2020.2 QDMA Linux Driver README File updated with proper simlink

2020.2 QDMA Linux Driver Release

2020.2 QDMA DPDK Driver Release

2020.2 QDMA Windows Driver Release

XDMA: dma_from/to_device: do NOT mark partial completion as failure. the bw is not calculated in the case of underflow (partial completion).

XDMA: 1. split module parameter sgdma_timeout to h2c_timeout & c2h_timeout. 2. value of 0 means no timeout (i.e., wait forever).

Fix warnings

2020.2 XVSEC Driver Release documentation updates pointing to https://xilinx.github.io/dma_ip_drivers/

2020.2 XVSEC Driver Release - Supports the MCAP functionality for US/US+ and Versal Devices

no need to use __init and __exit. Attributes are set by the the
module_init/module_exit macros

set name length to 16 and use snprintf

XDMA: fix build for Centos and RHEL

libxdma: fix next adjacent descriptors

Various fixes

XDMA: Mark engine as not running when stopping after timeouts

Change the checks for kernel versions to include checks for RHEL
versions in case they are present.
Add HAS_MMIOWB, ACCESS_OK_2_ARGS, HAS_WAKE_UP, and HAS_WAKE_UP_ONE
and use them

Updated the apps/include/qdma_nl.h

Updated the qdma_nl.h

Updated the license header for QDMA Linux Driver application include files

Fix the setting of the next adjacent fields in descriptors.

Following commit 5faf23ec the next_adj field of all descriptors is set
according to the index of the descriptor rather than its address which
causes issues when dma_alloc_coherent doesn't return an address which is
page aligned (which happens).
Moreover, in the case of a transfer which number of descriptors is
bigger than a full page, the next_adj field is set to the maximum (63)
for all descriptors untill the last page of descriptors where it starts
decreasing.
Last, even before this commit, the next_adj field inside a block of
adjacent descriptors is not decreasing untill coming near page end,
which is not compliant with what the documentation says :

"Every descriptor in the descriptor list must accurately describe the descriptor
or block ofdescriptors that follows. In a block of adjacent descriptors, the
Nxt_adj value decrements from the first descriptor to the second to last
descriptor which has a value of zero. Likewise, eachdescriptor in the block
points to the next descriptor in the block, except for the last descriptor
which might point to a new block or might terminate the list."

This commit aligns the blocks of adjacent descriptors to
XDMA_MAX_ADJ_BLOCK_SIZE and makes the next_adj field decrease inside
each block untill the second to last descriptor in the block or in the
full transfer. The size of the page being a multiple of the size of the
block (4096 = sizeof(xdma_desc) * 128 =
sizeof(xdma_desc) * 2 * XDMA_MAX_ADJ_BLOCK_SIZE

Resolved HW errors observed with QDMA4.0 MM only design

If pci_read_config_byte of register PCI_INTERRUPT_PIN returns 0, it
means that legacy interrupts are not supported so return an error
instead of trying to request an interrupt with val = 0.

pci_cleanup_aer_uncorrect_error_status replaced by
pci_aer_clear_nonfatal_status

To keep compatibility, 0 for MSI-x is replaced by 0 for Auto since Auto
will try MSI-x first.
Add 3 - MSI-x for MSI-x mode.

Currently err_engine and all following errors try to release the
resource they failed to create.

Unlike engine_start, which sets the engine's running field itself,
engine_stop instead requires its callers to clear the field. However,
not all of them do, and notably the timeout handlers do not, meaning
that after a request times out and we stop the engine we never start it
again, causing all future transfers on the channel to hit the software
timeout.

Instead, set running to 0 inside xdma_engine_stop to mirror engine_start
to both fix the bug and prevent future ones creeping in.

Fix wrong user irq max