1 files changed, 78 insertions, 43 deletions

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index cac0f0da9203..587545cb7e4c 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -444,25 +444,53 @@ struct mn10300_serial_int mn10300_serial_int_tbl[NR_IRQS];
 
 static void mn10300_serial_dis_tx_intr(struct mn10300_serial_port *port)
 {
-        unsigned long flags;
+        int retries = 100;
         u16 x;
 
-        flags = arch_local_cli_save();
-        *port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-        x = *port->tx_icr;
-        arch_local_irq_restore(flags);
+        /* nothing to do if irq isn't set up */
+        if (!mn10300_serial_int_tbl[port->tx_irq].port)
+                return;
+
+        port->tx_flags |= MNSCx_TX_STOP;
+        mb();
+
+        /*
+         * Here we wait for the irq to be disabled. Either it already is
+         * disabled or we wait some number of retries for the VDMA handler
+         * to disable it. The retries give the VDMA handler enough time to
+         * run to completion if it was already in progress. If the VDMA IRQ
+         * is enabled but the handler is not yet running when arrive here,
+         * the STOP flag will prevent the handler from conflicting with the
+         * driver code following this loop.
+         */
+        while ((*port->tx_icr & GxICR_ENABLE) && retries-- > 0)
+                ;
+        if (retries <= 0) {
+                *port->tx_icr =
+                        NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
+                x = *port->tx_icr;
+        }
 }
 
 static void mn10300_serial_en_tx_intr(struct mn10300_serial_port *port)
 {
-        unsigned long flags;
         u16 x;
 
-        flags = arch_local_cli_save();
+        /* nothing to do if irq isn't set up */
+        if (!mn10300_serial_int_tbl[port->tx_irq].port)
+                return;
+
+        /* stop vdma irq if not already stopped */
+        if (!(port->tx_flags & MNSCx_TX_STOP))
+                mn10300_serial_dis_tx_intr(port);
+
+        port->tx_flags &= ~MNSCx_TX_STOP;
+        mb();
+
         *port->tx_icr =
-                NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) | GxICR_ENABLE;
+                NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) |
+                GxICR_ENABLE | GxICR_REQUEST | GxICR_DETECT;
         x = *port->tx_icr;
-        arch_local_irq_restore(flags);
 }
 
 static void mn10300_serial_dis_rx_intr(struct mn10300_serial_port *port)
@@ -807,8 +835,6 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
         struct mn10300_serial_port *port =
                 container_of(_port, struct mn10300_serial_port, uart);
 
-        u16 x;
-
         _enter("%s{%lu}",
                port->name,
                CIRC_CNT(&port->uart.state->xmit.head,
@@ -816,14 +842,7 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
                         UART_XMIT_SIZE));
 
         /* kick the virtual DMA controller */
-        arch_local_cli();
-        x = *port->tx_icr;
-        x |= GxICR_ENABLE;
-
-        if (*port->_status & SC01STR_TBF)
-                x &= ~(GxICR_REQUEST | GxICR_DETECT);
-        else
-                x |= GxICR_REQUEST | GxICR_DETECT;
+        mn10300_serial_en_tx_intr(port);
 
         _debug("CTR=%04hx ICR=%02hx STR=%04x TMD=%02hx TBR=%04hx ICR=%04hx",
                *port->_control, *port->_intr, *port->_status,
@@ -831,10 +850,6 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
                (port->div_timer == MNSCx_DIV_TIMER_8BIT) ?
                    *(volatile u8 *)port->_tmxbr : *port->_tmxbr,
                *port->tx_icr);
-
-        *port->tx_icr = x;
-        x = *port->tx_icr;
-        arch_local_sti();
 }
 
 /*
@@ -844,13 +859,17 @@ static void mn10300_serial_send_xchar(struct uart_port *_port, char ch)
 {
         struct mn10300_serial_port *port =
                 container_of(_port, struct mn10300_serial_port, uart);
+        unsigned long flags;
 
         _enter("%s,%02x", port->name, ch);
 
         if (likely(port->gdbstub)) {
                 port->tx_xchar = ch;
-                if (ch)
+                if (ch) {
+                        spin_lock_irqsave(&port->uart.lock, flags);
                         mn10300_serial_en_tx_intr(port);
+                        spin_unlock_irqrestore(&port->uart.lock, flags);
+                }
         }
 }
 
@@ -911,18 +930,21 @@ static void mn10300_serial_break_ctl(struct uart_port *_port, int ctl)
 {
         struct mn10300_serial_port *port =
                 container_of(_port, struct mn10300_serial_port, uart);
+        unsigned long flags;
 
         _enter("%s,%d", port->name, ctl);
 
+        spin_lock_irqsave(&port->uart.lock, flags);
         if (ctl) {
                 /* tell the virtual DMA handler to assert BREAK */
-                port->tx_break = 1;
+                port->tx_flags |= MNSCx_TX_BREAK;
                 mn10300_serial_en_tx_intr(port);
         } else {
-                port->tx_break = 0;
+                port->tx_flags &= ~MNSCx_TX_BREAK;
                 *port->_control &= ~SC01CTR_BKE;
                 mn10300_serial_en_tx_intr(port);
         }
+        spin_unlock_irqrestore(&port->uart.lock, flags);
 }
 
 /*
@@ -945,6 +967,7 @@ static int mn10300_serial_startup(struct uart_port *_port)
                 return -ENOMEM;
 
         port->rx_inp = port->rx_outp = 0;
+        port->tx_flags = 0;
 
         /* finally, enable the device */
         *port->_intr = SC01ICR_TI;
@@ -994,14 +1017,22 @@ error:
  */
 static void mn10300_serial_shutdown(struct uart_port *_port)
 {
+        unsigned long flags;
         u16 x;
         struct mn10300_serial_port *port =
                 container_of(_port, struct mn10300_serial_port, uart);
 
         _enter("%s", port->name);
 
+        spin_lock_irqsave(&_port->lock, flags);
+        mn10300_serial_dis_tx_intr(port);
+
+        *port->rx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
+        x = *port->rx_icr;
+        port->tx_flags = 0;
+        spin_unlock_irqrestore(&_port->lock, flags);
+
         /* disable the serial port and its baud rate timer */
-        port->tx_break = 0;
         *port->_control &= ~(SC01CTR_TXE | SC01CTR_RXE | SC01CTR_BKE);
         *port->_tmxmd = 0;
 
@@ -1016,12 +1047,8 @@ static void mn10300_serial_shutdown(struct uart_port *_port)
         free_irq(port->rx_irq, port);
         free_irq(port->tx_irq, port);
 
-        arch_local_cli();
-        *port->rx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-        x = *port->rx_icr;
-        *port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-        x = *port->tx_icr;
-        arch_local_sti();
+        mn10300_serial_int_tbl[port->tx_irq].port = NULL;
+        mn10300_serial_int_tbl[port->rx_irq].port = NULL;
 }
 
 /*
@@ -1549,17 +1576,24 @@ static void mn10300_serial_console_write(struct console *co,
 {
         struct mn10300_serial_port *port;
         unsigned i;
-        u16 scxctr, txicr, tmp;
+        u16 scxctr;
         u8 tmxmd;
+        unsigned long flags;
+        int locked = 1;
 
         port = mn10300_serial_ports[co->index];
 
+        local_irq_save(flags);
+        if (port->uart.sysrq) {
+                /* mn10300_serial_interrupt() already took the lock */
+                locked = 0;
+        } else if (oops_in_progress) {
+                locked = spin_trylock(&port->uart.lock);
+        } else
+                spin_lock(&port->uart.lock);
+
         /* firstly hijack the serial port from the "virtual DMA" controller */
-        arch_local_cli();
-        txicr = *port->tx_icr;
-        *port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-        tmp = *port->tx_icr;
-        arch_local_sti();
+        mn10300_serial_dis_tx_intr(port);
 
         /* the transmitter may be disabled */
         scxctr = *port->_control;
@@ -1613,10 +1647,11 @@ static void mn10300_serial_console_write(struct console *co,
         if (!(scxctr & SC01CTR_TXE))
                 *port->_control = scxctr;
 
-        arch_local_cli();
-        *port->tx_icr = txicr;
-        tmp = *port->tx_icr;
-        arch_local_sti();
+        mn10300_serial_en_tx_intr(port);
+
+        if (locked)
+                spin_unlock(&port->uart.lock);
+        local_irq_restore(flags);
 }
 
 /*