[Xen-devel] [PATCH] xen: char: Remove unnecessary (uart->irq > 0) check

[Amit Singh Tomar <amittomer25@xxxxxxxxx>]

While working on MVEBU uart driver, Julien pointed out that (uart->irq > 0)
check is unnecessary during irq set up.if ever there is an invalid irq, driver
initialization itself would be bailed out from platform_get_irq.

This patch would remove similar check for other uart drivers present in XEN.

Signed-off-by: Amit Singh Tomar <amittomer25@xxxxxxxxx>
---
    * This patch is only compiled tested.
---
 xen/drivers/char/cadence-uart.c | 15 ++++++++-------
 xen/drivers/char/ns16550.c      | 35 ++++++++++++++---------------------
 xen/drivers/char/omap-uart.c    |  2 +-
 xen/drivers/char/pl011.c        | 13 +++++++------
 4 files changed, 30 insertions(+), 35 deletions(-)

diff --git a/xen/drivers/char/cadence-uart.c b/xen/drivers/char/cadence-uart.c
index 22905ba..1575787 100644
--- a/xen/drivers/char/cadence-uart.c
+++ b/xen/drivers/char/cadence-uart.c
@@ -72,13 +72,14 @@ static void __init cuart_init_postirq(struct serial_port 
*port)
     struct cuart *uart = port->uart;
     int rc;
 
-    if ( uart->irq > 0 )
+    uart->irqaction.handler = cuart_interrupt;
+    uart->irqaction.name    = "cadence-uart";
+    uart->irqaction.dev_id  = port;
+
+    if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
     {
-        uart->irqaction.handler = cuart_interrupt;
-        uart->irqaction.name    = "cadence-uart";
-        uart->irqaction.dev_id  = port;
-        if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
-            printk("ERROR: Failed to allocate cadence-uart IRQ %d\n", 
uart->irq);
+        printk("ERROR: Failed to allocate cadence-uart IRQ %d\n", uart->irq);
+        return;
     }
 
     /* Clear pending error interrupts */
@@ -130,7 +131,7 @@ static int __init cuart_irq(struct serial_port *port)
 {
     struct cuart *uart = port->uart;
 
-    return ( (uart->irq > 0) ? uart->irq : -1 );
+    return uart->irq;
 }
 
 static const struct vuart_info *cuart_vuart(struct serial_port *port)
diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index f32dbd3..ba50a1e 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -714,18 +714,12 @@ static void __init ns16550_init_preirq(struct serial_port 
*port)
 
 static void ns16550_setup_postirq(struct ns16550 *uart)
 {
-    if ( uart->irq > 0 )
-    {
-        /* Master interrupt enable; also keep DTR/RTS asserted. */
-        ns_write_reg(uart,
-                     UART_MCR, UART_MCR_OUT2 | UART_MCR_DTR | UART_MCR_RTS);
-
-        /* Enable receive interrupts. */
-        ns_write_reg(uart, UART_IER, UART_IER_ERDAI);
-    }
+    /* Master interrupt enable; also keep DTR/RTS asserted. */
+    ns_write_reg(uart, UART_MCR, UART_MCR_OUT2 | UART_MCR_DTR | UART_MCR_RTS);
+    /* Enable receive interrupts. */
+    ns_write_reg(uart, UART_IER, UART_IER_ERDAI);
 
-    if ( uart->irq >= 0 )
-        set_timer(&uart->timer, NOW() + MILLISECS(uart->timeout_ms));
+    set_timer(&uart->timer, NOW() + MILLISECS(uart->timeout_ms));
 }
 
 static void __init ns16550_init_postirq(struct serial_port *port)
@@ -733,9 +727,6 @@ static void __init ns16550_init_postirq(struct serial_port 
*port)
     struct ns16550 *uart = port->uart;
     int rc, bits;
 
-    if ( uart->irq < 0 )
-        return;
-
     serial_async_transmit(port);
 
     init_timer(&uart->timer, ns16550_poll, port, 0);
@@ -746,13 +737,14 @@ static void __init ns16550_init_postirq(struct 
serial_port *port)
     uart->timeout_ms = max_t(
         unsigned int, 1, (bits * uart->fifo_size * 1000) / uart->baud);
 
-    if ( uart->irq > 0 )
+    uart->irqaction.handler = ns16550_interrupt;
+    uart->irqaction.name    = "ns16550";
+    uart->irqaction.dev_id  = port;
+
+    if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
     {
-        uart->irqaction.handler = ns16550_interrupt;
-        uart->irqaction.name    = "ns16550";
-        uart->irqaction.dev_id  = port;
-        if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
-            printk("ERROR: Failed to allocate ns16550 IRQ %d\n", uart->irq);
+        printk("ERROR: Failed to allocate ns16550 IRQ %d\n", uart->irq);
+        return;
     }
 
     ns16550_setup_postirq(uart);
@@ -874,7 +866,8 @@ static void __init ns16550_endboot(struct serial_port *port)
 static int __init ns16550_irq(struct serial_port *port)
 {
     struct ns16550 *uart = port->uart;
-    return ((uart->irq > 0) ? uart->irq : -1);
+
+    return uart->irq;
 }
 
 static void ns16550_start_tx(struct serial_port *port)
diff --git a/xen/drivers/char/omap-uart.c b/xen/drivers/char/omap-uart.c
index d6a5d59..2ce4e71 100644
--- a/xen/drivers/char/omap-uart.c
+++ b/xen/drivers/char/omap-uart.c
@@ -294,7 +294,7 @@ static int __init omap_uart_irq(struct serial_port *port)
 {
     struct omap_uart *uart = port->uart;
 
-    return ((uart->irq > 0) ? uart->irq : -1);
+    return uart->irq;
 }
 
 static const struct vuart_info *omap_vuart_info(struct serial_port *port)
diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index be67242..e007918 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -128,13 +128,14 @@ static void __init pl011_init_postirq(struct serial_port 
*port)
     struct pl011 *uart = port->uart;
     int rc;
 
-    if ( uart->irq > 0 )
+    uart->irqaction.handler = pl011_interrupt;
+    uart->irqaction.name    = "pl011";
+    uart->irqaction.dev_id  = port;
+
+    if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
     {
-        uart->irqaction.handler = pl011_interrupt;
-        uart->irqaction.name    = "pl011";
-        uart->irqaction.dev_id  = port;
-        if ( (rc = setup_irq(uart->irq, 0, &uart->irqaction)) != 0 )
-            printk("ERROR: Failed to allocate pl011 IRQ %d\n", uart->irq);
+        printk("ERROR: Failed to allocate pl011 IRQ %d\n", uart->irq);
+        return;
     }
 
     /* Clear pending error interrupts */
-- 
1.9.1


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