Merge omap-upstream

[linux-2.6-omap-h63xx.git] / drivers / serial / 8250.c

diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c
index 8e2e57add67a820c997688ec88323f86c97b67f3..a235711fd02ac6765e2dd67256c8b993260217d2 100644 (file)
--- a/drivers/serial/8250.c
+++ b/drivers/serial/8250.c
@@ -129,7 +129,16 @@ struct uart_8250_port {
        unsigned char           mcr;
        unsigned char           mcr_mask;       /* mask of user bits */
        unsigned char           mcr_force;      /* mask of forced bits */
-       unsigned char           lsr_break_flag;
+
+       /*
+        * Some bits in registers are cleared on a read, so they must
+        * be saved whenever the register is read but the bits will not
+        * be immediately processed.
+        */
+#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
+       unsigned char           lsr_saved_flags;
+#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
+       unsigned char           msr_saved_flags;
 
        /*
         * We provide a per-port pm hook.
@@ -1238,6 +1247,7 @@ static void serial8250_start_tx(struct uart_port *port)
                if (up->bugs & UART_BUG_TXEN) {
                        unsigned char lsr, iir;
                        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 &&
@@ -1290,18 +1300,10 @@ receive_chars(struct uart_8250_port *up, unsigned int *status)
                flag = TTY_NORMAL;
                up->port.icount.rx++;
 
-#ifdef CONFIG_SERIAL_8250_CONSOLE
-               /*
-                * Recover the break flag from console xmit
-                */
-               if (up->port.line == up->port.cons->index) {
-                       lsr |= up->lsr_break_flag;
-                       up->lsr_break_flag = 0;
-               }
-#endif
+               lsr |= up->lsr_saved_flags;
+               up->lsr_saved_flags = 0;
 
-               if (unlikely(lsr & (UART_LSR_BI | UART_LSR_PE |
-                                   UART_LSR_FE | UART_LSR_OE))) {
+               if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
                        /*
                         * For statistics only
                         */
@@ -1392,6 +1394,8 @@ static unsigned int check_modem_status(struct uart_8250_port *up)
 {
        unsigned int status = serial_in(up, UART_MSR);
 
+       status |= up->msr_saved_flags;
+       up->msr_saved_flags = 0;
        if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
            up->port.info != NULL) {
                if (status & UART_MSR_TERI)
@@ -1595,7 +1599,8 @@ static void serial8250_timeout(unsigned long data)
 static void serial8250_backup_timeout(unsigned long data)
 {
        struct uart_8250_port *up = (struct uart_8250_port *)data;
-       unsigned int iir, ier = 0;
+       unsigned int iir, ier = 0, lsr;
+       unsigned long flags;
 
        /*
         * Must disable interrupts or else we risk racing with the interrupt
@@ -1614,9 +1619,13 @@ static void serial8250_backup_timeout(unsigned long data)
         * the "Diva" UART used on the management processor on many HP
         * ia64 and parisc boxes.
         */
+       spin_lock_irqsave(&up->port.lock, flags);
+       lsr = serial_in(up, UART_LSR);
+       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+       spin_unlock_irqrestore(&up->port.lock, flags);
        if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
            (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) &&
-           (serial_in(up, UART_LSR) & UART_LSR_THRE)) {
+           (lsr & UART_LSR_THRE)) {
                iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
                iir |= UART_IIR_THRI;
        }
@@ -1635,13 +1644,14 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
 {
        struct uart_8250_port *up = (struct uart_8250_port *)port;
        unsigned long flags;
-       unsigned int ret;
+       unsigned int lsr;
 
        spin_lock_irqsave(&up->port.lock, flags);
-       ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+       lsr = serial_in(up, UART_LSR);
+       up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
        spin_unlock_irqrestore(&up->port.lock, flags);
 
-       return ret;
+       return lsr & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
 }
 
 static unsigned int serial8250_get_mctrl(struct uart_port *port)
@@ -1712,8 +1722,7 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
        do {
                status = serial_in(up, UART_LSR);
 
-               if (status & UART_LSR_BI)
-                       up->lsr_break_flag = UART_LSR_BI;
+               up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
 
                if (--tmout == 0)
                        break;
@@ -1722,8 +1731,12 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits)
 
        /* Wait up to 1s for flow control if necessary */
        if (up->port.flags & UPF_CONS_FLOW) {
-               tmout = 1000000;
-               while (!(serial_in(up, UART_MSR) & UART_MSR_CTS) && --tmout) {
+               unsigned int tmout;
+               for (tmout = 1000000; tmout; tmout--) {
+                       unsigned int msr = serial_in(up, UART_MSR);
+                       up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
+                       if (msr & UART_MSR_CTS)
+                               break;
                        udelay(1);
                        touch_nmi_watchdog();
                }
@@ -1892,6 +1905,18 @@ static int serial8250_startup(struct uart_port *port)
 
        spin_unlock_irqrestore(&up->port.lock, flags);
 
+       /*
+        * Clear the interrupt registers again for luck, and clear the
+        * saved flags to avoid getting false values from polling
+        * routines or the previous session.
+        */
+       serial_inp(up, UART_LSR);
+       serial_inp(up, UART_RX);
+       serial_inp(up, UART_IIR);
+       serial_inp(up, UART_MSR);
+       up->lsr_saved_flags = 0;
+       up->msr_saved_flags = 0;
+
        /*
         * Finally, enable interrupts.  Note: Modem status interrupts
         * are set via set_termios(), which will be occurring imminently
@@ -1910,14 +1935,6 @@ static int serial8250_startup(struct uart_port *port)
                (void) inb_p(icp);
        }
 
-       /*
-        * And clear the interrupt registers again for luck.
-        */
-       (void) serial_inp(up, UART_LSR);
-       (void) serial_inp(up, UART_RX);
-       (void) serial_inp(up, UART_IIR);
-       (void) serial_inp(up, UART_MSR);
-
        return 0;
 }
 
@@ -2506,6 +2523,16 @@ serial8250_console_write(struct console *co, const char *s, unsigned int count)
        wait_for_xmitr(up, BOTH_EMPTY);
        serial_out(up, UART_IER, ier);
 
+       /*
+        *      The receive handling will happen properly because the
+        *      receive ready bit will still be set; it is not cleared
+        *      on read.  However, modem control will not, we must
+        *      call it if we have saved something in the saved flags
+        *      while processing with interrupts off.
+        */
+       if (up->msr_saved_flags)
+               check_modem_status(up);
+
        if (locked)
                spin_unlock(&up->port.lock);
        local_irq_restore(flags);