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

From: Robin Murphy
Date: Wed Sep 19 2018 - 09:25:44 EST

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
- 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

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

dev_48bit { ... };

periph_bus {
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 ;)


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.


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(-)