1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/serial/mpsc.c b/drivers/serial/mpsc.c
index 3d2fcc57b1ce..d09f2097d5b0 100644
--- a/drivers/serial/mpsc.c
+++ b/drivers/serial/mpsc.c
@@ -183,6 +183,7 @@ struct mpsc_port_info {
         u8 *txb_p;              /* Phys addr of txb */
         int txr_head;           /* Where new data goes */
         int txr_tail;           /* Where sent data comes off */
+        spinlock_t tx_lock;     /* transmit lock */
 
         /* Mirrored values of regs we can't read (if 'mirror_regs' set) */
         u32 MPSC_MPCR_m;
@@ -1212,6 +1213,9 @@ mpsc_tx_intr(struct mpsc_port_info *pi)
 {
         struct mpsc_tx_desc *txre;
         int rc = 0;
+        unsigned long iflags;
+
+        spin_lock_irqsave(&pi->tx_lock, iflags);
 
         if (!mpsc_sdma_tx_active(pi)) {
                 txre = (struct mpsc_tx_desc *)(pi->txr +
@@ -1248,6 +1252,7 @@ mpsc_tx_intr(struct mpsc_port_info *pi)
                 mpsc_sdma_start_tx(pi); /* start next desc if ready */
         }
 
+        spin_unlock_irqrestore(&pi->tx_lock, iflags);
         return rc;
 }
 
@@ -1338,11 +1343,16 @@ static void
 mpsc_start_tx(struct uart_port *port)
 {
         struct mpsc_port_info *pi = (struct mpsc_port_info *)port;
+        unsigned long iflags;
+
+        spin_lock_irqsave(&pi->tx_lock, iflags);
 
         mpsc_unfreeze(pi);
         mpsc_copy_tx_data(pi);
         mpsc_sdma_start_tx(pi);
 
+        spin_unlock_irqrestore(&pi->tx_lock, iflags);
+
         pr_debug("mpsc_start_tx[%d]\n", port->line);
         return;
 }
@@ -1625,6 +1635,16 @@ mpsc_console_write(struct console *co, const char *s, uint count)
         struct mpsc_port_info *pi = &mpsc_ports[co->index];
         u8 *bp, *dp, add_cr = 0;
         int i;
+        unsigned long iflags;
+
+        spin_lock_irqsave(&pi->tx_lock, iflags);
+
+        while (pi->txr_head != pi->txr_tail) {
+                while (mpsc_sdma_tx_active(pi))
+                        udelay(100);
+                mpsc_sdma_intr_ack(pi);
+                mpsc_tx_intr(pi);
+        }
 
         while (mpsc_sdma_tx_active(pi))
                 udelay(100);
@@ -1668,6 +1688,7 @@ mpsc_console_write(struct console *co, const char *s, uint count)
                 pi->txr_tail = (pi->txr_tail + 1) & (MPSC_TXR_ENTRIES - 1);
         }
 
+        spin_unlock_irqrestore(&pi->tx_lock, iflags);
         return;
 }
 
@@ -2005,7 +2026,8 @@ mpsc_drv_probe(struct platform_device *dev)
                 if (!(rc = mpsc_drv_map_regs(pi, dev))) {
                         mpsc_drv_get_platform_data(pi, dev, dev->id);
 
-                        if (!(rc = mpsc_make_ready(pi)))
+                        if (!(rc = mpsc_make_ready(pi))) {
+                                spin_lock_init(&pi->tx_lock);
                                 if (!(rc = uart_add_one_port(&mpsc_reg,
                                         &pi->port)))
                                         rc = 0;
@@ -2014,6 +2036,7 @@ mpsc_drv_probe(struct platform_device *dev)
                                                 (struct uart_port *)pi);
                                         mpsc_drv_unmap_regs(pi);
                                 }
+                        }
                         else
                                 mpsc_drv_unmap_regs(pi);
                 }