Change hardware flow control from poll to interrupt driven

Only the CTS bit is affected.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 82 insertions, 49 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index f9b5a72e261..fbbddb9e73f 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -63,7 +63,6 @@ static int kgdboc_break_enabled;
 #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);
@@ -71,8 +70,6 @@ static void bfin_serial_dma_tx_chars(struct bfin_serial_port *uart);
 static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
 #endif
 
-static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
-
 static void bfin_serial_reset_irda(struct uart_port *port);
 
 /*
@@ -264,12 +261,6 @@ static void bfin_serial_tx_chars(struct bfin_serial_port *uart)
 {
         struct circ_buf *xmit = &uart->port.info->xmit;
 
-        /*
-         * Check the modem control lines before
-         * transmitting anything.
-         */
-        bfin_serial_mctrl_check(uart);
-
         if (uart_circ_empty(xmit) || uart_tx_stopped(&uart->port)) {
 #ifdef CONFIG_BF54x
                 /* Clear TFI bit */
@@ -328,12 +319,6 @@ 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;
@@ -524,29 +509,21 @@ static void bfin_serial_set_mctrl(struct uart_port *port, unsigned int mctrl)
 #endif
 }
 
+#ifdef CONFIG_SERIAL_BFIN_CTSRTS
 /*
- * Handle any change of modem status signal since we were last called.
+ * Handle any change of modem status signal.
  */
-static void bfin_serial_mctrl_check(struct bfin_serial_port *uart)
+static irqreturn_t bfin_serial_mctrl_cts_int(int irq, void *dev_id)
 {
-#ifdef CONFIG_SERIAL_BFIN_CTSRTS
+        struct bfin_serial_port *uart = dev_id;
         unsigned int status;
-        struct uart_info *info = uart->port.info;
-        struct tty_struct *tty = info->port.tty;
 
         status = bfin_serial_get_mctrl(&uart->port);
         uart_handle_cts_change(&uart->port, status & TIOCM_CTS);
-        if (!(status & TIOCM_CTS)) {
-                tty->hw_stopped = 1;
-                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;
-        }
-#endif
+
+        return IRQ_HANDLED;
 }
+#endif
 
 /*
  * Interrupts are always disabled.
@@ -606,7 +583,7 @@ static int bfin_serial_startup(struct uart_port *port)
         uart->rx_dma_timer.expires = jiffies + DMA_RX_FLUSH_JIFFIES;
         add_timer(&(uart->rx_dma_timer));
 #else
-#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+# if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
         defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
         if (kgdboc_port_line == uart->port.line && kgdboc_break_enabled)
                 kgdboc_break_enabled = 0;
@@ -661,11 +638,28 @@ static int bfin_serial_startup(struct uart_port *port)
                 }
         }
 # endif
-#if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
+# if defined(CONFIG_KGDB_SERIAL_CONSOLE) || \
         defined(CONFIG_KGDB_SERIAL_CONSOLE_MODULE)
         }
 # endif
 #endif
+
+#ifdef CONFIG_SERIAL_BFIN_CTSRTS
+        if (uart->cts_pin >= 0) {
+                if (request_irq(gpio_to_irq(uart->cts_pin),
+                        bfin_serial_mctrl_cts_int,
+                        IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
+                        IRQF_DISABLED, "BFIN_UART_CTS", uart)) {
+                        uart->cts_pin = -1;
+                        pr_info("Unable to attach BlackFin UART CTS interrupt.\
+                                 So, disable it.\n");
+                }
+        }
+        if (uart->rts_pin >= 0) {
+                gpio_request(uart->rts_pin, DRIVER_NAME);
+                gpio_direction_output(uart->rts_pin, 0);
+        }
+#endif
         UART_SET_IER(uart, ERBFI);
         return 0;
 }
@@ -699,6 +693,13 @@ static void bfin_serial_shutdown(struct uart_port *port)
         free_irq(uart->port.irq, uart);
         free_irq(uart->port.irq+1, uart);
 #endif
+
+# ifdef CONFIG_SERIAL_BFIN_CTSRTS
+        if (uart->cts_pin >= 0)
+                free_irq(gpio_to_irq(uart->cts_pin), uart);
+        if (uart->rts_pin >= 0)
+                gpio_free(uart->rts_pin);
+# endif
 }
 
 static void
@@ -864,6 +865,20 @@ static void bfin_serial_set_ldisc(struct uart_port *port)
         }
 }
 
+static void bfin_serial_reset_irda(struct uart_port *port)
+{
+        int line = port->line;
+        unsigned short val;
+
+        val = UART_GET_GCTL(&bfin_serial_ports[line]);
+        val &= ~(IREN | RPOLC);
+        UART_PUT_GCTL(&bfin_serial_ports[line], val);
+        SSYNC();
+        val |= (IREN | RPOLC);
+        UART_PUT_GCTL(&bfin_serial_ports[line], val);
+        SSYNC();
+}
+
 #ifdef CONFIG_CONSOLE_POLL
 static void bfin_serial_poll_put_char(struct uart_port *port, unsigned char chr)
 {
@@ -909,20 +924,6 @@ static int bfin_kgdboc_port_startup(struct uart_port *port)
 }
 #endif
 
-static void bfin_serial_reset_irda(struct uart_port *port)
-{
-        int line = port->line;
-        unsigned short val;
-
-        val = UART_GET_GCTL(&bfin_serial_ports[line]);
-        val &= ~(IREN | RPOLC);
-        UART_PUT_GCTL(&bfin_serial_ports[line], val);
-        SSYNC();
-        val |= (IREN | RPOLC);
-        UART_PUT_GCTL(&bfin_serial_ports[line], val);
-        SSYNC();
-}
-
 static struct uart_ops bfin_serial_pops = {
         .tx_empty       = bfin_serial_tx_empty,
         .set_mctrl      = bfin_serial_set_mctrl,
@@ -952,6 +953,39 @@ static struct uart_ops bfin_serial_pops = {
 #endif
 };
 
+static void __init bfin_serial_hw_init(void)
+{
+#ifdef CONFIG_SERIAL_BFIN_UART0
+        peripheral_request(P_UART0_TX, DRIVER_NAME);
+        peripheral_request(P_UART0_RX, DRIVER_NAME);
+#endif
+
+#ifdef CONFIG_SERIAL_BFIN_UART1
+        peripheral_request(P_UART1_TX, DRIVER_NAME);
+        peripheral_request(P_UART1_RX, DRIVER_NAME);
+
+# if defined(CONFIG_BFIN_UART1_CTSRTS) && defined(CONFIG_BF54x)
+        peripheral_request(P_UART1_RTS, DRIVER_NAME);
+        peripheral_request(P_UART1_CTS, DRIVER_NAME);
+# endif
+#endif
+
+#ifdef CONFIG_SERIAL_BFIN_UART2
+        peripheral_request(P_UART2_TX, DRIVER_NAME);
+        peripheral_request(P_UART2_RX, DRIVER_NAME);
+#endif
+
+#ifdef CONFIG_SERIAL_BFIN_UART3
+        peripheral_request(P_UART3_TX, DRIVER_NAME);
+        peripheral_request(P_UART3_RX, DRIVER_NAME);
+
+# if defined(CONFIG_BFIN_UART3_CTSRTS) && defined(CONFIG_BF54x)
+        peripheral_request(P_UART3_RTS, DRIVER_NAME);
+        peripheral_request(P_UART3_CTS, DRIVER_NAME);
+# endif
+#endif
+}
+
 static void __init bfin_serial_init_ports(void)
 {
         static int first = 1;
@@ -961,6 +995,8 @@ static void __init bfin_serial_init_ports(void)
                 return;
         first = 0;
 
+        bfin_serial_hw_init();
+
         for (i = 0; i < nr_active_ports; i++) {
                 bfin_serial_ports[i].port.uartclk   = get_sclk();
                 bfin_serial_ports[i].port.fifosize  = BFIN_UART_TX_FIFO_SIZE;
@@ -984,15 +1020,12 @@ static void __init bfin_serial_init_ports(void)
                 init_timer(&(bfin_serial_ports[i].rx_dma_timer));
 #endif
 #ifdef CONFIG_SERIAL_BFIN_CTSRTS
-                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        =
                         bfin_serial_resource[i].uart_rts_pin;
 #endif
-                bfin_serial_hw_init(&bfin_serial_ports[i]);
         }
-
 }
 
 #if defined(CONFIG_SERIAL_BFIN_CONSOLE) || defined(CONFIG_EARLY_PRINTK)