Serial: Do not read IIR in serial8250_start_tx when UART_BUG_TXEN

[safe/jmp/linux-2.6] / drivers / serial / 8250.c

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 2209620..c3e37c8 100644 (file)
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -64,6 +64,8 @@ static int serial_index(struct uart_port *port)
        return (serial8250_reg.minor - 64) + port->line;
 }
 
+static unsigned int skip_txen_test; /* force skip of txen test at init time */
+
 /*
  * Debugging.
  */
@@ -1087,7 +1089,7 @@ static void autoconfig(struct uart_8250_port *up, unsigned int probeflags)
        if (!up->port.iobase && !up->port.mapbase && !up->port.membase)
                return;
 
-       DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04x, 0x%p): ",
+       DEBUG_AUTOCONF("ttyS%d: autoconf (0x%04lx, 0x%p): ",
                       serial_index(&up->port), up->port.iobase, up->port.membase);
 
        /*
@@ -1337,14 +1339,12 @@ static void serial8250_start_tx(struct uart_port *port)
                serial_out(up, UART_IER, up->ier);
 
                if (up->bugs & UART_BUG_TXEN) {
-                       unsigned char lsr, iir;
+                       unsigned char lsr;
                        lsr = serial_in(up, UART_LSR);
                        up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
-                       iir = serial_in(up, UART_IIR) & 0x0f;
                        if ((up->port.type == PORT_RM9000) ?
-                               (lsr & UART_LSR_THRE &&
-                               (iir == UART_IIR_NO_INT || iir == UART_IIR_THRI)) :
-                               (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT))
+                               (lsr & UART_LSR_THRE) :
+                               (lsr & UART_LSR_TEMT))
                                transmit_chars(up);
                }
        }
@@ -2108,7 +2108,7 @@ static int serial8250_startup(struct uart_port *port)
           is variable. So, let's just don't test if we receive
           TX irq. This way, we'll never enable UART_BUG_TXEN.
         */
-       if (up->port.flags & UPF_NO_TXEN_TEST)
+       if (skip_txen_test || up->port.flags & UPF_NO_TXEN_TEST)
                goto dont_test_tx_en;
 
        /*
@@ -2644,7 +2644,7 @@ static void __init serial8250_isa_init_ports(void)
 {
        struct uart_8250_port *up;
        static int first = 1;
-       int i;
+       int i, irqflag = 0;
 
        if (!first)
                return;
@@ -2668,6 +2668,9 @@ static void __init serial8250_isa_init_ports(void)
                up->port.ops = &serial8250_pops;
        }
 
+       if (share_irqs)
+               irqflag = IRQF_SHARED;
+
        for (i = 0, up = serial8250_ports;
             i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
             i++, up++) {
@@ -2681,8 +2684,7 @@ static void __init serial8250_isa_init_ports(void)
                up->port.iotype   = old_serial_port[i].io_type;
                up->port.regshift = old_serial_port[i].iomem_reg_shift;
                set_io_from_upio(&up->port);
-               if (share_irqs)
-                       up->port.irqflags |= IRQF_SHARED;
+               up->port.irqflags |= irqflag;
        }
 }
 
@@ -2938,10 +2940,13 @@ static int __devinit serial8250_probe(struct platform_device *dev)
 {
        struct plat_serial8250_port *p = dev->dev.platform_data;
        struct uart_port port;
-       int ret, i;
+       int ret, i, irqflag = 0;
 
        memset(&port, 0, sizeof(struct uart_port));
 
+       if (share_irqs)
+               irqflag = IRQF_SHARED;
+
        for (i = 0; p && p->flags != 0; p++, i++) {
                port.iobase             = p->iobase;
                port.membase            = p->membase;
@@ -2958,8 +2963,7 @@ static int __devinit serial8250_probe(struct platform_device *dev)
                port.serial_in          = p->serial_in;
                port.serial_out         = p->serial_out;
                port.dev                = &dev->dev;
-               if (share_irqs)
-                       port.irqflags |= IRQF_SHARED;
+               port.irqflags           |= irqflag;
                ret = serial8250_register_port(&port);
                if (ret < 0) {
                        dev_err(&dev->dev, "unable to register port at index %d "
@@ -3248,6 +3252,9 @@ MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices"
 module_param(nr_uarts, uint, 0644);
 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
 
+module_param(skip_txen_test, uint, 0644);
+MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
+
 #ifdef CONFIG_SERIAL_8250_RSA
 module_param_array(probe_rsa, ulong, &probe_rsa_count, 0444);
 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");