Blackfin Serial Driver: Use timer to poll CTS PIN instead of workqueue.

This allows other threads to run when the serial driver polls the CTS
PIN in 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 f20952c43cb83be784fbf4d35fceb0295ce44c8d..fd9bb777df286bfafeb9e36b306f7dbbe2e34e02 100644 (file)
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -49,6 +49,7 @@
 #define DMA_RX_YCOUNT          (PAGE_SIZE / DMA_RX_XCOUNT)
 
 #define DMA_RX_FLUSH_JIFFIES   (HZ / 50)
+#define CTS_CHECK_JIFFIES      (HZ / 50)
 
 #ifdef CONFIG_SERIAL_BFIN_DMA
 static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart);
@@ -290,11 +291,6 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
 {
        struct circ_buf *xmit = &uart->port.info->xmit;
 
-       if (uart->port.x_char) {
-               UART_PUT_CHAR(uart, uart->port.x_char);
-               uart->port.icount.tx++;
-               uart->port.x_char = 0;
-       }
        /*
         * Check the modem control lines before
         * transmitting anything.
@@ -306,6 +302,12 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
                return;
        }
 
+       if (uart->port.x_char) {
+               UART_PUT_CHAR(uart, uart->port.x_char);
+               uart->port.icount.tx++;
+               uart->port.x_char = 0;
+       }
+
        while ((UART_GET_LSR(uart) & THRE) && xmit->tail != xmit->head) {
                UART_PUT_CHAR(uart, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
@@ -345,15 +347,6 @@ static irqreturn_t bfin_serial_tx_int(int irq, void *dev_id)
 }
 #endif
 
-#ifdef CONFIG_SERIAL_BFIN_CTSRTS
-static void bfin_serial_do_work(struct work_struct *work)
-{
-       struct bfin_serial_port *uart = container_of(work, struct bfin_serial_port, cts_workqueue);
-
-       bfin_serial_mctrl_check(uart);
-}
-#endif
-
 #ifdef CONFIG_SERIAL_BFIN_DMA
 static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
 {
@@ -361,6 +354,12 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
 
        uart->tx_done = 0;
 
+       /*
+        * Check the modem control lines before
+        * transmitting anything.
+        */
+       bfin_serial_mctrl_check(uart);
+
        if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
                uart->tx_count = 0;
                uart->tx_done = 1;
@@ -373,12 +372,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart)
                uart->port.x_char = 0;
        }
 
-       /*
-        * Check the modem control lines before
-        * transmitting anything.
-        */
-       bfin_serial_mctrl_check(uart);
-
        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;
@@ -565,7 +558,10 @@ static void bfin_serial_mctrl_check(struct bfin_serial_port *uart)
        uart_handle_cts_change(&uart->port, status & TIOCM_CTS);
        if (!(status & TIOCM_CTS)) {
                tty->hw_stopped = 1;
-               schedule_work(&uart->cts_workqueue);
+               uart->cts_timer.data = (unsigned long)(uart);
+               uart->cts_timer.function = (void *)bfin_serial_mctrl_check;
+               uart->cts_timer.expires = jiffies + CTS_CHECK_JIFFIES;
+               add_timer(&(uart->cts_timer));
        } else {
                tty->hw_stopped = 0;
        }
@@ -885,7 +881,7 @@ static void __init bfin_serial_init_ports(void)
                init_timer(&(bfin_serial_ports[i].rx_dma_timer));
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-               INIT_WORK(&bfin_serial_ports[i].cts_workqueue, bfin_serial_do_work);
+               init_timer(&(bfin_serial_ports[i].cts_timer));
                bfin_serial_ports[i].cts_pin        =
                        bfin_serial_resource[i].uart_cts_pin;
                bfin_serial_ports[i].rts_pin        =

diff --git a/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
index 96bd09e31e3612b187bb931ad60b05008fa792e8..2526b6ed6faa78ce72d45d9e210743c589850f8e 100644 (file)
--- a/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf527/bfin_serial_5xx.h
@@ -96,7 +96,7 @@ struct bfin_serial_port {
        struct work_struct tx_dma_workqueue;
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-       struct work_struct cts_workqueue;
+       struct timer_list cts_timer;
        int cts_pin;
        int rts_pin;
 #endif

diff --git a/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h
index e924569ad1d8a668ba17685bb1b0ffa9b8b1f85a..ebf592b59aab4b88a1d790f013f86535d55ccfeb 100644 (file)
--- a/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf533/bfin_serial_5xx.h
@@ -88,7 +88,7 @@ struct bfin_serial_port {
 # endif
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-       struct work_struct      cts_workqueue;
+       struct timer_list       cts_timer;
        int                     cts_pin;
        int                     rts_pin;
 #endif

diff --git a/include/asm-blackfin/mach-bf537/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf537/bfin_serial_5xx.h
index 41d7b6490bb11b608303faa85a5ea6cdd439633f..1bf56ffa22f946236dfcfad9d14b27db6e26d090 100644 (file)
--- a/include/asm-blackfin/mach-bf537/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf537/bfin_serial_5xx.h
@@ -96,7 +96,7 @@ struct bfin_serial_port {
        struct work_struct      tx_dma_workqueue;
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-       struct work_struct      cts_workqueue;
+       struct timer_list       cts_timer;
        int             cts_pin;
        int             rts_pin;
 #endif

diff --git a/include/asm-blackfin/mach-bf548/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf548/bfin_serial_5xx.h
index aabe5b92f11c5a249a9ebb2786a05fb6f5ad2624..5e29446a8e03dde1acbf65bcc136a8cb83f5f60a 100644 (file)
--- a/include/asm-blackfin/mach-bf548/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf548/bfin_serial_5xx.h
@@ -99,7 +99,7 @@ struct bfin_serial_port {
        struct work_struct      tx_dma_workqueue;
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-       struct work_struct      cts_workqueue;
+       struct timer_list       cts_timer;
        int             cts_pin;
        int             rts_pin;
 #endif

diff --git a/include/asm-blackfin/mach-bf561/bfin_serial_5xx.h b/include/asm-blackfin/mach-bf561/bfin_serial_5xx.h
index 30d90b580f186cfed41520d3351dc47310eaca8d..8aa02780e642ccde6deee3e79b4fe401d481902d 100644 (file)
--- a/include/asm-blackfin/mach-bf561/bfin_serial_5xx.h
+++ b/include/asm-blackfin/mach-bf561/bfin_serial_5xx.h
@@ -88,7 +88,7 @@ struct bfin_serial_port {
 # endif
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-       struct work_struct      cts_workqueue;
+       struct timer_list       cts_timer;
        int                     cts_pin;
        int                     rts_pin;
 #endif