[ARM] tegra: hsuart: use a workqueue in the tx dma callback

Signed-off-by: Iliyan Malchev <malchev@google.com>

diff --git a/drivers/serial/tegra_hsuart.c b/drivers/serial/tegra_hsuart.c
index 4d20df2ce64dfbaccc989b4741e085d3118a92bc..2771c4a9e9a4eb24e61593101108be672aceb6df 100644 (file)
--- a/drivers/serial/tegra_hsuart.c
+++ b/drivers/serial/tegra_hsuart.c
@@ -40,6 +40,7 @@
 #include <linux/serial_8250.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>
+#include <linux/workqueue.h>
 #include <mach/dma.h>
 #include <mach/clk.h>
 
@@ -103,11 +104,12 @@ struct tegra_uart_port {
 
        dma_addr_t              xmit_dma_addr;
 
-       /* Rm DMA handles */
+       /* TX DMA */
        struct tegra_dma_req    tx_dma_req;
        struct tegra_dma_channel *tx_dma;
+       struct work_struct      tx_work;
 
-       /* DMA requests */
+       /* RX DMA */
        struct tegra_dma_req    rx_dma_req;
        struct tegra_dma_channel *rx_dma;
 
@@ -409,9 +411,11 @@ static void do_handle_tx_pio(struct tegra_uart_port *t)
        return;
 }
 
-static void tegra_tx_dma_complete_callback(struct tegra_dma_req *req)
+static void tegra_tx_dma_complete_work(struct work_struct *work)
 {
-       struct tegra_uart_port *t = req->dev;
+       struct tegra_uart_port *t =
+                       container_of(work, struct tegra_uart_port, tx_work);
+       struct tegra_dma_req *req = &t->tx_dma_req;
        struct circ_buf *xmit = &t->uport.state->xmit;
        int count = req->bytes_transferred;
        unsigned long flags;
@@ -442,6 +446,12 @@ static void tegra_tx_dma_complete_callback(struct tegra_dma_req *req)
        spin_unlock_irqrestore(&t->uport.lock, flags);
 }
 
+static void tegra_tx_dma_complete_callback(struct tegra_dma_req *req)
+{
+       struct tegra_uart_port *t = req->dev;
+       schedule_work(&t->tx_work);
+}
+
 static irqreturn_t tegra_uart_isr(int irq, void *data)
 {
        struct tegra_uart_port *t = data;
@@ -937,8 +947,10 @@ static void tegra_stop_tx(struct uart_port *u)
 
        t = container_of(u, struct tegra_uart_port, uport);
 
-       if (t->use_tx_dma)
+       if (t->use_tx_dma) {
                tegra_dma_dequeue_req(t->tx_dma, &t->tx_dma_req);
+               flush_work(&t->tx_work);
+       }
        t->tx_in_progress  = 0;
        return;
 }
@@ -1082,7 +1094,7 @@ static void tegra_flush_buffer(struct uart_port *u)
 {
        struct tegra_uart_port *t;
 
-       dev_vdbg(u->dev, "tegra_flush_buffer called");
+       dev_vdbg(u->dev, "%s called", __func__);
 
        t = container_of(u, struct tegra_uart_port, uport);
 
@@ -1245,6 +1257,7 @@ static int tegra_uart_probe(struct platform_device *pdev)
        pr_info("Registered UART port %s%d\n",
                tegra_uart_driver.dev_name, u->line);
 
+       INIT_WORK(&t->tx_work, tegra_tx_dma_complete_work);
        return ret;
 fail:
        kfree(t);