Add the driver for on-chip UART used on UniPhier SoCs.

This hardware is similar to 8250, but the register mapping is
slightly different:
  - The offset to FCR, MCR is different.
  - The divisor latch access bit does not exist.  Instead, the
    divisor latch register is available at offset 9.

This driver overrides serial_{in,out}, dl_{read,write} callbacks,
but wants to borrow most of code from 8250_core.c.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch provides a 8250-core based UART driver for the internal OMAP
UART. The long term goal is to provide the same functionality as the
current OMAP uart driver and DMA support.
I tried to merge omap-serial code together with the 8250-core code.
There should should be hardly a noticable difference. The trigger levels
are different compared to omap-serial:
- omap serial
  TX: Interrupt comes after TX FIFO has room for 16 bytes.
      TX of 4096 bytes in one go results in 256 interrupts

  RX: Interrupt comes after there is on byte in the FIFO.
      RX of 4096 bytes results in 4096 interrupts.

- this driver
  TX: Interrupt comes once the TX FIFO is empty.
      TX of 4096 bytes results in 65 interrupts. That means there will
      be gaps on the line while the driver reloads the FIFO.

  RX: Interrupt comes once there are 48 bytes in the FIFO or less over
      "longer" time frame. We have
          1 / 11520 * 10^3 * 16 => 1.38… ms
      1.38ms to react and purge the FIFO on 115200,8N1. Since the other
      driver fired after each byte it had ~5.47ms time to react. This
      _may_ cause problems if one relies on no missing bytes and has no
      flow control. On the other hand we get only 85 interrupts for the
      same amount of data.

It has been only tested as console UART on am335x-evm, dra7-evm and
beagle bone. I also did some longer raw-transfers to meassure the load.

The device name is ttyS based instead of ttyO. If a ttyO based node name
is required please ask udev for it. If both driver are activated (this
and omap-serial) then this serial driver will take control over the
device due to the link order

v9…v10:
	- Tony noticed that omap3 won't show anything after waking up
	  from core off. In v9 I reworked the register restore and set
	  IER to 0 by accident. This went unnoticed because start_tx
	  usually sets ier (either due to DMA bug or due to TX-complete
	  IRQ).
	- dropped EFR and SLEEP from capabilities. We do have both but
	  nobody should touch it. We already handle SLEEP ourself.
	- make the private copy of the registers (like EFR) u8 instead
	  u32
	- drop MDR1 & DL[ML] reset in restore registers. Does not look
	  required it is set to the required value later.
	- update MDR1 & SCR only if changed.
	- set MDR1 as the last thing. The errata says that we should
	  setup everything before MDR1 set.
	- avoid div by 0 in omap_8250_get_divisor() if baud rate gets
	  very large (Frans Klaver fixed the same thing omap-serial)
	- drop "is in early stage" from Kconfig.
v8…v9:
	- less on a file seems to hang the am335x after a while. I
	  believe I introduce this bug a while ago since I can reproduce
	  this prior to v8. Fixed by redoing the omap8250_restore_regs()
v7…v8:
	- redo the register write. There is now one function for that
	  which is used from set_termios() and runtime-resume.
	- drop PORT_OMAP_16750 and move the setup to the omap file. We
	  have our own set termios function anyway (Heikki Krogerus)
	- use MEM instead of MEM32. TRM of AM/DM37x says that 32bit
	  access on THR might result in data abort. We only need 32bit
	  access in the errata function which is before we use 8250's
	  read function so it doesn't matter.
v4…v7:
	- change trigger levels after some tests with raw transfers.
v3…v4:
	- drop RS485 support
	- wire up ->throttle / ->unthrottle
v2…v3:
	- wire up startup & shutdown for wakeup-irq handling.
	- RS485 handling (well the core does).

v1…v2:
	- added runtime PM. Could somebody could please double check
	  this?
	- added omap_8250_set_termios()
Reviewed-by: NTony Lindgren <tony@atomide.com>
Tested-by: NTony Lindgren <tony@atomide.com>
Tested-by: NFrans Klaver <frans.klaver@xsens.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The device has a highspeed register which influences the calcualtion
of the divisor. The chip lacks support for some baudrates. When requested,
we set the divisor to the next smaller baudrate and adjust the c_cflag
accordingly.
Signed-off-by: NMatthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch lets you set the RS485 cappabilites of the device through
TIOCSRS485 and TIOCGRS485 as defined on Documentation/serial/serial-rs485.txt

In order to probe the device, the PNP id and the device id is used.
Signed-off-by: NRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In 3.7 the 8250 module name was changed unintentionally from 8250 to
8250_core by commit 835d844d
(8250_pnp: do pnp probe before legacy probe). We then had to
re-introduce the old module options to ensure the old good
8250.nr_uart & co. still work. This can be done only by a very dirty
hack and we did it in f2b8dfd9
(serial: 8250: Keep 8250.<xxxx> module options functional after driver
rename).

That is so damn ugly so that I decided to revert to the old module
name and deprecate the new 8250_core options present in 3.7 and 3.8
only. The deprecation will happen in the following patch.

Note that this patch changes the hack above to support "8250_core.*",
because we now have "8250.*" natively.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support for dmaengine API. The drivers can implement the
struct uart_8250_dma member in struct uart_8250_port and
8250.c can take care of the rest.
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We first probe the legacy serial ports and then check pnp. If there
is a non-standard configuration then this might not work, also this
change is needed so we can blacklist Winbond CIR based on PNP ID.

For this to work the 8250_pnp driver must be merged into the 8250
module.
Signed-off-by: NSean Young <sean@mess.org>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The support for CONFIG_MCA is being removed, since the 20
year old hardware simply isn't capable of meeting today's
software demands on CPU and memory resources.

This commit removes the MCA specific 8250 UART code.

Cc: Alan Cox <alan@linux.intel.com>
Cc: linux-serial@vger.kernel.org
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>

This is V2 of the Emma Mobile 8250 platform driver.

The hardware itself has according to the data sheet
up to 64 byte FIFOs but at this point we only make
use of the 16550 compatible mode.

To support this piece of hardware the common UART
registers need to be remapped, and the access size
differences need to be handled.

The DLL and DLM registers can due to offset collision
not be remapped easily, and because of that this
driver makes use of ->dl_read() and ->dl_write()
callbacks. This in turn requires a registration
function that takes 8250-specific paramenters.

Future potential enhancements include DT support,
early platform driver console and fine grained PM.
Signed-off-by: NMagnus Damm <damm@opensource.se>
Acked-by: NAlan Cox <alan@linux.intel.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The drivers/tty/serial dir is already getting rather busy.
Relocate the 8250 related drivers to their own subdir to
reduce the clutter.

Note that sunsu.c is not included in this move -- it is
8250-like hardware, but it does not use any of the existing
infrastructure -- and does not depend on SERIAL_8250.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>