drivers: ti: uart: Update 16550 UART driver to support MULTI_CONSOLE_API ...

This patch updates the TI 16550 console driver to support the new
console API. The driver will continue to support the old API as well by
checking the MULTI_CONSOLE_API compile-time flag.

Change-Id: I60a44b7ba3c35c74561824c04b8dbe3e3039324c
Signed-off-by: Julius Werner <jwerner@chromium.org>

Use SPDX license identifiers ...

To make software license auditing simpler, use SPDX[0] license
identifiers instead of duplicating the license text in every file.

NOTE: Files that have been imported by FreeBSD have not been modified.

[0]: https://spdx.org/

Change-Id: I80a00e1f641b8cc075ca5a95b10607ed9ed8761a
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>

drivers: ti: uart: remove UART_FCR writes ...

This patch removes the code that touched UART_FCR, from
console_core_putc(). The check for whether transmit FIFO is
full is sufficient before writing to UART TX FIFO. In fact
setting UARTFCR_TXCLR immediately after a byte is written to
FIFO might even result in loss of that byte, if UART hasn't
sent that byte out yet.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>

Add console_core_flush() in upstream platforms ...

It is needed to add placeholders for this function because, as this is
not a `plat_xxx()` function, there aren't weak definitions of it in any
file.

If `console_flush()` is used and there isn't an implementation of
`console_core_flush()` in any file, the compilation will fail.

Change-Id: I50eb56d085c4c9fbc85d40c343e86af6412f3020
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>

uart: 16550: Fix getc ...

tbz check for RDR status is to check for a bit being zero.
Unfortunately, we are using a mask rather than the bit position.

Further as per http://www.ti.com/lit/ds/symlink/pc16550d.pdf (page 17),
LSR register bit 0 is Data ready status (RDR), not bit position 2.

Update the same to match the specification.

Reported-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>

Move console drivers to AArch64 folder ...

This patch moves the various assembly console drivers
into `aarch64` architecture specific folder. Stub files,
which include files from new location, are retained at the
original location for platform compatibility reasons.

Change-Id: I0069b6c1c0489ca47f5204d4e26e3bc3def533a8

Driver for 16550 UART interface ...

This patch adds driver for the 16550 UART interface. The driver is exposed
as a console, which platforms can use to dump their boot/crash logs.

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>