[PATCH 0/4] PCI: endpoint: Add BAR_DISABLED support to PCI endpoint framework
Manikanta Maddireddy
mmaddireddy at nvidia.com
Mon Feb 16 22:08:03 PST 2026
Apologies for sending the email twice. The mailing lists in CC were
missing in the
first email. I’ve added them and resent it.
Thanks,
Manikanta
On 17/02/26 11:24 am, Manikanta Maddireddy wrote:
> When Tegra194 runs in PCIe endpoint mode, BAR1–BAR5 are marked BAR_RESERVED so the
> EPF does not allocate backing memory. The host-side pci_endpoint_test driver
> still ioremaps all enabled BARs and runs BAR read/write tests on them. Writing to
> BAR2 (MSI-X table) or BAR4 (DMA registers) corrupts controller state and breaks
> CONSECUTIVE_BAR_TEST. A prior fix reset all BARs in the EPC .init(), so only
> BAR0 was visible to the host—tests passed but 64-bit BAR 2 and BAR 4 were no
> longer available for real use (e.g. host DMA via BAR4).
>
> This series addresses that by:
>
> 1) Adding BAR_DISABLED and clarifying BAR_RESERVED in the PCI endpoint core.
> BAR_RESERVED is used for (a) HW-backed BARs (MSI-X, DMA) that the EPC may
> leave enabled, and (b) the second register of a 64-bit BAR. BAR_DISABLED is
> for unused BARs that the EPC must disable in .init() and the EPF must not
> use. pci_epc_get_next_free_bar() treats both as not free.
>
> 2) Updating Tegra194 endpoint to use three 64-bit BARs at indices 0, 2, and 4:
> BAR0+BAR1 for EPF test/data, BAR2+BAR3 for MSI-X table, BAR4+BAR5 for DMA.
> Only BAR0 and BAR1 are reset in .init(); BAR2/BAR3 and BAR4/BAR5 stay
> enabled so the host can use MSI-X and DMA.
>
> 3) Adding a BAR skip mask to pci_endpoint_test so endpoints can skip the
> destructive BAR test on HW-backed BARs. Tegra EP test data skips BAR1–BAR5
> (test only BAR0). Adding NVIDIA Tegra194 EP (0x1AD4) and Tegra234 EP (0x229B)
> to the pci_endpoint_test_tbl so the host driver can bind and run tests
> without corrupting MSI-X or DMA registers.
>
> 4) Converting unused BAR_RESERVED to BAR_DISABLED in the Uniphier Pro5 endpoint
> (BAR4 and BAR5); BAR1 and BAR3 remain BAR_RESERVED as the high halves of
> 64-bit BAR0 and BAR2.
>
> With this, CONSECUTIVE_BAR_TEST and DMA tests pass while Tegra194 keeps 64-bit
> BAR 2 (MSI-X) and BAR 4 (DMA) enabled for host use.
>
> pci_endpoint_test results on Tegra234 SoC,
>
> $ ./pci_endpoint_test -f pci_ep_bar -f pci_ep_basic -v memcpy -T COPY_TEST -V dma
> TAP version 13
> 1..13
> Starting 13 tests from 8 test cases.
> RUN pci_ep_bar.BAR0.BAR_TEST ...
> OK pci_ep_bar.BAR0.BAR_TEST
> ok 1 pci_ep_bar.BAR0.BAR_TEST
> RUN pci_ep_bar.BAR1.BAR_TEST ...
> OK pci_ep_bar.BAR1.BAR_TEST
> ok 2 pci_ep_bar.BAR1.BAR_TEST
> RUN pci_ep_bar.BAR2.BAR_TEST ...
> OK pci_ep_bar.BAR2.BAR_TEST
> ok 3 pci_ep_bar.BAR2.BAR_TEST
> RUN pci_ep_bar.BAR3.BAR_TEST ...
> OK pci_ep_bar.BAR3.BAR_TEST
> ok 4 pci_ep_bar.BAR3.BAR_TEST
> RUN pci_ep_bar.BAR4.BAR_TEST ...
> OK pci_ep_bar.BAR4.BAR_TEST
> ok 5 pci_ep_bar.BAR4.BAR_TEST
> RUN pci_ep_bar.BAR5.BAR_TEST ...
> OK pci_ep_bar.BAR5.BAR_TEST
> ok 6 pci_ep_bar.BAR5.BAR_TEST
> RUN pci_ep_basic.CONSECUTIVE_BAR_TEST ...
> OK pci_ep_basic.CONSECUTIVE_BAR_TEST
> ok 7 pci_ep_basic.CONSECUTIVE_BAR_TEST
> RUN pci_ep_basic.LEGACY_IRQ_TEST ...
> OK pci_ep_basic.LEGACY_IRQ_TEST
> ok 8 pci_ep_basic.LEGACY_IRQ_TEST
> RUN pci_ep_basic.MSI_TEST ...
> SKIP MSI17 is disabled
> OK pci_ep_basic.MSI_TEST
> ok 9 pci_ep_basic.MSI_TEST # SKIP MSI17 is disabled
> RUN pci_ep_basic.MSIX_TEST ...
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X1
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X2
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X3
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X4
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X5
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X6
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X7
> pci_endpoint_test.c:144:MSIX_TEST:Expected 0 (0) == ret (-5)
> pci_endpoint_test.c:144:MSIX_TEST:Test failed for MSI-X8
> SKIP MSI-X9 is disabled
> OK pci_ep_basic.MSIX_TEST
> ok 10 pci_ep_basic.MSIX_TEST # SKIP MSI-X9 is disabled
> RUN pci_ep_data_transfer.memcpy.READ_TEST ...
> OK pci_ep_data_transfer.memcpy.READ_TEST
> ok 11 pci_ep_data_transfer.memcpy.READ_TEST
> RUN pci_ep_data_transfer.memcpy.WRITE_TEST ...
> OK pci_ep_data_transfer.memcpy.WRITE_TEST
> ok 12 pci_ep_data_transfer.memcpy.WRITE_TEST
> RUN pci_ep_data_transfer.memcpy.COPY_TEST ...
> OK pci_ep_data_transfer.memcpy.COPY_TEST
> ok 13 pci_ep_data_transfer.memcpy.COPY_TEST
> PASSED: 13 / 13 tests passed.
> 2 skipped test(s) detected. Consider enabling relevant config options to improve coverage.
> Totals: pass:11 fail:0 xfail:0 xpass:0 skip:2 error:0
>
> Signed-off-by: Manikanta Maddireddy <mmaddireddy at nvidia.com>
> ---
> Manikanta Maddireddy (4):
> PCI: endpoint: Add BAR_DISABLED and document BAR_RESERVED semantics
> PCI: tegra194: Use 64-bit BAR layout and reset only first BAR in EP mode
> misc: pci_endpoint_test: Add BAR skip mask and NVIDIA Tegra EP device IDs
> PCI: uniphier-ep: Convert unused BAR_RESERVED to BAR_DISABLED for Pro5
>
> drivers/misc/pci_endpoint_test.c | 34 ++++++++++++++++++++++++---
> drivers/pci/controller/dwc/pcie-tegra194.c | 26 +++++++++++---------
> drivers/pci/controller/dwc/pcie-uniphier-ep.c | 8 +++----
> drivers/pci/endpoint/pci-epc-core.c | 5 ++--
> include/linux/pci-epc.h | 13 ++++++++--
> 5 files changed, 64 insertions(+), 22 deletions(-)
> ---
> base-commit: 6f54fb70124423ec417b5efe81f8ced5b9891d62
> change-id: 20260217-master-27db95eb02bd
>
> Best regards,
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