linux/drivers/serial/clps711x.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

583 lines
13 KiB
C

/*
* linux/drivers/char/clps711x.c
*
* Driver for CLPS711x 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: clps711x.c,v 1.42 2002/07/28 10:03:28 rmk Exp $
*
*/
#if defined(CONFIG_SERIAL_CLPS711X_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/spinlock.h>
#include <linux/device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware/clps7111.h>
#define UART_NR 2
#define SERIAL_CLPS711X_MAJOR 204
#define SERIAL_CLPS711X_MINOR 40
#define SERIAL_CLPS711X_NR UART_NR
/*
* We use the relevant SYSCON register as a base address for these ports.
*/
#define UBRLCR(port) ((port)->iobase + UBRLCR1 - SYSCON1)
#define UARTDR(port) ((port)->iobase + UARTDR1 - SYSCON1)
#define SYSFLG(port) ((port)->iobase + SYSFLG1 - SYSCON1)
#define SYSCON(port) ((port)->iobase + SYSCON1 - SYSCON1)
#define TX_IRQ(port) ((port)->irq)
#define RX_IRQ(port) ((port)->irq + 1)
#define UART_ANY_ERR (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)
#define tx_enabled(port) ((port)->unused[0])
static void clps711xuart_stop_tx(struct uart_port *port)
{
if (tx_enabled(port)) {
disable_irq(TX_IRQ(port));
tx_enabled(port) = 0;
}
}
static void clps711xuart_start_tx(struct uart_port *port)
{
if (!tx_enabled(port)) {
enable_irq(TX_IRQ(port));
tx_enabled(port) = 1;
}
}
static void clps711xuart_stop_rx(struct uart_port *port)
{
disable_irq(RX_IRQ(port));
}
static void clps711xuart_enable_ms(struct uart_port *port)
{
}
static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
struct tty_struct *tty = port->info->tty;
unsigned int status, ch, flg;
status = clps_readl(SYSFLG(port));
while (!(status & SYSFLG_URXFE)) {
ch = clps_readl(UARTDR(port));
port->icount.rx++;
flg = TTY_NORMAL;
/*
* Note that the error handling code is
* out of the main execution path
*/
if (unlikely(ch & UART_ANY_ERR)) {
if (ch & UARTDR_PARERR)
port->icount.parity++;
else if (ch & UARTDR_FRMERR)
port->icount.frame++;
if (ch & UARTDR_OVERR)
port->icount.overrun++;
ch &= port->read_status_mask;
if (ch & UARTDR_PARERR)
flg = TTY_PARITY;
else if (ch & UARTDR_FRMERR)
flg = TTY_FRAME;
#ifdef SUPPORT_SYSRQ
port->sysrq = 0;
#endif
}
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
/*
* CHECK: does overrun affect the current character?
* ASSUMPTION: it does not.
*/
uart_insert_char(port, ch, UARTDR_OVERR, ch, flg);
ignore_char:
status = clps_readl(SYSFLG(port));
}
tty_flip_buffer_push(tty);
return IRQ_HANDLED;
}
static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
{
struct uart_port *port = dev_id;
struct circ_buf *xmit = &port->info->xmit;
int count;
if (port->x_char) {
clps_writel(port->x_char, UARTDR(port));
port->icount.tx++;
port->x_char = 0;
return IRQ_HANDLED;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
clps711xuart_stop_tx(port);
return IRQ_HANDLED;
}
count = port->fifosize >> 1;
do {
clps_writel(xmit->buf[xmit->tail], UARTDR(port));
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))
clps711xuart_stop_tx(port);
return IRQ_HANDLED;
}
static unsigned int clps711xuart_tx_empty(struct uart_port *port)
{
unsigned int status = clps_readl(SYSFLG(port));
return status & SYSFLG_UBUSY ? 0 : TIOCSER_TEMT;
}
static unsigned int clps711xuart_get_mctrl(struct uart_port *port)
{
unsigned int port_addr;
unsigned int result = 0;
unsigned int status;
port_addr = SYSFLG(port);
if (port_addr == SYSFLG1) {
status = clps_readl(SYSFLG1);
if (status & SYSFLG1_DCD)
result |= TIOCM_CAR;
if (status & SYSFLG1_DSR)
result |= TIOCM_DSR;
if (status & SYSFLG1_CTS)
result |= TIOCM_CTS;
}
return result;
}
static void
clps711xuart_set_mctrl_null(struct uart_port *port, unsigned int mctrl)
{
}
static void clps711xuart_break_ctl(struct uart_port *port, int break_state)
{
unsigned long flags;
unsigned int ubrlcr;
spin_lock_irqsave(&port->lock, flags);
ubrlcr = clps_readl(UBRLCR(port));
if (break_state == -1)
ubrlcr |= UBRLCR_BREAK;
else
ubrlcr &= ~UBRLCR_BREAK;
clps_writel(ubrlcr, UBRLCR(port));
spin_unlock_irqrestore(&port->lock, flags);
}
static int clps711xuart_startup(struct uart_port *port)
{
unsigned int syscon;
int retval;
tx_enabled(port) = 1;
/*
* Allocate the IRQs
*/
retval = request_irq(TX_IRQ(port), clps711xuart_int_tx, 0,
"clps711xuart_tx", port);
if (retval)
return retval;
retval = request_irq(RX_IRQ(port), clps711xuart_int_rx, 0,
"clps711xuart_rx", port);
if (retval) {
free_irq(TX_IRQ(port), port);
return retval;
}
/*
* enable the port
*/
syscon = clps_readl(SYSCON(port));
syscon |= SYSCON_UARTEN;
clps_writel(syscon, SYSCON(port));
return 0;
}
static void clps711xuart_shutdown(struct uart_port *port)
{
unsigned int ubrlcr, syscon;
/*
* Free the interrupt
*/
free_irq(TX_IRQ(port), port); /* TX interrupt */
free_irq(RX_IRQ(port), port); /* RX interrupt */
/*
* disable the port
*/
syscon = clps_readl(SYSCON(port));
syscon &= ~SYSCON_UARTEN;
clps_writel(syscon, SYSCON(port));
/*
* disable break condition and fifos
*/
ubrlcr = clps_readl(UBRLCR(port));
ubrlcr &= ~(UBRLCR_FIFOEN | UBRLCR_BREAK);
clps_writel(ubrlcr, UBRLCR(port));
}
static void
clps711xuart_set_termios(struct uart_port *port, struct termios *termios,
struct termios *old)
{
unsigned int ubrlcr, baud, quot;
unsigned long flags;
/*
* We don't implement CREAD.
*/
termios->c_cflag |= CREAD;
/*
* 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:
ubrlcr = UBRLCR_WRDLEN5;
break;
case CS6:
ubrlcr = UBRLCR_WRDLEN6;
break;
case CS7:
ubrlcr = UBRLCR_WRDLEN7;
break;
default: // CS8
ubrlcr = UBRLCR_WRDLEN8;
break;
}
if (termios->c_cflag & CSTOPB)
ubrlcr |= UBRLCR_XSTOP;
if (termios->c_cflag & PARENB) {
ubrlcr |= UBRLCR_PRTEN;
if (!(termios->c_cflag & PARODD))
ubrlcr |= UBRLCR_EVENPRT;
}
if (port->fifosize > 1)
ubrlcr |= UBRLCR_FIFOEN;
spin_lock_irqsave(&port->lock, flags);
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = UARTDR_OVERR;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UARTDR_PARERR | UARTDR_FRMERR;
/*
* Characters to ignore
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UARTDR_FRMERR | UARTDR_PARERR;
if (termios->c_iflag & IGNBRK) {
/*
* If we're ignoring parity and break indicators,
* ignore overruns to (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UARTDR_OVERR;
}
quot -= 1;
clps_writel(ubrlcr | quot, UBRLCR(port));
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *clps711xuart_type(struct uart_port *port)
{
return port->type == PORT_CLPS711X ? "CLPS711x" : NULL;
}
/*
* Configure/autoconfigure the port.
*/
static void clps711xuart_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE)
port->type = PORT_CLPS711X;
}
static void clps711xuart_release_port(struct uart_port *port)
{
}
static int clps711xuart_request_port(struct uart_port *port)
{
return 0;
}
static struct uart_ops clps711x_pops = {
.tx_empty = clps711xuart_tx_empty,
.set_mctrl = clps711xuart_set_mctrl_null,
.get_mctrl = clps711xuart_get_mctrl,
.stop_tx = clps711xuart_stop_tx,
.start_tx = clps711xuart_start_tx,
.stop_rx = clps711xuart_stop_rx,
.enable_ms = clps711xuart_enable_ms,
.break_ctl = clps711xuart_break_ctl,
.startup = clps711xuart_startup,
.shutdown = clps711xuart_shutdown,
.set_termios = clps711xuart_set_termios,
.type = clps711xuart_type,
.config_port = clps711xuart_config_port,
.release_port = clps711xuart_release_port,
.request_port = clps711xuart_request_port,
};
static struct uart_port clps711x_ports[UART_NR] = {
{
.iobase = SYSCON1,
.irq = IRQ_UTXINT1, /* IRQ_URXINT1, IRQ_UMSINT */
.uartclk = 3686400,
.fifosize = 16,
.ops = &clps711x_pops,
.line = 0,
.flags = UPF_BOOT_AUTOCONF,
},
{
.iobase = SYSCON2,
.irq = IRQ_UTXINT2, /* IRQ_URXINT2 */
.uartclk = 3686400,
.fifosize = 16,
.ops = &clps711x_pops,
.line = 1,
.flags = UPF_BOOT_AUTOCONF,
}
};
#ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
static void clps711xuart_console_putchar(struct uart_port *port, int ch)
{
while (clps_readl(SYSFLG(port)) & SYSFLG_UTXFF)
barrier();
clps_writel(ch, UARTDR(port));
}
/*
* Print a string to the serial port trying not to disturb
* any possible real use of the port...
*
* The console_lock must be held when we get here.
*
* Note that this is called with interrupts already disabled
*/
static void
clps711xuart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = clps711x_ports + co->index;
unsigned int status, syscon;
/*
* Ensure that the port is enabled.
*/
syscon = clps_readl(SYSCON(port));
clps_writel(syscon | SYSCON_UARTEN, SYSCON(port));
uart_console_write(port, s, count, clps711xuart_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the uart state.
*/
do {
status = clps_readl(SYSFLG(port));
} while (status & SYSFLG_UBUSY);
clps_writel(syscon, SYSCON(port));
}
static void __init
clps711xuart_console_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
if (clps_readl(SYSCON(port)) & SYSCON_UARTEN) {
unsigned int ubrlcr, quot;
ubrlcr = clps_readl(UBRLCR(port));
*parity = 'n';
if (ubrlcr & UBRLCR_PRTEN) {
if (ubrlcr & UBRLCR_EVENPRT)
*parity = 'e';
else
*parity = 'o';
}
if ((ubrlcr & UBRLCR_WRDLEN_MASK) == UBRLCR_WRDLEN7)
*bits = 7;
else
*bits = 8;
quot = ubrlcr & UBRLCR_BAUD_MASK;
*baud = port->uartclk / (16 * (quot + 1));
}
}
static int __init clps711xuart_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.
*/
port = uart_get_console(clps711x_ports, UART_NR, co);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
clps711xuart_console_get_options(port, &baud, &parity, &bits);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver clps711x_reg;
static struct console clps711x_console = {
.name = "ttyCL",
.write = clps711xuart_console_write,
.device = uart_console_device,
.setup = clps711xuart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &clps711x_reg,
};
static int __init clps711xuart_console_init(void)
{
register_console(&clps711x_console);
return 0;
}
console_initcall(clps711xuart_console_init);
#define CLPS711X_CONSOLE &clps711x_console
#else
#define CLPS711X_CONSOLE NULL
#endif
static struct uart_driver clps711x_reg = {
.driver_name = "ttyCL",
.dev_name = "ttyCL",
.major = SERIAL_CLPS711X_MAJOR,
.minor = SERIAL_CLPS711X_MINOR,
.nr = UART_NR,
.cons = CLPS711X_CONSOLE,
};
static int __init clps711xuart_init(void)
{
int ret, i;
printk(KERN_INFO "Serial: CLPS711x driver $Revision: 1.42 $\n");
ret = uart_register_driver(&clps711x_reg);
if (ret)
return ret;
for (i = 0; i < UART_NR; i++)
uart_add_one_port(&clps711x_reg, &clps711x_ports[i]);
return 0;
}
static void __exit clps711xuart_exit(void)
{
int i;
for (i = 0; i < UART_NR; i++)
uart_remove_one_port(&clps711x_reg, &clps711x_ports[i]);
uart_unregister_driver(&clps711x_reg);
}
module_init(clps711xuart_init);
module_exit(clps711xuart_exit);
MODULE_AUTHOR("Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("CLPS-711x generic serial driver $Revision: 1.42 $");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV(SERIAL_CLPS711X_MAJOR, SERIAL_CLPS711X_MINOR);