[Qemu-devel] [PATCH] pl061: implement input interrupt logic

[Colin Leitner <colin.leitner@googlemail.com>]

This patch adds the missing input interrupt logic to the pl061 GPIO device. To
keep the floating output pins to stay high, the old state variable had to be
split into two separate ones for input and output - which brings the vmstate
version to 3.

Edge level interrupts and I/O were tested under Linux 3.14. Level interrupt
handling hasn't been tested.

Signed-off-by: Colin Leitner <colin.leitner@googlemail.com>
---
 hw/gpio/pl061.c |   59 ++++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 45 insertions(+), 14 deletions(-)

diff --git a/hw/gpio/pl061.c b/hw/gpio/pl061.c
index dd4ea29..bd03e99 100644
--- a/hw/gpio/pl061.c
+++ b/hw/gpio/pl061.c
@@ -37,7 +37,8 @@ typedef struct PL061State {
     MemoryRegion iomem;
     uint32_t locked;
     uint32_t data;
-    uint32_t old_data;
+    uint32_t old_out_data;
+    uint32_t old_in_data;
     uint32_t dir;
     uint32_t isense;
     uint32_t ibe;
@@ -63,12 +64,13 @@ typedef struct PL061State {

 static const VMStateDescription vmstate_pl061 = {
     .name = "pl061",
-    .version_id = 2,
-    .minimum_version_id = 1,
+    .version_id = 3,
+    .minimum_version_id = 3,
     .fields = (VMStateField[]) {
         VMSTATE_UINT32(locked, PL061State),
         VMSTATE_UINT32(data, PL061State),
-        VMSTATE_UINT32(old_data, PL061State),
+        VMSTATE_UINT32(old_out_data, PL061State),
+        VMSTATE_UINT32(old_in_data, PL061State),
         VMSTATE_UINT32(dir, PL061State),
         VMSTATE_UINT32(isense, PL061State),
         VMSTATE_UINT32(ibe, PL061State),
@@ -98,23 +100,52 @@ static void pl061_update(PL061State *s)
     uint8_t out;
     int i;

+    DPRINTF("dir = %d, data = %d\n", s->dir, s->data);
+
     /* Outputs float high.  */
     /* FIXME: This is board dependent.  */
     out = (s->data & s->dir) | ~s->dir;
-    changed = s->old_data ^ out;
-    if (!changed)
-        return;
+    changed = s->old_out_data ^ out;
+    if (changed) {
+        s->old_out_data = out;
+        for (i = 0; i < 8; i++) {
+            mask = 1 << i;
+            if (changed & mask) {
+                DPRINTF("Set output %d = %d\n", i, (out & mask) != 0);
+                qemu_set_irq(s->out[i], (out & mask) != 0);
+            }
+        }
+    }

-    s->old_data = out;
-    for (i = 0; i < 8; i++) {
-        mask = 1 << i;
-        if (changed & mask) {
-            DPRINTF("Set output %d = %d\n", i, (out & mask) != 0);
-            qemu_set_irq(s->out[i], (out & mask) != 0);
+    /* Inputs */
+    changed = (s->old_in_data ^ s->data) & ~s->dir;
+    if (changed) {
+        s->old_in_data = s->data;
+        for (i = 0; i < 8; i++) {
+            mask = 1 << i;
+            if (changed & mask) {
+                DPRINTF("Changed input %d = %d\n", i, (s->data & mask) != 0);
+
+                if (!(s->isense & mask)) {
+                    /* Edge interrupt */
+                    if (s->ibe & mask) {
+                        /* Any edge triggers the interrupt */
+                        s->istate |= mask;
+                    } else {
+                        /* Edge is selected by IEV */
+                        s->istate |= ~(s->data ^ s->iev) & mask;
+                    }
+                }
+            }
         }
     }

-    /* FIXME: Implement input interrupts.  */
+    /* Level interrupt */
+    s->istate |= ~(s->data ^ s->iev) & s->isense;
+
+    DPRINTF("istate = %02X\n", s->istate);
+
+    qemu_set_irq(s->irq, (s->istate & s->im) != 0);
 }

 static uint64_t pl061_read(void *opaque, hwaddr offset,
-- 
1.7.10.4