1 files changed, 28 insertions, 2 deletions

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index 9ae024025ff3..6800f5f26241 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -159,6 +159,7 @@ struct uart_amba_port {
         unsigned int            fifosize;       /* vendor-specific */
         unsigned int            lcrh_tx;        /* vendor-specific */
         unsigned int            lcrh_rx;        /* vendor-specific */
+        unsigned int            old_cr;         /* state during shutdown */
         bool                    autorts;
         char                    type[12];
         bool                    interrupt_may_hang; /* vendor-specific */
@@ -1411,7 +1412,9 @@ static int pl011_startup(struct uart_port *port)
         while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
                 barrier();
 
-        cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
+        /* restore RTS and DTR */
+        cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
+        cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
         writew(cr, uap->port.membase + UART011_CR);
 
         /* Clear pending error interrupts */
@@ -1469,6 +1472,7 @@ static void pl011_shutdown_channel(struct uart_amba_port *uap,
 static void pl011_shutdown(struct uart_port *port)
 {
         struct uart_amba_port *uap = (struct uart_amba_port *)port;
+        unsigned int cr;
 
         /*
          * disable all interrupts
@@ -1488,9 +1492,16 @@ static void pl011_shutdown(struct uart_port *port)
 
         /*
          * disable the port
+         * disable the port. It should not disable RTS and DTR.
+         * Also RTS and DTR state should be preserved to restore
+         * it during startup().
          */
         uap->autorts = false;
-        writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR);
+        cr = readw(uap->port.membase + UART011_CR);
+        uap->old_cr = cr;
+        cr &= UART011_CR_RTS | UART011_CR_DTR;
+        cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
+        writew(cr, uap->port.membase + UART011_CR);
 
         /*
          * disable break condition and fifos
@@ -1740,9 +1751,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 {
         struct uart_amba_port *uap = amba_ports[co->index];
         unsigned int status, old_cr, new_cr;
+        unsigned long flags;
+        int locked = 1;
 
         clk_enable(uap->clk);
 
+        local_irq_save(flags);
+        if (uap->port.sysrq)
+                locked = 0;
+        else if (oops_in_progress)
+                locked = spin_trylock(&uap->port.lock);
+        else
+                spin_lock(&uap->port.lock);
+
         /*
          *      First save the CR then disable the interrupts
          */
@@ -1762,6 +1783,10 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
         } while (status & UART01x_FR_BUSY);
         writew(old_cr, uap->port.membase + UART011_CR);
 
+        if (locked)
+                spin_unlock(&uap->port.lock);
+        local_irq_restore(flags);
+
         clk_disable(uap->clk);
 }
 
@@ -1905,6 +1930,7 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
         uap->vendor = vendor;
         uap->lcrh_rx = vendor->lcrh_rx;
         uap->lcrh_tx = vendor->lcrh_tx;
+        uap->old_cr = 0;
         uap->fifosize = vendor->fifosize;
         uap->interrupt_may_hang = vendor->interrupt_may_hang;
         uap->port.dev = &dev->dev;