[PATCH] Raspberry PI GPIO interrupt support

[Davide Berardi]

The bcm2835 GPIOs now generate interrupts.
This modification enables QTEST clients to trigger interrupt-based
interfaces.

Signed-off-by: Davide Berardi <berardi.dav@gmail.com>
---
 hw/arm/bcm2835_peripherals.c   |   2 +
 hw/gpio/bcm2835_gpio.c         | 105 +++++++++++++++++++++++++++++++++
 hw/intc/bcm2835_ic.c           |   2 -
 include/hw/gpio/bcm2835_gpio.h |  12 ++++
 4 files changed, 119 insertions(+), 2 deletions(-)

diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c
index dcff13433e..101c3e6fba 100644
--- a/hw/arm/bcm2835_peripherals.c
+++ b/hw/arm/bcm2835_peripherals.c
@@ -114,6 +114,8 @@ static void bcm2835_peripherals_init(Object *obj)
                                    OBJECT(&s->sdhci.sdbus));
     object_property_add_const_link(OBJECT(&s->gpio), "sdbus-sdhost",
                                    OBJECT(&s->sdhost.sdbus));
+    object_property_add_const_link(OBJECT(&s->gpio), "ic",
+                                   OBJECT(&s->ic));
 
     /* Mphi */
     object_initialize_child(obj, "mphi", &s->mphi, TYPE_BCM2835_MPHI);
diff --git a/hw/gpio/bcm2835_gpio.c b/hw/gpio/bcm2835_gpio.c
index abdddbc67c..2952ebe1da 100644
--- a/hw/gpio/bcm2835_gpio.c
+++ b/hw/gpio/bcm2835_gpio.c
@@ -7,6 +7,9 @@
  *  Clement Deschamps <clement.deschamps@antfield.fr>
  *  Luc Michel <luc.michel@antfield.fr>
  *
+ * GPIO Interrupt support
+ *  Davide Berardi <berardi.dav@gmail.com>
+ *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  */
@@ -20,6 +23,7 @@
 #include "migration/vmstate.h"
 #include "hw/sd/sd.h"
 #include "hw/gpio/bcm2835_gpio.h"
+#include "hw/intc/bcm2835_ic.h"
 #include "hw/irq.h"
 
 #define GPFSEL0   0x00
@@ -110,6 +114,29 @@ static int gpfsel_is_out(BCM2835GpioState *s, int index)
     return 0;
 }
 
+static inline int get_bit_2_u32(const uint32_t idx,
+                                const uint32_t v1, const uint32_t v2)
+{
+    uint64_t v = v1 | ((uint64_t)v2) << 32;
+    return !!(v & (1 << idx));
+}
+
+static int ren_detect(BCM2835GpioState *s, int index)
+{
+    if (index >= 0 && index < 54) {
+        return get_bit_2_u32(index, s->ren0, s->ren1);
+    }
+    return 0;
+}
+
+static int fen_detect(BCM2835GpioState *s, int index)
+{
+    if (index >= 0 && index < 54) {
+        return get_bit_2_u32(index, s->fen0, s->fen1);
+    }
+    return 0;
+}
+
 static void gpset(BCM2835GpioState *s,
         uint32_t val, uint8_t start, uint8_t count, uint32_t *lev)
 {
@@ -120,6 +147,20 @@ static void gpset(BCM2835GpioState *s,
     for (i = 0; i < count; i++) {
         if ((changes & cur) && (gpfsel_is_out(s, start + i))) {
             qemu_set_irq(s->out[start + i], 1);
+        } else if ((changes & cur) && ren_detect(s, start + i)) {
+            /* If this is an input and must check rising edge */
+            int irqline = 0;
+            if (i > 27)
+                irqline = 1;
+            if (i > 45)
+                irqline = 2;
+
+            /* Set the bit in the events */
+            if (i < 32)
+                s->eds0 |= cur;
+            else
+                s->eds1 |= cur;
+            qemu_set_irq(s->irq[irqline], 1);
         }
         cur <<= 1;
     }
@@ -137,6 +178,15 @@ static void gpclr(BCM2835GpioState *s,
     for (i = 0; i < count; i++) {
         if ((changes & cur) && (gpfsel_is_out(s, start + i))) {
             qemu_set_irq(s->out[start + i], 0);
+        } else if ((changes & cur) && fen_detect(s, start + i)) {
+            /* If this is an input we must check falling edge */
+            int irqline = 0;
+            if (i > 27)
+                irqline = 1;
+            if (i > 45)
+              irqline = 2;
+
+            qemu_set_irq(s->irq[irqline], 1);
         }
         cur <<= 1;
     }
@@ -144,6 +194,34 @@ static void gpclr(BCM2835GpioState *s,
     *lev &= ~val;
 }
 
+static int gpio_from_value(uint64_t value, int bank)
+{
+    int i;
+    for (i = 0 ; i < 32; ++i)
+        if (value & (1 << i))
+           return i + (32 * bank);
+    return 0;
+}
+
+static void eds_clear(BCM2835GpioState *s, uint64_t value, int bank)
+{
+    int gpio = 0;
+    int irqline = 0;
+    if (bank) {
+        s->eds0 &= ~value;
+    } else {
+        s->eds1 &= (~value & 0x3f);
+    }
+    gpio = gpio_from_value(value, bank);
+
+    if (gpio > 27)
+       irqline = 1;
+    if (gpio > 45)
+       irqline = 2;
+
+    qemu_set_irq(s->irq[irqline], 0);
+}
+
 static uint64_t bcm2835_gpio_read(void *opaque, hwaddr offset,
         unsigned size)
 {
@@ -170,11 +248,17 @@ static uint64_t bcm2835_gpio_read(void *opaque, hwaddr 
offset,
     case GPLEV1:
         return s->lev1;
     case GPEDS0:
+        return s->eds0;
     case GPEDS1:
+        return s->eds1;
     case GPREN0:
+        return s->ren0;
     case GPREN1:
+        return s->ren1;
     case GPFEN0:
+        return s->fen0;
     case GPFEN1:
+        return s->fen1;
     case GPHEN0:
     case GPHEN1:
     case GPLEN0:
@@ -228,11 +312,23 @@ static void bcm2835_gpio_write(void *opaque, hwaddr 
offset,
         /* Read Only */
         break;
     case GPEDS0:
+        eds_clear(s, value, 0);
+        break;
     case GPEDS1:
+        eds_clear(s, value, 1);
+        break;
     case GPREN0:
+        s->ren0 = value;
+        break;
     case GPREN1:
+        s->ren1 = value;
+        break;
     case GPFEN0:
+        s->fen0 = value;
+        break;
     case GPFEN1:
+        s->fen1 = value;
+        break;
     case GPHEN0:
     case GPHEN1:
     case GPLEN0:
@@ -310,6 +406,7 @@ static void bcm2835_gpio_init(Object *obj)
 
 static void bcm2835_gpio_realize(DeviceState *dev, Error **errp)
 {
+    int i;
     BCM2835GpioState *s = BCM2835_GPIO(dev);
     Object *obj;
 
@@ -318,6 +415,14 @@ static void bcm2835_gpio_realize(DeviceState *dev, Error **errp)
 
     obj = object_property_get_link(OBJECT(dev), "sdbus-sdhost", &error_abort);
     s->sdbus_sdhost = SD_BUS(obj);
+
+    obj = object_property_get_link(OBJECT(dev), "ic", &error_abort);
+    s->ic = BCM2835_IC(obj);
+
+    for (i = 0 ; i < 3; ++i) {
+        s->irq[i] = qdev_get_gpio_in_named(DEVICE(obj),
+                                           BCM2835_IC_GPU_IRQ, i + 49);
+    }
 }
 
 static void bcm2835_gpio_class_init(ObjectClass *klass, void *data)
diff --git a/hw/intc/bcm2835_ic.c b/hw/intc/bcm2835_ic.c
index 9000d995e8..b381dc6603 100644
--- a/hw/intc/bcm2835_ic.c
+++ b/hw/intc/bcm2835_ic.c
@@ -57,7 +57,6 @@ static void bcm2835_ic_update(BCM2835ICState *s)
 static void bcm2835_ic_set_gpu_irq(void *opaque, int irq, int level)
 {
     BCM2835ICState *s = opaque;
-
     assert(irq >= 0 && irq < 64);
     trace_bcm2835_ic_set_gpu_irq(irq, level);
     s->gpu_irq_level = deposit64(s->gpu_irq_level, irq, 1, level != 0);
@@ -67,7 +66,6 @@ static void bcm2835_ic_set_gpu_irq(void *opaque, int irq, int 
level)
 static void bcm2835_ic_set_arm_irq(void *opaque, int irq, int level)
 {
     BCM2835ICState *s = opaque;
-
     assert(irq >= 0 && irq < 8);
     trace_bcm2835_ic_set_cpu_irq(irq, level);
     s->arm_irq_level = deposit32(s->arm_irq_level, irq, 1, level != 0);
diff --git a/include/hw/gpio/bcm2835_gpio.h b/include/hw/gpio/bcm2835_gpio.h
index 1c53a05090..cad3e987d3 100644
--- a/include/hw/gpio/bcm2835_gpio.h
+++ b/include/hw/gpio/bcm2835_gpio.h
@@ -7,6 +7,9 @@
  *  Clement Deschamps <clement.deschamps@antfield.fr>
  *  Luc Michel <luc.michel@antfield.fr>
  *
+ * GPIO External support
+ *  Davide Berardi <berardi.dav@gmail.com>
+ *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  */
@@ -17,6 +20,7 @@
 #include "hw/sd/sd.h"
 #include "hw/sysbus.h"
 #include "qom/object.h"
+#include "hw/intc/bcm2835_ic.h"
 
 struct BCM2835GpioState {
     SysBusDevice parent_obj;
@@ -27,11 +31,19 @@ struct BCM2835GpioState {
     SDBus sdbus;
     SDBus *sdbus_sdhci;
     SDBus *sdbus_sdhost;
+    BCM2835ICState *ic;
 
     uint8_t fsel[54];
     uint32_t lev0, lev1;
+    /* Event detection */
+    uint32_t eds0, eds1;
+    /* Edge selector */
+    uint32_t ren0, ren1;
+    uint32_t fen0, fen1;
+
     uint8_t sd_fsel;
     qemu_irq out[54];
+    qemu_irq irq[3];
 };
 
 #define TYPE_BCM2835_GPIO "bcm2835_gpio"
--
2.30.0