,000062ff pause=10 link=0 
> >>> an=1
> >>> [ 4159.142466] stmmaceth 70000000.ethernet eth0: phy link up 
> >>> gmii/1Gbps/Full
> >>> [ 4159.142475] stmmaceth 70000000.ethernet eth0: phylink_mac_config: 
> >>> mode=phy/gmii/1Gbps/Full adv=00,00000000,00000000 pause=0f link=1 an=0
> >>> [ 4159.142481] stmmaceth 70000000.ethernet eth0: Link is Up - 1Gbps/Full 
> >>> - flow control rx/tx
> >>>
> >>> The only missing point is the NFS boot that I can't replicate with this 
> >>> setup. But I did some sanity checks:
> >>>
> >>> Remote Enpoint:
> >>> # dd if=/dev/urandom of=output.dat bs=128M count=1
> >>> # nc -c 192.168.0.2 1234 < output.dat
> >>> # md5sum output.dat 
> >>> fde9e0818281836e4fc0edfede2b8762  output.dat
> >>>
> >>> DUT:
> >>> # nc -l -c -p 1234 > output.dat
> >>> # md5sum output.dat 
> >>> fde9e0818281836e4fc0edfede2b8762  output.dat
> >>
> >> On my setup, if I do not use NFS to mount the rootfs, but then manually
> >> mount the NFS share after booting, I do not see any problems reading or
> >> writing to files on the share. So I am not sure if it is some sort of
> >> race that is occurring when mounting the NFS share on boot. It is 100%
> >> reproducible when using NFS for the root file-system.
> > 
> > I don't understand how can there be corruption then unless the IP AXI 
> > parameters are misconfigured which can lead to sporadic undefined 
> > behavior.
> > 
> > These prints from your logs:
> > [   14.579392] Run /init as init process
> > /init: line 58: chmod: command not found
> > [ 10:22:46 ] L4T-INITRD Build DATE: Mon Jul 22 10:22:46 UTC 2019
> > [ 10:22:46 ] Root device found: nfs
> > [ 10:22:46 ] Ethernet interfaces: eth0
> > [ 10:22:46 ] IP Address: 10.21.140.41
> > 
> > Where are they coming from ? Do you have any extra init script ?
> 
> By default there is an initial ramdisk that is loaded first and then the
> rootfs is mounted over NFS. However, even if I remove this ramdisk and
> directly mount the rootfs via NFS without it the problem persists. So I
> don't see any issue with the ramdisk and whats more is we have been
> using this for a long long time. Nothing has changed here.

OK. Can you please test what Ilias mentioned ?

Basically you can hard-code the order to 0 in 
alloc_dma_rx_desc_resources():
- pp_params.order = DIV_ROUND_UP(priv->dma_buf_sz, PAGE_SIZE);
+ pp_params.order = 0;

Unless you use a MTU > PAGE_SIZE.

---
Thanks,
Jose Miguel Abreu
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