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>

1 files changed, 29 insertions, 22 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 2fb3081c5022..2a4117485799 100644
--- 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);