Sending a break on the SOC UARTs found in some MPC83xx/85xx/86xx
chips seems to cause a short lived IRQ storm (/proc/interrupts
typically shows somewhere between 300 and 1500 events).  Unfortunately
this renders SysRQ over the serial console completely inoperable.

The suggested workaround in the errata is to read the Rx register,
wait one character period, and then read the Rx register again.
We achieve this by tracking the old LSR value, and on the subsequent
interrupt event after a break, we don't read LSR, instead we just
read the RBR again and return immediately.

The "fsl,ns16550" is used in the compatible field of the serial
device to mark UARTs known to have this issue.

Thanks to Scott Wood for providing the errata data which led to
a much cleaner fix.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

For drivers that need to construct their own IRQ handler, the
three components are seen in the current handle_port -- i.e.
Rx, Tx and modem_status.

Make these exported symbols so that "almost" 8250 UARTs can
construct their own IRQ handler with these shared components,
while working around their own unique errata issues.

The function names are given a serial8250 prefix, since they
are now entering the global namespace.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

This reverts commit 6b1a98d1c4851235d9b6764b3f7b7db7909fc760.

It causes a build error that needs to be resolved differently.

Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

The Synopsys DesignWare 8250 is an 8250 that has an extra interrupt that
gets raised when writing to the LCR when busy.  To handle this we need
special serial_out, serial_in and handle_irq methods.  Add a new
function serial8250_use_designware_io() that configures a uart_port with
these accessors.

Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Some ports (e.g. Synopsys DesignWare 8250) have special requirements for
handling the interrupts.  Allow these platforms to specify their own
interrupt handler that will override the default.
serial8250_handle_irq() is provided so that platforms can extend the IRQ
handler rather than completely replacing it.

Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Not every platform that has generic legacy 8250 ports manages to have them
clocked the right way or without errata. Provide a generic interface to
allow platforms to override the default behaviour in a manner that dumps
the complexity in *their* code not the 8250 driver.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Add a hook for platforms to specify custom pm methods.

Signed-off-by: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

UART Features extract from STEricsson U6715 data-sheet (arm926 SoC for mobile phone):
* Fully compatible with industry standard 16C550 and 16C450 from various
manufacturers
* RX and TX 64 byte FIFO reduces CPU interrupts
* Full double buffering
* Modem control signals include CTS, RTS, (and DSR, DTR on UART1 only)
* Automatic baud rate selection
* Manual or automatic RTS/CTS smart hardware flow control
* Programmable serial characteristics:
– Baud rate generation (50 to 3.25M baud)
– 5, 6, 7 or 8-bit characters
– Even, odd or no-parity bit generation and detection
– 1, 1.5 or 2 stop bit generation
* Independent control of transmit, receive, line status, data set interrupts and FIFOs
* Full status-reporting capabilities
* Separate DMA signaling for RX and TX
* Timed interrupt to spread receive interrupt on known duration
* DMA time-out interrupt to allow detection of end of reception
* Carkit pulse coding and decoding compliant with USB carkit control interface [40]

In 16550A auto-configuration, if the fifo size is 64 then it's an U6 16550A port
Add set_termios hook & export serial8250_do_set_termios to change uart
clock following baudrate

Signed-off-by: Philippe Langlais <philippe.langlais@stericsson.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

There is currently no provision for passing IRQ trigger flags for
serial IRQs with triggering requirements (such as GPIO IRQs)

This patch adds irqflags to plat_serial8250_port that can be passed
from board file to reqest_irq() of 8250 driver

Changes are backward compatible with boards passing UPF_SHARE_IRQ flag

Tested on Zoom2 board that has IRQF_TRIGGER_RISING requirement for 8250 irq

[Moved new flag to end to fix bugs in the original with the old_serial array
	-- Alan]

Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Add flag value UPF_FIXED_TYPE which specifies that the UART type is
known and should not be probed.  For this case the UARTs properties
are just copied out of the uart_config entry.

This allows us to keep SOC specific 8250 probe code out of 8250.c.  In
this case we know the serial hardware will not be changing as it is on
the same silicon as the CPU, and we can specify it with certainty in
the board/cpu setup code.

The alternative is to load up 8250.c with a bunch of OCTEON specific
special cases in the probing code.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>