Blackfin Serial Driver: Fix bug - update tx dma buffer tail before wake up processes.

Also make rx dma buffer work as a loop.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 2fb3081..2a41174 100644 (file)
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -415,7 +415,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
         */
        bfin_serial_mctrl_check(uart);
 
-       spin_lock_irqsave(&uart->port.lock, flags);
        uart->tx_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
        if (uart->tx_count > (UART_XMIT_SIZE - xmit->tail))
                uart->tx_count = UART_XMIT_SIZE - xmit->tail;
@@ -439,7 +438,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
        ier |= ETBEI;
        UART_PUT_IER(uart, ier);
 #endif
-       spin_unlock_irqrestore(&uart->port.lock, flags);
 }
 
 static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
@@ -450,7 +448,9 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
        status = UART_GET_LSR(uart);
        UART_CLEAR_LSR(uart);
 
-       uart->port.icount.rx += CIRC_CNT(uart->rx_dma_buf.head, uart->rx_dma_buf.tail, UART_XMIT_SIZE);;
+       uart->port.icount.rx +=
+               CIRC_CNT(uart->rx_dma_buf.head, uart->rx_dma_buf.tail,
+               UART_XMIT_SIZE);
 
        if (status & BI) {
                uart->port.icount.brk++;
@@ -476,10 +476,12 @@ static void bfin_serial_dma_rx_chars(struct bfin_serial_port *uart)
        else
                flg = TTY_NORMAL;
 
-       for (i = uart->rx_dma_buf.head; i < uart->rx_dma_buf.tail; i++) {
-               if (uart_handle_sysrq_char(&uart->port, uart->rx_dma_buf.buf[i]))
-                       goto dma_ignore_char;
-               uart_insert_char(&uart->port, status, OE, uart->rx_dma_buf.buf[i], flg);
+       for (i = uart->rx_dma_buf.tail; i != uart->rx_dma_buf.head; i++) {
+               if (i >= UART_XMIT_SIZE)
+                       i = 0;
+               if (!uart_handle_sysrq_char(&uart->port, uart->rx_dma_buf.buf[i]))
+                       uart_insert_char(&uart->port, status, OE,
+                               uart->rx_dma_buf.buf[i], flg);
        }
 
  dma_ignore_char:
@@ -492,16 +494,20 @@ void bfin_serial_rx_dma_timeout(struct bfin_serial_port *uart)
        int flags = 0;
 
        spin_lock_irqsave(&uart->port.lock, flags);
-       x_pos = DMA_RX_XCOUNT - get_dma_curr_xcount(uart->rx_dma_channel);
+       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)
+               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) {
-               uart->rx_dma_buf.tail = pos;
+       if (pos != uart->rx_dma_buf.tail) {
+               uart->rx_dma_buf.head = pos;
                bfin_serial_dma_rx_chars(uart);
-               uart->rx_dma_buf.head = uart->rx_dma_buf.tail;
+               uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
        }
        spin_unlock_irqrestore(&uart->port.lock, flags);
        uart->rx_dma_timer.expires = jiffies + DMA_RX_FLUSH_JIFFIES;
@@ -525,12 +531,12 @@ static irqreturn_t bfin_serial_dma_tx_int(int irq, void *dev_id)
                ier &= ~ETBEI;
                UART_PUT_IER(uart, ier);
 #endif
-               if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
-                       uart_write_wakeup(&uart->port);
-
                xmit->tail = (xmit->tail + uart->tx_count) & (UART_XMIT_SIZE - 1);
                uart->port.icount.tx += uart->tx_count;
 
+               if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+                       uart_write_wakeup(&uart->port);
+
                bfin_serial_dma_tx_chars(uart);
        }
 
@@ -542,15 +548,16 @@ static irqreturn_t bfin_serial_dma_rx_int(int irq, void *dev_id)
 {
        struct bfin_serial_port *uart = dev_id;
        unsigned short irqstat;
+       int pos;
 
-       uart->rx_dma_nrows++;
-       uart->rx_dma_buf.tail = DMA_RX_XCOUNT * uart->rx_dma_nrows;
-       bfin_serial_dma_rx_chars(uart);
-       if (uart->rx_dma_nrows >= DMA_RX_YCOUNT) {
-               uart->rx_dma_nrows = 0;
-               uart->rx_dma_buf.tail = 0;
+       uart->rx_dma_nrows = DMA_RX_YCOUNT -
+               get_dma_curr_ycount(uart->rx_dma_channel);
+       pos = DMA_RX_XCOUNT * uart->rx_dma_nrows;
+       if (pos != uart->rx_dma_buf.tail) {
+               uart->rx_dma_buf.head = pos;
+               bfin_serial_dma_rx_chars(uart);
+               uart->rx_dma_buf.tail = uart->rx_dma_buf.head;
        }
-       uart->rx_dma_buf.head = uart->rx_dma_buf.tail;
 
        spin_lock(&uart->port.lock);
        irqstat = get_dma_curr_irqstat(uart->rx_dma_channel);