[Qemu-devel] [PATCH] TSC2005 interrupt handling fix

[Riihimaki Juha (Nokia-D-MSW/Helsinki)]

Fixing couple of timing related issues in the TSC2005 emulation.

Problems:
1) Setting DAV bits while previous conversion results are being read  
results in PINTDAV interrupt line never being released.
2) Altering PINTDAV state during SPI data transfer can result in an  
inconsistent interrupt state.

Solution proposal:
Moved PINTDAV altering code from tsc2005_pin_update to  
tsc2005_timer_tick and prohibited setting of DAV bits unless PINTDAV  
is to be set.


Index: hw/tsc2005.c
===================================================================
--- hw/tsc2005.c        (revision 6098)
+++ hw/tsc2005.c        (working copy)
@@ -230,26 +230,7 @@
 static void tsc2005_pin_update(struct tsc2005_state_s *s)
 {
     int64_t expires;
-    int pin_state;

-    switch (s->pin_func) {
-    case 0:
-        pin_state = !s->pressure && !!s->dav;
-        break;
-    case 1:
-    case 3:
-    default:
-        pin_state = !s->dav;
-        break;
-    case 2:
-        pin_state = !s->pressure;
-    }
-
-    if (pin_state != s->irq) {
-        s->irq = pin_state;
-        qemu_set_irq(s->pint, s->irq);
-    }
-
     switch (s->nextfunction) {
     case TSC_MODE_XYZ_SCAN:
     case TSC_MODE_XY_SCAN:
@@ -401,16 +382,35 @@
 static void tsc2005_timer_tick(void *opaque)
 {
     struct tsc2005_state_s *s = opaque;
+       int pin_state;

     /* Timer ticked -- a set of conversions has been finished.  */

     if (!s->busy)
         return;

-    s->busy = 0;
-    s->dav |= mode_regs[s->function];
-    s->function = -1;
-    tsc2005_pin_update(s);
+       switch (s->pin_func) {
+               case 0:
+                       pin_state = !s->pressure && !!s->dav;
+                       break;
+               case 1:
+               case 3:
+               default:
+                       pin_state = !s->dav;
+                       break;
+               case 2:
+                       pin_state = !s->pressure;
+    }
+       
+       s->busy = 0;
+       if (pin_state && !s->irq) s->dav |= mode_regs[s->function];
+       s->function = -1;
+       tsc2005_pin_update(s);
+
+    if (pin_state != s->irq) {
+        s->irq = pin_state;
+        qemu_set_irq(s->pint, s->irq);
+    }
 }

 static void tsc2005_touchscreen_event(void *opaque,