Subject: serial: Add a polled interface to the 8250 driver
Remove the console code from the 8250 driver and add the poll code and
setup to use the console over the polled interface.
Signed-off-by: Corey Minyard <minyard@xxxxxxx>
drivers/serial/8250.c | 220 +++++++++++++++++++++++++-------------------------
1 file changed, 112 insertions(+), 108 deletions(-)
Index: linux-2.6.21/drivers/serial/8250.c
===================================================================
--- linux-2.6.21.orig/drivers/serial/8250.c
+++ linux-2.6.21/drivers/serial/8250.c
@@ -1549,9 +1549,14 @@ static unsigned int serial8250_tx_empty(
struct uart_8250_port *up = (struct uart_8250_port *)port;
unsigned long flags;
unsigned int ret;
+ unsigned int status;
spin_lock_irqsave(&up->port.lock, flags);
- ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+ status = serial_in(up, UART_LSR);
+ /* If we see a break, record it for the serial console */
+ if (status & UART_LSR_BI)
+ up->lsr_break_flag = UART_LSR_BI;
+ ret = status & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
spin_unlock_irqrestore(&up->port.lock, flags);
return ret;
@@ -1612,8 +1617,6 @@ static void serial8250_break_ctl(struct
spin_unlock_irqrestore(&up->port.lock, flags);
}
-#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
-
/*
* Wait for transmitter & holding register to empty
*/
@@ -2264,6 +2267,72 @@ serial8250_type(struct uart_port *port)
return uart_config[type].name;
}
+static unsigned int serial8250_poll(struct uart_port *port, unsigned int flags)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *)port;
+ unsigned int status;
+ unsigned int rv = 0;
+
+ status = serial_inp(up, UART_LSR);
+
+ if ((flags & UART_POLL_FLAGS_RX) && (status & UART_LSR_DR)) {
+ if (receive_chars(up, &status))
+ rv |= UART_POLL_RETFLAGS_RX;
+ }
+ if (flags & UART_POLL_FLAGS_MCTRL) {
+ if (check_modem_status(up, NULL))
+ rv |= UART_POLL_RETFLAGS_MCTRL;
+ }
+ if ((flags & UART_POLL_FLAGS_TX) && (status & UART_LSR_THRE)) {
+ struct circ_buf *xmit = uart_get_circ_buf(&up->port);
+
+ if (uart_circ_empty(xmit))
+ goto out;
+
+ do {
+ serial_out(up, UART_TX, xmit->buf[xmit->tail]);
+ xmit->tail = uart_wrap_circ_buf(xmit->tail + 1);
+ up->port.icount.tx++;
+ if (uart_circ_empty(xmit))
+ break;
+ status = serial_inp(up, UART_LSR);
+ } while (status & UART_LSR_THRE);
+ }
+
+ out:
+ return rv;
+}
+
+static int serial8250_poll_startup(struct uart_port *port,
+ unsigned long *pflags)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *) port;
+
+ *pflags = serial_in(up, UART_IER);
+
+ if (up->capabilities & UART_CAP_UUE)
+ serial_out(up, UART_IER, UART_IER_UUE);
+ else
+ serial_out(up, UART_IER, 0);
+
+ return 0;
+}
+
+static void serial8250_poll_shutdown(struct uart_port *port,
+ unsigned long pflags)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *) port;
+
+ serial_out(up, UART_IER, pflags);
+}
+
+int serial8250_in_flow_control(struct uart_port *port)
+{
+ struct uart_8250_port *up = (struct uart_8250_port *) port;
+
+ return !(serial_in(up, UART_MSR) & UART_MSR_CTS);
+}
+
static struct uart_ops serial8250_pops = {
.tx_empty = serial8250_tx_empty,
.set_mctrl = serial8250_set_mctrl,
@@ -2277,6 +2346,10 @@ static struct uart_ops serial8250_pops =
.shutdown = serial8250_shutdown,
.set_termios = serial8250_set_termios,
.pm = serial8250_pm,
+ .poll = serial8250_poll,
+ .poll_startup = serial8250_poll_startup,
+ .poll_shutdown = serial8250_poll_shutdown,
+ .in_flow_control= serial8250_in_flow_control,
.type = serial8250_type,
.release_port = serial8250_release_port,
.request_port = serial8250_request_port,
@@ -2285,6 +2358,7 @@ static struct uart_ops serial8250_pops =
};
static struct uart_8250_port serial8250_ports[UART_NR];
+static struct uart_port *serial8250_pollable_ports[UART_NR];
static void __init serial8250_isa_init_ports(void)
{
@@ -2346,108 +2420,10 @@ serial8250_register_ports(struct uart_dr
}
#ifdef CONFIG_SERIAL_8250_CONSOLE
-
-static void serial8250_console_putchar(struct uart_port *port, int ch)
-{
- struct uart_8250_port *up = (struct uart_8250_port *)port;
-
- wait_for_xmitr(up, UART_LSR_THRE);
- serial_out(up, UART_TX, ch);
-}
-
-/*
- * 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.
- */
-static void
-serial8250_console_write(struct console *co, const char *s, unsigned int count)
-{
- struct uart_8250_port *up = &serial8250_ports[co->index];
- unsigned long flags;
- unsigned int ier;
- int locked = 1;
-
- touch_nmi_watchdog();
-
- local_irq_save(flags);
- if (up->port.sysrq) {
- /* serial8250_handle_port() already took the lock */
- locked = 0;
- } else if (oops_in_progress) {
- locked = spin_trylock(&up->port.lock);
- } else
- spin_lock(&up->port.lock);
-
- /*
- * First save the IER then disable the interrupts
- */
- ier = serial_in(up, UART_IER);
-
- if (up->capabilities & UART_CAP_UUE)
- serial_out(up, UART_IER, UART_IER_UUE);
- else
- serial_out(up, UART_IER, 0);
-
- uart_console_write(&up->port, s, count, serial8250_console_putchar);
-
- /*
- * Finally, wait for transmitter to become empty
- * and restore the IER
- */
- wait_for_xmitr(up, BOTH_EMPTY);
- serial_out(up, UART_IER, ier);
-
- if (locked)
- spin_unlock(&up->port.lock);
- local_irq_restore(flags);
-}
-
-static int __init serial8250_console_setup(struct console *co, char *options)
-{
- struct uart_port *port;
- 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 >= nr_uarts)
- co->index = 0;
- port = &serial8250_ports[co->index].port;
- if (!port->iobase && !port->membase)
- return -ENODEV;
-
- if (options)
- uart_parse_options(options, &baud, &parity, &bits, &flow);
-
- return uart_set_options(port, co, baud, parity, bits, flow);
-}
-
-static struct uart_driver serial8250_reg;
static struct console serial8250_console = {
- .name = "ttyS",
- .write = serial8250_console_write,
- .device = uart_console_device,
- .setup = serial8250_console_setup,
- .flags = CON_PRINTBUFFER,
- .index = -1,
- .data = &serial8250_reg,
+ .name = "ttyS"
};
-static int __init serial8250_console_init(void)
-{
- serial8250_isa_init_ports();
- register_console(&serial8250_console);
- return 0;
-}
-console_initcall(serial8250_console_init);
-
static int __init find_port(struct uart_port *p)
{
int line;
@@ -2496,6 +2472,36 @@ static struct uart_driver serial8250_reg
.cons = SERIAL8250_CONSOLE,
};
+static int __init serial8250_polled_init(void)
+{
+ int i;
+ static int initialized = 0;
+
+ if (initialized)
+ return 0;
+ initialized = 1;
+
+ if (nr_uarts > UART_NR)
+ nr_uarts = UART_NR;
+
+ serial8250_isa_init_ports();
+
+ for (i = 0; i < NR_IRQS; i++)
+ spin_lock_init(&irq_lists[i].lock);
+
+ for (i = 0; i < nr_uarts; i++) {
+ serial8250_ports[i].port.ops = &serial8250_pops;
+ serial8250_pollable_ports[i] = &serial8250_ports[i].port;
+ }
+ serial8250_reg.pollable_ports = serial8250_pollable_ports;
+ serial8250_reg.nr_pollable = nr_uarts;
+
+ uart_register_polled(&serial8250_reg);
+
+ return 0;
+}
+console_initcall(serial8250_polled_init);
+
/*
* early_serial_setup - early registration for 8250 ports
*
@@ -2747,17 +2753,13 @@ EXPORT_SYMBOL(serial8250_unregister_port
static int __init serial8250_init(void)
{
- int ret, i;
-
- if (nr_uarts > UART_NR)
- nr_uarts = UART_NR;
+ int ret;
printk(KERN_INFO "Serial: 8250/16550 driver $Revision: 1.90 $ "
"%d ports, IRQ sharing %sabled\n", nr_uarts,
share_irqs ? "en" : "dis");
- for (i = 0; i < NR_IRQS; i++)
- spin_lock_init(&irq_lists[i].lock);
+ serial8250_polled_init();
ret = uart_register_driver(&serial8250_reg);
if (ret)
@@ -2804,6 +2806,8 @@ static void __exit serial8250_exit(void)
platform_device_unregister(isa_dev);
uart_unregister_driver(&serial8250_reg);
+
+ uart_unregister_polled(&serial8250_reg);
}
module_init(serial8250_init);
-
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