Hi,
Some DesignWare PCIe endpoint platforms integrate a DesignWare eDMA
instance alongside the PCIe controller. In remote eDMA use cases, the host
needs access to the eDMA register block and the per-channel linked-list
(LL) regions via PCIe BARs, while the endpoint may still boot with a
standard EP configuration (and may also use dw-edma locally).
This series focuses on using DesignWare eDMA emulated interrupt doorbell as
a pci-ep-msi fallback, in a generalized manner without exporting any
DesignWare eDMA-specific API.
* dmaengine:
1. Add explicit deassert handling for eDMA interrupt emulation in the
IRQ handler so level-triggered/shared IRQ lines don't remain stuck.
=> Patch 01/08
2. Cache per-channel IRQ number and an interrupt-emulation doorbell
register offset, so integrated-controller drivers can expose these
to EPF users via the auxiliary resource metadata.
=> Patch 02/08
* pci/endpoint:
1. Add a generic auxiliary resource enumeration API
(pci_epc_get_aux_resources()) for EPF drivers to discover
controller-owned resources that can be mapped into BAR space (e.g.
an integrated DMA MMIO window and per-channel LL regions metadata).
=> Patch 03/08 - 05/08
2. Add an "embedded (DMA) doorbell" fallback to pci_epf_alloc_doorbell()
(used when platform MSI doorbells are unavailable/unusable), and
update in-tree users (pci-epf-test, pci-epf-vntb) to request IRQs
correctly (shared IRQ constraints, required flags).
=> Patch 06/08 - 08/08
Note: As discussed in the v4 thread, v4 Patch 01/09 (dw-edma per-channel
interrupt routing control via dma_slave_config.peripheral_config) is
dropped from this series for now, so the series contains only what's needed
by the current, concrete consumer.
This series evolved out of:
https://lore.kernel.org/linux-pci/[email protected]/
Kernel base
===========
Patches 1-8 cleanly apply to pci.git 'controller/dwc':
Commit 43d324eeb08c ("PCI: dwc: Fix missing iATU setup when ECAM is enabled")
Tested on
=========
I tested the embedded (DMA) doorbell fallback path (via pci-epf-test) on
R-Car Spider boards:
$ ./pci_endpoint_test -t DOORBELL_TEST
TAP version 13
1..1
# Starting 1 tests from 1 test cases.
# RUN pcie_ep_doorbell.DOORBELL_TEST ...
# OK pcie_ep_doorbell.DOORBELL_TEST
ok 1 pcie_ep_doorbell.DOORBELL_TEST
# PASSED: 1 / 1 tests passed.
# Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
with the following message observed on the EP side:
[ 80.464653] pci_epf_test pci_epf_test.0: Using embedded (DMA) doorbell
fallback
(Note: for the test to pass on R-Car Spider, one of the following was required:
- echo 1048576 > functions/pci_epf_test/func1/pci_epf_test.0/bar2_size
- apply https://lore.kernel.org/all/[email protected]/)
Changelog
=========
* v4->v5 changes:
- Change the series subject now that the series has evolved into a
consumer-driven set focused on the embedded doorbell fallback and its
in-tree users (epf-test and epf-vntb).
- Drop [PATCH v4 01/09] (dw-edma per-channel interrupt routing control)
from this series for now, so the series focuses on what's needed by the
current consumer (i.e. the doorbell fallback implementation).
- Replace the v4 embedded-doorbell "test variant + host/kselftest
plumbing" with a generic embedded-doorbell fallback in
pci_epf_alloc_doorbell(), including exposing required IRQ request flags
to EPF drivers.
- Two preparatory fix patches (Patch 6/8 and 7/8) to clean up error
handling and state management ahead of Patch 8/8.
- Rename *_get_remote_resource() to *_get_aux_resources() and adjust
relevant variable namings and kernel docs. Discussion may continue.
- Rework dw-edma per-channel metadata exposure to cache the needed info
in dw_edma_chip (IRQ number + emulation doorbell offset) and consume it
from the DesignWare EPC auxiliary resource provider without calling back
to dw-edma.
* v3->v4 changes:
- Drop dma_slave_caps.hw_id and the dmaengine selfirq callback
registration API. Instead, add a dw-edma specific dw_edma_chan_info()
helper and extend the EPC remote resource metadata accordingly.
- Add explicit acking for eDMA interrupt emulation and adjust the
dw-edma IRQ path for embedded-doorbell usage.
- Replace the previous EPC API smoke test with an embedded doorbell
test variant (pci-epf-test + pci_endpoint_test/selftests).
- Rebase onto pci.git controller/dwc commit 43d324eeb08c.
* v2->v3 changes:
- Replace DWC-specific helpers with a generic EPC remote resource query API.
- Add pci-epf-test smoke test and host/kselftest support for the new API.
- Drop the dw-edma-specific notify-only channel and polling approach
([PATCH v2 4/7] and [PATCH v2 5/7]), and rework notification handling
around a generic dmaengine_(un)register_selfirq() API implemented
by dw-edma.
* v1->v2 changes:
- Combine the two previously posted series into a single set (per Frank's
suggestion). Order dmaengine/dw-edma patches first so hw_id support
lands before the PCI LL-region helper, which assumes
dma_slave_caps.hw_id availability.
v4: https://lore.kernel.org/all/[email protected]/
v3: https://lore.kernel.org/all/[email protected]/
v2: https://lore.kernel.org/all/[email protected]/
v1:
https://lore.kernel.org/dmaengine/[email protected]/
+
https://lore.kernel.org/linux-pci/[email protected]/
Thanks for reviewing,
Koichiro Den (8):
dmaengine: dw-edma: Deassert emulated interrupts in the IRQ handler
dmaengine: dw-edma: Cache per-channel IRQ and emulation doorbell
offset
PCI: endpoint: Add auxiliary resource query API
PCI: dwc: Record integrated eDMA register window
PCI: dwc: ep: Report integrated eDMA resources via EPC aux-resource
API
PCI: endpoint: pci-epf-test: Don't free doorbell IRQ unless requested
PCI: endpoint: pci-ep-msi: Fix error unwind and prevent double alloc
PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback
drivers/dma/dw-edma/dw-edma-core.c | 57 ++++++-
drivers/dma/dw-edma/dw-edma-core.h | 19 +++
drivers/dma/dw-edma/dw-edma-v0-core.c | 22 +++
drivers/dma/dw-edma/dw-hdma-v0-core.c | 8 +
.../pci/controller/dwc/pcie-designware-ep.c | 78 ++++++++++
drivers/pci/controller/dwc/pcie-designware.c | 4 +
drivers/pci/controller/dwc/pcie-designware.h | 2 +
drivers/pci/endpoint/functions/pci-epf-test.c | 38 ++++-
drivers/pci/endpoint/functions/pci-epf-vntb.c | 3 +-
drivers/pci/endpoint/pci-ep-msi.c | 141 ++++++++++++++++--
drivers/pci/endpoint/pci-epc-core.c | 41 +++++
include/linux/dma/edma.h | 17 +++
include/linux/pci-epc.h | 46 ++++++
include/linux/pci-epf.h | 17 ++-
14 files changed, 471 insertions(+), 22 deletions(-)
--
2.51.0
