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kernel-fxtec-pro1x/drivers/serial/amba-pl010.c
Lennert Buytenhek a4ed06ad83 [PATCH] amba-pl010: clear error flags on rx error 
The pl010 primecell documentation specifies that an error indicated via RSR
should be cleared by a write to ECR.  We didn't do this, which was causing
errors to be re-reported on every call to pl010_rx_chars().

Doing a write to ECR once we detect an error appears to prevent the ep93xx
console UART driver from going into a mode where it reports "ttyAM0: X
input overrun(s)" every couple of keystrokes.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:44 -08:00

768 lines
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/*
* linux/drivers/char/amba.c
*
* Driver for AMBA serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* Copyright 1999 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd.
*
* 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
*
* $Id: amba.c,v 1.41 2002/07/28 10:03:27 rmk Exp $
*
* This is a generic driver for ARM AMBA-type serial ports. They
* have a lot of 16550-like features, but are not register compatible.
* Note that although they do have CTS, DCD and DSR inputs, they do
* not have an RI input, nor do they have DTR or RTS outputs. If
* required, these have to be supplied via some other means (eg, GPIO)
* and hooked into this driver.
*/
#if defined(CONFIG_SERIAL_AMBA_PL010_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/device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/amba/bus.h>
#include <linux/amba/serial.h>
#include <asm/io.h>
#define UART_NR 8
#define SERIAL_AMBA_MAJOR 204
#define SERIAL_AMBA_MINOR 16
#define SERIAL_AMBA_NR UART_NR
#define AMBA_ISR_PASS_LIMIT 256
#define UART_RX_DATA(s) (((s) & UART01x_FR_RXFE) == 0)
#define UART_TX_READY(s) (((s) & UART01x_FR_TXFF) == 0)
#define UART_DUMMY_RSR_RX 256
#define UART_PORT_SIZE 64
/*
* We wrap our port structure around the generic uart_port.
*/
struct uart_amba_port {
struct uart_port port;
struct amba_device *dev;
struct amba_pl010_data *data;
unsigned int old_status;
};
static void pl010_stop_tx(struct uart_port *port)
{
unsigned int cr;
cr = readb(port->membase + UART010_CR);
cr &= ~UART010_CR_TIE;
writel(cr, port->membase + UART010_CR);
}
static void pl010_start_tx(struct uart_port *port)
{
unsigned int cr;
cr = readb(port->membase + UART010_CR);
cr |= UART010_CR_TIE;
writel(cr, port->membase + UART010_CR);
}
static void pl010_stop_rx(struct uart_port *port)
{
unsigned int cr;
cr = readb(port->membase + UART010_CR);
cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
writel(cr, port->membase + UART010_CR);
}
static void pl010_enable_ms(struct uart_port *port)
{
unsigned int cr;
cr = readb(port->membase + UART010_CR);
cr |= UART010_CR_MSIE;
writel(cr, port->membase + UART010_CR);
}
static void pl010_rx_chars(struct uart_port *port)
{
struct tty_struct *tty = port->info->tty;
unsigned int status, ch, flag, rsr, max_count = 256;
status = readb(port->membase + UART01x_FR);
while (UART_RX_DATA(status) && max_count--) {
ch = readb(port->membase + UART01x_DR);
flag = TTY_NORMAL;
port->icount.rx++;
/*
* Note that the error handling code is
* out of the main execution path
*/
rsr = readb(port->membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
if (unlikely(rsr & UART01x_RSR_ANY)) {
writel(0, port->membase + UART01x_ECR);
if (rsr & UART01x_RSR_BE) {
rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
port->icount.brk++;
if (uart_handle_break(port))
goto ignore_char;
} else if (rsr & UART01x_RSR_PE)
port->icount.parity++;
else if (rsr & UART01x_RSR_FE)
port->icount.frame++;
if (rsr & UART01x_RSR_OE)
port->icount.overrun++;
rsr &= port->read_status_mask;
if (rsr & UART01x_RSR_BE)
flag = TTY_BREAK;
else if (rsr & UART01x_RSR_PE)
flag = TTY_PARITY;
else if (rsr & UART01x_RSR_FE)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
uart_insert_char(port, rsr, UART01x_RSR_OE, ch, flag);
ignore_char:
status = readb(port->membase + UART01x_FR);
}
tty_flip_buffer_push(tty);
return;
}
static void pl010_tx_chars(struct uart_port *port)
{
struct circ_buf *xmit = &port->info->xmit;
int count;
if (port->x_char) {
writel(port->x_char, port->membase + UART01x_DR);
port->icount.tx++;
port->x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
pl010_stop_tx(port);
return;
}
count = port->fifosize >> 1;
do {
writel(xmit->buf[xmit->tail], port->membase + UART01x_DR);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
pl010_stop_tx(port);
}
static void pl010_modem_status(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int status, delta;
writel(0, uap->port.membase + UART010_ICR);
status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
delta = status ^ uap->old_status;
uap->old_status = status;
if (!delta)
return;
if (delta & UART01x_FR_DCD)
uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
if (delta & UART01x_FR_DSR)
uap->port.icount.dsr++;
if (delta & UART01x_FR_CTS)
uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
wake_up_interruptible(&uap->port.info->delta_msr_wait);
}
static irqreturn_t pl010_int(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
int handled = 0;
spin_lock(&port->lock);
status = readb(port->membase + UART010_IIR);
if (status) {
do {
if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
pl010_rx_chars(port);
if (status & UART010_IIR_MIS)
pl010_modem_status(port);
if (status & UART010_IIR_TIS)
pl010_tx_chars(port);
if (pass_counter-- == 0)
break;
status = readb(port->membase + UART010_IIR);
} while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
UART010_IIR_TIS));
handled = 1;
}
spin_unlock(&port->lock);
return IRQ_RETVAL(handled);
}
static unsigned int pl010_tx_empty(struct uart_port *port)
{
return readb(port->membase + UART01x_FR) & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
}
static unsigned int pl010_get_mctrl(struct uart_port *port)
{
unsigned int result = 0;
unsigned int status;
status = readb(port->membase + UART01x_FR);
if (status & UART01x_FR_DCD)
result |= TIOCM_CAR;
if (status & UART01x_FR_DSR)
result |= TIOCM_DSR;
if (status & UART01x_FR_CTS)
result |= TIOCM_CTS;
return result;
}
static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
if (uap->data)
uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
}
static void pl010_break_ctl(struct uart_port *port, int break_state)
{
unsigned long flags;
unsigned int lcr_h;
spin_lock_irqsave(&port->lock, flags);
lcr_h = readb(port->membase + UART010_LCRH);
if (break_state == -1)
lcr_h |= UART01x_LCRH_BRK;
else
lcr_h &= ~UART01x_LCRH_BRK;
writel(lcr_h, port->membase + UART010_LCRH);
spin_unlock_irqrestore(&port->lock, flags);
}
static int pl010_startup(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
int retval;
/*
* Allocate the IRQ
*/
retval = request_irq(port->irq, pl010_int, 0, "uart-pl010", port);
if (retval)
return retval;
/*
* initialise the old status of the modem signals
*/
uap->old_status = readb(port->membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
/*
* Finally, enable interrupts
*/
writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
port->membase + UART010_CR);
return 0;
}
static void pl010_shutdown(struct uart_port *port)
{
/*
* Free the interrupt
*/
free_irq(port->irq, port);
/*
* disable all interrupts, disable the port
*/
writel(0, port->membase + UART010_CR);
/* disable break condition and fifos */
writel(readb(port->membase + UART010_LCRH) &
~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
port->membase + UART010_LCRH);
}
static void
pl010_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
unsigned int lcr_h, old_cr;
unsigned long flags;
unsigned int baud, quot;
/*
* 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);
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr_h = UART01x_LCRH_WLEN_5;
break;
case CS6:
lcr_h = UART01x_LCRH_WLEN_6;
break;
case CS7:
lcr_h = UART01x_LCRH_WLEN_7;
break;
default: // CS8
lcr_h = UART01x_LCRH_WLEN_8;
break;
}
if (termios->c_cflag & CSTOPB)
lcr_h |= UART01x_LCRH_STP2;
if (termios->c_cflag & PARENB) {
lcr_h |= UART01x_LCRH_PEN;
if (!(termios->c_cflag & PARODD))
lcr_h |= UART01x_LCRH_EPS;
}
if (port->fifosize > 1)
lcr_h |= UART01x_LCRH_FEN;
spin_lock_irqsave(&port->lock, flags);
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = UART01x_RSR_OE;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
if (termios->c_iflag & (BRKINT | PARMRK))
port->read_status_mask |= UART01x_RSR_BE;
/*
* Characters to ignore
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= UART01x_RSR_BE;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART01x_RSR_OE;
}
/*
* Ignore all characters if CREAD is not set.
*/
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= UART_DUMMY_RSR_RX;
/* first, disable everything */
old_cr = readb(port->membase + UART010_CR) & ~UART010_CR_MSIE;
if (UART_ENABLE_MS(port, termios->c_cflag))
old_cr |= UART010_CR_MSIE;
writel(0, port->membase + UART010_CR);
/* Set baud rate */
quot -= 1;
writel((quot & 0xf00) >> 8, port->membase + UART010_LCRM);
writel(quot & 0xff, port->membase + UART010_LCRL);
/*
* ----------v----------v----------v----------v-----
* NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
* ----------^----------^----------^----------^-----
*/
writel(lcr_h, port->membase + UART010_LCRH);
writel(old_cr, port->membase + UART010_CR);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *pl010_type(struct uart_port *port)
{
return port->type == PORT_AMBA ? "AMBA" : NULL;
}
/*
* Release the memory region(s) being used by 'port'
*/
static void pl010_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, UART_PORT_SIZE);
}
/*
* Request the memory region(s) being used by 'port'
*/
static int pl010_request_port(struct uart_port *port)
{
return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
!= NULL ? 0 : -EBUSY;
}
/*
* Configure/autoconfigure the port.
*/
static void pl010_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE) {
port->type = PORT_AMBA;
pl010_request_port(port);
}
}
/*
* verify the new serial_struct (for TIOCSSERIAL).
*/
static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
ret = -EINVAL;
if (ser->irq < 0 || ser->irq >= NR_IRQS)
ret = -EINVAL;
if (ser->baud_base < 9600)
ret = -EINVAL;
return ret;
}
static struct uart_ops amba_pl010_pops = {
.tx_empty = pl010_tx_empty,
.set_mctrl = pl010_set_mctrl,
.get_mctrl = pl010_get_mctrl,
.stop_tx = pl010_stop_tx,
.start_tx = pl010_start_tx,
.stop_rx = pl010_stop_rx,
.enable_ms = pl010_enable_ms,
.break_ctl = pl010_break_ctl,
.startup = pl010_startup,
.shutdown = pl010_shutdown,
.set_termios = pl010_set_termios,
.type = pl010_type,
.release_port = pl010_release_port,
.request_port = pl010_request_port,
.config_port = pl010_config_port,
.verify_port = pl010_verify_port,
};
static struct uart_amba_port *amba_ports[UART_NR];
#ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
static void pl010_console_putchar(struct uart_port *port, int ch)
{
unsigned int status;
do {
status = readb(port->membase + UART01x_FR);
barrier();
} while (!UART_TX_READY(status));
writel(ch, port->membase + UART01x_DR);
}
static void
pl010_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_port *port = &amba_ports[co->index]->port;
unsigned int status, old_cr;
/*
* First save the CR then disable the interrupts
*/
old_cr = readb(port->membase + UART010_CR);
writel(UART01x_CR_UARTEN, port->membase + UART010_CR);
uart_console_write(port, s, count, pl010_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the TCR
*/
do {
status = readb(port->membase + UART01x_FR);
barrier();
} while (status & UART01x_FR_BUSY);
writel(old_cr, port->membase + UART010_CR);
}
static void __init
pl010_console_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
if (readb(port->membase + UART010_CR) & UART01x_CR_UARTEN) {
unsigned int lcr_h, quot;
lcr_h = readb(port->membase + UART010_LCRH);
*parity = 'n';
if (lcr_h & UART01x_LCRH_PEN) {
if (lcr_h & UART01x_LCRH_EPS)
*parity = 'e';
else
*parity = 'o';
}
if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
*bits = 7;
else
*bits = 8;
quot = readb(port->membase + UART010_LCRL) | readb(port->membase + UART010_LCRM) << 8;
*baud = port->uartclk / (16 * (quot + 1));
}
}
static int __init pl010_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 38400;
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 >= UART_NR)
co->index = 0;
port = &amba_ports[co->index]->port;
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
pl010_console_get_options(port, &baud, &parity, &bits);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver amba_reg;
static struct console amba_console = {
.name = "ttyAM",
.write = pl010_console_write,
.device = uart_console_device,
.setup = pl010_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &amba_reg,
};
#define AMBA_CONSOLE &amba_console
#else
#define AMBA_CONSOLE NULL
#endif
static struct uart_driver amba_reg = {
.owner = THIS_MODULE,
.driver_name = "ttyAM",
.dev_name = "ttyAM",
.major = SERIAL_AMBA_MAJOR,
.minor = SERIAL_AMBA_MINOR,
.nr = UART_NR,
.cons = AMBA_CONSOLE,
};
static int pl010_probe(struct amba_device *dev, void *id)
{
struct uart_amba_port *port;
void __iomem *base;
int i, ret;
for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
if (amba_ports[i] == NULL)
break;
if (i == ARRAY_SIZE(amba_ports)) {
ret = -EBUSY;
goto out;
}
port = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
if (!port) {
ret = -ENOMEM;
goto out;
}
base = ioremap(dev->res.start, PAGE_SIZE);
if (!base) {
ret = -ENOMEM;
goto free;
}
port->port.dev = &dev->dev;
port->port.mapbase = dev->res.start;
port->port.membase = base;
port->port.iotype = UPIO_MEM;
port->port.irq = dev->irq[0];
port->port.uartclk = 14745600;
port->port.fifosize = 16;
port->port.ops = &amba_pl010_pops;
port->port.flags = UPF_BOOT_AUTOCONF;
port->port.line = i;
port->dev = dev;
port->data = dev->dev.platform_data;
amba_ports[i] = port;
amba_set_drvdata(dev, port);
ret = uart_add_one_port(&amba_reg, &port->port);
if (ret) {
amba_set_drvdata(dev, NULL);
amba_ports[i] = NULL;
iounmap(base);
free:
kfree(port);
}
out:
return ret;
}
static int pl010_remove(struct amba_device *dev)
{
struct uart_amba_port *port = amba_get_drvdata(dev);
int i;
amba_set_drvdata(dev, NULL);
uart_remove_one_port(&amba_reg, &port->port);
for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
if (amba_ports[i] == port)
amba_ports[i] = NULL;
iounmap(port->port.membase);
kfree(port);
return 0;
}
static int pl010_suspend(struct amba_device *dev, pm_message_t state)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
if (uap)
uart_suspend_port(&amba_reg, &uap->port);
return 0;
}
static int pl010_resume(struct amba_device *dev)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
if (uap)
uart_resume_port(&amba_reg, &uap->port);
return 0;
}
static struct amba_id pl010_ids[] __initdata = {
{
.id = 0x00041010,
.mask = 0x000fffff,
},
{ 0, 0 },
};
static struct amba_driver pl010_driver = {
.drv = {
.name = "uart-pl010",
},
.id_table = pl010_ids,
.probe = pl010_probe,
.remove = pl010_remove,
.suspend = pl010_suspend,
.resume = pl010_resume,
};
static int __init pl010_init(void)
{
int ret;
printk(KERN_INFO "Serial: AMBA driver $Revision: 1.41 $\n");
ret = uart_register_driver(&amba_reg);
if (ret == 0) {
ret = amba_driver_register(&pl010_driver);
if (ret)
uart_unregister_driver(&amba_reg);
}
return ret;
}
static void __exit pl010_exit(void)
{
amba_driver_unregister(&pl010_driver);
uart_unregister_driver(&amba_reg);
}
module_init(pl010_init);
module_exit(pl010_exit);
MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("ARM AMBA serial port driver $Revision: 1.41 $");
MODULE_LICENSE("GPL");
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