We have functions to setup the i.MX uart for early use, but these all
depend on DEBUG_LL. Move them to imx-uart.h to make them usable for
the regular PBL console.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

We recently introduced ungate_all_peripherals and SoC specific low
level UART init functions. Add some more for i.MX5 SoCs.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Move all of the common clock ungating code in early UART
initialization into a dedicated subroutine that can be shared by all
of the users.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Convert PUTC_LL to use IOMEM instead of explicit casting to 'void *',
since the former seem to be more appropriate to the situation.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

It appears that all i.MX51 and i.MX6 based boards that support early
debug output inevitably do exactly the same thing with the registers
of the UART peripheral. So to avoid code duplication three new
subroutines are introduced:

  - imx_uart_setup_ll() that allows user to perform aforementioned
    "same thing" on any arbitrary UART at 'uartbase' and clocked at
    'refclock' Hz.

  - imx6_uart_setup_ll() and imx5_uart_setup_ll() that do those
    actions assuming UART to be the one specified in configuration and
    'refclock' to be equal to what it is when SoC comes out of reset.

NOTE: Please note that 'imx*_uart_setup_ll' functions do add a slight
difference in behaviour by dropping the initialization of ONEMS and
UESC registers since those do not seem to be needed for early UART
functionality

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Move UART definitions into a separate file to avoid redefinition in
<mach/debug_ll.h> and magical constants in low level UART
initialization code.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Convert to static inline functions and use lower case letters for function
names. Also, include mach/debug_ll.h when an architecture provides support
for debug_ll, not only when it's actually enabled. This allows architecures
to put some UART initialization code into mach/debug_ll.h which is compiled
out when debug_ll is disabled.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

To make early debugging on i.MX a bit simpler. This uses a similar
magic than the kernel does.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

This adds lowlevel debug functions for i.MX. As we have a great variety
of different UARTs on i.MX currently no Kconfig support for chosing the
correct one is added. Instead we expect the user to add the correct
define and issue a compiler warning if he hasn't.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>