Messages in this thread | | | Date | Mon, 23 Apr 2018 17:32:50 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH 0/7] Level-triggered MSI support |
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Hi Marc,
On Mon, 23 Apr 2018 11:34:33 +0100, Marc Zyngier <marc.zyngier@arm.com> wrote:
> This series is a first shot at teaching the kernel about the oxymoron > expressed in $SUBJECT. Over the past couple of years, we've seen some > SoCs coming up with ways of signalling level interrupts using a new > flavor of MSIs, where the MSI controller uses two distinct messages: > one that raises a virtual line, and one that lowers it. The target MSI > controller is in charge of maintaining the state of the line. > > This allows for a much simplified HW signal routing (no need to have > hundreds of discrete lines to signal level interrupts if you already > have a memory bus), but results in a departure from the current idea > the kernel has of MSIs. > > This series takes a minimal approach to the problem, which is to allow > MSI controllers to use not only one, but up to two messages at a > time. This is controlled by a flag exposed at MSI irq domain creation, > and is only supported with platform MSI. > > The rest of the series repaints the Marvell ICU/GICP drivers which > already make use of this feature with a side-channel, and adds support > for the same feature in GICv3. A side effect of the last GICv3 patch > is that you can also use SPIs to signal PCI MSIs. This is a last > resort measure for SoCs where the ITS is unusable for unspeakable > reasons. > > Marc Zyngier (7): > genirq/msi: Allow level-triggered MSIs to be exposed by MSI providers > genirq/msi: Limit level-triggered MSI to platform devices > irqchip/mvebu-gicp: Use level-triggered MSIs between ICU and GICP > dma-iommu: Fix compilation when !CONFIG_IOMMU_DMA > irqchip/gic-v3: Add support for Message Based Interrupts as an MSI > controller > irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver > dt-bindings/gic-v3: Add documentation for MBI support > > .../bindings/interrupt-controller/arm,gic-v3.txt | 17 + > drivers/base/platform-msi.c | 3 + > drivers/irqchip/Makefile | 2 +- > drivers/irqchip/irq-gic-v3-mbi.c | 343 +++++++++++++++++++++ > drivers/irqchip/irq-gic-v3.c | 6 + > drivers/irqchip/irq-mvebu-gicp.c | 37 +-- > drivers/irqchip/irq-mvebu-gicp.h | 12 - > drivers/irqchip/irq-mvebu-icu.c | 33 +- > drivers/pci/msi.c | 3 + > include/linux/dma-iommu.h | 1 + > include/linux/irqchip/arm-gic-v3.h | 1 + > include/linux/msi.h | 2 + > kernel/irq/msi.c | 32 +- > 13 files changed, 427 insertions(+), 65 deletions(-) > create mode 100644 drivers/irqchip/irq-gic-v3-mbi.c > delete mode 100644 drivers/irqchip/irq-mvebu-gicp.h >
Thanks for the series, I gave it a try on Armada-8040-DB:
# cat /proc/interrupts | grep ICU 28: 0 0 0 0 ICU.f21e0000 107 Level ahci[f2540000.sata] 29: 0 0 0 0 ICU.f41e0000 107 Level ahci[f4540000.sata] 35: 2 0 0 0 ICU.f21e0000 129 Level 36: 3 0 0 0 ICU.f21e0000 41 Level eth1 37: 0 0 0 0 ICU.f21e0000 45 Level eth1 38: 0 0 4 0 ICU.f21e0000 49 Level eth1 39: 0 0 0 2 ICU.f21e0000 53 Level eth1 40: 128 0 0 0 ICU.f21e0000 57 Level eth1 47: 2 0 0 0 ICU.f41e0000 129 Level 54: 82 0 0 0 ICU.f21e0000 106 Level xhci-hcd:usb3 55: 82 0 0 0 ICU.f21e0000 105 Level xhci-hcd:usb5 56: 4 0 0 0 ICU.f41e0000 106 Level xhci-hcd:usb7 57: 0 0 0 0 ICU.f41e0000 105 Level xhci-hcd:usb1 58: 0 0 0 0 ICU.f41e0000 77 Level f4284000.rtc 59: 224 0 0 0 ICU.f21e0000 120 Level mv64xxx_i2c 60: 0 0 0 0 ICU.f41e0000 120 Level mv64xxx_i2c 61: 52 0 0 0 ICU.f21e0000 27 Level mmc1 63: 0 0 0 0 ICU.f21e0000 22 Level armada8k-pcie, PCIe PME, aerdrv 64: 0 0 0 0 ICU.f21e0000 23 Level armada8k-pcie, PCIe PME, aerdrv 65: 0 0 0 0 ICU.f41e0000 22 Level armada8k-pcie, PCIe PME, aerdrv 66: 0 0 0 0 ICU.f41e0000 24 Level armada8k-pcie, PCIe PME, aerdrv 67: 0 0 0 0 ICU.f41e0000 23 Level armada8k-pcie, PCIe PME, aerdrv
All these interrupts are NSRs and go through the GICP. I was able to use the network (CP0), an I2C bus (CP0) and the USB host ports (on each CP).
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
Thanks, Miquèl
-- Miquel Raynal, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering https://bootlin.com
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