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 completely software device 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 four 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

Since this is a virtual device, all these registers will be present
in RAM and will be allocated using one of the standard memory allocation
API (in this case dma_alloc_coherent)

*) 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.

PCI ENDPOINT TEST DRIVER (EP SIDE)
==================================

The Endpoint side function driver is present in
drivers/pci/endpoint/functions/pci-epf-test.c

This function driver initializes the PCI endpoint test device and
responds to commands from the host driver.

The function driver is also responsible for updating the STATUS
register.

PCI ENDPOINT TEST DRIVER (HOST SIDE)
====================================

The host side PCI driver is present in
drivers/misc/pci_endpoint_test.c

The PCI driver for the test device performs 3 tests
	*) verifying addresses programmed in BAR
	*) raise legacy IRQ
	*) raise MSI IRQ
	*) read data
	*) write data
	*) copy data