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linux/drivers/serial/imx.c
Alan Cox 33f0f88f1c [PATCH] TTY layer buffering revamp 
The API and code have been through various bits of initial review by
serial driver people but they definitely need to live somewhere for a
while so the unconverted drivers can get knocked into shape, existing
drivers that have been updated can be better tuned and bugs whacked out.

This replaces the tty flip buffers with kmalloc objects in rings. In the
normal situation for an IRQ driven serial port at typical speeds the
behaviour is pretty much the same, two buffers end up allocated and the
kernel cycles between them as before.

When there are delays or at high speed we now behave far better as the
buffer pool can grow a bit rather than lose characters. This also means
that we can operate at higher speeds reliably.

For drivers that receive characters in blocks (DMA based, USB and
especially virtualisation) the layer allows a lot of driver specific
code that works around the tty layer with private secondary queues to be
removed. The IBM folks need this sort of layer, the smart serial port
people do, the virtualisers do (because a virtualised tty typically
operates at infinite speed rather than emulating 9600 baud).

Finally many drivers had invalid and unsafe attempts to avoid buffer
overflows by directly invoking tty methods extracted out of the innards
of work queue structs. These are no longer needed and all go away. That
fixes various random hangs with serial ports on overflow.

The other change in here is to optimise the receive_room path that is
used by some callers. It turns out that only one ldisc uses receive room
except asa constant and it updates it far far less than the value is
read. We thus make it a variable not a function call.

I expect the code to contain bugs due to the size alone but I'll be
watching and squashing them and feeding out new patches as it goes.

Because the buffers now dynamically expand you should only run out of
buffering when the kernel runs out of memory for real.  That means a lot of
the horrible hacks high performance drivers used to do just aren't needed any
more.

Description:

tty_insert_flip_char is an old API and continues to work as before, as does
tty_flip_buffer_push() [this is why many drivers dont need modification].  It
does now also return the number of chars inserted

There are also

tty_buffer_request_room(tty, len)

which asks for a buffer block of the length requested and returns the space
found.  This improves efficiency with hardware that knows how much to
transfer.

and tty_insert_flip_string_flags(tty, str, flags, len)

to insert a string of characters and flags

For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

More description!

At the moment tty buffers are attached directly to the tty.  This is causing a
lot of the problems related to tty layer locking, also problems at high speed
and also with bursty data (such as occurs in virtualised environments)

I'm working on ripping out the flip buffers and replacing them with a pool of
dynamically allocated buffers.  This allows both for old style "byte I/O"
devices and also helps virtualisation and smart devices where large blocks of
data suddenely materialise and need storing.

So far so good.  Lots of drivers reference tty->flip.*.  Several of them also
call directly and unsafely into function pointers it provides.  This will all
break.  Most drivers can use tty_insert_flip_char which can be kept as an API
but others need more.

At the moment I've added the following interfaces, if people think more will
be needed now is a good time to say

 int tty_buffer_request_room(tty, size)

Try and ensure at least size bytes are available, returns actual room (may be
zero).  At the moment it just uses the flipbuf space but that will change.
Repeated calls without characters being added are not cumulative.  (ie if you
call it with 1, 1, 1, and then 4 you'll have four characters of space.  The
other functions will also try and grow buffers in future but this will be a
more efficient way when you know block sizes.

 int tty_insert_flip_char(tty, ch, flag)

As before insert a character if there is room.  Now returns 1 for success, 0
for failure.

 int tty_insert_flip_string(tty, str, len)

Insert a block of non error characters.  Returns the number inserted.

 int tty_prepare_flip_string(tty, strptr, len)

Adjust the buffer to allow len characters to be added.  Returns a buffer
pointer in strptr and the length available.  This allows for hardware that
needs to use functions like insl or mencpy_fromio.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Paul Fulghum <paulkf@microgate.com>
Signed-off-by: Hirokazu Takata <takata@linux-m32r.org>
Signed-off-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 08:01:59 -08:00

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/*
* linux/drivers/serial/imx.c
*
* Driver for Motorola IMX serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* Author: Sascha Hauer <sascha@saschahauer.de>
* Copyright (C) 2004 Pengutronix
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* [29-Mar-2005] Mike Lee
* Added hardware handshake
*/
#include <linux/config.h>
#if defined(CONFIG_SERIAL_IMX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_IMX_MAJOR 204
#define MINOR_START 41
#define NR_PORTS 2
#define IMX_ISR_PASS_LIMIT 256
/*
* This is the size of our serial port register set.
*/
#define UART_PORT_SIZE 0x100
/*
* This determines how often we check the modem status signals
* for any change. They generally aren't connected to an IRQ
* so we have to poll them. We also check immediately before
* filling the TX fifo incase CTS has been dropped.
*/
#define MCTRL_TIMEOUT (250*HZ/1000)
#define DRIVER_NAME "IMX-uart"
struct imx_port {
struct uart_port port;
struct timer_list timer;
unsigned int old_status;
int txirq,rxirq,rtsirq;
};
/*
* Handle any change of modem status signal since we were last called.
*/
static void imx_mctrl_check(struct imx_port *sport)
{
unsigned int status, changed;
status = sport->port.ops->get_mctrl(&sport->port);
changed = status ^ sport->old_status;
if (changed == 0)
return;
sport->old_status = status;
if (changed & TIOCM_RI)
sport->port.icount.rng++;
if (changed & TIOCM_DSR)
sport->port.icount.dsr++;
if (changed & TIOCM_CAR)
uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
if (changed & TIOCM_CTS)
uart_handle_cts_change(&sport->port, status & TIOCM_CTS);
wake_up_interruptible(&sport->port.info->delta_msr_wait);
}
/*
* This is our per-port timeout handler, for checking the
* modem status signals.
*/
static void imx_timeout(unsigned long data)
{
struct imx_port *sport = (struct imx_port *)data;
unsigned long flags;
if (sport->port.info) {
spin_lock_irqsave(&sport->port.lock, flags);
imx_mctrl_check(sport);
spin_unlock_irqrestore(&sport->port.lock, flags);
mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
}
}
/*
* interrupts disabled on entry
*/
static void imx_stop_tx(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
UCR1((u32)sport->port.membase) &= ~UCR1_TXMPTYEN;
}
/*
* interrupts disabled on entry
*/
static void imx_stop_rx(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
UCR2((u32)sport->port.membase) &= ~UCR2_RXEN;
}
/*
* Set the modem control timer to fire immediately.
*/
static void imx_enable_ms(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
mod_timer(&sport->timer, jiffies);
}
static inline void imx_transmit_buffer(struct imx_port *sport)
{
struct circ_buf *xmit = &sport->port.info->xmit;
do {
/* send xmit->buf[xmit->tail]
* out the port here */
URTX0((u32)sport->port.membase) = xmit->buf[xmit->tail];
xmit->tail = (xmit->tail + 1) &
(UART_XMIT_SIZE - 1);
sport->port.icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (!(UTS((u32)sport->port.membase) & UTS_TXFULL));
if (uart_circ_empty(xmit))
imx_stop_tx(&sport->port);
}
/*
* interrupts disabled on entry
*/
static void imx_start_tx(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
UCR1((u32)sport->port.membase) |= UCR1_TXMPTYEN;
if(UTS((u32)sport->port.membase) & UTS_TXEMPTY)
imx_transmit_buffer(sport);
}
static irqreturn_t imx_rtsint(int irq, void *dev_id, struct pt_regs *regs)
{
struct imx_port *sport = (struct imx_port *)dev_id;
unsigned int val = USR1((u32)sport->port.membase)&USR1_RTSS;
unsigned long flags;
spin_lock_irqsave(&sport->port.lock, flags);
USR1((u32)sport->port.membase) = USR1_RTSD;
uart_handle_cts_change(&sport->port, !!val);
wake_up_interruptible(&sport->port.info->delta_msr_wait);
spin_unlock_irqrestore(&sport->port.lock, flags);
return IRQ_HANDLED;
}
static irqreturn_t imx_txint(int irq, void *dev_id, struct pt_regs *regs)
{
struct imx_port *sport = (struct imx_port *)dev_id;
struct circ_buf *xmit = &sport->port.info->xmit;
unsigned long flags;
spin_lock_irqsave(&sport->port.lock,flags);
if (sport->port.x_char)
{
/* Send next char */
URTX0((u32)sport->port.membase) = sport->port.x_char;
goto out;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
imx_stop_tx(&sport->port);
goto out;
}
imx_transmit_buffer(sport);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&sport->port);
out:
spin_unlock_irqrestore(&sport->port.lock,flags);
return IRQ_HANDLED;
}
static irqreturn_t imx_rxint(int irq, void *dev_id, struct pt_regs *regs)
{
struct imx_port *sport = dev_id;
unsigned int rx,flg,ignored = 0;
struct tty_struct *tty = sport->port.info->tty;
unsigned long flags;
rx = URXD0((u32)sport->port.membase);
spin_lock_irqsave(&sport->port.lock,flags);
do {
flg = TTY_NORMAL;
sport->port.icount.rx++;
if( USR2((u32)sport->port.membase) & USR2_BRCD ) {
USR2((u32)sport->port.membase) |= USR2_BRCD;
if(uart_handle_break(&sport->port))
goto ignore_char;
}
if (uart_handle_sysrq_char
(&sport->port, (unsigned char)rx, regs))
goto ignore_char;
if( rx & (URXD_PRERR | URXD_OVRRUN | URXD_FRMERR) )
goto handle_error;
error_return:
tty_insert_flip_char(tty, rx, flg);
ignore_char:
rx = URXD0((u32)sport->port.membase);
} while(rx & URXD_CHARRDY);
out:
spin_unlock_irqrestore(&sport->port.lock,flags);
tty_flip_buffer_push(tty);
return IRQ_HANDLED;
handle_error:
if (rx & URXD_PRERR)
sport->port.icount.parity++;
else if (rx & URXD_FRMERR)
sport->port.icount.frame++;
if (rx & URXD_OVRRUN)
sport->port.icount.overrun++;
if (rx & sport->port.ignore_status_mask) {
if (++ignored > 100)
goto out;
goto ignore_char;
}
rx &= sport->port.read_status_mask;
if (rx & URXD_PRERR)
flg = TTY_PARITY;
else if (rx & URXD_FRMERR)
flg = TTY_FRAME;
if (rx & URXD_OVRRUN)
flg = TTY_OVERRUN;
#ifdef SUPPORT_SYSRQ
sport->port.sysrq = 0;
#endif
goto error_return;
}
/*
* Return TIOCSER_TEMT when transmitter is not busy.
*/
static unsigned int imx_tx_empty(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
return USR2((u32)sport->port.membase) & USR2_TXDC ? TIOCSER_TEMT : 0;
}
/*
* We have a modem side uart, so the meanings of RTS and CTS are inverted.
*/
static unsigned int imx_get_mctrl(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
unsigned int tmp = TIOCM_DSR | TIOCM_CAR;
if (USR1((u32)sport->port.membase) & USR1_RTSS)
tmp |= TIOCM_CTS;
if (UCR2((u32)sport->port.membase) & UCR2_CTS)
tmp |= TIOCM_RTS;
return tmp;
}
static void imx_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct imx_port *sport = (struct imx_port *)port;
if (mctrl & TIOCM_RTS)
UCR2((u32)sport->port.membase) |= UCR2_CTS;
else
UCR2((u32)sport->port.membase) &= ~UCR2_CTS;
}
/*
* Interrupts always disabled.
*/
static void imx_break_ctl(struct uart_port *port, int break_state)
{
struct imx_port *sport = (struct imx_port *)port;
unsigned long flags;
spin_lock_irqsave(&sport->port.lock, flags);
if ( break_state != 0 )
UCR1((u32)sport->port.membase) |= UCR1_SNDBRK;
else
UCR1((u32)sport->port.membase) &= ~UCR1_SNDBRK;
spin_unlock_irqrestore(&sport->port.lock, flags);
}
#define TXTL 2 /* reset default */
#define RXTL 1 /* reset default */
static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
{
unsigned int val;
unsigned int ufcr_rfdiv;
/* set receiver / transmitter trigger level.
* RFDIV is set such way to satisfy requested uartclk value
*/
val = TXTL<<10 | RXTL;
ufcr_rfdiv = (imx_get_perclk1() + sport->port.uartclk / 2) / sport->port.uartclk;
if(!ufcr_rfdiv)
ufcr_rfdiv = 1;
if(ufcr_rfdiv >= 7)
ufcr_rfdiv = 6;
else
ufcr_rfdiv = 6 - ufcr_rfdiv;
val |= UFCR_RFDIV & (ufcr_rfdiv << 7);
UFCR((u32)sport->port.membase) = val;
return 0;
}
static int imx_startup(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
int retval;
unsigned long flags;
imx_setup_ufcr(sport, 0);
/* disable the DREN bit (Data Ready interrupt enable) before
* requesting IRQs
*/
UCR4((u32)sport->port.membase) &= ~UCR4_DREN;
/*
* Allocate the IRQ
*/
retval = request_irq(sport->rxirq, imx_rxint, 0,
DRIVER_NAME, sport);
if (retval) goto error_out1;
retval = request_irq(sport->txirq, imx_txint, 0,
DRIVER_NAME, sport);
if (retval) goto error_out2;
retval = request_irq(sport->rtsirq, imx_rtsint, 0,
DRIVER_NAME, sport);
if (retval) goto error_out3;
set_irq_type(sport->rtsirq, IRQT_BOTHEDGE);
/*
* Finally, clear and enable interrupts
*/
USR1((u32)sport->port.membase) = USR1_RTSD;
UCR1((u32)sport->port.membase) |=
(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
UCR2((u32)sport->port.membase) |= (UCR2_RXEN | UCR2_TXEN);
/*
* Enable modem status interrupts
*/
spin_lock_irqsave(&sport->port.lock,flags);
imx_enable_ms(&sport->port);
spin_unlock_irqrestore(&sport->port.lock,flags);
return 0;
error_out3:
free_irq(sport->txirq, sport);
error_out2:
free_irq(sport->rxirq, sport);
error_out1:
return retval;
}
static void imx_shutdown(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
/*
* Stop our timer.
*/
del_timer_sync(&sport->timer);
/*
* Free the interrupts
*/
free_irq(sport->rtsirq, sport);
free_irq(sport->txirq, sport);
free_irq(sport->rxirq, sport);
/*
* Disable all interrupts, port and break condition.
*/
UCR1((u32)sport->port.membase) &=
~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN);
}
static void
imx_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
struct imx_port *sport = (struct imx_port *)port;
unsigned long flags;
unsigned int ucr2, old_ucr1, old_txrxen, baud, quot;
unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;
/*
* If we don't support modem control lines, don't allow
* these to be set.
*/
if (0) {
termios->c_cflag &= ~(HUPCL | CRTSCTS | CMSPAR);
termios->c_cflag |= CLOCAL;
}
/*
* We only support CS7 and CS8.
*/
while ((termios->c_cflag & CSIZE) != CS7 &&
(termios->c_cflag & CSIZE) != CS8) {
termios->c_cflag &= ~CSIZE;
termios->c_cflag |= old_csize;
old_csize = CS8;
}
if ((termios->c_cflag & CSIZE) == CS8)
ucr2 = UCR2_WS | UCR2_SRST | UCR2_IRTS;
else
ucr2 = UCR2_SRST | UCR2_IRTS;
if (termios->c_cflag & CRTSCTS) {
ucr2 &= ~UCR2_IRTS;
ucr2 |= UCR2_CTSC;
}
if (termios->c_cflag & CSTOPB)
ucr2 |= UCR2_STPB;
if (termios->c_cflag & PARENB) {
ucr2 |= UCR2_PREN;
if (!(termios->c_cflag & PARODD))
ucr2 |= UCR2_PROE;
}
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
quot = uart_get_divisor(port, baud);
spin_lock_irqsave(&sport->port.lock, flags);
sport->port.read_status_mask = 0;
if (termios->c_iflag & INPCK)
sport->port.read_status_mask |= (URXD_FRMERR | URXD_PRERR);
if (termios->c_iflag & (BRKINT | PARMRK))
sport->port.read_status_mask |= URXD_BRK;
/*
* Characters to ignore
*/
sport->port.ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
sport->port.ignore_status_mask |= URXD_PRERR;
if (termios->c_iflag & IGNBRK) {
sport->port.ignore_status_mask |= URXD_BRK;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
sport->port.ignore_status_mask |= URXD_OVRRUN;
}
del_timer_sync(&sport->timer);
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
/*
* disable interrupts and drain transmitter
*/
old_ucr1 = UCR1((u32)sport->port.membase);
UCR1((u32)sport->port.membase) &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
while ( !(USR2((u32)sport->port.membase) & USR2_TXDC))
barrier();
/* then, disable everything */
old_txrxen = UCR2((u32)sport->port.membase) & ( UCR2_TXEN | UCR2_RXEN );
UCR2((u32)sport->port.membase) &= ~( UCR2_TXEN | UCR2_RXEN);
/* set the parity, stop bits and data size */
UCR2((u32)sport->port.membase) = ucr2;
/* set the baud rate. We assume uartclk = 16 MHz
*
* baud * 16 UBIR - 1
* --------- = --------
* uartclk UBMR - 1
*/
UBIR((u32)sport->port.membase) = (baud / 100) - 1;
UBMR((u32)sport->port.membase) = 10000 - 1;
UCR1((u32)sport->port.membase) = old_ucr1;
UCR2((u32)sport->port.membase) |= old_txrxen;
if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
imx_enable_ms(&sport->port);
spin_unlock_irqrestore(&sport->port.lock, flags);
}
static const char *imx_type(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
return sport->port.type == PORT_IMX ? "IMX" : NULL;
}
/*
* Release the memory region(s) being used by 'port'.
*/
static void imx_release_port(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
release_mem_region(sport->port.mapbase, UART_PORT_SIZE);
}
/*
* Request the memory region(s) being used by 'port'.
*/
static int imx_request_port(struct uart_port *port)
{
struct imx_port *sport = (struct imx_port *)port;
return request_mem_region(sport->port.mapbase, UART_PORT_SIZE,
"imx-uart") != NULL ? 0 : -EBUSY;
}
/*
* Configure/autoconfigure the port.
*/
static void imx_config_port(struct uart_port *port, int flags)
{
struct imx_port *sport = (struct imx_port *)port;
if (flags & UART_CONFIG_TYPE &&
imx_request_port(&sport->port) == 0)
sport->port.type = PORT_IMX;
}
/*
* Verify the new serial_struct (for TIOCSSERIAL).
* The only change we allow are to the flags and type, and
* even then only between PORT_IMX and PORT_UNKNOWN
*/
static int
imx_verify_port(struct uart_port *port, struct serial_struct *ser)
{
struct imx_port *sport = (struct imx_port *)port;
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_IMX)
ret = -EINVAL;
if (sport->port.irq != ser->irq)
ret = -EINVAL;
if (ser->io_type != UPIO_MEM)
ret = -EINVAL;
if (sport->port.uartclk / 16 != ser->baud_base)
ret = -EINVAL;
if ((void *)sport->port.mapbase != ser->iomem_base)
ret = -EINVAL;
if (sport->port.iobase != ser->port)
ret = -EINVAL;
if (ser->hub6 != 0)
ret = -EINVAL;
return ret;
}
static struct uart_ops imx_pops = {
.tx_empty = imx_tx_empty,
.set_mctrl = imx_set_mctrl,
.get_mctrl = imx_get_mctrl,
.stop_tx = imx_stop_tx,
.start_tx = imx_start_tx,
.stop_rx = imx_stop_rx,
.enable_ms = imx_enable_ms,
.break_ctl = imx_break_ctl,
.startup = imx_startup,
.shutdown = imx_shutdown,
.set_termios = imx_set_termios,
.type = imx_type,
.release_port = imx_release_port,
.request_port = imx_request_port,
.config_port = imx_config_port,
.verify_port = imx_verify_port,
};
static struct imx_port imx_ports[] = {
{
.txirq = UART1_MINT_TX,
.rxirq = UART1_MINT_RX,
.rtsirq = UART1_MINT_RTS,
.port = {
.type = PORT_IMX,
.iotype = SERIAL_IO_MEM,
.membase = (void *)IMX_UART1_BASE,
.mapbase = IMX_UART1_BASE, /* FIXME */
.irq = UART1_MINT_RX,
.uartclk = 16000000,
.fifosize = 8,
.flags = ASYNC_BOOT_AUTOCONF,
.ops = &imx_pops,
.line = 0,
},
}, {
.txirq = UART2_MINT_TX,
.rxirq = UART2_MINT_RX,
.rtsirq = UART2_MINT_RTS,
.port = {
.type = PORT_IMX,
.iotype = SERIAL_IO_MEM,
.membase = (void *)IMX_UART2_BASE,
.mapbase = IMX_UART2_BASE, /* FIXME */
.irq = UART2_MINT_RX,
.uartclk = 16000000,
.fifosize = 8,
.flags = ASYNC_BOOT_AUTOCONF,
.ops = &imx_pops,
.line = 1,
},
}
};
/*
* Setup the IMX serial ports.
* Note also that we support "console=ttySMXx" where "x" is either 0 or 1.
* Which serial port this ends up being depends on the machine you're
* running this kernel on. I'm not convinced that this is a good idea,
* but that's the way it traditionally works.
*
*/
static void __init imx_init_ports(void)
{
static int first = 1;
int i;
if (!first)
return;
first = 0;
for (i = 0; i < ARRAY_SIZE(imx_ports); i++) {
init_timer(&imx_ports[i].timer);
imx_ports[i].timer.function = imx_timeout;
imx_ports[i].timer.data = (unsigned long)&imx_ports[i];
}
imx_gpio_mode(PC9_PF_UART1_CTS);
imx_gpio_mode(PC10_PF_UART1_RTS);
imx_gpio_mode(PC11_PF_UART1_TXD);
imx_gpio_mode(PC12_PF_UART1_RXD);
imx_gpio_mode(PB28_PF_UART2_CTS);
imx_gpio_mode(PB29_PF_UART2_RTS);
imx_gpio_mode(PB30_PF_UART2_TXD);
imx_gpio_mode(PB31_PF_UART2_RXD);
#if 0 /* We don't need these, on the mx1 the _modem_ side of the uart
* is implemented.
*/
imx_gpio_mode(PD7_AF_UART2_DTR);
imx_gpio_mode(PD8_AF_UART2_DCD);
imx_gpio_mode(PD9_AF_UART2_RI);
imx_gpio_mode(PD10_AF_UART2_DSR);
#endif
}
#ifdef CONFIG_SERIAL_IMX_CONSOLE
/*
* Interrupts are disabled on entering
*/
static void
imx_console_write(struct console *co, const char *s, unsigned int count)
{
struct imx_port *sport = &imx_ports[co->index];
unsigned int old_ucr1, old_ucr2, i;
/*
* First, save UCR1/2 and then disable interrupts
*/
old_ucr1 = UCR1((u32)sport->port.membase);
old_ucr2 = UCR2((u32)sport->port.membase);
UCR1((u32)sport->port.membase) =
(old_ucr1 | UCR1_UARTCLKEN | UCR1_UARTEN)
& ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN);
UCR2((u32)sport->port.membase) = old_ucr2 | UCR2_TXEN;
/*
* Now, do each character
*/
for (i = 0; i < count; i++) {
while ((UTS((u32)sport->port.membase) & UTS_TXFULL))
barrier();
URTX0((u32)sport->port.membase) = s[i];
if (s[i] == '\n') {
while ((UTS((u32)sport->port.membase) & UTS_TXFULL))
barrier();
URTX0((u32)sport->port.membase) = '\r';
}
}
/*
* Finally, wait for transmitter to become empty
* and restore UCR1/2
*/
while (!(USR2((u32)sport->port.membase) & USR2_TXDC));
UCR1((u32)sport->port.membase) = old_ucr1;
UCR2((u32)sport->port.membase) = old_ucr2;
}
/*
* If the port was already initialised (eg, by a boot loader),
* try to determine the current setup.
*/
static void __init
imx_console_get_options(struct imx_port *sport, int *baud,
int *parity, int *bits)
{
if ( UCR1((u32)sport->port.membase) | UCR1_UARTEN ) {
/* ok, the port was enabled */
unsigned int ucr2, ubir,ubmr, uartclk;
unsigned int baud_raw;
unsigned int ucfr_rfdiv;
ucr2 = UCR2((u32)sport->port.membase);
*parity = 'n';
if (ucr2 & UCR2_PREN) {
if (ucr2 & UCR2_PROE)
*parity = 'o';
else
*parity = 'e';
}
if (ucr2 & UCR2_WS)
*bits = 8;
else
*bits = 7;
ubir = UBIR((u32)sport->port.membase) & 0xffff;
ubmr = UBMR((u32)sport->port.membase) & 0xffff;
ucfr_rfdiv = (UFCR((u32)sport->port.membase) & UFCR_RFDIV) >> 7;
if (ucfr_rfdiv == 6)
ucfr_rfdiv = 7;
else
ucfr_rfdiv = 6 - ucfr_rfdiv;
uartclk = imx_get_perclk1();
uartclk /= ucfr_rfdiv;
{ /*
* The next code provides exact computation of
* baud_raw = round(((uartclk/16) * (ubir + 1)) / (ubmr + 1))
* without need of float support or long long division,
* which would be required to prevent 32bit arithmetic overflow
*/
unsigned int mul = ubir + 1;
unsigned int div = 16 * (ubmr + 1);
unsigned int rem = uartclk % div;
baud_raw = (uartclk / div) * mul;
baud_raw += (rem * mul + div / 2) / div;
*baud = (baud_raw + 50) / 100 * 100;
}
if(*baud != baud_raw)
printk(KERN_INFO "Serial: Console IMX rounded baud rate from %d to %d\n",
baud_raw, *baud);
}
}
static int __init
imx_console_setup(struct console *co, char *options)
{
struct imx_port *sport;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
if (co->index == -1 || co->index >= ARRAY_SIZE(imx_ports))
co->index = 0;
sport = &imx_ports[co->index];
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
imx_console_get_options(sport, &baud, &parity, &bits);
imx_setup_ufcr(sport, 0);
return uart_set_options(&sport->port, co, baud, parity, bits, flow);
}
static struct uart_driver imx_reg;
static struct console imx_console = {
.name = "ttySMX",
.write = imx_console_write,
.device = uart_console_device,
.setup = imx_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &imx_reg,
};
static int __init imx_rs_console_init(void)
{
imx_init_ports();
register_console(&imx_console);
return 0;
}
console_initcall(imx_rs_console_init);
#define IMX_CONSOLE &imx_console
#else
#define IMX_CONSOLE NULL
#endif
static struct uart_driver imx_reg = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME,
.dev_name = "ttySMX",
.devfs_name = "ttsmx/",
.major = SERIAL_IMX_MAJOR,
.minor = MINOR_START,
.nr = ARRAY_SIZE(imx_ports),
.cons = IMX_CONSOLE,
};
static int serial_imx_suspend(struct platform_device *dev, pm_message_t state)
{
struct imx_port *sport = platform_get_drvdata(dev);
if (sport)
uart_suspend_port(&imx_reg, &sport->port);
return 0;
}
static int serial_imx_resume(struct platform_device *dev)
{
struct imx_port *sport = platform_get_drvdata(dev);
if (sport)
uart_resume_port(&imx_reg, &sport->port);
return 0;
}
static int serial_imx_probe(struct platform_device *dev)
{
imx_ports[dev->id].port.dev = &dev->dev;
uart_add_one_port(&imx_reg, &imx_ports[dev->id].port);
platform_set_drvdata(dev, &imx_ports[dev->id]);
return 0;
}
static int serial_imx_remove(struct platform_device *dev)
{
struct imx_port *sport = platform_get_drvdata(dev);
platform_set_drvdata(dev, NULL);
if (sport)
uart_remove_one_port(&imx_reg, &sport->port);
return 0;
}
static struct platform_driver serial_imx_driver = {
.probe = serial_imx_probe,
.remove = serial_imx_remove,
.suspend = serial_imx_suspend,
.resume = serial_imx_resume,
.driver = {
.name = "imx-uart",
},
};
static int __init imx_serial_init(void)
{
int ret;
printk(KERN_INFO "Serial: IMX driver\n");
imx_init_ports();
ret = uart_register_driver(&imx_reg);
if (ret)
return ret;
ret = platform_driver_register(&serial_imx_driver);
if (ret != 0)
uart_unregister_driver(&imx_reg);
return 0;
}
static void __exit imx_serial_exit(void)
{
uart_unregister_driver(&imx_reg);
platform_driver_unregister(&serial_imx_driver);
}
module_init(imx_serial_init);
module_exit(imx_serial_exit);
MODULE_AUTHOR("Sascha Hauer");
MODULE_DESCRIPTION("IMX generic serial port driver");
MODULE_LICENSE("GPL");
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