serial: 8250: Separate legacy irq handling from core port operations

Prepare for 8250 split; decouple irq setup/teardown and handler from
core port operations.

Introduce setup_irq() and release_irq() 8250 driver methods; the 8250
core will use these methods to install and remove irq handling for
the given 8250 port.

Refactor irq chain linking/unlinking from 8250 core into
univ8250_setup_irq()/univ8250_release_irq() for the universal 8250 driver.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 625f81c9b55eec17a72fd9b82fe068160ce8cf73..06bb2ced2c94e52679d0ed2e2d378e130fb62579 100644 (file)
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1890,6 +1890,48 @@ static void serial8250_backup_timeout(unsigned long data)
                jiffies + uart_poll_timeout(&up->port) + HZ / 5);
 }
 
+static int univ8250_setup_irq(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+       int retval = 0;
+
+       /*
+        * The above check will only give an accurate result the first time
+        * the port is opened so this value needs to be preserved.
+        */
+       if (up->bugs & UART_BUG_THRE) {
+               pr_debug("ttyS%d - using backup timer\n", serial_index(port));
+
+               up->timer.function = serial8250_backup_timeout;
+               up->timer.data = (unsigned long)up;
+               mod_timer(&up->timer, jiffies +
+                         uart_poll_timeout(port) + HZ / 5);
+       }
+
+       /*
+        * If the "interrupt" for this port doesn't correspond with any
+        * hardware interrupt, we use a timer-based system.  The original
+        * driver used to do this with IRQ0.
+        */
+       if (!port->irq) {
+               up->timer.data = (unsigned long)up;
+               mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
+       } else
+               retval = serial_link_irq_chain(up);
+
+       return retval;
+}
+
+static void univ8250_release_irq(struct uart_8250_port *up)
+{
+       struct uart_port *port = &up->port;
+
+       del_timer_sync(&up->timer);
+       up->timer.function = serial8250_timeout;
+       if (port->irq)
+               serial_unlink_irq_chain(up);
+}
+
 static unsigned int serial8250_tx_empty(struct uart_port *port)
 {
        struct uart_8250_port *up = up_to_u8250p(port);
@@ -2194,35 +2236,12 @@ int serial8250_do_startup(struct uart_port *port)
                if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
                    up->port.flags & UPF_BUG_THRE) {
                        up->bugs |= UART_BUG_THRE;
-                       pr_debug("ttyS%d - using backup timer\n",
-                                serial_index(port));
                }
        }
 
-       /*
-        * The above check will only give an accurate result the first time
-        * the port is opened so this value needs to be preserved.
-        */
-       if (up->bugs & UART_BUG_THRE) {
-               up->timer.function = serial8250_backup_timeout;
-               up->timer.data = (unsigned long)up;
-               mod_timer(&up->timer, jiffies +
-                       uart_poll_timeout(port) + HZ / 5);
-       }
-
-       /*
-        * If the "interrupt" for this port doesn't correspond with any
-        * hardware interrupt, we use a timer-based system.  The original
-        * driver used to do this with IRQ0.
-        */
-       if (!port->irq) {
-               up->timer.data = (unsigned long)up;
-               mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
-       } else {
-               retval = serial_link_irq_chain(up);
-               if (retval)
-                       goto out;
-       }
+       retval = up->ops->setup_irq(up);
+       if (retval)
+               goto out;
 
        /*
         * Now, initialize the UART
@@ -2380,10 +2399,7 @@ void serial8250_do_shutdown(struct uart_port *port)
        serial_port_in(port, UART_RX);
        serial8250_rpm_put(up);
 
-       del_timer_sync(&up->timer);
-       up->timer.function = serial8250_timeout;
-       if (port->irq)
-               serial_unlink_irq_chain(up);
+       up->ops->release_irq(up);
 }
 EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
 
@@ -3083,6 +3099,11 @@ static struct uart_ops serial8250_pops = {
 #endif
 };
 
+static const struct uart_8250_ops univ8250_driver_ops = {
+       .setup_irq      = univ8250_setup_irq,
+       .release_irq    = univ8250_release_irq,
+};
+
 static struct uart_8250_port serial8250_ports[UART_NR];
 
 /**
@@ -3137,6 +3158,8 @@ static void __init serial8250_isa_init_ports(void)
                up->timer.function = serial8250_timeout;
                up->cur_iotype = 0xFF;
 
+               up->ops = &univ8250_driver_ops;
+
                /*
                 * ALPHA_KLUDGE_MCR needs to be killed.
                 */

diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index ca9f87beac63e8d64161793e42f6ff4d04b1f881..50735a9ad598d9b10c92243069d49e056f281fcb 100644 (file)
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -60,6 +60,20 @@ enum {
 };
 
 struct uart_8250_dma;
+struct uart_8250_port;
+
+/**
+ * 8250 core driver operations
+ *
+ * @setup_irq()                Setup irq handling. The universal 8250 driver links this
+ *                     port to the irq chain. Other drivers may @request_irq().
+ * @release_irq()      Undo irq handling. The universal 8250 driver unlinks
+ *                     the port from the irq chain.
+ */
+struct uart_8250_ops {
+       int             (*setup_irq)(struct uart_8250_port *);
+       void            (*release_irq)(struct uart_8250_port *);
+};
 
 /*
  * This should be used by drivers which want to register
@@ -100,6 +114,7 @@ struct uart_8250_port {
        unsigned char           msr_saved_flags;
 
        struct uart_8250_dma    *dma;
+       const struct uart_8250_ops *ops;
 
        /* 8250 specific callbacks */
        int                     (*dl_read)(struct uart_8250_port *);