Looking at the existing serial drivers (esp. the 8250 derived
variants) we see a common trend.  They create a hardware specific
port struct, which in turn contains a generic serial_port struct.

The other trend, is that they all create some sort of shortcut
to go through the hardware specific struct, to the serial_port
struct, which has the basic in/out operations within.  Looking
for the serial_in and serial_out in several drivers shows this.

Rather than let this continue, lets create a generic set of
similar helper wrappers that can be used on a struct port, so
we can eliminate bouncing out through hardware specific struct
pointers just to come back into struct port where possible.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial_8250_port struct contains within a serial_port struct
and many times one or the other, or both are in scope within
functions via a passed in arg, or via container_of.

However there are a lot of cases where we have access directly
to the port pointer, but yet go through the parent 8250_port
structure instead to get it.  These should just use the port
struct directly.

Similarly there are cases where it makes sense (from a code
cleanliness point of view) to declare a local for the port
struct, so we aren't going through the parent 8250_port struct
repeatedly to get to it.

We get a small reduction in text size, but it appears that
gcc was smart enough to internally be doing most of this
already, so the readability improvement is the larger gain.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These might have worked some magic with an ancient gcc back in
1992, but "objdump --disassemble" on gcc 4.6 on x86-64 shows
identical output before and after this commit.  Send the casts
and their hysterical rasins to the bitbucket.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently 8250.c has serial_in and serial_out as shortcuts
to doing the port I/O.  They are implemented as macros a
ways down in the file.  This isn't by accident, but is
implicitly required, so cpp doesn't mangle other instances
of the common string "serial_in", as it exists as a field
in the port struct itself.

The above mangling avoidance violates the principle of least
surprise, and it also prevents the shortcuts from being
relocated up to the top of file, or into 8250.h -- either
being a better location than the current one.

Move them to 8250.h so other 8250-like drivers can also use
the shortcuts, and in the process, make the conflicting
names go away by using static inlines instead of macros.
The object file size remains unchanged with this modification.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is the last traces of pausing I/O that we had back some
twenty years ago.  Probably was only required for 8MHz ISA
cards running "on the edge" at 12MHz.  Anyway it hasn't been
in use for years, so lets just bury it for good.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Document default_baud and user_uartclk module parameters.
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Rather than hardcode 9600, use the existing default_baud parameter (which
also defaults to 9600).
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For cases where boards with non-default clocks are not yet added to the kernel
or when the clock varies across hardware revisions, it is useful to be
able to specify the UART clock on the kernel command line.

Add the user_uartclk parameter and prefer it, if set, to the default and
board specific UART clock settings. Specify user_uartclock on the command-line
with "pch_uart.user_uartclk=48000000".
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support for the Fish River Island II (FRI2) UART clock following the CM-iTC
quirk handling mechanism. Depending on the firmware installed on the device, the
FRI2 uses a 48MHz or a 64MHz UART clock. This is detected with DMI strings.

Add similar UART clock quirk handling to the pch_console_setup() function to
enable kernel messages on boards with non-standard UART clocks.

Per Alan's suggestion, abstract out UART clock selection into
pch_uart_get_uartclk() to avoid code duplication.
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The term "base baud" refers to the fastest baud rate the device can communicate
at. This is clock/16. pch_uart is using base_baud as the clock itself. Rename
the variables to be semantically correct.
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
CC: Tomoya MORINAGA <tomoya.rohm@gmail.com>
CC: Feng Tang <feng.tang@intel.com>
CC: Alan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In addition to the /32 prescaler, the MPC5200B supports a second
baudrate prescaler /4 to reach higher baudrates.

The current calculation (introduced with commit 0d1f22e4) in the kernel
preferes this low prescaler as often as possible, but with some
imprecise counterparts the communication on low baudrates fails.

According a support-mail from freescale the low prescaler (/4) allows
just 1% tolerance in bittiming in contrast to 4% of the high prescaler
(/32).  The prescaler not only affects the baudrate-calculation, but
also the sampling of the bits on the wire.

With this patch, we use the slightly less precise, but higher tolerant
prescaler calculation on low baudrates up to (and including) 115200 baud
and the more precise calculation above.

Tested on a custom MPC5200B board with "fsl,mpc5200b-psc-uart".

Calculation Examples with prescaler (PS) 4 and 32 and divisor (DIV) on
various baudrates. Real stands for the real baudrate generated and Diff
for the differences between:
     50 Baud PS 32 DIV 0xa122 Real      50 Diff   0.00%
     75 Baud PS 32 DIV 0x6b6c Real      75 Diff   0.00%
    110 Baud PS 32 DIV 0x493e Real     110 Diff   0.00%
    134 Baud PS 32 DIV 0x3c20 Real     133 Diff   0.75%
    150 Baud PS 32 DIV 0x35b6 Real     150 Diff   0.00%
    200 Baud PS 32 DIV 0x2849 Real     199 Diff   0.50%
    300 Baud PS  4 DIV 0xd6d8 Real     300 Diff   0.00%
             PS 32 DIV 0x1adb Real     300 Diff   0.00%
    600 Baud PS  4 DIV 0x6b6c Real     600 Diff   0.00%
             PS 32 DIV 0x0d6e Real     599 Diff   0.17%
   1200 Baud PS  4 DIV 0x35b6 Real    1200 Diff   0.00%
             PS 32 DIV 0x06b7 Real    1199 Diff   0.08%
   1800 Baud PS  4 DIV 0x23cf Real    1799 Diff   0.06%
             PS 32 DIV 0x047a Real    1799 Diff   0.06%
   2400 Baud PS  4 DIV 0x1adb Real    2400 Diff   0.00%
             PS 32 DIV 0x035b Real    2401 Diff - 0.04%
   4800 Baud PS  4 DIV 0x0d6e Real    4799 Diff   0.02%
             PS 32 DIV 0x01ae Real    4796 Diff   0.08%
   9600 Baud PS  4 DIV 0x06b7 Real    9598 Diff   0.02%
             PS 32 DIV 0x00d7 Real    9593 Diff   0.07%
  19200 Baud PS  4 DIV 0x035b Real   19208 Diff - 0.04%
             PS 32 DIV 0x006b Real   19275 Diff - 0.39%
  38400 Baud PS  4 DIV 0x01ae Real   38372 Diff   0.07%
             PS 32 DIV 0x0036 Real   38194 Diff   0.54%
  57600 Baud PS  4 DIV 0x011e Real   57692 Diff - 0.16%
             PS 32 DIV 0x0024 Real   57291 Diff   0.54%
  76800 Baud PS  4 DIV 0x00d7 Real   76744 Diff   0.07%
             PS 32 DIV 0x001b Real   76388 Diff   0.54%
 115200 Baud PS  4 DIV 0x008f Real  115384 Diff - 0.16%
             PS 32 DIV 0x0012 Real  114583 Diff   0.54%
 153600 Baud PS  4 DIV 0x006b Real  154205 Diff - 0.39%
             PS 32 DIV 0x000d Real  158653 Diff - 3.29%
 230400 Baud PS  4 DIV 0x0048 Real  229166 Diff   0.54%
             PS 32 DIV 0x0009 Real  229166 Diff   0.54%
 307200 Baud PS  4 DIV 0x0036 Real  305555 Diff   0.54%
             PS 32 DIV 0x0007 Real  294642 Diff   4.09%
 460800 Baud PS  4 DIV 0x0024 Real  458333 Diff   0.54%
             PS 32 DIV 0x0005 Real  412500 Diff  10.48%
 500000 Baud PS  4 DIV 0x0021 Real  500000 Diff   0.00%
             PS 32 DIV 0x0004 Real  515625 Diff - 3.13%
 576000 Baud PS  4 DIV 0x001d Real  568965 Diff   1.22%
             PS 32 DIV 0x0004 Real  515625 Diff  10.48%
 614400 Baud PS  4 DIV 0x001b Real  611111 Diff   0.54%
             PS 32 DIV 0x0003 Real  687500 Diff -11.90%
 921600 Baud PS  4 DIV 0x0012 Real  916666 Diff   0.54%
             PS 32 DIV 0x0002 Real 1031250 Diff -11.90%
1000000 Baud PS  4 DIV 0x0011 Real  970588 Diff   2.94%
             PS 32 DIV 0x0002 Real 1031250 Diff - 3.13%
1152000 Baud PS  4 DIV 0x000e Real 1178571 Diff - 2.31%
             PS 32 DIV 0x0002 Real 1031250 Diff  10.48%
1500000 Baud PS  4 DIV 0x000b Real 1500000 Diff   0.00%
             PS 32 DIV 0x0001 Real 2062500 Diff -37.50%
2000000 Baud PS  4 DIV 0x0008 Real 2062500 Diff - 3.13%
             PS 32 DIV 0x0001 Real 2062500 Diff - 3.13%
2500000 Baud PS  4 DIV 0x0007 Real 2357142 Diff   5.71%
             PS 32 DIV 0x0001 Real 2062500 Diff  17.50%
3000000 Baud PS  4 DIV 0x0006 Real 2750000 Diff   8.33%
             PS 32 DIV 0x0001 Real 2062500 Diff  31.25%
3500000 Baud PS  4 DIV 0x0005 Real 3300000 Diff   5.71%
             PS 32 DIV 0x0001 Real 2062500 Diff  41.07%
4000000 Baud PS  4 DIV 0x0004 Real 4125000 Diff - 3.13%
             PS 32 DIV 0x0001 Real 2062500 Diff  48.44%
Signed-off-by: NFrank Benkert <frank.benkert@avat.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is supposed to be doing a shift before the comparison instead of
just doing a bitwise AND directly.  The current code means the start()
just returns without doing anything.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NJiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Let us port the code to use tty_port. We now use open_count and tty
from there. This allows us also to use tty_port_tty_set with tty
refcounting instead of hand-written locking and logic.

Note that tty and open_count are no longer protected by cs->lock. It is
protected by tty_port->lock. But since all the places where they were
used are now switched to the helpers, we are fine.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Acked-by: NTilman Schmidt <tilman@imap.cc>
Cc: <gigaset307x-common@lists.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Close the window in open where driver_data is reset to NULL on each
open. It could cause other processes to get invalid retval from the
tty->ops operations because of the checks all over the code.

With this change we may do other cleanups. Now, the only valid check
for tty->driver_data != NULL is in close. This can happen only if open
fails at gigaset_get_cs_by_tty or try_module_get. The rest of checks
in various tty->ops->* are invalid as driver_data cannot be NULL
there. The same holds for cs->open_count. So remove them.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Hansjoerg Lipp <hjlipp@web.de>
Cc: Tilman Schmidt <tilman@imap.cc>
Cc: gigaset307x-common@lists.sourceforge.net
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of digging a tty out of the tty_driver struct, which is not
defined to work, use tty_port properly. This includes proper tty
refcounting even though there is no possible race currently. But we
will need tty_port for tty buffers in the future anyway.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Assign the pointer to pdc_console_tty_driver (a tty_driver) earlier.
Otherwise the timer may dereference NULL.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The timer is initialized too late. tty->open may fire an invalid
timer. So initialize the timer earlier using DEFINE_TIMER.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The tty->count test in the timer was racy. Let's remove the test and
properly delete the timer and wait for the body to finish using _sync
version of del_timer.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Again, no need to duplicate the code. Let's use the helper.

Amiserial changes are only free of compilation errors. I have no
access to the hardware.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Hmm, the code was sleeping with interrupts disabled. This was not
good. Fix this by turning interrupts at an appropriate place. (The
race is protected by CLOSING flag.)

After the move, the code is identical to tty_port_close_end, so use
it!
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Hmm, 150 lines of duplicated stuff is gone now.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is a preparation for a switch to tty_port_block_til_ready. We
need amiga_carrier_raised and amiga_dtr_rts. The implementation is
taken from startup, shutdown and current block_til_ready.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

amiserial is the last user of serialP.h. Let's move struct
serial_state directly to amiserial and remove serialP crap from
includes. Finally, remove the header from the tree completely.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* instead of line, use tty->index or iterator...
* irq and type are left unset. So get rid of them.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

And use it to make the code more readable.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* remove pointless checks (tty cannot be NULL at that points)
* fix some printks (use __func__, print text directly w/o using global
  strings)
* remove some empty lines

This is the last patch for simserial. Overall, the driver is 400 lines
shorter. Being now at 560 lines.

It was tested using ski with a busybox userspace.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make the code to conform to the standard. Also make it readable.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use headers from linux/* instead of asm/. Remove declaration of
console_drivers, it's in linux/console.h already.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Or the obsolete ones like:
   "Let's have a little bit of fun"
I have never had fun with software. For fun, one needs hard-ware.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert shutdown to be tty_port_operations->shutdown. Then we can use
tty_port_hangup. (And we have to use tty_port_close.)

This means we no longer touch ASYNC_INITIALIZED, TTY_IO_ERROR. Also we
do not need to do any peculiar TTY logic in the file now.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

So now we convert startup to be ->activate of tty_port. This means we
no longer care about INITIALIZED and TTY_IO_ERROR flags.

After we have ->activate much of the code may go as it duplicates what
tty_port_open does. In this case tty_port_open adds block_til_ready to
the path. But we do not define carrier hooks, so it is a noop.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

So that we will not be surprised in the ISR anymore.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I.e. remove more copied bloat.

The only change is that we wait_until_sent now. Which is what we
really should do.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The code is identical except locking. But added locks to protect
counts do not hurt here. Rather the contrary.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

All ->start, ->stop and ->wait_until_sent are empty and need not be
defined. The time to remove them is now.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

And use it to make the code more readable.

Since tport doesn't conflict with port anymore and there are not many
tport accessors left, do also s/\<tport\>/port/g.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Let's do a spin-off of serial_state structure with only needed
elements.

And remove serialP crap from includes.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* instead of line, use tty->index or an iterator
* icount is not made public, only the tx path increments it
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It is totally unused.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We do not use any of the preinitialized rs_state members for something
real. So there is no need to initialize them. At the places we used
them for printing, just print the values.

And since only one port is supported, get rid of the loop. This
simplifies simrs_init a heap. Thus we can handle fail paths in a
standard way without panicing.
Signed-off-by: NJiri Slaby <jslaby@suse.cz>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>