1 files changed, 67 insertions, 10 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index d86123e0339..e2f6b1bfac9 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -330,6 +330,11 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
                 /* Clear TFI bit */
                 UART_PUT_LSR(uart, TFI);
 #endif
+                /* Anomaly notes:
+                 *  05000215 -  we always clear ETBEI within last UART TX
+                 *              interrupt to end a string. It is always set
+                 *              when start a new tx.
+                 */
                 UART_CLEAR_IER(uart, ETBEI);
                 return;
         }
@@ -415,6 +420,7 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
         set_dma_start_addr(uart->tx_dma_channel, (unsigned long)(xmit->buf+xmit->tail));
         set_dma_x_count(uart->tx_dma_channel, uart->tx_count);
         set_dma_x_modify(uart->tx_dma_channel, 1);
+        SSYNC();
         enable_dma(uart->tx_dma_channel);
 
         UART_SET_IER(uart, ETBEI);
@@ -473,27 +479,41 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
 void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
 {
         int x_pos, pos;
-        unsigned long flags;
-
-        spin_lock_irqsave(&uart->port.lock, flags);
 
+        dma_disable_irq(uart->rx_dma_channel);
+        spin_lock_bh(&uart->port.lock);
+
+        /* 2D DMA RX buffer ring is used. Because curr_y_count and
+         * curr_x_count can't be read as an atomic operation,
+         * curr_y_count should be read before curr_x_count. When
+         * curr_x_count is read, curr_y_count may already indicate
+         * next buffer line. But, the position calculated here is
+         * still indicate the old line. The wrong position data may
+         * be smaller than current buffer tail, which cause garbages
+         * are received if it is not prohibit.
+         */
         uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel);
         x_pos = get_dma_curr_xcount(uart->rx_dma_channel);
         uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows;
-        if (uart->rx_dma_nrows == DMA_RX_YCOUNT)
+        if (uart->rx_dma_nrows == DMA_RX_YCOUNT || x_pos == 0)
                 uart->rx_dma_nrows = 0;
         x_pos = DMA_RX_XCOUNT - x_pos;
         if (x_pos == DMA_RX_XCOUNT)
                 x_pos = 0;
 
         pos = uart->rx_dma_nrows * DMA_RX_XCOUNT + x_pos;
-        if (pos != uart->rx_dma_buf.tail) {
+        /* Ignore receiving data if new position is in the same line of
+         * current buffer tail and small.
+         */
+        if (pos > uart->rx_dma_buf.tail ||
+                uart->rx_dma_nrows < (uart->rx_dma_buf.tail/DMA_RX_XCOUNT)) {
                 uart->rx_dma_buf.head = pos;
                 bfin_serial_dma_rx_chars(uart);
                 uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
         }
 
-        spin_unlock_irqrestore(&uart->port.lock, flags);
+        spin_unlock_bh(&uart->port.lock);
+        dma_enable_irq(uart->rx_dma_channel);
 
         mod_timer(&(uart->rx_dma_timer), jiffies + DMA_RX_FLUSH_JIFFIES);
 }
@@ -514,6 +534,11 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
         if (!(get_dma_curr_irqstat(uart->tx_dma_channel)&DMA_RUN)) {
                 disable_dma(uart->tx_dma_channel);
                 clear_dma_irqstat(uart->tx_dma_channel);
+                /* Anomaly notes:
+                 *  05000215 -  we always clear ETBEI within last UART TX
+                 *              interrupt to end a string. It is always set
+                 *              when start a new tx.
+                 */
                 UART_CLEAR_IER(uart, ETBEI);
                 xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
                 uart->port.icount.tx += uart->tx_count;
@@ -532,11 +557,26 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id)
 {
         struct bfin_serial_port *uart = dev_id;
         unsigned short irqstat;
+        int x_pos, pos;
 
         spin_lock(&uart->port.lock);
         irqstat = get_dma_curr_irqstat(uart->rx_dma_channel);
         clear_dma_irqstat(uart->rx_dma_channel);
-        bfin_serial_dma_rx_chars(uart);
+
+        uart->rx_dma_nrows = get_dma_curr_ycount(uart->rx_dma_channel);
+        x_pos = get_dma_curr_xcount(uart->rx_dma_channel);
+        uart->rx_dma_nrows = DMA_RX_YCOUNT - uart->rx_dma_nrows;
+        if (uart->rx_dma_nrows == DMA_RX_YCOUNT || x_pos == 0)
+                uart->rx_dma_nrows = 0;
+
+        pos = uart->rx_dma_nrows * DMA_RX_XCOUNT;
+        if (pos > uart->rx_dma_buf.tail ||
+                uart->rx_dma_nrows < (uart->rx_dma_buf.tail/DMA_RX_XCOUNT)) {
+                uart->rx_dma_buf.head = pos;
+                bfin_serial_dma_rx_chars(uart);
+                uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
+        }
+
         spin_unlock(&uart->port.lock);
 
         return IRQ_HANDLED;
@@ -789,8 +829,16 @@ bfin_serial_set_termios(struct uart_port *port, struct ktermios *termios,
                         __func__);
         }
 
-        if (termios->c_cflag & CSTOPB)
-                lcr |= STB;
+        /* Anomaly notes:
+         *  05000231 -  STOP bit is always set to 1 whatever the user is set.
+         */
+        if (termios->c_cflag & CSTOPB) {
+                if (ANOMALY_05000231)
+                        printk(KERN_WARNING "STOP bits other than 1 is not "
+                                "supported in case of anomaly 05000231.\n");
+                else
+                        lcr |= STB;
+        }
         if (termios->c_cflag & PARENB)
                 lcr |= PEN;
         if (!(termios->c_cflag & PARODD))
@@ -940,6 +988,10 @@ static void bfin_serial_reset_irda(struct uart_port *port)
 }
 
 #ifdef CONFIG_CONSOLE_POLL
+/* Anomaly notes:
+ *  05000099 -  Because we only use THRE in poll_put and DR in poll_get,
+ *              losing other bits of UART_LSR is not a problem here.
+ */
 static void bfin_serial_poll_put_char(struct uart_port *port, unsigned char chr)
 {
         struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
@@ -1245,12 +1297,17 @@ static __init void early_serial_write(struct console *con, const char *s,
         }
 }
 
+/*
+ * This should have a .setup or .early_setup in it, but then things get called
+ * without the command line options, and the baud rate gets messed up - so
+ * don't let the common infrastructure play with things. (see calls to setup
+ * & earlysetup in ./kernel/printk.c:register_console()
+ */
 static struct __initdata console bfin_early_serial_console = {
         .name = "early_BFuart",
         .write = early_serial_write,
         .device = uart_console_device,
         .flags = CON_PRINTBUFFER,
-        .setup = bfin_serial_console_setup,
         .index = -1,
         .data  = &bfin_serial_reg,
 };