mfd: twl4030 irq fixes

The TWL4030 IRQ handler has a bug which leads to spinlock lock-up. It is
calling the 'unmask' function in a process context. :The mask/unmask/ack
functions are only designed to be called from the IRQ handler code,
or the proper API interfaces found in linux/interrupt.h.

Also there is no need to have IRQ chaining mechanism. The right way to
handle this is to claim the parent interrupt as a standard interrupt
and arrange for handle_twl4030_pih to take care of the rest of the devices.

Mail thread on this issue can be found at:
http://marc.info/?l=linux-arm-kernel&m=124629940123396&w=2

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 24 insertions, 31 deletions

diff --git a/drivers/mfd/twl4030-irq.c b/drivers/mfd/twl4030-irq.c
index bae61b22501c..7d430835655f 100644
--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -180,14 +180,9 @@ static struct completion irq_event;
 static int twl4030_irq_thread(void *data)
 {
         long irq = (long)data;
-        struct irq_desc *desc = irq_to_desc(irq);
         static unsigned i2c_errors;
         static const unsigned max_i2c_errors = 100;
 
-        if (!desc) {
-                pr_err("twl4030: Invalid IRQ: %ld\n", irq);
-                return -EINVAL;
-        }
 
         current->flags |= PF_NOFREEZE;
 
@@ -240,7 +235,7 @@ static int twl4030_irq_thread(void *data)
                 }
                 local_irq_enable();
 
-                desc->chip->unmask(irq);
+                enable_irq(irq);
         }
 
         return 0;
@@ -255,25 +250,13 @@ static int twl4030_irq_thread(void *data)
  * thread.  All we do here is acknowledge and mask the interrupt and wakeup
  * the kernel thread.
  */
-static void handle_twl4030_pih(unsigned int irq, struct irq_desc *desc)
+static irqreturn_t handle_twl4030_pih(int irq, void *devid)
 {
         /* Acknowledge, clear *AND* mask the interrupt... */
-        desc->chip->ack(irq);
-        complete(&irq_event);
-}
-
-static struct task_struct *start_twl4030_irq_thread(long irq)
-{
-        struct task_struct *thread;
-
-        init_completion(&irq_event);
-        thread = kthread_run(twl4030_irq_thread, (void *)irq, "twl4030-irq");
-        if (!thread)
-                pr_err("twl4030: could not create irq %ld thread!\n", irq);
-
-        return thread;
+        disable_irq_nosync(irq);
+        complete(devid);
+        return IRQ_HANDLED;
 }
-
 /*----------------------------------------------------------------------*/
 
 /*
@@ -734,18 +717,28 @@ int twl_init_irq(int irq_num, unsigned irq_base, unsigned irq_end)
         }
 
         /* install an irq handler to demultiplex the TWL4030 interrupt */
-        task = start_twl4030_irq_thread(irq_num);
-        if (!task) {
-                pr_err("twl4030: irq thread FAIL\n");
-                status = -ESRCH;
-                goto fail;
-        }
 
-        set_irq_data(irq_num, task);
-        set_irq_chained_handler(irq_num, handle_twl4030_pih);
 
-        return status;
+        init_completion(&irq_event);
 
+        status = request_irq(irq_num, handle_twl4030_pih, IRQF_DISABLED,
+                                "TWL4030-PIH", &irq_event);
+        if (status < 0) {
+                pr_err("twl4030: could not claim irq%d: %d\n", irq_num, status);
+                goto fail_rqirq;
+        }
+
+        task = kthread_run(twl4030_irq_thread, (void *)irq_num, "twl4030-irq");
+        if (IS_ERR(task)) {
+                pr_err("twl4030: could not create irq %d thread!\n", irq_num);
+                status = PTR_ERR(task);
+                goto fail_kthread;
+        }
+        return status;
+fail_kthread:
+        free_irq(irq_num, &irq_event);
+fail_rqirq:
+        /* clean up twl4030_sih_setup */
 fail:
         for (i = irq_base; i < irq_end; i++)
                 set_irq_chip_and_handler(i, NULL, NULL);