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authorLinus Torvalds <torvalds@linux-foundation.org>2026-10-02 12:17:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-10-02 12:17:24 -0700
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treeb767d7f6e26bc64334d3f14f8422d187239dc45d /Documentation/PCI/endpoint/pci-test-function.rst
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Merge tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linuxgrafted
Pull io_uring fixes from Jens Axboe: - Fix a task_work add use-after-free with SQPOLL. The sqpoll thread could pop and complete the last request while io_req_normal_work_add() was still looking at them after the mpscq push. Use the same approach as DEFER_TASKRUN to protect from that, holding an RCU read lock across the add, and have exit wait for an RCU grace period for SQPOLL rings as well. - CQE32 ring fixes: correct the free entry check for 32b CQEs, zero the big_cqe for aux CQEs, and only post the dummy skip CQE on CQE_MIXED rings - Mark the source filter table as COW when cloning bpf filters, so registering another filter on the source doesn't modify the shared table in place - Initialize the task context before running the BPF loop - Requeue zcrx multishot receives stopped by a local resource - End a TX_TIMESTAMP multishot cmd when the CQ is full (lollipopkit) * tag 'io_uring-7.3-20261002' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: io_uring: fix task_work add use-after-free with SQPOLL io_uring/cmd_net: end TX_TIMESTAMP multishot when the CQ is full io_uring/zcrx: requeue multishot receives stopped by a local resource io_uring: initialize task context before running the BPF loop io_uring: zero big_cqe for aux CQEs on CQE32 rings io_uring: fix free entry check for 32b CQEs on CQE32 rings io_uring: only post the dummy skip CQE on CQE_MIXED rings io_uring/bpf_filter: mark source as COW when cloning filters
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+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+PCI Test Function
+=================
+
+:Author: Kishon Vijay Abraham I <kishon@ti.com>
+
+Traditionally PCI RC has always been validated by using standard
+PCI cards like ethernet PCI cards or USB PCI cards or SATA PCI cards.
+However with the addition of EP-core in linux kernel, it is possible
+to configure a PCI controller that can operate in EP mode to work as
+a test device.
+
+The PCI endpoint test device is a virtual device (defined in software)
+used to test the endpoint functionality and serve as a sample driver
+for other PCI endpoint devices (to use the EP framework).
+
+The PCI endpoint test device has the following registers:
+
+ 1) PCI_ENDPOINT_TEST_MAGIC
+ 2) PCI_ENDPOINT_TEST_COMMAND
+ 3) PCI_ENDPOINT_TEST_STATUS
+ 4) PCI_ENDPOINT_TEST_SRC_ADDR
+ 5) PCI_ENDPOINT_TEST_DST_ADDR
+ 6) PCI_ENDPOINT_TEST_SIZE
+ 7) PCI_ENDPOINT_TEST_CHECKSUM
+ 8) PCI_ENDPOINT_TEST_IRQ_TYPE
+ 9) PCI_ENDPOINT_TEST_IRQ_NUMBER
+
+* PCI_ENDPOINT_TEST_MAGIC
+
+This register will be used to test BAR0. A known pattern will be written
+and read back from MAGIC register to verify BAR0.
+
+* PCI_ENDPOINT_TEST_COMMAND
+
+This register will be used by the host driver to indicate the function
+that the endpoint device must perform.
+
+======== ================================================================
+Bitfield Description
+======== ================================================================
+Bit 0 raise legacy IRQ
+Bit 1 raise MSI IRQ
+Bit 2 raise MSI-X IRQ
+Bit 3 read command (read data from RC buffer)
+Bit 4 write command (write data to RC buffer)
+Bit 5 copy command (copy data from one RC buffer to another RC buffer)
+======== ================================================================
+
+* PCI_ENDPOINT_TEST_STATUS
+
+This register reflects the status of the PCI endpoint device.
+
+======== ==============================
+Bitfield Description
+======== ==============================
+Bit 0 read success
+Bit 1 read fail
+Bit 2 write success
+Bit 3 write fail
+Bit 4 copy success
+Bit 5 copy fail
+Bit 6 IRQ raised
+Bit 7 source address is invalid
+Bit 8 destination address is invalid
+======== ==============================
+
+* PCI_ENDPOINT_TEST_SRC_ADDR
+
+This register contains the source address (RC buffer address) for the
+COPY/READ command.
+
+* PCI_ENDPOINT_TEST_DST_ADDR
+
+This register contains the destination address (RC buffer address) for
+the COPY/WRITE command.
+
+* PCI_ENDPOINT_TEST_IRQ_TYPE
+
+This register contains the interrupt type (Legacy/MSI) triggered
+for the READ/WRITE/COPY and raise IRQ (Legacy/MSI) commands.
+
+Possible types:
+
+====== ==
+Legacy 0
+MSI 1
+MSI-X 2
+====== ==
+
+* PCI_ENDPOINT_TEST_IRQ_NUMBER
+
+This register contains the triggered ID interrupt.
+
+Admissible values:
+
+====== ===========
+Legacy 0
+MSI [1 .. 32]
+MSI-X [1 .. 2048]
+====== ===========