Re: [PATCH 00/21] SMMU enablement for NXP LS1043A and LS1046A

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On 19/09/18 15:18, Laurentiu Tudor wrote:
Hi Robin,

On 19.09.2018 16:25, Robin Murphy wrote:
Hi Laurentiu,

On 19/09/18 13:35, laurentiu.tudor@xxxxxxx wrote:
From: Laurentiu Tudor <laurentiu.tudor@xxxxxxx>

This patch series adds SMMU support for NXP LS1043A and LS1046A chips
and consists mostly in important driver fixes and the required device
tree updates. It touches several subsystems and consists of three main
parts:
   - changes in soc/drivers/fsl/qbman drivers adding iommu mapping of
     reserved memory areas, fixes and defered probe support
   - changes in drivers/net/ethernet/freescale/dpaa_eth drivers
     consisting in misc dma mapping related fixes and probe ordering
   - addition of the actual arm smmu device tree node together with
     various adjustments to the device trees

Performance impact

      Running iperf benchmarks in a back-to-back setup (both sides
      having smmu enabled) on a 10GBps port show an important
      networking performance degradation of around %40 (9.48Gbps
      linerate vs 5.45Gbps). If you need performance but without
      SMMU support you can use "iommu.passthrough=1" to disable
      SMMU.

USB issue and workaround

      There's a problem with the usb controllers in these chips
      generating smaller, 40-bit wide dma addresses instead of the 48-bit
      supported at the smmu input. So you end up in a situation where the
      smmu is mapped with 48-bit address translations, but the device
      generates transactions with clipped 40-bit addresses, thus smmu
      context faults are triggered. I encountered a similar situation for
      mmc that I  managed to fix in software [1] however for USB I did not
      find a proper place in the code to add a similar fix. The only
      workaround I found was to add this kernel parameter which limits the
      usb dma to 32-bit size: "xhci-hcd.quirks=0x800000".
      This workaround if far from ideal, so any suggestions for a code
      based workaround in this area would be greatly appreciated.

If you have a nominally-64-bit device with a
narrower-than-the-main-interconnect link in front of it, that should
already be fixed in 4.19-rc by bus_dma_mask picking up DT dma-ranges,
provided the interconnect hierarchy can be described appropriately (or
at least massaged sufficiently to satisfy the binding), e.g.:

/ {
      ...

      soc {
          ranges;
          dma-ranges = <0 0 10000 0>;

          dev_48bit { ... };

          periph_bus {
              ranges;
              dma-ranges = <0 0 100 0>;

              dev_40bit { ... };
          };
      };
};

and if that fails to work as expected (except for PCI hosts where
handling dma-ranges properly still needs sorting out), please do let us
know ;)


Just to confirm, Is this [1] the change I was supposed to test?

Not quite - dma-ranges is only valid for nodes representing a bus, so putting it directly in the USB device nodes doesn't work (FWIW that's why PCI is broken, because the parser doesn't expect the bus-as-leaf-node case). That's teh point of that intermediate simple-bus node represented by "periph_bus" in my example (sorry, I should have put compatibles in to make it clearer) - often that's actually true to life (i.e. "soc" is something like a CCI and "periph_bus" is something like an AXI NIC gluing a bunch of lower-bandwidth DMA masters to one of the CCI ports) but at worst it's just a necessary evil to make the binding happy (if it literally only represents the point-to-point link between the device master port and interconnect slave port).

Because if so, I'm still seeing context faults [2] with what looks like
clipped to 40-bits addresses. :-(
IIRC, the usb subsystem explicitly set 64-bit dma masks which in turn
will be limited to the SMMU input size of 48-bit. Won't that overwrite
the default dma mask derived from dma-ranges?

Indeed it will, but those default masks were effectively only ever a best-effort thing anyway - it's an ease-of-implementation detail that bus_dma_mask is not currently reflected in the device masks, although we may eventually change that; the crucial part is that the DMA ops implementations know about it and should now enforce it properly regardless of whether drivers set something wider.

Robin.


---
Best Regards, Laurentiu

[1] -----------------------------------------------------------------

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
b/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
index 3bdea0470f69..a214c3df37fd 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1046a.dtsi
@@ -612,6 +612,7 @@
                          compatible = "snps,dwc3";
                          reg = <0x0 0x2f00000 0x0 0x10000>;
                          interrupts = <GIC_SPI 60 IRQ_TYPE_LEVEL_HIGH>;
+                       dma-ranges = <0x0 0x0 0x0 0x0 0x100 0x00000000>;
                          dr_mode = "host";
                          snps,quirk-frame-length-adjustment = <0x20>;
                          snps,dis_rxdet_inp3_quirk;
@@ -621,6 +622,7 @@
                          compatible = "snps,dwc3";
                          reg = <0x0 0x3000000 0x0 0x10000>;
                          interrupts = <GIC_SPI 61 IRQ_TYPE_LEVEL_HIGH>;
+                       dma-ranges = <0x0 0x0 0x0 0x0 0x100 0x00000000>;
                          dr_mode = "host";
                          snps,quirk-frame-length-adjustment = <0x20>;
                          snps,dis_rxdet_inp3_quirk;
@@ -630,6 +632,7 @@
                          compatible = "snps,dwc3";
                          reg = <0x0 0x3100000 0x0 0x10000>;
                          interrupts = <GIC_SPI 63 IRQ_TYPE_LEVEL_HIGH>;
+                       dma-ranges = <0x0 0x0 0x0 0x0 0x100 0x00000000>;
                          dr_mode = "host";
                          snps,quirk-frame-length-adjustment = <0x20>;
                          snps,dis_rxdet_inp3_quirk;

[2] -----------------------------------------------------------------
[    2.090577] xhci-hcd xhci-hcd.0.auto: xHCI Host Controller
[    2.096064] xhci-hcd xhci-hcd.0.auto: new USB bus registered,
assigned bus number 2
[    2.103720] xhci-hcd xhci-hcd.0.auto: Host supports USB 3.0  SuperSpeed
[    2.110346] arm-smmu 9000000.iommu: Unhandled context fault:
fsr=0x402, iova=0xffffffb000, fsynr=0x1b0000, cb=3
[    2.120449] usb usb2: We don't know the algorithms for LPM for this
host, disabling LPM.
[    2.128717] hub 2-0:1.0: USB hub found
[    2.132473] hub 2-0:1.0: 1 port detected
[    2.136527] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller
[    2.142014] xhci-hcd xhci-hcd.1.auto: new USB bus registered,
assigned bus number 3
[    2.149747] xhci-hcd xhci-hcd.1.auto: hcc params 0x0220f66d hci
version 0x100 quirks 0x0000000002010010
[    2.159149] xhci-hcd xhci-hcd.1.auto: irq 50, io mem 0x03000000
[    2.165284] hub 3-0:1.0: USB hub found
[    2.169039] hub 3-0:1.0: 1 port detected
[    2.173051] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller
[    2.178536] xhci-hcd xhci-hcd.1.auto: new USB bus registered,
assigned bus number 4
[    2.186193] xhci-hcd xhci-hcd.1.auto: Host supports USB 3.0  SuperSpeed
[    2.192809] arm-smmu 9000000.iommu: Unhandled context fault:
fsr=0x402, iova=0xffffffb000, fsynr=0x1f0000, cb=4
[    2.192822] usb usb4: We don't know the algorithms for LPM for this
host, disabling LPM.
[    2.211141] hub 4-0:1.0: USB hub found
[    2.214896] hub 4-0:1.0: 1 port detected
[    2.218935] xhci-hcd xhci-hcd.2.auto: xHCI Host Controller
[    2.224425] xhci-hcd xhci-hcd.2.auto: new USB bus registered,
assigned bus number 5
[    2.232153] xhci-hcd xhci-hcd.2.auto: hcc params 0x0220f66d hci
version 0x100 quirks 0x0000000002010010
[    2.241562] xhci-hcd xhci-hcd.2.auto: irq 51, io mem 0x03100000
[    2.247694] hub 5-0:1.0: USB hub found
[    2.251449] hub 5-0:1.0: 1 port detected
[    2.255458] xhci-hcd xhci-hcd.2.auto: xHCI Host Controller
[    2.260945] xhci-hcd xhci-hcd.2.auto: new USB bus registered,
assigned bus number 6
[    2.268601] xhci-hcd xhci-hcd.2.auto: Host supports USB 3.0  SuperSpeed
[    2.275218] arm-smmu 9000000.iommu: Unhandled context fault:
fsr=0x402, iova=0xffffffb000, fsynr=0x110000, cb=5
[    2.275230] usb usb6: We don't know the algorithms for LPM for this
host, disabling LPM.


The patch set is based on net-next so, if generally agreed, I'd suggest
to get the patches through the netdev tree after getting all the Acks.

[1]
https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fpatch%2F10506627%2F&amp;data=02%7C01%7Claurentiu.tudor%40nxp.com%7C63c4e1dfc126488eb4ba08d61e336607%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C636729603447603039&amp;sdata=XhjOX9aLgoe%2BSTBgZztv6zCz0vMebSXW%2Fnb2QcD5shY%3D&amp;reserved=0


Laurentiu Tudor (21):
    soc/fsl/qman: fixup liodns only on ppc targets
    soc/fsl/bman: map FBPR area in the iommu
    soc/fsl/qman: map FQD and PFDR areas in the iommu
    soc/fsl/qman-portal: map CENA area in the iommu
    soc/fsl/qbman: add APIs to retrieve the probing status
    soc/fsl/qman_portals: defer probe after qman's probe
    soc/fsl/bman_portals: defer probe after bman's probe
    soc/fsl/qbman_portals: add APIs to retrieve the probing status
    fsl/fman: backup and restore ICID registers
    fsl/fman: add API to get the device behind a fman port
    dpaa_eth: defer probing after qbman
    dpaa_eth: base dma mappings on the fman rx port
    dpaa_eth: fix iova handling for contiguous frames
    dpaa_eth: fix iova handling for sg frames
    dpaa_eth: fix SG frame cleanup
    arm64: dts: ls1046a: add smmu node
    arm64: dts: ls1043a: add smmu node
    arm64: dts: ls104xa: set mask to drop TBU ID from StreamID
    arm64: dts: ls104x: add missing dma ranges property
    arm64: dts: ls104x: add iommu-map to pci controllers
    arm64: dts: ls104x: make dma-coherent global to the SoC

   .../arm64/boot/dts/freescale/fsl-ls1043a.dtsi |  52 ++++++-
   .../arm64/boot/dts/freescale/fsl-ls1046a.dtsi |  48 +++++++
   .../net/ethernet/freescale/dpaa/dpaa_eth.c    | 136 ++++++++++++------
   drivers/net/ethernet/freescale/fman/fman.c    |  35 ++++-
   drivers/net/ethernet/freescale/fman/fman.h    |   4 +
   .../net/ethernet/freescale/fman/fman_port.c   |  14 ++
   .../net/ethernet/freescale/fman/fman_port.h   |   2 +
   drivers/soc/fsl/qbman/bman_ccsr.c             |  23 +++
   drivers/soc/fsl/qbman/bman_portal.c           |  20 ++-
   drivers/soc/fsl/qbman/qman_ccsr.c             |  30 ++++
   drivers/soc/fsl/qbman/qman_portal.c           |  35 +++++
   include/soc/fsl/bman.h                        |  16 +++
   include/soc/fsl/qman.h                        |  17 +++
   13 files changed, 379 insertions(+), 53 deletions(-)
>



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