csu3_am335x/board-support/linux-4.9.59+gitAUTOINC+a75d8e9305-ga75d8e9305/Documentation/PCI/endpoint/pci-test-function.txt

				PCI TEST
		    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

*) 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 - 7	: MSI interrupt number
  Bit 8		: read command (read data from RC buffer)
  Bit 9		: write command (write data to RC buffer)
  Bit 10	: 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.