OMAP3: Fixed crash bug with serial + suspend

It was possible for an unhandled interrupt to occur if there was incoming
serial traffic during wakeup from suspend. This was caused by the code
in arch-arm/mach-omap2/serial.c keeping interrupt enabled all the time,
but not acking its interrupts. Applies on top of PM branch.

Use the PM begin/end hooks to ensure that the "serial idle" interrupts
are disabled during the suspend path.  Also, since begin/end hooks are
now used, use the suspend_state that is passed in the begin hook instead
of the enter hook as per the platform_suspend_ops docs.

Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
index 528f725..b07efb2 100644 (file)
--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c
@@ -296,6 +296,8 @@ out:
 }
 
 #ifdef CONFIG_SUSPEND
+static suspend_state_t suspend_state;
+
 static int omap3_pm_prepare(void)
 {
        disable_hlt();
@@ -342,11 +344,11 @@ restore:
        return ret;
 }
 
-static int omap3_pm_enter(suspend_state_t state)
+static int omap3_pm_enter(suspend_state_t unused)
 {
        int ret = 0;
 
-       switch (state) {
+       switch (suspend_state) {
        case PM_SUSPEND_STANDBY:
        case PM_SUSPEND_MEM:
                ret = omap3_pm_suspend();
@@ -363,7 +365,24 @@ static void omap3_pm_finish(void)
        enable_hlt();
 }
 
+/* Hooks to enable / disable UART interrupts during suspend */
+static int omap3_pm_begin(suspend_state_t state)
+{
+       suspend_state = state;
+       omap_uart_enable_irqs(0);
+       return 0;
+}
+
+static void omap3_pm_end(void)
+{
+       suspend_state = PM_SUSPEND_ON;
+       omap_uart_enable_irqs(1);
+       return;
+}
+
 static struct platform_suspend_ops omap_pm_ops = {
+       .begin          = omap3_pm_begin,
+       .end            = omap3_pm_end,
        .prepare        = omap3_pm_prepare,
        .enter          = omap3_pm_enter,
        .finish         = omap3_pm_finish,

diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c
index c82ec95..5352d05 100644 (file)
--- a/arch/arm/mach-omap2/serial.c
+++ b/arch/arm/mach-omap2/serial.c
@@ -435,6 +435,20 @@ static void omap_uart_idle_init(struct omap_uart_state *uart)
        WARN_ON(ret);
 }
 
+void omap_uart_enable_irqs(int enable)
+{
+       int ret;
+       struct omap_uart_state *uart;
+
+       list_for_each_entry(uart, &uart_list, node) {
+               if (enable)
+                       ret = request_irq(uart->p->irq, omap_uart_interrupt,
+                               IRQF_SHARED, "serial idle", (void *)uart);
+               else
+                       free_irq(uart->p->irq, (void *)uart);
+       }
+}
+
 static ssize_t sleep_timeout_show(struct kobject *kobj,
                                  struct kobj_attribute *attr,
                                  char *buf)

diff --git a/arch/arm/plat-omap/include/mach/serial.h b/arch/arm/plat-omap/include/mach/serial.h
index 13abd02..def0529 100644 (file)
--- a/arch/arm/plat-omap/include/mach/serial.h
+++ b/arch/arm/plat-omap/include/mach/serial.h
@@ -59,6 +59,7 @@ extern void omap_uart_check_wakeup(void);
 extern void omap_uart_prepare_suspend(void);
 extern void omap_uart_prepare_idle(int num);
 extern void omap_uart_resume_idle(int num);
+extern void omap_uart_enable_irqs(int enable);
 #endif
 
 #endif